indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.2, december 2022, pp. 40 48 doi: 10.12928/irip.v5i2.6084 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 40 cognitive engagement and creative thinking: intervention with research-based e-learning and students' social attitudes in learning physics at public high school i wayan santyasa*, iwan suswandi, gede saindra santydiputra, and made juniantari department of physics education, faculty of mathematics and natural science, universitas pendidikan ganesha, indonesia email: santyasa@undiksha.ac.id article info abstract article history received: may 18, 2022 revised: dec 12, 2022 accepted: dec 15, 2022 physics learning in high school is closely related to students' social attitudes in conducting cognitive engagement to achieve creative thinking. this study aims to analyze students' cognitive engagement and creative thinking using researchbased e-learning (rbel) and directed learning (del) about students' social attitudes. the samples were randomly selected from 4 classes (two experimental and two control classes). this study used a post-test-only control group design. data on social attitudes and cognitive engagement were collected using questionnaires, and data on creative thinking using essay tests. data were analyzed using a two-way manova and hypothesis testing using a significance level of 5%. the results showed significant differences in the cognitive engagement of students who were intervened using rbel and del. intervention using rbel was more effective than del in achieving cognitive engagement. there is a significant difference between the creative thinking of students who are intervened using rbel and del. the rbel intervention was more effective than del in achieving creative thinking. there are similarities in cognitive engagement and creative thinking among students with hsa and lsa. there was no interaction between learning models and social attitudes regarding cognitive engagement and creative thinking in students. the achievement of cognitive involvement and creative thinking of 10th-grade students in learning physics is more effective using research-based e-learning models. this is an open-access article under the cc–by-sa license. keywords: cognitive engagement creative thinking research-based e-learning social attitudes to cite this article: i. w. santyasa, i. suswandi, g. s. santydiputra, and m. juniantari, “cognitive engagement and creative thinking: intervention with research-based e-learning and students' social attitudes in learning physics at public high school,” indones. rev. phys., vol. 5, no. 2, pp. 40–48, 2022, doi: 10.12928/irip.v5i2.6084. i. introduction we must realize that school learning still tolerates how the teacher delivers material orally. teachers are likelier to deliver one-way learning material (teachercentered learning/tcl) [1]. weimer identified five activities carried out by tcl teachers, namely having full power in the class as a source of learning content, dominating roles in class, the teacher being more responsible in learning, dominating the learning process, and separate evaluation [2]. the impact is felt that learning with tcl becomes one of the obstacles to an optimal learning process, which ultimately leads to low learning products [1], [3]–[5]. physics learning with tcl tends to hinder students from building physics knowledge [6]–[8]. along with the times, to match the needs of students in improving their personal quality, student-centered learning (scl) models have emerged as an alternative to learning to answer the problem of incompatibility with tcl models. a learner-centered learning strategy is scl. according to the scl approach, teachers must effectively fulfill their duties as facilitators, innovators, and motivators. [4]. kurniawan et al. [4] argued more http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i2.6084 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 41 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 forcefully that teachers were also expected to assist students in finding solutions to problems when they encountered challenges during the learning process, in addition to giving lessons in front of the class. in recent decades, scl has become an effective environment for enhancing student learning experiences [3], [6]. scl is more effective in achieving student learning outcomes than traditional learning [5]. according to yilmaz [5], pull-out learning, teacher demands, and knowledge, skill, and experience transmission are the main focuses of conventional education. unlike scl, which emphasizes process, output, and result. scl aids in the development of practical skills in pupils, including teamwork and problem-solving. active learning, small group learning, question-directed instruction, inquiryguided learning, cooperative learning, problem-based learning, peer instruction, active learning, collaborative learning, inquiry-based learning, project-based learning, and just-in-time teaching are some of the approaches used in scl [9]. in entering the classroom, students already have knowledge, skills, attitudes, and beliefs about the content of various subjects. so, when they come to class, they already have an initial knowledge about the new knowledge they will learn. therefore, teachers should consider and empower students' prior knowledge in designing and implementing meaningful learning. before teaching new material, teachers should assume their students' prior knowledge if they wish to develop scl for effective learning. in this situation, the teacher can quiz the students on their knowledge of the subject [10]. active participation and permanent learning are very important factors for learning. the active learning framework is aimed at three strategies for students to be intellectually active, socially active, and physically active [11]. small group projects, entire class activities, and conversations in small groups can all be used to create socially engaged learning practices. both the teacher and the pupils receive feedback from the system employed in the classroom. as a result, the class begins to discuss the feedback, including correct or incorrect replies. active learning is affected by interactions between students and between students and teachers during debates. scl is a learning approach that can replace lecture learning with active learning, integration of scl programs, or group collaboration, and in the end, students take responsibility for their progress [12]. the scl environment has an advantage over the tcl approach because, in scl, students are provided time to exchange ideas and complement and interact with one another. with scl, students can better understand themselves as subjects and the content's nature. the scl environment provides students with a major focus on knowledge sharing, and when learning is done properly, scl can become a lifelong learning process [12], [13]. tcl uses lecture and class discussion learning strategies, while in the scl class, the strategies used are research, collaborative, and discovery learning, which invite students to formulate questions [12]. scl models lead to finding basic information and possible solutions to formulated questions, including in an investigation-based debate. in the scl learning environment, students can perform complex functions such as finding and empowering information from complex conceptual frameworks, interacting with the social environment to impart knowledge, and controlling their learning through reflection [13]. this shows that the social attitudes of students greatly determine the learning process and product. discovery-based collaborative activities, social attitudes, formulating questions, and gathering information to formulate solutions based on conceptual frameworks will develop students' cognitive engagement and creative thinking. meanwhile, social interaction activities and learning to control learning based on selfreflection lead to the synergy between students to interact with learning models. the way teachers teach creates an impact on student learning development. teaching approaches and teacher strategies influence students' learning skills and strategies [13]. thus, teachers should change their views which are implemented in practice, to apply scl in their teaching. scl becomes a resistance for students to master their learning skills and strategies, and they can develop their learning methods. if the teacher has skills in organizing the preparation and delivery of learning with scl, students can develop these learning skills. when teachers use scl more in class, students' learning skills and strategies develop significantly. the use of scl by teachers provides more opportunities for improving student learning skills and strategies [13]. based on the explanation above, scl models are appropriate for students to make them learn by doing. students need to be involved in their learning process to adapt their skills and strategies to become responsible learners. students must develop their learning skills and strategies as scl provides a vehicle for students to build life-long learning skills that they can use not only for learning in school but also as an effort to prepare for their future in the next life. based on these thoughts, this study initiated the scl application and examined its effect on cognitive engagement attitudes and creative thinking in terms of student attitudes in learning physics in high school. based on this background, the research problem can be formulated, namely, "are there differences in the main effect and interactive effect of the scl model compared to the tcl model in achieving cognitive involvement and creative thinking in terms of students' attitudes in learning physics in high school?" ii. theory scl provides an active learning process for students inside and outside the classroom. active learning is a relevant strategy in scl implementation [14]. active learning strategy is learning oriented towards student activities and applies the principle of learning by doing. active participation and permanent learning are critical http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 42 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 factors. the purpose of scl is to influence academic achievement and social skills. they show that scl models can improve the performance of students from low age to high age in school. in scl, students engage in new experiences by fulfilling their responsibilities or projects in class. in scl, students have direct access to the knowledge base, work individually, and are empowered in small groups to solve authentic problems. the social attitudes of students largely determine the success of learning in small groups. the component of interpersonal intelligence is social attitude. social attitudes include four main components, group management attitudes, problem-solving attitudes, attitudes to upholding interpersonal bonds, and attitudes to conducting social analysis [15]–[17]. the governing group's mindset is a social mindset that a learner frequently needs for learning. this approach entails organizing and leading initiatives to move people. a mediator's skill in averting or ending confrontations is their approach to negotiating solutions. this mindset is the foundation for coming to an agreement, resolving or mediating conflicts, and having the diplomatic and social skills necessary to resolve conflicts. being able to empathize and forge relationships has frequently been referred to as having a relationship-building mentality. with this mindset, it is simpler for individuals to interact with others or to identify and address the sentiments and problems of others. students with this mindset make dependable "team players," dependable partners, devoted friends, or trusted business associates. they can be effective supervisors, salespeople, or teachers in the workplace. the mindset required for social analysis is the mindset needed to recognize and comprehend the thoughts, feelings, and concerns of others. pleasant intimacy or a sense of belonging will result from understanding the other person's emotions. learning physics using the scl model is successfully implemented by students at school. based on observations, students generally begin to understand the concept of scl [6]. he stated that scl provides a learning process for students to develop interpersonal and independent learning skills, practice on time, actively generate ideas in groups, and are good motivators to friends. in scl, students tend to respond to learning positively, and teachers consider themselves successful in their quest to create more learner-centered learning [2]. in scl, the development team members engage in open communication and a genuine desire to succeed. most of the time is spent, for instance, on creating novel task types, adapting tools to evaluate how students work in groups, and attempting to make sense of the data gathered during laboratory learning [7]. therefore, students can use creative thinking in scl to support better learning processes and products. the creativity of students who follow scl learning strategies is higher than students who follow direct learning strategies. there is a strong interaction between learning strategies and spatial abilities in achieving creativity, meaning that in achieving creativity, scl tends to interact strongly with high spatial ability. in contrast, direct learning interacts strongly with low spatial ability. research comparing tcl and scl methods in medical science shows that many students tend to stick to traditional methods [12]. however, evidence shows that the increase in learning processes and products is higher for those who use scl [12]. this shows that the scl learning environment must be created sustainably in learning, although the application of scl often experiences obstacles in practice. iii. method this quasi-experimental study used a post-test-only control group design. this design is used because the school randomly and naturally forms the subjects, so academically homogeneous classes are formed. this study's population was five classes consisting of 185 10thgrade students from a public high school 2 in singaraja. four classes, totaling 149 students (79.7% of the population), were chosen randomly to make up the sample. furthermore, with this technique, two classes (75 students) were also assigned as an experimental group using the rbel model and two classes (75 students) as a control group using the del model. for purposing data analysis, each group was divided into high and low social attitudes. the basis is 27% of the total number of students in each group, so the fourth unit cell in the analysis design is 20 students. the variables examined in this study were rbel and del as independent variables, high and low social attitudes as moderator variables, and cognitive engagement and students' creative thinking as dependent variables, respectively. a likert model questionnaire measured students' social and cognitive engagement attitudes, and a physics test measured students' creative thinking. the concept of social attitudes—which includes four main dimensions [15]–[17]—was used to develop the social attitude scale. these dimensions are 1) the attitude of maintaining personal relationships; 2) the attitude of conducting social analysis; 3) the attitude of negotiating solutions; and 4) the organizing group's attitude. the 30 items on social attitude instruments are divided into four social attitude dimensions. a likert rating scale is used for each item. the total-item correlation coefficient of the social attitude questionnaire varied from 0.36 to 0.60, according to the trial findings with 291 respondents, and 30 questions had a cronbach alpha reliability coefficient = 0.91, which was an excellent qualification. the motivated strategy and learning use questionnaire (mlsq) [18], [19] can be used to gauge students' cognitive engagement. three indicators of selfregulation are 1) preparing cognitive methods for learning activities, 2) keeping track of the understanding gained from the subject matter being studied, and 3) correcting incorrect learning behaviors. three aspects comprise the cognitive strategy: training, elaboration, and knowledge organization for in-depth understanding. twenty-nine questionnaire items measuring cognitive engagement were http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 43 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 created based on these factors and evaluated on 185 students. the item-total correlation increases from r = 0.318 to r = 0.591 after the test results. cronbach's alpha was used to assess the reliability of 29 items from the cognitive engagement questionnaire, and a value of 0.864 was achieved, placing the items' reliability in the very high category. the creative thinking test instrument includes four dimensions: fluent thinking, flexible thinking, original thinking, and elaborative thinking. the creative thinking test developed consists of 15 items, with the distribution of 4 items of fluent thinking, three of flexible thinking, 4 of original thinking, and 4 of elaborative thinking. the test's internal consistency improved from r = 0.388 to r = 0.772, and the test's reliability was measured by cronbach's alpha, which was 0.897 with a very high category. this value indicates that the test used is reliable in measuring the ability to think creatively. this research was conducted for six weeks, from apr 1 to may 12, 2020. each week the students studied with a time allocation of 120 minutes. the intervention with the rbel model and the del model used each model's operational learning steps as the e-learning pedagogy's content. rbel uses scl operational steps, while del uses tcl operational steps. the stages of the research based e-learning (rbel) paradigm include the following steps: creating a general question, reviewing the research literature; defining the question; planning the research activities, outlining the methods/methodologies; conducting the investigation, analyzing the data; interpreting and taking into account the results; reporting, and presenting the findings [20]. di learning steps include (1) setting learning goals for lessons, activities, and projects and ensuring students understand the goals first. (2) deliberately planning and organizing the sequence of lessons, assignments, and projects that advance students toward a more profound understanding and achievement of specific academic goals. (3) review activity instructions or carry out procedures, such as a science experiment, so students understand what is expected of them. (4) provide detailed explanations, descriptions, and examples to students about the concepts and skills being taught. (5) check whether students understand what has been taught by asking them questions [21]. data analysis using two-way manova. manova analysis takes place if the assumptions of normality, homogeneity, non-collinearity, and similarity of the covariance matrix are met. the first assumption test uses kolmogorov-smirnov and shapiro wilk statistics, the second assumption uses the levene statistic, the third assumption uses the product-moment correlation statistic, and the fourth assumption uses the box'm statistic. hypothesis examiners use a sig. level of 5%. iv. results and discussion the results of the descriptive analysis of the effect of rbel on cognitive engagement and creative thinking in terms of students' social attitudes are presented in figure 1. figure 1 shows that students who study with rbel have cognitive engagement ce-mt1 = 44.93 with sd = 4.45, which is included in the low category. likewise, those who studied with del ce-mt2 = 41.13 with sd = 4.96 were included in the low category. meanwhile, for students who learn to use rbel to think creatively, ct-mt1 = 61.28 with sd = 6.85 in the medium category, and for students who learn to use del, ct-mt2 = 43.83 with sd = 8.05 in the low category. judging from the influence of social attitudes, students with high social attitudes (hsa) show cognitive engagement ce-m1t = 43.73 with sd = 4.87 in the low category. likewise, students with low social attitudes (lsa) with cognitive engagement are ce-m2t = 42.33 with sd = 5.20, also in the low category. while the creative thinking of students who have hsa is ct-m1t = 53.40 with sd = 10.88 in the low category, and those who have lsa are ct-m2t = 51.80 with sd = 12.18 in the low category. the results of the normality test of cognitive engagement (ce) data distribution and creative thinking (ct) are presented in table 1. table 1 show that numbers of sig > 0.05 accompany all kolmogorov-smirnov and shapiro-wilk statistical values. these results indicate that ce and ct data distribution is normally distributed. the results of the homogeneity test of the ce and ct variants between those who studied with rbel and del are presented in table 2, sig. > 0.05 accompany the levene statistical values. this states that the ce and ct variants are homogeneous according to grouping based on learning models and social attitudes. the next manova assumption is that there is no collinearity effect between the two dependent variables, ce and ct. the correlation test results in table 3 prove that the correlation coefficient between ce scores and ct scores is r = 357. this r value is < 0.80, so there is no collinearity effect between the two dependent variables. figure 1. mean value (m) and standard deviation (sd) of cognitive engagement (ce) and creative thinking (ct) the results of the covariance matrices similarity test are presented in table 4, that the box's m statistical value is f = 0.756 with a sig. = 0.658. the sig. number > 0.05, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 44 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 so the covariance matrices between the two dependent variables are not significantly different. the results of the variance similarity test are simultaneously shown in table 5, that the levene statistical value is f = 0.980 for ce and f = 0.712 for ct, each with sig. = 0.407 and sig. = 0.548. the numbers of sig. > 0.05 so that the variants of the two dependent variables are not significantly different. next, the results of the manova are presented in table 6. in table 6, it appears that from the source of the influence of model simultaneously on the two dependent variables, the statistical values of pillai's trace, wilks' lambda, hotelling's trace, and roy's largest root are f = 56,471 each with a sig. = 0.001. this significant number is less than 0.05, so there is a significant difference in the learning model of rbel and del simultaneously on the engagement of students' ce and their ct. however, from the social impact source, there is no significant effect between the two levels of social attitudes on the students' ce and ct. likewise, from the source of the influence of social * model, social attitudes and learning models have no significant interaction effect based on students' ce and ct. the next step is to present the results of the tests of between-subjects effects, as shown in table 7. first, from the source of the influence of model on ce, it was found that the statistical value of f = 13.007 with a sig = 0.001. this significant number is smaller than the critical value of 0.05. these findings suggest that the rbel and del models have differing effects on students' cognitive engagement. the average value in table 8 shows that mce-rbel = 44,925; sd = 0.745 and mce-del = 41,125; sd = 0.745, where mce-rbel > mce-del, so it can be stated that the rbel model has a greater effect than del on student cognitive engagement. table 1. tests of normality based on the learning model and social attitude source model learning model social attitude kolmogorov-smirnova shapiro-wilk kolmogorov-smirnova shapiro-wilk statistic df sig. statistic df sig. statistic df sig. statistic df sig. ce 1.00 0.121 40 0.146 0.970 40 0.359 0.155 40 0.017 0.967 40 0.298 2.00 0.110 40 0.200* 0.976 40 0.538 0.100 40 0.200* 0.973 40 0.435 ct 1.00 0.124 40 0.120 0.961 40 0.186 0.089 40 0.200* 0.963 40 0.208 2.00 0.140 40 0.046 0.964 40 0.231 0.125 40 0.120 0.951 40 0.083 table 2. test of homogeneity of variance based on the learning model and social attitude source learning model social attitude levene statistic df1 df2 sig. levene statistic df1 df2 sig. ce based on mean 0.001 1 78 0.977 0.000 1 78 0.998 based on median 0.006 1 78 0.939 0.006 1 78 0.938 based on the median and with adjusted df 0.006 1 75.140 0.939 0.006 1 73.971 0.938 based on trimmed mean 0.000 1 78 0.993 0.001 1 78 0.979 ct based on mean 1.396 1 78 0.241 1.474 1 78 0.228 based on median 1.603 1 78 0.209 1.380 1 78 0.244 based on the median and with adjusted df 1.603 1 77.982 0.209 1.380 1 77.988 0.244 based on trimmed mean 1.429 1 78 0.236 1.454 1 78 0.231 table 3. correlations between ce scores dan ct scores ce ct ce pearson correlation 1 0.357** sig. (2-tailed) 0.001 n 80 80 ct pearson correlation 0.357** 1 sig. (2-tailed) 0.001 n 80 80 table 4. box's test of equality of covariance matrices score box's m 7.145 f 0.756 df1 9 df2 66191.846 sig. 0.658 table 5. levene's test of equality of error variances source f df1 df2 sig. cogment 0.980 3 76 0.407 creative 0.712 3 76 0.548 http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 45 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 table 6. multivariate test results effect value f hypothesis df error df sig. intercept pt 0.992 4767.818b 2.000 75.000 0.000 wl 0.008 4767.818b 2.000 75.000 0.000 ht 127.142 4767.818b 2.000 75.000 0.000 rlr 127.142 4767.818b 2.000 75.000 0.000 model pt 0.601 56.471b 2.000 75.000 0.000 wl 0.399 56.471b 2.000 75.000 0.000 ht 1.506 56.471b 2.000 75.000 0.000 rlr 1.506 56.471b 2.000 75.000 0.000 social pt 0.030 1.160b 2.000 75.000 0.319 wl 0.970 1.160b 2.000 75.000 0.319 ht 0.031 1.160b 2.000 75.000 0.319 rlr 0.031 1.160b 2.000 75.000 0.319 social * model pt 0.005 0.196b 2.000 75.000 0.823 wl 0.995 0.196b 2.000 75.000 0.823 ht 0.005 0.196b 2.000 75.000 0.823 rlr 0.005 0.196b 2.000 75.000 0.823 *note: pt = pillai's trace, wl = wilks' lambda, ht = hotelling's trace, rlr = roy's largest root table 7. tests of between-subjects effects source dv type iii sum of squares df ms f sig. corrected model ce 330.450a 3 110.150 4.961 0.003 ct 6153.100b 3 2051.033 36.279 0.000 intercept ce 148092.050 1 148092.050 6669.627 0.000 ct 220920.200 1 220920.200 3907.635 0.000 model ce 288.800 1 288.800 13.007 0.001 ct 6090.050 1 6090.050 107.721 0.000 social ce 39.200 1 39.200 1.765 0.188 ct 45.000 1 45.000 0.796 0.375 social * model ce 2.450 1 2.450 0.110 0.741 ct 18.050 1 18.050 0.319 0.574 error ce 1687.500 76 22.204 ct 4296.700 76 56.536 total ce 150110.000 80 ct 231370.000 80 corrected total ce 2017.950 79 ct 10449.800 79 table 8. mean value (m) and standard deviation (sd) of cognitive engagement and creative thinking in the rbel and del models dependent variable model m sd 95% confidence interval lower bound upper bound ce rbel 44.925 0.745 43.441 46.409 del 41.125 0.745 39.641 42.609 ct rbel 61.275 1.189 58.907 63.643 del 43.825 1.189 41.457 46.193 second, from the source of the influence of model (table 7) on creative thinking (ct), it was found that the statistical value of f = 107,721 with a sig. = 0.001. this significant number is smaller than the critical value of 0.05. these findings suggest that the rbel and del models have differing effects on students' creative thinking. table 8 shows that the mean value of creative thinking is mct-rbel = 61,275; sd = 1.189 and mctdel = 43,825; sd = 1.189, where mct-rbel > mctdel. these findings imply that the rbel model has a higher impact on creative thinking than the del model. third, from the source of the effect of social (table 7) on cognitive engagement (ce) and creative thinking (ct), respectively, the statistical values of f = 1,765 with a significance value of sig. = 0.188 and f = 0.796 with a sig. = 0.375. the numbers of sig > 0.05. therefore, the effect of students with high and low social attitudes on cognitive engagement and creative thinking is the same. fourth, from the source of the influence of social * model (table 7) on ce and ct, respectively, the statistical values of f = 0.110 were found with a sig. = 0.741 and f = 0.319 with a sig. = 0.574. the numbers of sig. > 0.05. as a result, there is no significant interaction between the learning model and the social attitudes of the students concerning cognitive engagement and creative thinking. the weak interaction profiles are presented in figure 2 and figure 3, respectively. up to now, physics learning in high school mostly tolerates teacher-centered learning, which is one of the factors that causes students' less optimal cognitive engagement in learning, ultimately leading to low student creative thinking. therefore, the study tested the studentcentered learning model, research-based e-learning, with http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 46 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 students' social attitudes as the moderator variable. the study aimed to examine the primary and interacting influences of social attitudes and learning models on students' cognitive engagement and creative thinking while learning physics in high school. the results showed that the research-based e-learning (rbel) model had a greater effect than the direct elearning (del) model on students' cognitive engagement in learning physics. the study results follow the results of previous studies [20, 21]. the rbel model becomes a facility for students to learn more actively in class and practice so that learning becomes more meaningful [22]. with rbel, students become more active in group collaboration [22]. with rbel, students become more active and creative in problem-solving learning than in del [23]. the students' activeness in learning, solving problems, in practice, and group work shows that enthusiastic students show optimal cognitive engagement performance. this is because, with rbel, students feel aroused in their motivation and curiosity, so the learning process looks fun. although quantitatively, mce-rbel = 44,925; sd = 0.745 and mce-del = 41,125; sd = 0.745, where mce-rbel > mce-del, but descriptively qualitatively on a scale of 100, the two mean scores are in a low category. these results are below the success criteria for learning physics at a public high school 2 in singaraja, namely 70.00. the low achievement is because students need to get used to learning using rbel. therefore, the rbel model should be used on an ongoing basis so that students are familiar with the work steps offered by the model. regarding rbel and del on students' creative thinking while learning physics, research shows that rbel has a stronger impact than del on students' creative thinking. these results follow the results of previous studies [24]–[26]. rbel can facilitate students to learn with high motivation and use their thinking logically, critically, and systematically, thus influencing the optimization of their creative thinking. quantitatively, mct-rbel = 61,275; sd = 1.189 and mct-del = 43,825; sd = 1.189, where mct-rbel > mct-del. descriptively qualitatively, students' creative thinking in the rbel group, mct-rbel = 61,275 in the sufficient category, and the del group, mct-del = 43,825 with the low category. the average score obtained by students in the rbel group still needed to reach the success criteria, namely, 70.00. this is inseparable from changing students 'mindsets from learning habits with the del model to learning habits with the innovative rbel learning model, which requires sufficient time according to students' abilities. therefore, the rbel model should be implemented continuously so that students become familiar with the rbel learning process to achieve optimal creative thinking. the main effect of the variable high social attitude and low social attitude showed no different results on students’ cognitive engagement and creative thinking. likewise, regarding the interactive effect of learning models and social attitudes on students’ cognitive engagement and creative thinking, the results of this study indicate an insignificant interaction. these results indicate that the two learning models (rbel and del) are accommodative of the two levels of social attitudes, namely high and low social attitudes. figure 2. the profile of the weak interactive influence between the learning model (1 = rbel and 2 = del) and social attitudes (1 = hsa, 2 = lsa) on students' ce. figure 3. the profile of the weak interactive effect between learning models (1 = rbel and 2 = del) and social attitudes (1 = hsa, 2 = lsa) on students' ct v. conclusion the following research conclusions can be proposed based on the research results and discussion. there are differences in students’ cognitive engagement between those who intervened with research-based e-learning and direct e-learning. intervention with research-based elearning is more effective than direct e-learning in achieving cognitive engagement. there are differences in http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 40 48 47 santyasa, et al. cognitive engagement and creative thinking: intervention with …. p-issn: 2621-3761 e-issn: 2621-2889 students’ creative thinking between those intervened with research-based e-learning and direct e-learning. intervention with research-based e-learning is more effective than direct e-learning in achieving creative thinking. there is no difference in cognitive engagement and creative thinking between students with high and low social attitudes. there is no interactive effect between learning models and social attitudes on students’ cognitive engagement and creative thinking. in achieving students’ cognitive engagement, and creative thinking in learning physics, 10th-grade students on the subject matter of work, energy, impulses, and momentum will be effective in achieving students’ cognitive engagement and creative thinking if researchbased e-learning models intervene them. therefore, high school physics teachers should familiarize themselves with using research-based learning as e-learning content. research-based physics learning is one of the innovative lessons rich in literacy processes in mind-on and hands-on activities. vi. acknowledgment thank you to the physics teacher and the principal of public high school 2 in singaraja, who has helped a lot with this research. thanks to the ganesha university research institute and friends for their support. references [1] l. a. nugroho, b. a. prayitno, and p. karyanto, “efektivitas model pembelajaran problem based learning terhadap kemampuan literasi ekologi siswa kelas x sekolah menengah atas [the effectiveness of the problem based learning learning model on the ecological literacy ability of class x high school students],” j. konseling dan pendidik., vol. 6, no. 1, pp. 1–7, feb. 2018, doi: 10.29210/117900. 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[23] s. suntusia, d. dafik, and h. hobri, “the effectiveness of research based learning in improving students’ achievement in solving two-dimensional arithmetic sequence problems,” int. j. instr., vol. 12, no. 1, pp. 17– 32, jan. 2019, doi: 10.29333/iji.2019.1212a. [24] n. nursofah, r. komala, and r. rusdi, “the effect of research based learning model and creative thinking ability on students learning outcomes,” indones. j. sci. educ., vol. 2, no. 2, pp. 168–173, oct. 2018, doi: 10.31002/ijose.v2i2.584. [25] f. r. rahim, “implementasi research based learning (rbl) pada mata kuliah ipa terpadu di program studi pendidikan fisika [implementation of research based learning (rbl) in integrated science courses in the physics education study program],” j. eksakta pendidik., vol. 3, no. 1, p. 82, may 2019, doi: 10.24036/jep/vol3iss1/321. [26] a. tungkasamit, “the effect of using research based learning model in history practicum in school course,” pedagog. j. pendidik., vol. 8, no. 1, pp. 9–17, feb. 2019, doi: 10.21070/pedagogia.v8i1.1770. declarations author contribution : all research initiatives are under the direction of i wayan santyasa. additionally, he oversaw co-writer collaboration and scriptwriting. iwan suswandi assisted with the manuscript's conception and writing. made juniantari helped with data gathering and analysis, while gede saidra santydiputra took part in the analysis. all authors approved this final paper. funding statement : this research did not receive any funding. conflict of interest : both authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1152/advan.00034.2019 https://doi.org/10.29333/iji.2019.1212a https://doi.org/10.31002/ijose.v2i2.584 https://doi.org/10.24036/jep/vol3-iss1/321 https://doi.org/10.24036/jep/vol3-iss1/321 https://doi.org/10.21070/pedagogia.v8i1.1770 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.2, december 2022, pp. 49 56 doi: 10.12928/irip.v5i2.6544 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 49 perception scale of online learning in the indonesian context during the covid19 pandemic: psychometric properties based on the rasch model eko nursulistiyo1*, toni kus indratno2, ety dwiastuti3, fitria arifiyanti4, ariati dina puspitasari5, nurul syafiqah yap binti abdullah6, and moh. irma sukarelawan7 1,2,5 department of physics education, faculty of teacher training and education, universitas ahmad dahlan, indonesia 3 vocational high school 2 yogyakarta, indonesia 4 doctoral school of education, university of szeged 6 department of physics, faculty of science and mathematics, universiti pendidikan sultan idris, malaysia 7 postgraduate program of physics education, faculty of teacher training and education, universitas ahmad dahlan, indonesia email: eko.nursulistiyo@pfis.uad.ac.id article info abstract article history received: aug 29, 2022 revision: dec 26, 2022 accepted: dec 29, 2022 this study aims to evaluate the psychometric properties of students' perception scales about online learning during the covid-19 pandemic in indonesian culture. this study involved 176 students (male = 54% and female = 46%) at the junior and senior high school levels from public schools in yogyakarta, indonesia. the age of the respondents ranged from 11 to 17 years, with a mean of 13.5 years and a standard deviation of 1.4 years. the online learning perception scale adopts 16 items developed by bhagat and colleagues. the psychometric properties of the scale were evaluated based on the reliability of the person and item, the suitability of the rasch model, the functionality of using a 5-point rating scale, and its unidimensionality. the analysis results show that the scale has good consistency and performance in the indonesian context. sixteen items are a good fit for the model and are unidimensional. the 4-point likert rating scale is more effective than the original 5-point rating scale. so, 16 items in postol have adequate psychometric properties to be used on students in indonesia. this is an open-access article under the cc–by-sa license. keywords: psychometric properties students’ perception online learning rasch model to cite this article: e. nursulistiyo et al., “perception scale of online learning in the indonesian context during the covid-19 pandemic: psychometric properties based on the rasch model,” indones. rev. phys., vol. 5, no. 2, pp. 49–56, 2022, doi: 10.12928/irip.v5i2.6544. i. introduction the covid-19 pandemic has accelerated sudden and unanticipated shifts in students' and teachers' preferred learning modes. the greatest temporary approach to reducing the rate of covid-19 transmission in various parts of the world, including indonesia, is to use online learning techniques. supporting online learning methods is crucial for minimizing the effects of pandemics on education [1]– [3]. online learning media have increased students' knowledge capacity and skills [4], [5]. however, due to these rapid and unpredictable changes, students may not be fully prepared for online learning [6], [7]. analyzing student perceptions of online learning will thus assist teachers and stakeholders in developing the following policy. students' perception of online learning is an essential issue in online education [8]. students perceive the benefits and drawbacks of internet-based learning [9], [10]. a good attitude toward online learning will help with integration and process success [11]. on the other hand, online learning strategies burden students and parents [12]–[14]. the support of resources and encouragement of learning requirements influence students' learning throughout the pandemic [15]. these facilities include the availability of hardware and software as well as internet connections [16], [17], and the internet in indonesia is still uneven [8], [18]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i2.6544 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 49 56 50 nursulistyo, et al. perception scale of online learning in the indonesian context … p-issn: 2621-3761 e-issn: 2621-2889 numerous research has examined students' perceptions of online learning over the past two years [19]–[23]. one of the scales developed to measure perception is the perception of students towards online learning (postol). this scale was developed by bhagat et al. [24] and has been implemented by undergraduate, master, and doctoral students in taiwan. one of the scales that has been evaluated to determine how students feel about online learning is postol. through the use of the classical test theory, postol's quality has been evaluated. postol is formed by four factors: social presence (sp), instructor characteristics (ic), instructional design (id), and trust (tr). however, because of the disparities in educational levels and cultural circumstances, this scale cannot be directly applied to students in indonesia. therefore, a process of adaptation is required to assess postol's psychometric attributes [25]–[27]. evaluation of students' perceptions of online learning needs to be done immediately to see the supports and obstacles to its implementation over the last two years. it aims to increase the effectiveness and efficiency of online learning. so, this does not cause a loss of learning in students. the evaluation results will provide relevant and accurate information when using a scale that has good psychometric properties. the evaluation outcomes using the classical test theory approaches, efa, and cfa, which have previously been reported, have not given comprehensive information on psychometric properties. so, a contemporary test theory must be used to support it (rasch model). the rasch model provides additional in-depth details on psychometric properties. examples of psychometric properties that cannot be described by classical test theory include the likert rating scale's functioning, unidimensionality, the scale's bias towards respondent demographics, and item fit (item difficulty level and respondent ability) [28]. therefore, this study aims to evaluate, using the rasch model, the psychometric properties of postol in high school students and the indonesian cultural environment. this paper adds to and supports postol psychometrics' ability to operate across cultural boundaries. ii. theory cross-cultural adaptation process one of the common mistakes while adapting measuring instruments is relying solely on translation from the original language to the destination language. furthermore, the adaptation process is more than merely translating measuring instruments. however, it is necessary to contextualize the socio-cultural situation of the destination user. it is widely understood that the items must be linguistically translated and culturally contextualized if a measurement tool is to be used across cultures. the linguistically and culturally translated items seek to uphold the conceptual validity of the instrument's content across various cultural contexts. the self-report scale by beaton et al. [29] was translated and culturally adapted following their crosscultural adaptation standards. the generally accepted standards approved the final version for choosing measuring tools [26]. the adaptation process aims to ensure that the source and target questionnaires are semantically, idiomatically, experientially, and conceptually equivalent. the suggested procedure for cross-cultural adaptation is shown in figure 1. figure 1. cross-cultural adaptation process [29] http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 49 56 51 nursulistyo, et al. perception scale of online learning in the indonesian context … p-issn: 2621-3761 e-issn: 2621-2889 postol scale the postol is one of the scales bhagat et al. [24] developed to evaluate students' perceptions of implementing online learning. due to the covid-19 pandemic, almost all learning currently uses the online mode, shifting from the face-to-face mode that has been done previously. one strategy to stop the spread of the covid-19 virus is implementing online education. more than two years of learning activities have taken place online. students experience various experiences during online learning. this raises different perceptions between individual students. the postol scale developed by bhagat et al. [24] consists of four dimensions: social presence (sp), instructor characteristics (ic), instructional design (id), and trust (tr). these four dimensions have been established through 2-stage factor analysis. the first-factor analysis was carried out through exploratory factor analysis (efa). all items are naturally grouped based on the existing data at this stage. the next stage is the structure formed at the efa stage, re-confirmed through confirmatory factor analysis (cfa), and 16 items have been obtained that have met the fit for the model. rasch model the rasch model was first developed by a danish mathematician, georg rasch [30]. rasch modeling is part of the item response theory (irt) which only focuses on one logistic parameter, namely the item difficulty level, which is viewed from two sides (item difficulty level and person ability) [31]. the rasch model was developed to measure latent human traits, such as cognitive and noncognitive aspects (opinions or perceptions). because the measurement is a latent variable, the rasch model places its position as a model that can change the instrument into a measuring scale as a measuring instrument in physics. therefore, the fundamental idea behind the rasch model is to create a logit ruler with the same interval scale for both the difficulty of the item and the person's ability [32]. this model can create a hierarchy between persons (test takers or students) and test items [33]. the rasch model employs a probabilistic model. students can provide an accurate response depending on comparing a person's ability and item difficulty. the raw scores are processed using a logarithmic equation to compare the person's abilities and the item's level of difficulty directly. psychometric properties when choosing and employing an instrument to measure unobservable constructs, it is critical to examine its psychometric properties [34]. the validity and reliability of measuring devices are referred to as psychometric properties [35]. before it can be declared that the questionnaire has good psychometric features, which means that it is trustworthy and valid, the scale must be thoroughly analyzed [36]. the main activities in psychometry include the construction or compilation of various psychological theories into psychological measuring tools/psychological test tools, as well as the development and analysis of data from these measurements [37]. the investigation of measuring qualities like measurement invariance, internal consistency, and structural validity in education has been conducted extensively using the rasch analysis as a contemporary psychometric approach [38]. aspects investigated to evaluate psychometric properties include (a) person and item reliability, person and item separation index and internal consistency, (b) item fit with the model and its level of difficulty, (c) principal component analysis (pca) of residual for structural validity, and (d) item differential function (dif) to measure invariant [28], [39]–[41]. iii. method participants the sample size must be determined to ensure the stability of the estimation results. a minimum sample size of 50 people is needed to reach an accuracy of 1 logit with a confidence level of 99 percent [42]. ling lee et al. [43] suggest using between 50 to 250 respondents to evaluate the model's goodness. therefore, it is believed that the 176 respondents satisfied the minimum sample size. the analysis did not include 3 of the 176 respondents since they were in an outlier situation. table 1 lists the respondents' demographic information. instrument the postol, translated into the indonesian version, came from the scale of students' perceptions of online learning developed by bhagat et al. [24]. postol consists of 4 factors/dimensions, namely: social presence (sp, 5 items), instructor characteristics (ic, 5 items), instructional design (id, 3 items), and trust (tr, 3 items). the translation process is carried out by lecturers from the english language field using forward-backward translation techniques [44]. a whatsapp survey is created from the translation and sent to possible respondents. local school teachers participated in the two-week data collection process. the researcher guarantees the confidentiality of the information provided by the respondents, and student participation is optional. we emphasize this when introducing the instrument to give respondents flexibility in their responses. table 1. demographic statistics demographics category number % gender male 95 54.0 female 81 46.0 total 176 100.0 level of school junior 119 67.6 senior 57 32.4 total 176 100.0 age (years) average 13.5 sd 1.4 data analysis http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 49 56 52 nursulistyo, et al. perception scale of online learning in the indonesian context … p-issn: 2621-3761 e-issn: 2621-2889 four key metrics—reliability, model fit, use of a 5point likert rating scale, and unidimensionality—were used to assess the psychometric properties of postol. the rasch model was used to examine the instrument's psychometric properties. to analyze the data, winsteps 4.6.1 and ms. excel were both used. we use a cut-off value of ≥ 0.70 to show reliability because it is recommended [45]. the item's fit against the model was evaluated using the infit mnsq and outfit mnsq criteria in the range of 0.5 1.5 [46]. the functionality of the likert rating scale was evaluated according to the criteria used by llamas-ramos et al. [47]. meanwhile, unidimensionality is evaluated based on raw variance explained by measures and unexplained variance in the 1st contrast. iv. results and discussion summary statistics of postol an overview of the statistical findings from the postol instrument adaption is presented in table 2. the study reveals that the item and person separation index are 8.00 and 1.67. the reliability for the person is 0.74, and the reliability for the item is 0.98. at the same time, the test reliability score, indicated by the cronbach alpha value, is 0.75. item characteristics table 3 summarizes the match index of the 16 items in postol by entry. based on table 3, the infit mnsq is 0.74 to 1.45, while the outfit mnsq is in the 0.71 to 1.52 range. the item analysis yields a difficulty level ranging from -1.65 to 1.19 logit, and the standard error (s.e) model ranges from 0.08-0.17 logit. id3 is the easiest item with a model s.e value of 0.17. in contrast, the most difficult item is owned by tr2 with a model s.e value of 0.08. the average value of the items is 0.00, and the standard deviation is 0.93. likert rating scale rating scale analysis was performed to prove the functionality of the 5-point likert rating scale used in postol. table 4 shows the nature of the structure of the likert rating scale used. in the second column, most of the response categories are in categories 5 (strongly agree), 4 (agree), and 3 (doubtful). the third column shows the average of all people who chose each category. this average increases monotonically. in the fourth and fifth columns, infit mnsq is in the range of 0.92 to 1.19, and the outfit mnsq value is 0.88 to 1.29, indicating that each category is within the acceptable limits. the sixth column shows the estimated postol thresholds in the order of zero, -1.03, -0.86, 0.17, and 1.72. graphically, the responses of each category are represented through the probability curve in figure 2. based on the probability curve, the category 2 scale does not show a separate peak, so it does not represent a unit of construction being measured. this follows the threshold value in table 4. table 2. summary of postol statistics separation reliability person 1.67 0.74 item 8.00 0.98 test 0.75 table 3. characteristics of items in postol item measure model s.e infit mnsq outfit mnsq pt. mea. corr ic1 -1.15 0.14 1.01 0.93 0.36 ic2 -0.71 0.12 1.00 0.94 0.38 ic3 -1.09 0.14 0.96 1.03 0.33 ic4 -0.76 0.13 0.86 0.92 0.43 ic5 -1.15 0.14 1.10 0.93 0.43 sp1 0.36 0.10 0.86 0.85 0.53 sp2 0.54 0.09 0.92 0.95 0.53 sp3 0.43 0.10 0.78 0.85 0.53 sp4 0.15 0.10 0.74 0.71 0.58 sp5 1.13 0.08 1.45 1.52 0.36 id1 0.23 0.10 0.87 0.87 0.52 id2 0.49 0.09 0.94 0.95 0.40 id3 -1.65 0.17 1.04 0.93 0.28 tr1 0.45 0.09 1.20 1.16 0.55 tr2 1.19 0.08 1.24 1.25 0.44 tr3 1.54 0.08 1.00 1.01 0.52 table 4. five-point likert rating scale functionality statistics category rating scale count (%) observed average infit mnsq outfit mnsq andrich threshold strongly disagree 1 60 (2) -0.15 1.19 1.29 none don't agree 2 145 (5) -0.01 0.92 0.88 -1.03 doubtful 3 470 (17) 0.59 1.01 1.01 -0.86 agree 4 1007 (36) 1.29 1.00 0.91 0.17 strongly agree 5 1086 (39) 2.33 1.00 0.99 1.72 http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 49 56 53 nursulistyo, et al. perception scale of online learning in the indonesian context … p-issn: 2621-3761 e-issn: 2621-2889 figure 2. five-point likert rating scale probability curve in postol unidimensionality the unidimensionality of the postol scale was determined through pca of the residues. empirically, the raw variance explained by measures is 45.7%, the unexplained variance in the 1st contrast is 10.0%, and the eigenvalues are 2.78. this metric is needed to determine whether postol can accurately measure students' perceptions during online learning. if the raw variance explained by measures is more than 40% and the unexplained variance in the 1st contrast is less than 15%, scale unidimensionality is achieved [48], [49]. this indicates that postol has good unidimensionality. discussions this study aims to evaluate the psychometric qualities of the adapted instrument used to gauge students' perceptions of online learning during covid-19. winsteps software version 4.6.1 was used to analyze the data to verify the construct validity of the postol [50]. the results of the initial statistical test showed that the person could distinguish 16 items in 8 groups [51]. linacre [52] states that a good separation index is > 2.0. person reliability is included in the good category, and item reliability is included in the special category [45], [53]. this shows consistency in the respondents' answers, and the quality of the items in postol is special. on the other hand, the quality of the interaction between the person and the item as a whole is viewed from the cronbach alpha value [33]. the analysis results show that the person and item have a good interaction. this finding supports the results of the consistency analysis of the postol instrument, as evaluated by bhagat et al. [24]. the next step is carefully studying the match index through infit mnsq and outfit mnsq. the analysis results show that all items fit well with the rasch model except for the sp5 item, "reading my classmates' work will help improve the quality of my work." item sp5 has an outfit mnsq value of 1.52, outside the range of 0.5-1.5. however, the pt. mea. corr. have values from 0.30-0.70 [54], [55]. pt. mea. corr. a high level indicates that an item can distinguish the respondent's ability [54]. that is, the response pattern has an orientation in the same direction as the general response pattern. so sp5 items need to be preserved. the discrepancy of sp5 items can be in the form of using negative words or giving a negative impression [56]. the indonesian version of postol using the rasch model supports the validity of the original version of postol, which was analyzed using a factor analysis approach [24]. the functionality of the 5-point likert scale is evaluated in order of threshold. although there is an increase in the threshold value with the category value, the threshold increases irregularly. this shows that the categories are not clearly defined for the respondents. respondents cannot clearly distinguish the 5 likert scale options provided, so it is necessary to simplify the rating scale to 4 likert rating scales [57]. figure 2 visualizes us combining scales 2 and 3 because scale 2 does not have a peak of its own. so the use of the scale becomes more effective because the category interval becomes wider [56]. these findings complement the psychometric properties of postol that have not been previously reported by bhagat et al. [24]. unidimensionality is one of the fundamental measures to assess an instrument's ability to measure what will be measured [33], [58]. based on the value of raw variance explained by measures and unexplained variance in the 1st contrast, it shows that 16 items in the postol instrument can be treated as a measure of unidimensionality, and there is no noise in the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 49 56 54 nursulistyo, et al. perception scale of online learning in the indonesian context … p-issn: 2621-3761 e-issn: 2621-2889 measurement. in more depth, the absence of items from other dimensions was explored through eigenvalue, less than 3. thus, the postol instrument adapted had good unidimensionality, and no indication of noise and items from other dimensions was found. the non-fulfillment of the unidimensionality measure can jeopardize the reliability and construct validity estimates [58]. v. acknowledgment thanks to the institute for research and community service, universitas ahmad dahlan, for facilitating and funding this research. vi. conclusion the psychometric properties of the postol instrument in the indonesian version were evaluated based on the rasch model. the analysis results show that the postol instrument has good psychometric properties to measure student perceptions of online learning in indonesia for junior and senior high schools. statistically, the indonesian version of the postol instrument meets the elements of good validity and reliability. sixteen items tested met the element of good fit to the rasch model. using a 4-point likert rating scale is more effective for junior and senior high schools in indonesia than the 5-point rating scale in the original version. in addition, the results of the unidimensionality test show that all items in the postol instrument in indonesian meet the unidimensional element. this finding recommends that teachers or instructors evaluate students' perceptions of the learning they have done during the covid-19 pandemic. these findings must be limited to the junior and senior high school levels because they have yet to reach various student demographics. future research must evaluate the instrument's psychometric properties in a more heterogeneous context. the diversity of types of schools and student disciplines (social, science, health, or vocational) need to be considered to obtain information on their use in a broader area. we recommend evaluating the psychometric properties of postol in elementary school-level students. references [1] a. e. clark, h. nong, h. zhu, and r. zhu, “compensating for academic loss: online learning and student performance during the covid-19 pandemic,” china econ. rev., vol. 68, no. may, p. 101629, 2021, doi: 10.1016/j.chieco.2021.101629. 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for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1177/2047487320902322 https://doi.org/10.1016/j.yebeh.2022.108637 https://doi.org/10.1016/j.jvoice.2020.04.022 https://doi.org/10.1108/ijse-07-2017-0294 https://doi.org/10.1016/j.jpainsymman.2018.02.017 http://www.winsteps.com/ https://doi.org/10.1186/s12884-020-02975-z https://doi.org/10.1186/s12884-020-02975-z https://doi.org/10.32698/0111 https://doi.org/10.1016/j.jsps.2015.01.011 https://doi.org/10.12973/iji.2018.11210a microsoft word layout-27-05-2019-rismawan.doc indonesian review of physics, volume 1, number 2, 2018 48 signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring using arduino uno rev.3 rismawan1, moh. toifur2 universitas ahmad dahlan jl. dr. soepomo, sh., janturan, warungboto, umbulharjo, yogyakarta, indonesia. dick.aries@gmail.com abstract the c-rtd (coil-resistance temperature detector) output signal is an analog signal in the form of a direct voltage. this value changes with changes in rtd temperature. this analog signal can be read by users using a multimeter or similar device but does not directly indicate the rtd temperature. in order to obtain rtd temperature values, an additional device is required. in order to have a useful value and practicality, a device that can convert analog signals into values can be read directly by the user. the microcontroller was chosen as a used device. the selected microcontroller system is arduino uno because has been coupled with input and output ports so users only need to enter programs related to the system being created. in the other hand arduino uno by considering the low cost and practical. for the measurement system, the rtd output signal must be conditioned into a digital signal using the adc so that it can be processed by the microcontroller. from testing instrument obtained that the system has been able to convert analog rtd signals into digital signals. the range of measurement is -176°c to 0°c with an accuracy of ± 0.20 / mv. keywords: adc, arduino uno, calibration curve, analog signal i. introduction temperature is the degree of the amount of energy contained in objects [1]. the more energy contained the object, the greater the temperature. this is related to the movement of particles making up objects. the higher the energy, the more agile the movement of particles making up the object. as energy, heat has the property of being able to move and interact with objects around it. the heat flowing through the conductive wire can cause an increase in the electrical resistance of a wire. the principle of interaction of heat energy with this object can be used to measure the amount of energy of an object. one of the uses of these properties is temperature measurement through changes in wire resistance due to changes in temperature [2]. the copper coil has been widely used as a resistant temperature detector (rtd). in riswanto's research, copper wire-based rtd has been produced which has a cross-sectional area of 0.2 mm cross section and 500 turns. this rtd is used to measure liquid nitrogen temperatures from 0 to 1900c. the study also produces a relationship between voltage and temperature following secondorder polynomials, namely with values [3]. with the determination index, it can be interpreted that the error rate of the relationship between v and t is only 10-5% or almost no errors. further research conducted by rismawan and moh. toifur obtained rtd output signal from copper wire with a diameter of 0.3 mm and a length of 5 meters which was formed into a coil. this study produces a pattern of relations between voltage and temperature in the form of polynomials cxy ae b-= + (1) research that uses rtd as a temperature sensor needs to be continued so that it can be used for practical purposes. the calibration curves of voltage to temperature done manually need to be followed up into a system that can work automatically and practically. the system can work 24 hours and continuously. one effort that can be done is to use a microcontroller system. this system rismawan & toifur signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring... indonesian review of physics, volume 1, number 2, 2018 49 can be designed to work independently and continuously. with a small form and need a little extra equipment, a complete system can be made. the microcontroller is able to process input signals from rtd to temperature values through two sequential processes. first digitizing rtd voltage analog signals. in this process, analog signals are converted into digital by the microcontroller. the next process is the conversion of digital signals from rtd to temperature values through an algorithm determined by microcontroller users [4]. the use of a microcontroller system as an analog signal processing device into a temperature value has been carried out in various fields, including sound to obtain sound intensity, light to measure the intensity emitted by light sources, measuring temperature without touching the object [5]. in this study, a microcontroller is used to process analog temperature signals into digital data then provide temperature output in the form of numerical data. ii. experiment procedure research method processing rtd signals into digital input into microcontrollers have specific characteristics. the data from signal logging show the minimum voltage is 0.5 volts and the maximum voltage is 1.876 volts. in order the signal from the rtd that has been amplified is possible to be processed by the microcontroller it is necessary to make a device with the following specifications: minimum input voltage = 0 volts maximum input voltage = 2 volts operating voltage = 9 volts (adjusted for battery) the flow of processing an analog signal into digital is shown in figure 1. this program needs to be systematically programmed so that the input signal can be converted into a temperature value by the microcontroller. the value of data processing can be known by streaming data that have been processed by the microcontroller through the arduino usb port to the pc and recording the data. figure 1. flow chart of rtd data acquisition to the microcontroller conversion analog rtd output signals to digital. rtd analog signals need to be converted into digital signals for further processing by microcontrollers. adc converts analog signals into digital signals through the principle of a voltage divider. the voltage that enters the adc will pass a voltage divider circuit and compare the value with the reference voltage. these values are then stored in registers which are then released together into data bits. the number of data bits depends on the desired resolution [6]. for measurement needs with very small voltage changes, an adc with large resolution and small noise are needed. the presence of noise in small signal changes can cause incorrect readings of the adc. in this study, the mcp3202 adc with 12 bits of data was used. the reference voltage used is the maximum voltage released by the signal amplifier, which is 2.7 volts. so, the selected adc reference voltage is 2.7 volts. this is so that the adc can change all the voltages of the rtd amplifier. adc conversion results follow equation (2) adc *2,7 bit 4095 adcv= (2) linearization of exponential equations figure 2. calibration of voltage curve with respect to temperature the equation of the microcontroller input signal from rtd is a signal that satisfies the exponential curve with the shape as shown in figure 2 so that it matches to the eq. (1). by using the curve equation that has been obtained from the previous rtd voltage measurement, we get the equation, 0.007954 0, 5468 2.337xy e-= + (3) rtd data adc mikrocontroler output rismawan & toifur signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring... indonesian review of physics, volume 1, number 2, 2018 50 where x is temperature, and y is voltage. this curve is a voltage curve as a function of temperature. for the purposes of processing a voltage signal into a temperature function, the equation of the curve needs to be converted into a temperature curve as a function of voltage. the equation of the curve as expressed in (1) can be processed by the temperature expressed as a function of voltage. 1 ( ) ln y b x c a = (4) where each of x and y is temperatur and voltage. this curve is a voltage as a function of temperature. for the purposes of processing a voltage signal into temperature, the equation of the curve needs to be converted into a temperature curve as a function of voltage. the curve equation as expressed in (1) can process the temperature quantity into a voltage quantity. linearization is needed in the process of temperature measurement. by obtaining a linear relationship between voltage and temperature, the signal processing from the rtd sensor becomes simple [7]. some sensors have a signal output that is not linear with temperature changes. some rtds have output signal characteristics in the form of polynomial equations. this condition makes it difficult in making the instrument. programming of arduino uno arduino uno is a minimum system for develope the use of microcontroller [8]. this minimum system has been completed with an integrated development environment (ide). this ide can be downloaded freely through the official arduino website. the arduino ide can be enriched with programming libraries or known as a library that has been developed by many communities [9]. this library makes it easy for developers to create a system that suits their needs. for the purposes of processing rtd signals, arduino programming is needed with the path as shown in figure 3. figure 3. flow chart of arduino uno programming iii. results and discussion the use of linearization equations as given in eq. (1) to eq. (4) has produced by microcontroller where the output voltage is proportional to temperature. the temperature output match value of the microcontroller with the reading of the medium temperature by the rtd has a reading range of 176°c to 20°c. reliable reading values based on device calibration made with vernier temperature probes are -139°c to 0°c. the value of the microcontroller reading for each temperature change is seen in figure 4. the values outside the range are generated from extrapolation by the microcontroller. extrapolation data obtained from the equation of the voltage calibration curve with respect to temperature. this can be interpreted that the processing of rtd voltage signals using a microcontroller has the advantage of being able to measure temperatures lower than those used for calibration. the temperature produced by the microcontroller through voltage conversion by the calibration curve equation is digital data in the form of a serial. this serial data can be recorded to other devices, such as pcs and data loggers. this data can be used further for equipment control purposes or for telemetry. this opens opportunities for wide development. figure 4. comparison of rtd voltage signal and adc processing signals processing signals of rtd output into digital signals for further purposes can be done with arduino uno revision 3. analog signals from rtd with minimum voltage, i.e. the voltage when inserted into liquid nitrogen, is 0.5 volts, and the maximum voltage was set at 0°c, has been successfully done. signal processing using arduino uno has produced a linear voltage signal with respect to temperature. this output signal has a resolution of 0.2°c / mv from the width value of the adc data used. rismawan & toifur signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring... indonesian review of physics, volume 1, number 2, 2018 51 the process of linearizing the signal equation from rtd has simplified processing by the microcontroller. this is because the microcontroller does not need to iterate to find the inverse value of the function for an input voltage value. iv. conclusion it has been successfully made a c-rtd output signal processor from voltage to numeric by utilizing arduino uno rev.3 microcontroller. from the testing the equipment was obtained for temperature data from -176°c to 0°c has an accuracy of ± 0.20 / mv. with this converter tool, it is possible to convert temperature data with a wider range of -176°c to 0°c as long as that it still follows a linear relationship between voltage and temperature. reference [1] serway, r. s, and jewett j. a, “fisika untuk sains dan teknik”, jakarta: salemba satika, 2010 [2] anonim, “measuring temperatures with rtd”, natonal instruments, application note 046, 1996 [3] fraden j, “handbook of modern sensors: physic, design, and applications”,new york:springer,1993 [4] riswanto, “optimasi panjang kawat dan diameter kawat tembaga sebagai piranti sensor suhu rendah berbasis 4wcb rtd”, tesis, yogyakarta, 2016 [5] hendian h. rachmat, fuad ughi, “pengembangan termometer suara bagi tuna netra berbasis mikrokontroler dengan sensor suara resistif”,jurnal rekayasa institut teknologi nasional, halaman 49-59, april-juni 2010 [6] mccarthy, mary, and dillon, eamon, “adc requirements for temperatures measurement systems”, analog devices, application note, 2006 [7] trump, bruce, “analog linearization of resistances temperature detector”, texas instruments incorporated, 2011 [8] desa, douglass, “applied technology in instrumentation and process control”, new york: taylor and francis, 2004. [9] oxer j., blemmings h., “pratical arduino: cool project for open source hardware”, new york: apress, 2009. microsoft word layout-27-05-2019-raisal.doc indonesian review of physics, volume 1, number 2, 2018 33 effectiveness of active learning method quiz team type on student learning outcomes in subject ohm law in sma negeri 1 pundong abu yazid raisal1, nanang suwondo2 universitas ahmad dahlan jl. dr. soepomo, sh., janturan, warungboto, umbulharjo, yogyakarta, indonesia. abuyazidraisal@gmail.com abstract this study aims to measure the increase in student learning outcomes from cognitive aspects and student activity between active quiz type learning methods and conventional methods. the sampling technique is non-random sampling. data was collected using the pre-test and post-test for cognitive aspects while the affective aspects used the observation. analysis of the data used the normality test, homogeneity test, and hypothesis testing. the hypothesis test used is a two-party t test. the results show that tcount = 7.273 > ttable = 2.01 at a significant level of 5%. it means that there are significant differences for cognitive aspects between learning outcomes using the team quiz type and conventional methods of active learning methods. overall the team quiz method is more effective for improving student learning outcomes from cognitive aspects, and student activities. keywords: active learning, team quizzes, learning outcomes i. introduction the teacher is the facilitator in the learning process. therefore, in the learning process the teacher must be able to use the right methods and media so that learning objectives can be achieved. the teacher must try to carry out the learning process that can stimulate student learning activities as much as possible. one of the efforts made by the teacher to obtain optimal results is to create a learning atmosphere that can actively involve students. active involvement of students in learning activities will enable these students to develop their potential [1] the value of learning outcomes is one indicator that can be used to measure the success of one's learning. in the teaching and learning process, there are many factors that influence the achievement of student learning outcomes, both from within the student (internal) and the external environment. internal factors are related to discipline, response and student motivation. while external factors are the learning environment, learning objectives, creativity in the selection of learning media by educators and learning methods [2]. based on the results of the interview with suryani, a physics teacher at pundong bantul public high school 1, most students had difficulty understanding physics subjects. the physics score of students on average is in kkm, not many students get grades above kkm. the teaching method used so far is the conventional method, namely the lecture method. it is expected that the methods that can make students have no difficulty understanding physics lessons so that the learning outcomes obtained are satisfactory. appropriate learning methods will produce good learning outcomes, namely methods that can improve student learning outcomes according to their development. one method that can be done is by the team quiz type active learning method. therefore, researchers conducting research using the team quiz method are expected to produce positive results on student learning outcomes and student activities. ii. theory learning is an activity or a process to gain knowledge, improve skills, improve behavior, attitudes, and strengthen personality. in the context of becoming aware or the process of gaining raisal & suwondo effectiveness of active learning method quiz team type on student learning outcomes in… indonesian review of physics, volume 1, number 2, 2018 34 knowledge, according to conventional scientific understanding, human contact with nature, termed experience (experience). experience that occurs repeatedly gives birth to knowledge, or a body of knowledge [3]. active learning is a learning that invites students to learn actively. when students learn actively, it means that they dominate learning activities. with this they actively use the brain, both to find the main ideas of the lecture material, solve problems, or apply what they have just learned into one problem that exists in real life. with this active learning, students are invited to participate in all learning processes, not only mentally but also physically. in this way students will usually feel a more pleasant atmosphere so that learning outcomes can be maximized [4]. effective teaching is teaching that provides opportunities for students to learn on their own or do their own activities [5]. one method that can be done is by the team quiz type active learning method. team quizzes come from the word "quiz" which means a short oral or written test and "team" which means group or group. team quiz means short oral or written examinations conducted in groups. team quizzes can increase student learning responsibilities in a pleasant atmosphere. learning procedures using the type of team quiz are as follows: 1. the teacher selects a topic that can be presented in three parts. 2. students are divided into three teams, namely team a, team b, and team c. 3. the teacher explains the learning scenario. 4. the teacher presents learning material. 5. the teacher asks team a to prepare a short answer quiz, while teams b and c use the time to check their notes. 6. team a gives a quiz to team b. if team b cannot answer the question, team c is given the opportunity to immediately answer it. 7. team a continues the next question to team member c and repeat the process. 8. when the quiz is finished, continue with the second part of the lesson and point team b as the quiz leader. 9. after the team completes the exam, continue with the third part and determine team c as the quiz leader [6]. learning outcomes can be explained by understanding the two words that make it up, namely "results" and "learning". understanding the results (product) refers to an acquisition due to an activity or process that results in functional changes in input. likewise in teaching and learning activities, after experiencing learning students change their behavior compared to before. learning is done to try to change behavior in individuals who learn. changes in behavior is the acquisition of learning outcomes [7]. iii. methodology this research included a type of quasiexperimental research. quasi-experimental research can be interpreted as research that approaches experiments or quasi-experiments. in quasiexperimental research, researchers can divide existing groups without differentiating between controls and groups significantly while still referring to existing natural forms [8]. in this research the data collection techniques used were achievement tests, namely tests used to measure achievement of someone who had learned something. the test method in this study was conducted twice. the first test was conducted to determine the students' initial ability (pre-test), then the final test (post-test) was carried out to determine the level of student understanding after the treatment was carried out. the population of this study were students of class x semester 2 of sma 1 pundong bantul with the samples taken were classes x3 as the experimental class and x2 as the control class. the number of students in the experimental class was 25 students and the control class was 24 students. the experimental class is taught by the team quiz method, while the control class is taught as usual, using conventional methods. the steps of the research are: (1) conducting a preliminary survey, (2) preparing a plan for implementing learning, student work sheets, and research instruments, (3) conducting research instrument trials, (4) analyzing trial data, (5) giving pre-test in the experimental class and control class students, (6) giving treatment by carrying out active learning with team quiz techniques in the experimental class students, while the control class students carried out conventional learning, (7) giving post-tests to the experimental class and control class , (8) analyzing data and interpreting the results obtained. the hypothesis in this study are as follows: h0 = there is no difference in student learning outcomes between using the active learning method team quiz type and conventional learning models h1 = there are differences in student learning outcomes between using the active learning method team quiz type with conventional learning models iv. results and discussion the achievement tests was prepared by the researcher with the help of expert judgment to determine the validity of the test contents. validity, reliability, level of difficulty, and different power of raisal & suwondo effectiveness of active learning method quiz team type on student learning outcomes in… indonesian review of physics, volume 1, number 2, 2018 35 test questions were obtained through research instrument trials. after going through the trial process, 20 physics test results were obtained. test data were analyzed descriptively to find out the results of student physics learning. the difference in the average score of the learning outcomes of the experimental class and control class students was analyzed using the t-test. before testing the hypothesis, the normality test and homogeneity test are carried out first. normalization test aims to determine whether the data obtained is normally distributed or not. the homogeneity test was conducted to determine whether the two samples studied had the same variance level or not. table 1. normality test results for data distribution pre-test and post-test test group significan t level !"#$%&' !"#$%& ' dk distributi on pre-test expe 5% 2,15 7,81 3 normal pre-test control 5% 5,46 7,81 3 normal post-test expe 5% 3,58 7,81 3 normal post-test control 5% 7,73 7,81 3 normal table 1 shows normality test results for data distribution pre-test and post-test. from the calculation of the normality test the value of 2countc pre-test for the group of students taught by the quiz type active learning method = 2.15 with 2tablec = 7.81 at the significant level of 5% and dk = 3. whereas the value 2countc pre-tests for groups of students taught with conventional methods = 5.46 with 2tablec = 7.81 at a significant level of 5% and dk = 3. the data is in accordance with the provisions, then the data is normally distributed. from the calculation of the normality test obtained the value of 2countc post-test for the group of students taught by the team quiz type active learning method = 3.58 with 2tablec = 7.81 at a significant level of 5% and dk = 3. whereas the value 2countc post-tests for groups of students taught by conventional methods = 7.73 with 2tablec = 7.81 at a significant level of 5% and dk = 3. the data is in accordance with the provisions, then the data is normally distributed. table 2. homogeneity test results for data distribution pre-test and post-test test group significant level !"#$%&' !"#$%&' dk distribution pretest 5% 4,23 7,81 3 homogen posttest 5% 0,05 7,81 3 homogen table 2 shows homogeneity test results for data distribution pre-test and post-test. the homogeneity test of the data in this study uses the barlett test with the provision of homogeneity if 2countc ≤ 2 tablec . it can be seen that the value of 2countc lower then 2 tablec for data distribution pre-test and post-test with significant level 5% and dk = 3. it can be concluded that the sample comes from a homogeneous population. based on the results of the normality test and the homogeneity test of the learning outcomes of the experimental and control class students, it can be determined that the different test scores on the average student learning outcomes can use the t-test (with the formula for normal and homogeneous data). the t-test was used to determine the differences in student learning outcomes that were significant between the experimental class and the control class. table 3. summary of the results of the t-test dk significant level !"#$%& !"#$%& conclusion 47 5 % 7,273 2,01 h0 rejected table 3 shows summary of the results of the t-test. from the table 3, it can be seen that the value of tcount = 7.273 > ttable = 2.01 from the distribution table t with a significant level of 5% and dk = 47 obtained the price t = 2.01 so that h0 is rejected and h1 is accepted namely "there are differences in student learning outcomes between using team quiz learning model with conventional learning models ". the quiz team encourages students to be active in the lesson so that students more easily understand the material provided. students are encouraged to create and solve problems themselves. unlike the conventional method, students only listen to what is taught by the teacher without actively participating in learning. students just sit and pay attention to the teacher explaining the material being taught. so that it is possible for many students who do not know clearly how to solve the problem. raisal & suwondo effectiveness of active learning method quiz team type on student learning outcomes in… indonesian review of physics, volume 1, number 2, 2018 36 v. conclusion there is an increase between student learning outcomes using team and conventional quiz methods. this can be proven by the results of the ttest which shows that tcount > ttable is 7.273 > 2.01. the quiz team encourages students to be active in the lesson so that students more easily understand the material provided. students are encouraged to create and solve problems themselves. reference [1] usmeldi, efektivitas pembelajaran aktif dengan teknik kuis tim pada mata pelajaran fisika di smkn 1 bukittinggi, prosiding seminar nasional fisika, 2012, pp.131-136. [2] maisaroh and rostrieningsih, peningkatan hasil belajar siswa dengan menggunakan metode pembelajaran active learning tipe quiz team pada mata pelajaran keterampilan dasar komunikasi di smk negeri 1 bogor, jurnal ekonomi & pendidikan, 2010,pp. 157-172. [3] suyono, and hariyanto, belajar dan pembelajaran. bandung: pt. remaja rosdakarya, 2011. [4] h. zaini, b. munthe, and s. a aryani, strategi pembelajaran aktif, yogyakarta: institut agama islam negeri yogyakarta. 2007 [5] o. hamalik, proses belajar mengajar, jakarta, bumi aksara, 2012. [6] m. l. silberman, active learning: 101 cara belajar siswa aktif, bandung: nusamedia, 2009. [7] purwanto, evaluasi hasil belajar, yogyakarta, pustaka pelajar, 2013. [8] sukardi, metodologi penelitian pendidikan, jakarta, bumi aksara, 2003. microsoft word layout-27-05-2019-nurahman.doc indonesian review of physics, volume 1, number 2, 2018 37 the development of worksheet based on guided discovery learning method helped by phet simulations interactive media in newton's laws of motion to improve learning outcomes and interest of vocational education 10th grade students arip nurahman1, widodo2, and ishafit3,butch o saulon4 123program studi magister pendidikan fisika, universitas ahmad dahlan, yogyakarta jl. pramuka 42, sidikan, umbulharjo, yogyakarta 55161. indonesia. 4nueva caceres university, philippine hernandez ave, naga, camarines sur, filipina nebulaarip99@gmail.com abstract this research was aimed to produce students worksheet (lkpd) based on phet interactive simulations software in cognitive through the application of physicsbased guided discovery learning model that is devoted to the concept of newton's law of motion. guided discovery-based approach is expected and is believed to develop students' skills in various aspects of one study that showed achievement levels mastery of physics students after participating in the learning process under the expected educational purposes. researchers conducted a study on the process of learning physics for the discovery-oriented at vocational senior high school students in newton's law of motion with r&d. subjects were students of class x tkro in the first semester of the academic year 2018-2019 in vocational high school in ciamis, west java province as many as 35 students. data collected through tests, observations and interviews. keywords: vocational education, worksheet, guided discovery learning, phet interactive simulations i. introduction in the process of teaching and learning activities, and in designing learning the teacher must consider the media aspects of the learning plan. for this reason the teacher must try to use and apply learning with the help of existing media. the selection and use of media must be aligned with the learning objectives to be achieved, the characteristics of students, and the student learning environment. learning by using phet simulations is one of the computing media that provides physics animations that are used as blogs. in phet simulations can display something material that is abstract and can be explained easily and precisely to students. teacher need to prepare a programmed learning facility so students reach expected mastery of learning [1]. the main role of the teacher is to help students become independent learners by presenting contextual problems, then guiding students to raise problems and facilitate investigations to solve these problems independently. one of the main goals of school activities is to increase students' ability to think critically, make rational decisions about what done or what is believed [2]. schools should teach and empower students' thinking skills because empowering thinking skills is believed to have the potential to empower humans [3]. this phenomenon in the field is caused by the learning methods carried out by teachers tend to be dominated by certain methods, so students are passive in the learning process. the teacher only increases the cognitive knowledge of students by providing memorization of the theory of the material. the learning method is the point of view of a teacher in looking at all the problems that exist in the learning process. this point of view is a teacher's way of thinking in addressing and resolving problems that occur in the learning process. one of the learning methods that can be used in physics subjects to enhance logical, rational, creative, and critical thinking including guided discovery learning methods, gdl is a teaching method that regulates teaching in such a way that the child obtains knowledge that he did not yet nurahman et al. the development of worksheet based on guided discovery learning method helped by phet…. indonesian review of physics, volume 1, number 2, 2018 38 know was not through notification, partially or entirely found on his own. in guided discovery learning activities or learning are designed so that students can find concepts and principles through their mental processes. in finding concepts, students make observations, classify, make guesses, explain, draw conclusions and so on to find some concepts or principles [4]. based on the background above, we are interested in conducting research on: “the development of worksheet based on guided discovery learning method helped by phet simulations interactive media in newton's laws of motion to improve learning outcomes and interest of vocational education 10th grade students.” in line with the description above, this study aims to find out: are the worksheet’s based on guided discovery learning method using the phet interactive simulations software on newton law of motion fulfilling the learning media eligibility criteria? how can a worksheet’s based on guided discovery learning method using the phet interactive simulations software on newton law of motionimprove understanding of students' concepts in learning newton's law of motion? ii. literary review the following are the theories that support this research: a. discovery learning the guided discovery learning method is learning approach which defined as the learning process that occurs when students are not presented with lessons in their final form but are expected to organise themselves. as bruner's opinion, that: "discovery learning defined as the learning that takes place when the student not presented with the subject matter in the final form, but rather is required to organise it friction" [5] “guided discovery, is characterized by convergent thinking. the instructor devises a series of statements or questions that guide the learner, step by logical step, making a series of discoveries that leads to a single predetermined goal. in other words the instructor initiates a stimulus and the learner reacts by engaging in active inquiry thereby discovering the appropriate response [6]. b. newton's law of motion the subject of physics is the main branch of science because its principles form the basis of other branches of science [9]. newton's first law. if the resultant of the forces acting on an object is zero (f = 0), then the object: (1) an object at rest stays, and a something in motion stays in motion with the equivalent speed and the same direction unless moved upon by an unbalanced force and (2) if move in a straight, uniform manner, it will still move in a straight line. the situation mentioned above is also called the law of inertia. s f = 0 and a = 0 (1) because objects move in translation, the cartesian coordinate system can be written: s fx = 0 and s fy = 0. (2) newton's second law. the acceleration caused by force acting on an object is directly proportional to that force and inversely proportional to the mass of the object. figure 1. the acceleration caused by the force the law of motion first summarised by isaac newton in his work philosophiæ naturalis principia mathematica first published on july 5, 1687. newton used his work to explain and examine the motion of various physical and systemic objects, for example in volume three of the text, and newton showed that by combining the laws of motion with the general law of gravity, he could explain kepler's laws of planetary motion. newton's law applied to objects that are considered to be particles, in the evaluation of movement, for example, the length of the object ignored because the calculated object can be considered small, relative to the distance travelled, deformation and rotation of an object. table 1. notation of force in mks and cgs unit c. student worksheet (lkpd) student worksheets (lkpd) are one of the means to help and facilitate teaching and learning activities so that effective interactions between students and educators formed so that students can improve their activities in improving learning achievement [7]. student worksheets (lkpd) are one source of learning that can be developed by educators as facilitators in learning activities. the lkpd v a l u e n o t a t i o n m k s c g s force f newton (n) dyne mass m kg gram acceleration a m/sec2 cm/sec2 nurahman et al. the development of worksheet based on guided discovery learning method helped by phet…. indonesian review of physics, volume 1, number 2, 2018 39 prepared designed and developed under the conditions and situations of the learning activities that will be faced. student worksheets (lkpd) are sheets containing assignments that must be done by students. activity sheets are usually in the form of instructions, steps to complete a task. the advantage of using lkpd is to make it easier for educators to carry out learning, for students to learn independently and learn to understand and carry out a written task [8]. in the preparation of the lkpd must meet various requirements, namely didactic requirements, construction requirements and technical requirements, didactic requirements; lkpd as a form of teaching and learning process must fulfill didactic requirements, meaning that an lkpd must follow the principles of effective teaching and learning, namely: paying attention to individual differences, so that a good lkpd can be used by slow learners. technical requirements, from a technical point of view, have several discussions, namely: using printed letters and not using latin or roman letters, using rather large bold letters, not ordinary letters that are underlined, using no more than 10 words in a row, using frames to differentiate command sentences from students' answers, try to compare the size of the letters with the size of the matching image. d. phet interactive simulations software visual physics is the physics whose events can be seen with eyes include electric magnets, fluids, optics and mechanics [10]. phet is an interactive simulation of physical phenomena, based on research provided free of charge. researchers believe that with a research-based approach, which combines the results of previous research and what the authors do themselves allows students to connect real-life phenomena and the underlying knowledge, which can ultimately deepen understanding and increase their interest in physics. it is founded in 2002 by nobel physics laureate prof. carl wieman, phd in university colorado, usa. investigate the forces at work while sloping toward a cart, and pushing an icebox, stone, or student. create an employed force and see how it makes objects move. change friction and see how it affects the motion of objects [12]. iii. method of research a. type of research the type of research used is research and development (r & d) research with model analysis-design-development-implementationevaluation (addie). appeared in the 1990s developed by reiser and mollenda, one of the functions of addie is to be a guideline in developing efficient and dynamic training program equipment and infrastructure and supporting the performance of the training itself. this model was accepted because the addie model is often used to describe a systematic approach to instructional development. in addition, the addie model is a general learning model that is suitable for development research. this term is almost identical to the development of instructional systems. when used in the development, this process is considered sequential but also interactive, where the evaluation results of each stage can bring the development of learning to the previous stage. the final result of a stage is the initial product for the next stage. following is the description of the five stages of the addie development model: analysis (analisis), design (rancangan), development (pengembangan), implementation (implementasi), evaluation (evaluasi) b. research purposes this study aims to produce appropriate teaching materials in the form of student worksheets based on discovery learning assisted by phet newton law subject matter for students of smkn 1 rajadesa, ciamis, west java. c. place and time of research the research was conducted at ahmad dahlan university in yogyakarta and tested on class x automotive light vehicle engineering department of smk 1 raja desa, ciamis, west java. the time for media development trials is carried out in september-december 2019. d. respondents the feasibility test and readability of student worksheets developed involve experts and product users, including material experts, media experts, physics teachers, and students of smk 1 rajadesa, ciamis, west java, on the 10th grade of automotive light vehicle engineering department in limited numbers. the subjects of this study were all students in the first semester of the automotive light vehicle engineering department smkn 1 rajadesa ciamis, west java, the 2018/2019 school year with 35 students. e. data collection technique in this development research, the data used is in the form of the results of expert trials, teachers, and the performance and knowledge of students. data were obtained using a test instrument in the form of a rating scale questionnaire and a skill assessment sheet (psychomotor) and knowledge (cognitive) nurahman et al. the development of worksheet based on guided discovery learning method helped by phet…. indonesian review of physics, volume 1, number 2, 2018 40 with the assessment rubric. the produced shown to respondents namely material experts, media experts, linguists, students and physics teachers of class x smkn. after examining the product, respondents then fill out the questionnaire has been given. data obtained in the form of a questionnaire that has been filled out by the respondent. f. research instrument the instruments used in this study consist of: analysis of needs for teachers and student, analysis of summative test items including validity, reliability, level of difficulty, and differentiation, evaluation questionnaire for physicists, learning media experts, and physics teachers field trial questionnaire g. data analysis technique the data obtained were investigated by calculating using a likert scale. likert scale is a scale used to measure attitudes, opinions, and perceptions of a person or group of people about social phenomena. the data obtained were examined using the likert scale calculation with points 1 to 4. iv. results and discussion after doing the research, obtained guided discovery-based lkpd on newton's law material using phet interactive simulations software, then the activity to obtain a valid and practical guided discovery-based lkpd begins with passing the defining stage. based on the products that have been designing, the results of the lkpd validation obtained according to physicists and multimedia experts. overall results of guided discovery-based lkpd validation by the validator is 95.85%. while the results of practical findings based lkpd guided by teachers and students as a whole is 90.75%. the shows that discovery-based lkpd is valid and very practical. guided lkpd based on the newton law material using valid phet interactive simulations software based on the results of the validator's assessment as follows: a the material presented at the lkpd is by the competencies achieved. b examples of questions on lkpd are following the substance. c the presentation of the pictures on the lkpd is bright and attractive. d lkpd can guide students' skills to discover concepts themselves. e lkpd in newton's law has a characteristic, namely lkpd developed based on guided discovery using phet interactive simulations software. guided lkpd based on the material of newton's law is practically based on the results of assessments from teachers and students as follows: a. the instructions for using lkpd can be clearly understood. b. the presentation of the subject matter contained in lkpd is more practical and can learn repeatedly. c. not using a long time to fill in the lkpd because there are clear instructions. d. the pictures on the lkpd can be clearly understood and easily understood. in this study, two lessons conducted. 1st learning with the subject of newton's laws i and ii. 2nd learning with the subject of newton's third law. the following data obtained from the study: tabel 2. recapitulations of results of observation of learning activities conducted by teachers learning activity implementation percentage (%) category 1 91,3 very good 2 95,6 very good based on table 2, it observed that the learning process is carried out maximally by the teacher. it is indicated by the percentage of implementation first learning 95.6% with a very good category and second learning 91.3% with a very good category. while the results of the recapitulation of student responses to the processes that occur during learning are as follows. table 3. recapitulations of observation results of student response to every activity in learning learning percentage (%) category 1 76.2 good 2 80.9 good based on table 3, it viewed that the learning process is responded to well by students. it indicated by the percentage of student responses in the first learning 76.2% with good categories and second learning 80.9% with good categories. as many as 20 students interviewed stated that the use of lkpd in this learning was more active because they could carry out simple experiments and demonstrations on the concepts of newton's law i, ii and iii. seven students interviewed stated that there were obstacles when conducting guided discovery-oriented learning with lkpd, 30 students after being interviewed were satisfied and pleased with the guided discovery learning method with this lkpd. a total of 21 students interviewed could answer exactly newton's nurahman et al. the development of worksheet based on guided discovery learning method helped by phet…. indonesian review of physics, volume 1, number 2, 2018 41 law i, 30 students answered that newton's second law was f = m a, and as many as 35 students answered that newton's third law was about action-reaction. this study are to answer the problem formulation: lkpd or worksheets based on guided discovery learning physics assisted by phet simulations interactive media on the material of newton's law, testing the feasibility of physics-based lkpd guided discovery learning is assisted by phet simulations interactive media through the validation of material experts, media experts, and users, and examines the effect of using physical lkpd on newton's law aided by phet simulations interactive media on results or learning achievement and learning interest of grade x students of 1 rajadesa vocational school, ciamis district, west java v. conclusion the results of the validation of the accuracy and suitability of the material on physics-guided discovery learning lkpd conducted by material experts get an interpretation of all indicators, for the two indicators assessed by material experts with 12 questions obtained an average value of 95.85%. it shows that from the learning strategy and content of the substantial lkpd discovery learning guided physics has been very good and feasible used as a source of learning in physics learning. the results of guided discovery learning lkpd validation conducted by media experts get a very good interpretation on all indicators, for the two indicators assessed by two learning media experts with eight questions obtained an average value of 90.75%. the shows that in terms of appearance and language, lkpd discovery learning guided physics has been very good and feasible to use as one of the learning resources in learning. for field trials, researchers are researching smk 1 raja desa, ciamis, west java.. references [1] c. huda, d. sulisworo, and m. toifur, analisis buku ajar termodinamika dengan konsep technological pedagogical and content knowledge (tpack) untuk penguatan kompetensi belajar mahasiswa, jurnal penelitian pembelajaran fisika, vol. 8, no.1, 2017, pp.1-7. [2] r h. ennis, critical thinking and subject specificity clarification and needed research. educational researcher, sage journals, vol. 18, no.3, 1989, pp. 4-10. [3] p. r. wikandari. pengajaran berpusat kepada siswa dan pendekatan konstruktivis dalam pengajaran. unesa. 2008. [4] a. a. carin, teaching science through discovery, mcmillan publishing company, 1993. [5] j. s. bruner, the act of discovery, harvard educational, vol. 31, no.1, 1961, pp. 21–32. [6] leutner, detlev, (1993), guided discovery learning with computer-based simulation games: effects of adaptive and non-adaptive instructional support, learning and instruction, 3 (2) p113-32. [7] e. widjajanti, kualitas lembar kerja siswa, makalah pengabdian kepada masyarakat. universitas negeri yogyakarta, yogyakarta, 2008. [8] depdiknas, peraturan menteri pendidikan republik indonesia no. 22 tahun 2006 tentang standar isi untuk satuan pendidikan dasar dan menengah. dirjen dikdasmen, jakarta, 2006. [9] bambang, surahmadi, and ishafit, usaha menumbuhkan kreativitas peserta didik dalam membuat karya ipa dengan model pembelajaran problem based instruction di smp negeri 1 temanggung, prosiding seminar nasional sains dan pendidikan sains ix, uksw, vol. 5, no. 1, 2014, pp. 380-385. [10] r. mahmudah, y. pramudya, d. sulisworo, analisis validitas butir soal certainty of respons index (cri) untuk identifikasi miskonsepsi materi tata surya dan fenomena astronomi. prosiding seminar nasional pendidikan sains, pp.579-587, 2016. [11] m. molenda, in search of the ellusive addie model, pervormance improvement, vol. 42, no.5, 2003, pp.34-36. [12] y. ekawati, a. haris, and b.d. amin, penerapan media simulasi menggunakan phet (physics education and technology) terhadap hasil belajar fisika peserta didik kelas x sma muhammadiyah limbung. jurnal pendidikan fisika, vol.3, no.1. 2015. pp.74-82. indonesian review of physics, volume 2, number 1, 2019 22 flipped classroom as a millenial teaching model yoga budi bhakti1, irnin agustina dwi astuti1, ria asep sumarni1, dwi sulisworo2, and m. toifur2 1universitas indraprasta pgri, 2universitas ahmad dahlan 1jl. nangka no. 58c, tanjung barat, jagakarsa-jakarta selatan 12530 2jl. pramuka no.42, pandeyan, umbulharjo, yogyakarta, daerah istimewa yogyakarta 55161 bhaktiyoga.budi@gmail.com abstract – this study is a literature review. the flipped classroom is the latest pedagogical model that has the potential to change the current traditional way of teaching. flipped classroom emphasizes on learning activities that promote critical thinking and motivation among the students with the assistance of technology. the flipped classroom allows educators to move from ‘the sage on the stage’ to ‘the guide on the side. the basic and simplest form of flipped classroom is students are expected to watch digital resources prior to class. the students are then required to come prepared for class and perform hands-on activities that are related to the digital resources. the digital resources can be in any form such as video, audio or the internet. this allows teachers to spend more time with their students to carry out in class activities and allow immediate response to students’ needs. student feedback on this pedagogy was generally very positive with many respondents considering it effective and helpful for learning. one of the biggest advantages mentioned by students is that they had the option to watch each video lecture as many times as required to be prepared for class. keywords: flipped classroom, active learning, millennial teaching model i. introduction this learning is implemented in the 21st century, demanding learner-centered learning. the goal that you want to achieve is not just learning outcomes, but in the learning process experienced by learners. it is certainly not an easy challenge for a learner, they will find many difficulties in the learning process. one of the difficulties often experienced by learners in the learning process especially in the learning of physics is the difficulty in the completion of homework given by the teacher. another problem that can be experienced by learners in the learning process is to understand and respond to the material provided by the teacher. therefore, the teacher needs to choose the right method to use in the learning process. the preferred method should be able to increase the learning interest and independence of learners, so that the learning process is meaningful and student learning outcomes can be achieved optimally. regulation ministry of education no. 65 year 2013 states that the learning process in each unit of primary and secondary education is interactive, inspirational, fun, challenging, and motivating learners to actively participate, as well as providing ample space for initiative, creativity, and independence in accordance with the talents, interests, and physical development, as well as the psychological learners. based on the explanation of the regulation ministry of education, you can know that in the learning process, learners have a very important role, so that teachers should be able to design learning physics that performed at school tends to be done with lectures and discussions. the activities of the students are more on listening and recording teacher explanations. in addition, the bhakti et al. flipped classroom as a millenial teaching model indonesian review of physics, volume 2, number 1, 2019 23 media used by the teacher is only a package book, so learners feel uninterested in physics learning. therefore, a learning method is required that can attract students ' attention and be able to overcome the difficulties experienced by learners. one of the methods that can be applied is the flipped classroom method. through flipped classroom methods, learn the theory yourself and in the learning class by applying the previously learned theories [1]. learners study material at home first before the material is explained and in a student class with the teacher solves the problem students find when learning at home learning by using flipped methods classroom involves individual learners ' active participation to dive into lesson materials outside of the classroom with an unlimited period of time before lessons in the class begin, helping learners to be more active, and more self-reliant in the learning process and the time in the classroom is used to solve problems that learners find in home study [2] [3]. "flipping" the classroom employs easy-to-use, readily accessihle technology in order to free class time from lecture . this allows for an expanded range of learning activities during class time. using class time for active learning versus lecture provides opportunities for greater teacher-to-student mentoring, peer-to-peer collaboration and crossdisciplinary engagement. this review of literature addresses the challenges of engaging today's students in lecture based classrooms and presents an argument for application of the "flipped classroom" model hy educators in the disciplines of family and consumer sciences. a sense of urgency to adapt to millennial learning preferences is heightened as educators increasingly struggle to capture the attention of today's students. unlike previous generations, millennials reared on rapidly evolving technologies demonstrate decreased tolerance for lecture-style dissemination of course information. incorporation of active learning strategies into the classroom is critical in order to reach millennial students. millennial students, referred to as "digital natives" [4], have been exposed to information technology from a very young age. millennials' access to technology, information, and digital media is greater than that of any prior generation. ii. method of research this research is a research study of literature by studying some journals related to flipped classroom. the results of these literary studies will be used to review flipped classroom model learning steps. iii. research results and discussion the flipped classroom active learning pedagogies continue to evolve, and new methods of delivering course material are being developed. assimilating active learning can be as simple as integrating in-class activities alongside traditional lecture. yet educators in elementary through post-secondary education are finding innovative ways to restructure the classroom in order to focus attention on the learner [5]. instructors adopting the flipped classroom model assign the class lecture or instructional content as homework. in preparation for class, students are required to view the lecture. according to tucker [6], students utilize the time in class to work through problems, advance concepts, and engage in collaborative learning. the flipped classroom method as an alternative to the current traditional teaching method by using technologies. rapid technology has played an important role in the educational world. the use of technology in teaching and learning facilitates in increasing students’ understanding toward critical and creative thinking, if used systematically. bhakti et al. flipped classroom as a millenial teaching model indonesian review of physics, volume 2, number 1, 2019 24 table i. the flipped classroom stages stage activity i before the study began, students were asked to study independently at home about the material for the next meeting, by watching the teacher's own learning videos or learning videos from other people's uploads. ii in classroom learning, learners are divided into groups iii teachers give quizzes or tests that correspond to the materials learned in the learning videos that the teacher has provided iv teachers appoint one of the learners to answer the quiz that the teacher has given v teachers asked other students for feedback on the answer to convince that all learners are involved in ongoing activities. however, if the learner had difficulty with answers or answers given as inappropriate, improper, or silent, then the teacher asked other questions that the answer was a guide to completion of the answer. vi teachers appoint one of the different learners with new questions to see if learning has been thoroughly conveyed and understood by all learners a flipped, or inverted, classroom model could be adapted easily to multiple disciplines such as textile design, apparel design and construction, interior design, and nutrition. of particular relevance are courses in which a lecture is primarily based on disseminating information and learning occurs when students apply these instructions to complete a task or an assignment. the flipped classroom model suggests the use of a variety of technologies in preparing and posting lessons for students' access prior to class. flipping the classroom allows for a range of teaching methodologies to be employed such as videotaping the instructor while lecturing, creating videos with voiceover and screen-capture software, instructions accompanied by visual aids, utilizing videos found online from sources such as youtube and teachertube, and integrating discipline-specific websites of videos available through professional organizations and companies [7]. this allows instructors to improve communication and connection with students possessing a broad range of abilities. with a traditional lecture format, teachers might not be aware of student progress until after testing [8]. a flipped classroom allows teachers greater insight into students' grasp of information and learning as a result of increased student/teacher interaction. the time gained by removing the lecture portion from class allows for more one-on-one personal engagement between the teacher and students. furthermore, a flipped classroom allows students who may be hesitant to ask questions in the middle of a lecture to seek assistance from the teacher during their individual feedback sessions. students also have the opportunity to "replay" the lectures several times before formulating their questions. challenges with the flipped classroom model include adapting traditional lectures to alternative media in order to post content online. other challenges teachers face include making changes to the online lectures. the flexibility required to make adjustments to course content may be dependent on the technology originally used to create the lecture. complexity of making changes could vary between re-recording an entire video lecture or could be as simple as adding an additional slide to a powerpoint presentation. as technology used for presenting information gets smarter, faster, better, and cheaper, educators will be forced to learn and access more of these tools [9] the flipped classrooms, as well as active learning, require students to assume more responsibility for their individual learning experience. teachers must include clear expectations of self direction and motivation within their syllabus or framework of the course. for this reason, verification, through application of information in a projectbased scenario, may be one indication that students have performed the task of viewing the lecture prior to entering the classroom. bhakti et al. flipped classroom as a millenial teaching model indonesian review of physics, volume 2, number 1, 2019 25 figure 1. the tradition classroom and flipped classroom [8] flipped classroom also provides opportunity for excellent students to learn in a group. group activity in a flipped classroom could increase interaction between students and teacher, and between students themselves through learning activities such as inquiry-based learning, problem-based learning and project based learning [10]. the millenial student’s millennial students, referred to as "digital natives" [4], have been exposed to information technology from a very young age. millennials' access to technology, information, and digital media is greater than that of any prior generation. according to mcmahon and pospisil [11], characteristics of millennial students include 24/7 information connectedness, a preference for environments that support multitasking, and gravitation toward group activity and appreciation of the social aspects of learning. this generation is distinguished by their access to technological and collaborative experiences. millennial students drive change in learning environments around the world. the technology, with which digital natives matured, has induced today's students to "think and process information fundamentally differently from their predecessors" [4]. although educators bemoan this generations' inability to focus. millennial expert pointed out that "it is not our students' attention capabilities that have changed, but rather their tolerance and needs". this characteristic actually validates the urgency to adopt alternative methods of instruction, and many teachers are incorporating active learning strategies as a better way to engage these students. technology used in flipped classroom technology is a catalyst in the teaching and learning processes. technology that is used accurately and systematically would facilitate the teachers in imparting the knowledge, and the students in their learning [12]. previous studies on flipped classroom in school also found that it is not an excluded from the use of technology. digital learning media is also known as multimedia learning. the term multimedia contains different understandings for different people. for some people multimedia is in front of the computer terminal and enjoy a presentation consisting of text on the screen, on-screen graphics or animations on the screen and sound out of the loudspeakers. as for others multimedia means "live" presentation where a group of people sit in a space while watching the image that appears on screen while listening to music through the loudspeakers. watching tv and video also includes multimedia, presentations using powerpoint and explaining slides also include multimedia. even teachers write and draw with lime while explaining also including multimedia though not using high technology. the most basic form of multimedia is a handbook containing writings and drawings [13] . in traditional learning, learning messages are presented in verbal form (spoken and written). but in line with the advancement of multimedia learning information technology into something necessary, especially in electronic learning (e-learning), since e-learning is self-learning and students can easily move from one screen to another if the learning is not interesting [14] [15]. in the context of multimedia messaging there are three different views that are reviewed from the introductory media, representation format, and sensor modalities. based on the media used to present the message, the main concern lies in the medium that is the equipment used to present the material, for example: computer screen, loudspeaker, projector, video, dvd and other equipment. this view is the most appropriate view in terms of the bhakti et al. flipped classroom as a millenial teaching model indonesian review of physics, volume 2, number 1, 2019 26 meaning of the words, because this view focuses on the use of media. here the attention is aimed at the sophistication of equipment than the study. this view is a more advanced view of technology-centered. the next view is based on the format of representation used. here the attention is aimed at how the material is presented, namely through words and images. for example, the "computer-based multimedia" material is verbally represented on the screen can be text on display and narrative and pictorial can be a form of static images and animations. in "lecturebased multimedia" the material can be presented verbally as speech and pictorial in the form of a projected image or video. in the handbook (textbook) the material can be presented in the form of printed text and static images. this view can be said to be the view of "learner-centered" because it is assumed that learners are able to use various coding systems for the presentation of knowledge, namely the verbal presentation and piktorial. this view is consistent with the cognitive theory of learning which assumes that humans have different channels in the processing of verbal knowledge and pictorial knowledge. the most recent view is based on sensory modality, this view is a sense of the sensory reception of learners to receive information/knowledge. this view corresponds to the dual code theory of paivio, and this view includes the view learner centered [2]. media is one of the defining factors of learning success. through the media the learning process can be more interesting and enjoyable [16]. by the proper use of appropriate media, students will be able to more easily understand the material being taught. the learning process requires the media to be able to take place as expected. games that contain learning materials that are packed with great fun will be very helpful, because students seem to feel like learning. another important aspect of media use is that it helps clarify learning messages. in learning "flipped classroom" the most suitable media is a video, podcast, but if the teacher is still not ready with the production of the video itself, can obtain material that is on the internet. but it is advisable that the most appropriate video footage of the teaching teacher is doing, with the learner feeling as if the teaching was not done outside of school, but was in the middle. iv. conclusion active learning activities have proven to be highly effective in cultivating millenials’ engagement. active and learning however require technological support; and flipped classroom is suggested to be one of the pedagogical approaches to complement the whole process of learning. flipped classroom is the latest pedagogical method that has the potential to change the current traditional way of teaching. flipped classroom emphasizes on learning activities that promote critical thinking and motivation among the students with the assistance of technology. implementation of the flipped classroom method could change the direction of the current traditional class and shape the students’ learning. acknowledgment the authors would like thank to universitas indraprasta pgri, universitas ahmad dahlan and ministry of technology research and higher education for their continuous support and encouragement in carrying out this study. reference [1] basal a, 2015 the implementation of a flipped classroom in foreign language teaching turkish online j. … 16, 4 p. 28–37. [2] f a f r sukestiyarno s and mariani s, 2019 mathematical literacy based on students self -regulated learning by flipped classroom with whatsapp module unnes j. math. educ. res. 8, 2 p. 125–132. [3] rahman a a abdullah z mohammed h zaid n m and aris b, 2014 flipped classroom reviving cognitive development among school students in 3rd international seminar on quality and affordable education p. 67. [4] prensky m, 2001 digital natives, digital immigrants part 1 horiz. 9, 5 p. 1–6. [5] bergmann j and sams a, 2012 flipping the classroom tech learn. 32, 10 p. 42–43. [6] tucker b, 2012, the flipped classroomonline instruction at home frees class time for learning, in education next, p. 8283-. [7] roehl a m y reddy s l and shannon g j, 2013 the flipped classroom: an opportunity to engage millennial students through active learning strategies j. fam. consum. sci. 105, 2 p. 44–49. bhakti et al. flipped classroom as a millenial teaching model indonesian review of physics, volume 2, number 1, 2019 27 [8] mok h n, 2014 teaching tip: the flipped classroom j. inf. syst. educ. 25, 1 p. 7–11. [9] enfield j, 2013 looking at the impact of the flipped classroom model of instruction on undergraduate multimedia students at csun techtrends 57, 6 p. 14–15. [10] zainuddin z, 2017 firstyear college students experiences in the efl flipped classroom a case study in indonesia int. j. instr. 10, 1 p. 133–150. [11] mcmahon m and pospisil r, 2005 laptops for a digital lifestyle millennial students and wireless mobile technologies in proceedings of the australasian society for computers in learning in tertiary education 2 p. 421– 431. [12] bishop j l and verleger m a, 2013 the flipped classroom a survey of the research the flipped classrom : a survey of the research in 120th asee annual conference & exposition. [13] mayer r e and moreno r, 2002 animation as an aid to multimedia learning educ. psychol. rev. 14, 1 p. 87–88. [14] unal z and unal a, 2017 comparison of student performance student perception and teacher satisfaction with traditional versus flipped classroom models int. j. instr. 10, 4 p. 145–164. [15] awedh m mueen, a. zafar b and manzoor u, 2014 using socrative and smartphones for the support of collaborative learning int. j. integr. technol. educ. 3, 4 p. 17–24. [16] paristiowati m fitriani e and aldi n h, 2017 the effect of inquiry-flipped classroom model toward students achievement on chemical reaction rate in aip conf. proc 30006 p. 1–6. yoga budi bhakti1, irnin agustina dwi astuti1, ria asep sumarni1, dwi sulisworo2, and m. toifur2 keywords: flipped classroom, active learning, millennial teaching model reference indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 55 60 doi: 10.12928/irip.v4i2.4020 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 55 application of self-potential method to observe groundwater flow in tanjungpura university area, pontianak muhardi*, kaharudin, and mathaliul anwar department of geophysics, universitas tanjungpura, indonesia email: muhardi@physics.untan.ac.id article info abstract article history received: apr 27, 2021 revised: dec 28, 2021 accepted: dec 28, 2021 the study aims to observe groundwater flow in the tanjungpura university area, pontianak, west kalimantan. data collection applied three lines have a length of 65 m, a distance between the lines is 5 m, and a space between the porous pots is 5 m. each line has 12 points to measure the self-potential value. the results showed that the variation of the self-potential value before the correction was -9.98 mv to 17.24 mv, while after correction, it was -10.52 mv to 16.92 mv. the self-potential distribution shows that the relatively high potential value is in the south, while the low is in the north. the distribution of self-potential values in the study location is caused by groundwater movement, which flows north. in addition, groundwater also flows to the south, especially at 20-30 m from the base station. thus, the low self-potential value in the north can be used as a reference to identify groundwater accumulation to explore raw water in the study location. this is an open-access article under the cc–by-sa license. keywords: groundwater self-potential pontianak to cite this article: m. muhardi, k. kaharudin, and m. anwar, “application of self-potential method to observe groundwater flow in tanjungpura university area, pontianak,” indones. rev. phys., vol. 4, no. 2, pp. 55–60, 2021, doi: 10.12928/irip.v4i2.4020. i. introduction the groundwater has a significant role because its use is needed in everyday life. it can be found at different depths, and it depends on local geological conditions [1]. even though its availability is abundant in the aquifer layer, information about groundwater presence is needed so that it can be used optimally. one of the information required by society for groundwater utilization is groundwater flow so that its existence can be identified. groundwater is water that comes from layers of soil or rocks. it has an essential role in living things, including maintaining the balance of nature, maintaining the availability of raw water for domestic and industrial purposes. the aquifer layer contains alternative raw water that can be used for the community’s daily needs. as the population increases, the amount of water demand also increases. the need for clean water in pontianak, especially at the tanjungpura university area, is provided by perusahaan daerah air minum (pdam). however, the availability of water managed by pdam has a few obstacles in the dry season. the water quality sometimes decreases, for example, a change in taste to be more brackish and even salty. therefore, it is necessary to provide information about alternative raw water sources to solve these problems. geophysical methods have been conducted to investigate the condition and presence of groundwater. for example, groundwater conditions in coastal areas are generally carried out to determine the effect of intrusion on its presence [2]. both unconfined and confined aquifers exist that store and stream groundwater [3][4]. so that information can be used as a reference for exploiting groundwater in domestic and industrial. one of the methods in geophysics that can be used to analyze subsurface conditions is self-potential [5]. the self-potential method is a passive method that utilizes self-potential that occurs under the earth’s surface. this method has been used to identify groundwater movement [6][7], seawater intrusion [8][9], leachate distribution [10], soil movement [11][12], monitoring contaminant [13], underground river flow [14], and water leakage through dams [15]. self-potential on the surface is caused by the presence of electrochemical and mechanical activities [16]. this method’s use is relatively more uncomplicated [17] because the costs required are http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 55 60 56 muhardi, et al. application of self-potential method to observe groundwater …. p-issn: 2621-3761 e-issn: 2621-2889 relatively cheap. this method’s working principle measures the static stress on the earth’s surface by using two porous pots (porous electrodes) [18] connected to a multimeter. the purpose of using a porous pot is to eliminate the effect of electrode polarization during measurements [17]. this method is considered very responsive for identifying conductive objects, for example, metal minerals [19]. based on the description above, it is necessary to determine the distribution of potential values and groundwater flow around the area of tanjungpura university, pontianak using the sp method. ii. theory self-potential (spontaneous potential) occurs below the earth’s surface caused by electrochemical or mechanical activity. one of the factors that control these two activities is subsurface water. the potential is also related to the weathering of sulfide mineral bodies, mineral density of various rocks at geological contact, material organisms’ bioelectric activity, corrosion, temperature, and pressure gradient in subsurface fluids. the types of self-potential anomalies and their sources, as shown in table 1. table 1. the types of self-potential anomalies and their sources [16] source type of anomaly ▪ sulphide ore bodies ▪ graphite ore bodies ▪ magnetic and other electronically conducting minerals ▪ coal ▪ manganese negative [ hundreds of mv ] ▪ quartz vein ▪ pegmatites positive [ tens of mv ] ▪ fluid streaming, geochemical reaction, etc positive/negative [ ≤ 100 mv ] ▪ bioelectric (plants, tree) negative [ ≤ 300 mv ] ▪ groundwater movement positive/negative [ up to hundreds of mv ] ▪ topography negative [ up to 2 v ] four mechanisms can produce self-potential, namely as follows : a. electrokinetic potential (streaming potential) electrokinetic potential occurs when something moves, namely fluid (electrolyte solution) in the pores of rock. the moving fluid will produce a difference in hydrostatic pressure so that it will produce an electric potential difference which is expressed in the following equation (1) [16]. 𝛿𝑉 = 𝜇𝐶𝐸 𝛿𝑃 4𝜋𝜂 (1) where 𝛿𝑉 is the electric potential difference, is the dielectric constant, 𝜇 is the electrolyte resistivity, 𝐶𝐸 is the electrofiltration coupling coefficient, 𝛿𝑃 is the difference in hydrostatic pressure, and 𝜂 is the dynamic viscosity of the electrolyte. streaming potential can cause high anomaly values to the topography so that higher areas generally have more negative potential values. for an example of the selfpotential anomaly produced by pumping from a well as shown in figure 1. b. diffusion potential (liquid junction) diffusion potential will arise when two metal electrodes are inserted into two solutions of different concentrations. in rocks, variations in electrolyte concentrations produce a diffusion potential when there is a difference in the movement of anions and cations. c. nerst potential nerst potential can be found in the clay layer with a negative charge when two identical electrodes are inserted into a homogeneous electrolyte with different concentrations. in the solution, there is no difference in potential. however, at other electrodes, there is a potential difference. d. mineralization potential mineralization potential occurs when two metals as different electrodes are inserted into a homogeneous solution. there is a potential difference between these electrodes, which is known as electrolytic contact potential. it occurs with both the streaming and the diffusion potential. figure 1. example of the self-potential anomaly produced by pumping from a well [16] iii. method the study was conducted in the area of tanjungpura university, pontianak city, which is at coordinates 0003’08.60”s 0003’14.10”s and 109020’56.50’’e 109021’05.40”e. the potential value measurement applied three lines (l1, l2, l3) with a length of 65 m each. the design and measurement locations are shown in figure 2. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 55 60 57 muhardi, et al. application of self-potential method to observe groundwater …. p-issn: 2621-3761 e-issn: 2621-2889 figure 2. survey design at the study location this measurement applies a fixed base configuration using two electrodes (porous pots). the fixed base configuration has the advantage that looping is not required in measurement and the data processing is simpler. the measuring point’s potential is measured by one porous pot at the reference point (base station), and another porous pot moves along the measurement path at a fixed distance. the reference point in the mineralized zone measurement is an area not included in the mineralized zone being measured. the cable required in this configuration is relatively long because one electrode is fixed at the reference point and one of the other electrodes is measured at the farthest. an illustration of the potential measurement with a fixed base configuration and the spot axis’s schematic is shown in figure 3. data acquisition in the field is conducted using two methods: time and position functions. the data based on the time function is used to make corrections to the data based on the position function. this reference point is outside the survey target area and used to collect the database. this rover measurement is conducted along the measurement line with the planned distance. each line’s potential value distribution is then plotted over an area to observe the groundwater flow in the study location. figure 3. a) illustration of potential measurement by fixed base configuration [20]; b) schematic of porous spot [18] iv. results and discussion as a function of time, the data acquisition process is conducted outside the target survey area. it is used as a place for collecting the self-potential database. the results of the self-potential variation based on the time function are shown in figure 4. measurements were conducted during the data acquisition process in the field at 11.54 am 01.30 pm. this data is obtained every two minutes, assuming that it can correct the potential value obtained based on the position function. the variation of the potential value during measurement is 3.72 6.94 mv. the data acquisition process as a function of the position is conducted in 3 lines. the line length is 65 m, the distance between the lines is 5 m, and the space between the porous pots is 5 m. each line is conducted at 12 points to measure the potential value. figure 5 shows the results of the potential measurements on the three lines. the potential value on line 1 is -10.52 mv to 18.24 mv, on line 2 is -3.92 mv to 12.10 mv, and on line 3 is -7.74 mv to 2.92 mv. figure 4. self-potential base on daily variation a) b) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 55 60 58 muhardi, et al. application of self-potential method to observe groundwater …. p-issn: 2621-3761 e-issn: 2621-2889 figure 6 shows the distribution of self-potential values at the study location. this distribution is obtained by combining the self-potential values on the three lines. based on the isopotential contour map, the variation before correction is -9.98 mv to 17.24 mv, while after correction is -10.52 mv to 16.92 mv. the interpretation process is based on the distribution of self-potential values that have been corrected for daily variations. in general, the selfpotential distribution pattern shows that the relatively high potential value is in the south (shown in white to red), while the relatively low potential value is in the north (purple to blue). the distribution of self-potential values in the study location is thought to be caused by groundwater flow movement [16]. the self-potential distribution with a value of ≤ 100 mv is a value caused by fluid movement [5][21]. figure 7 shows the groundwater flow below the surface. a black arrow symbol indicates groundwater flow prediction. the arrow’s length indicates the flow velocity based on qualitative interpretation [6]. the groundwater flows from high potential to low potential [14]. the low potential value indicates groundwater distribution to the area [22]. in general, groundwater is thought to flow to the north. in addition, groundwater also flows to the south of the study location, especially at 20-30 m from the base station. thus, the low self-potential value in the north (purple to blue) can be used as a reference to identify groundwater accumulation to explore raw water in the study location. figure 5. the measurement result of self-potential; line 1 (top), line 2 (middle), and line 3 (bottom) figure 6. self-potential distribution; before daily variation corection (top) ; and after daily variation corection (bottom) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 55 60 59 muhardi, et al. application of self-potential method to observe groundwater …. p-issn: 2621-3761 e-issn: 2621-2889 figure 7. prediction of subsurface groundwater flow v. conclusion based on the results of this study, it can be concluded that the variation in the self-potential value before correction is -9.98 mv to 17.24 mv, while after correction, it is -10.52 mv to 16.92 mv. the self-potential distribution shows that the relatively high potential value is in the south, while the low is in the north. the distribution of selfpotential values in the study location is caused by groundwater movement, which flows north. in addition, groundwater also flows to the south, especially at 20-30 m from the base station. thus, the low self-potential value in the north can be used as a reference to identify groundwater accumulation to explore raw water in the study location. vi. acknowledgment the authors would like to thank the laboratory of geophysics and gis, faculty of mathematics and natural science, tanjungpura university, for facilitating the study and lending the self-potential equipment. references [1] r. rustadi, g. a. pauzi, and o. taufik, “investigasi geologi dan geolistrik untuk menafsirkan keberadaan air tanah dangkal di ambarawa, lampung [geological and geoelectrical investigations to interpret the existence of shallow groundwater in ambarawa, lampung],” j. teor. dan apl. fis., vol. 06, no. 01, pp. 109–114, 2018, doi: 10.23960%2fjtaf.v6i1.1832 [2] m. muhardi, f. faurizal, and w. widodo, “analisis pengaruh intrusi air laut terhadap keberadaan air tanah di desa nusapati, kabupaten mempawah menggunakan metode geolistrik resistivitas [analysis of the effect of seawater intrusion on the presence of groundwater in nusapati 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[22] m. f. r. hasan, t. w. swastika, n. martina, and l. s. wulandari, “identification of groundwater distribution using self potential method,” appl. res. civ. eng. environ., vol. 1, no. 1, pp. 16–23, 2019, doi: 10.32722/arcee.v1i01.1953. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.33332/jgsm.geologi.v21i1.497 https://doi.org/10.24198/jiif.v2i1.15392 https://doi.org/10.3997/2214-4609.201414147 https://doi.org/10.26480/esmy.02.2020.152.155 https://doi.org/10.1017/cbo9781139167932 https://doi.org/10.1190/int-2020-0012.1 https://doi.org/10.1017/cbo9781139088435 https://doi.org/10.1017/cbo9781139024358 https://ejurnalunsam.id/index.php/jh/article/view/2626 https://doi.org/10.32722/arcee.v1i01.1953 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 27 31 doi: 10.12928/irip.v4i1.3601 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 27 synthesis nanofiber pva/chitosan using electrospinning method and application for gold recovery dwi sabda budi prasetya1*, ahmadi2, dwi pangga3, ari dwi nugraheni4, harsojo5, edy supriyanto6, habibi7 1,2,3,7 department of physics education, faculty of science, engineering and applied, universitas pendidikan mandalika, indonesia 4,5 department of physics, faculty of mathematics and natural sciences, universitas gadjah mada, indonesia 6 department of physics, faculty of mathematics and natural sciences, universitas jember, indonesia email: dwisabda@ikipmataram.ac.id article info abstract article history received: feb 01, 2021 revised: jun 05, 2021 accepted: jul 03, 2021 this paper introduces a new process of gold recovery using nanofiber pva/chitosan from a gold-cyanide solution. gold recovery in cyanide solution is made using nanofiber pva/chitosan produced with electrospinning technique. this research was conducted through several stages, 1) the designing of electrospinning tool, 2) synthesis of nanofiber pva/chitosan with electrospinning technique, and 3) gold recovery experiment using nanofiber pva/chitosan biosorption with the variations of initial concentration and time. the results showed that nanofiber pva/chitosan could be used as a gold ion absorber. the occuration of the isotherm process follows the freundlich isotherm model, which is advantageous and occurs on a heterogeneous surface. from the results, it was agreed that nanofiber pva/chitosan is potential for gold recovery. this is an open-access article under the cc–by-sa license. keywords: chitosan electrospinning gold recovery high voltage nanofibers to cite this article: d. s. b. prasetya et al., “synthesis nanofiber pva/chitosan using electrospinning method and application for gold recovery,” indones. rev. phys., vol. 4, no. 1, pp. 27–31, 2021, doi: 10.12928/irip.v4i1.3601. i. introduction nanofibers have become a fascinating topic for researchers due to their application in various research fields such as biotechnology, biomedical, electrical & electronics, environmental and energy resources due to their advanced nature and high potential. the method for the manufacture of nanofiber, which is currently still being developed, is the electrospinning method. electrospinning is a method for producing nanofibers that utilizes an electric force applied to attract charged threads in a polymer solution to the diameter of the fiber in nanometers. the working principle of electrospinning is that when sufficient voltage is supplied to the liquid droplet, it becomes charged. an electrostatic repulsion occurs against the surface tension. the droplet is stretched at the critical point of flow where the liquid droplet erupts from the surface and becomes a fiber, as shown in figure 1. [1], [2]. this article shows the work of an electrospinning unit that was designed by utilizing a flyback transformer. the electrospinning unit was tested to synthesize pva/chitosan nanofibers applied as gold ion absorbers. the test results are compared with the results of previous studies to indicate whether the tool from this study is stable or not [3]. figure 1. the scheme of the electrospinning tool http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3601 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 27 31 28 prasetya et al. synthesis nanofiber pva/chitosan using electrospinning …. p-issn: 2621-3761 e-issn: 2621-2889 this research focused on the functional test of electrospinning tool to synthesize nanofiber pva/chitosan, which will be applied as gold recovery material in cyanide solution. the application of pva/chitosan nanofiber as biosorption is a novelty that is excelled in this research. previous studies have successfully performed gold recovery in cyanide solution using chitosan and nanofiber pva/chitosan as biosorption [3]–[5]. based on the results of some previous studies, the testing indicators in this research will be analyzed using the freundlich isotherm model [5]. ii. theory electrospinning is the most powerful, efficient, and easy technique for fabricating very thin fibers from polymer solutions [6], [7]. electrospinning techniques are capable of producing continuous fibers and homogeneous diameters. the size diameters produced can be micrometers up to nanometers. it depends on the parameters during the electrospinning process. those size diameters provide an exceptional value as a superior material that has been applied as bone tissue engineering, wound dressing [8], [9], nanomedical [10], nanocomposite [6], and nanoparticle filtration membrane [11]. electrospinning has three main components: a high voltage dc source, a syringe pump, and a collector plate or collector drum. the electrospinning scheme, which consists of three main components, can be seen in figure 1. the high voltage dc (hvdc) source in the electrospinning process has a significant role because the high voltage can produce coulomb force in the solution released from the syringe pump to produce nanofibers and collected to the collector [12]. the electrospinning process requires a high voltage between 15-20 kv, so it is essential to design an hvdc to support this research. previous researchers have done it a lot with many different methods [13]–[17]. iii. method material tools and materials prepared in this study: multimeter, richmeter, microcontroller arduino, dc 12v and 24v power supply, 5v, and 9v voltage regulator, driver flyback, transformator flyback and step-up circuit, electrical wires, syringes, aluminum foil, preparat, beaker glass, magnetic hot plate stirrer, digital scale, atomic absorption spectrometry (aas), polyvinyl alcohol (pva) (having molecular weights of 13.000 – 23.000 g/mol) was purchased from the sigma-aldrich corporation, chitosan (self-development from shrimp shells local ntb), acetic acid (sigma-aldrich corporation), gold solution, and aquadest. method the design of the hvdc in this study was carried out to create a high voltage source of 0-20 kv using the arduino-based pwm technique. furthermore, electrospinning and performance tools are set up for the manufacture of nanofiber pva/chitosan. a general diagram of research completion is shown in figure 2. figure 2. a general diagram of research completion. after preparing all the hardware, each hardware is assembled into the hvdc system. furthermore, hvdc is set up with the other main components of electrospinning. then, a complete electrospinning tool unit as the result of this research can be seen in figure 3. figure 3. electrospinning tool unit without syringe pump, solution flowrate is controlled manually by direct observation the synthesis process of nanofiber pva/chitosan in preparation for the first solution, 10% of pva (1 g) is added with 10 ml aquadest, and stirred using a magnetic stirrer at the speed of 500 rpm and a temperature of 80 oc until the solution is homogeneous. preparation for the second solution, 10 ml acetic acid 1% (0.1 ml) is added with 9.9 ml aquadest, 1% chitosan (0.1 g) is added and then http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://www.thermofisher.com/id/en/home/industrial/spectroscopy-elemental-isotope-analysis/spectroscopy-elemental-isotope-analysis-learning-center/trace-elemental-analysis-tea-information/atomic-absorption-aa-information.html https://www.thermofisher.com/id/en/home/industrial/spectroscopy-elemental-isotope-analysis/spectroscopy-elemental-isotope-analysis-learning-center/trace-elemental-analysis-tea-information/atomic-absorption-aa-information.html indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 27 31 29 prasetya et al. synthesis nanofiber pva/chitosan using electrospinning …. p-issn: 2621-3761 e-issn: 2621-2889 stirred using a magnetic stirrer at the speed of 500 rpm until the solution is homogeneous. pva solution and chitosan solution were mixed with a 9:1 volume/volume (v/v) percentage ratio (sample 1), stirred using a magnetic stirrer at the speed of 500 rpm until the solution is homogeneous. this process is repeated for 2 pva and chitosan solutions in a ratio of 5:5 (sample 2) and 1:9 (sample 3). electrospinning technique the mixture of pva solution and chitosan is ready to be processed with the electrospinning technique. two ml of the solution is added to the syringe. set the distance of the firing needle to the collector of 10 cm with a voltage of 20 kv within 1.5 hours. biosorption experiment the biosorption of gold using nanofiber pva/chitosan is done by filtering 10 ml gold solution with the initial concentrations of 10 ppm, 20 ppm, and 30 ppm. each solution was filtered with time variations of 10, 30, 45, 60, 90, and 120 minutes. the absorption data analyzed using aas can be seen in table 1. table 1. results of analysis of aas biosorption au by nanofiber pva/chitosan with variations in initial concentration of the solution and initial concentration time (minute) 10 ppm (g/ton) 20 ppm (g/ton) 30 ppm (g/ton) 10 2.783 2.670 2.924 30 3.045 3.558 3.508 45 3.270 4.096 3.661 60 3.231 3.483 4.150 90 3.217 3.475 3.937 120 3.172 4.111 4.528 based on the data in table 1, the graph equilibrium plotting can be obtained from the gold biosorption isotherm process using nanofiber pva/chitosan for each solution with the initial concentration of 10 ppm, 20 ppm, and 30 ppm. the equilibrium graph of the gold biosorption isotherm process can be seen in figure 4. figure 4. the equilibrium graph of the gold biosorption isotherm process iv. results and discussion the designing of electrospinning tool the 24 v positive voltage generated by the 24 v power supply will be fed directly to an inductor with a value of 100uh and is connected directly to the primary winding. the magnetic field in the primary winding changes due to a pulsing current and will produce an induced current on the secondary winding, which has more winding to increase the voltage. in this section, the voltage will be increased from 0-24 v to the voltage in the kv order. the output voltage for tfb in this study can reach voltages in the range of 22 kv. hvdc that is ready and can produce a voltage of 0-22 kv is set up with the other main components, and an electrospinning tool unit is formed, as shown in figure 2. for the initial test, input voltage (vi) and output voltage (vo) are measured. the measurement data can be seen in figure 5. the graph in figure 5 shows that the relationship between an input voltage and output voltage is the linear graph. it indicates that the hvdc is stable. figure 5. the graph of vi and vo synthesis of nanofiber pva/chitosan synthesis of nanofiber pva/chitosan is a direct step used for the electrospinning tool’s performance test. nanofiber pva/chitosan is the result of electrospinning that can be seen in figure 6. the electrospinning process is carried out using a voltage of 20 kv. the distance between the tip of the needle and the collector is 10 cm. figure 6. a photo nanofiber pva/chitosan from microscope with a size 1000x http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 27 31 30 prasetya et al. synthesis nanofiber pva/chitosan using electrospinning …. p-issn: 2621-3761 e-issn: 2621-2889 furthermore, a mechanical test was carried out on the nanofiber to show the mechanical properties of pva/chitosan, which are tensile strength and young’s modulus. the result of the nanofiber mechanical test using the tansilon machine can be seen in table 2. tabel 2. the result data of nanofiber pva/chitosan mechanical test no. τ (mpa) e (mpa) 1 22.059 579.16 2 20.260 25.044 3 18.793 5.562 note: 𝜏 = tensile strength and e = young’s modulus the data of tensile test values in table 2 shows the highest tensile strength properties possessed by nanofiber pva/chitosan sample 1. sample 1 contains less chitosan with a tensile strength of 22.059 mpa. sample 2 has a tensile strength of 20.260 mpa, while the lowest tensile strength is 18.793 mpa, owned by sample 3. the more chitosan is added to the sample. it turns out to decrease the mechanical properties of pva/chitosan nanofibers. based on the result above, this study also proves that polyvinyl alcohol (pva) is one of the polymers often used as a blending material to improve thermal and mechanical stability. dissolves easily in water, mechanical stability, flexible, easily formed into thin fibers, and non-toxic are the properties of pva. those are why pva is used for medical, cosmetics, and agriculture [18], [19]. freundlich biosorption isotherm the freundlich isotherm model is an empiric equation widely used to explain heterogeneous surface adsorption, active site, and exponentially distributed energy [20]. empirically stated in equation (1). 1 n e f e q k c= (1) the linearization of equation (1) is obtained: 1 e f e logq logk logc n = + (2) where ce is the equilibrium concentration of adsorbate (g.dm-3), qe is the amount of metal adsorbed per 1 g of the adsorbent at equilibrium (mg.g-1). the kf is a constant as an indicator to estimate the absorption capacity. at the same time, 1 n is a function of adsorption intensity in the adsorption process [21] or surface heterogeneity [22]. the slope value 1 0 1 n   indicates that the adsorption isotherm is beneficial. if the slop value is 1 0 n  , the surface of the adsorbent is more heterogeneous, and the nonlinear adsorption isotherm and 1 1 n  indicates that the adsorption isotherm is not beneficial [23] and indicates a cooperative adsorption process [24]. figure 7 is a graph plot following the freundlich isotherm equation and obtained 2 0.98r = , and the linear regression equation for this process is 30.179 2. 98.y x= + based on the linear regression equation obtained 1 0.179 n = , n = 5.593, and 250.207fk = . the graph plot results in figure 7 indicate that au biosorption by nanofiber pva/chitosan is a beneficial isotherm and occurs on heterogeneous surfaces. the freundlich isotherm occurs in (1) many layers (multilayer), (2) active sites on heterogeneous surfaces, and (3) involves the van der walls force such that the adsorbate can migrate from one area of the surface to another, according to atkin (1996) in bedolla et al. 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"the problem solving as a thinking process by which the learner discovers a combination of previously learned rules that he can apply to solve a novel problem" [4]. many theories used in understanding the personality type of students. one theory that is often used and continues to be developed is the personality theory of hippocratesgalenus typology [4]. ii. theory a. definition of metacognition "metacognition refers to high order thinking which involves active control over the cognitive processes engaged in learning." the meaning of that sentence is the metacognition refers to high-level thinking that involves the active control of the cognitive process in learning. the component of metacognition ability in problem-solving consists of knowledge and skill components [5-6]. b. problem solving problem-solving steps include understanding the problem (understanding the problem), making a problem-solving plan (devising a plan), setyawati et al. analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates... indonesian review of physics, volume 1, number 2, 2018 43 implementing the plan (carrying out the plan), and checking back the results obtained (looking back). the conclusion is that the steps in problem-solving are understanding the problem, making a problemsolving plan, implementing the solving plan that has created, checking back the results that have been obtained or interpreting the results obtained [7]. c. hippocrates – galenus personality type personality divided into several types, one of that is the personality type developed by galenus based on hippocrates. hippocrates states that in each person's body there are four kinds of liquids that have characteristics like the four natural elements, namely: the dry that owned by chole or yellow bile, the wet that owned by melancholy or black bile, the cold found on phlegm or mucus, the heat that owned by sanguine or blood furthermore, galenus stated that these fluids were in the human body in specific proportions. according to galenus, the personality type that owned by an individual is as follows [4] : 1. the sanguinis type the character is the mood of someone emotion is always full of hope, everything at one time seen as important, but only for a while then he does not think about it anymore, feel happy to help others, friendly and cheerful person in a relationship, generally not a timid person, but if guilty it is hard to regret. 2. the melankholis type the character is that all thing related to him seen as important and always accompanied by indecision, their attention mainly focused on the aspects of their difficulties, they cannot make promises easily, this also caused them to lack confidence and cannot accept the hospitality of others easily, their mood is generally too contradictory to the anguished feeling and cannot see the pleasure of others. 3. the kholeris type the character is irritable but calm easily without hating. their actions are fast but not constant, always busy, but in that busy life, they prefer to order it rather than do it themselves. their passion is to pursue the honor, happy to be active in front of many people and likes to praised openly, wants to be generous and protect, always dressed carefully and neatly, because in this way they seemed more intellectual than they are 4. the phlegmatic type the character is they do not like rushed (calm), not easily influenced, loyal. d. static fluid hydrostatic pressure is the pressure that transpires under water. hydrostatic pressure caused by immovable fluid. the hydrostatic pressure experienced by a point in the fluid caused by the fluid gravity above that point. formulated with equations (1) [8]. ghph r= (1) with: r = density of an object (kg/m3 ) g = gravitational acceleration (m/s2 ) h = depth point (m) hp = pressure (newton) pascal's law the pressure is as a given force given divided by the area that receives the force. can use equations (2): a f p = (2) pascal's law, "the pressure returned in a closed space is continued as big as the direction in all directions."note the scheme 1 of the hydraulic mechanism above. because the liquid cannot be added or exits the closed system, the volume of fluid pushed on the left will push the piston (solid cylinder) on the right towards the top. figure1. the relationship between cross-sectional area and hydrostatic pressure on u pipe pascal's law from the picture above can be written with equation (3) and (4): outin pp = (3) 2 2 1 1 a f a f = (4) with: p =pressure (newton) a =cross-sectional area (m) f =force (newton) setyawati et al. analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates... indonesian review of physics, volume 1, number 2, 2018 44 archimedes law the archimedes law "an object that entirely or partially submerged in a fluid lifted upward by an equal force to the weight of the fluid removed, equation (5) written: vgf ca r= (5) in archimedes law, there are three possibilities: cb rr < the object is hovering (the object is neither rises or sinks), cb rr = the object submerged in cb rr > . based on the research by oktaviyanti (2016), the highest student misconception was the concept of the hydrostatic pressure of (58.3%) and floating concepts (33.3%) [9]. iii. methodology this research included in the type of qualitative research. subjects in this study were selected based on several considerations, namely: class xi students already have sufficient learning experience so that they are expected to solve the problems correctly, subjects were not randomly selected, but were chosen by considering the ability to communicate so that the disclosure of the metacognition process can take place properly. grouping of subjects is based on personality types, namely personality types choleric, sanguinis, melancholic, and phlegmatic, totaling 25 students from 32 students. the technique of taking subjects in this study was purposive sampling. data collection techniques obtained through questionnaire techniques, tests, and interviews. after that, the data analyzed and validated using time triangulation. this data analysis method uses a likert scale as a measurement scale. calculate the value of all components with the formula following equation (6) [10]. %100x n s p = (6) with: n is the maximum number of scores s is the sum of the total sub-variable scores obtained p is the percentage of respondents table 1. an interval value of metacognition analysis interval (p) information 80% 100% very (agree, good, like) 66% 79% agree 56% 65% enough 0 – 55% not good/disagree iv. results and discussion based on the research that has done obtained quantitative and qualitative data that covering the causes students' metacognition difficulties and data about the learning outcomes of the thinking process in problem-solving in terms of hippocrates – galenus. to find a description of the causes of students metacognition difficulties used descriptive data retrieval based on responses to statements in the questionnaire totaling 25 statement items.in 25 statements consisting of indicators of achievement of aspects of knowledge (declarative knowledge, procedural knowledge, conditional knowledge. aspects of experience/skills: planning skills, predictive skills, monitoring skills, evaluation skills. based on the recapitulation of the results of the answers, the respondents count the average using the likert scale with the equation (6) : from the likert scale calculation above, can see the results in the pie chart two below: figure 2. results of student’s questionnaire analysis of metacognition difficulties from the results obtained for 64.92% of respondents agreed that physics subjects are the subject that is difficult to understand. it seen from the statement items in general, including students lack understanding of the concept of physics, lack of knowledge of symbols, formulations, notation and calculations that will be done in each problem solving, and lack of understanding strategies in problems solving the next step the researcher consulted with the counseling guidance teacher and the physics subject teacher to determine the research subject obtained static fluid material. from the results of the counseling guidance and physics teacher's consideration, students found to meet the criteria of the subject which the students could express ideas setyawati et al. analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates... indonesian review of physics, volume 1, number 2, 2018 45 verbally well and able to work on the questions that accompanied by the students' thinking process [11]. from the results of the classification of personality types, it seen that there are seven students have the melancholic personality type, five students have the sanguinis personality type, seven students have the phlegmatic personality type, six students have the choleric personality type.from each personality type, the researcher focuses on one indicator in each type. from the results of data analysis, the following results obtained : 1. students have melancholic personality types analysis of metacognition difficulties of students have melancholic personality type based on the metacognition process in four problem-solving steps according to polya namely understanding the problem, making a problem-solving plan (devising a plan), implementing the plan (carrying out the plan), and re-check the results (looking back). according to the theory, students have this type of personality think that everything important related to them is essential and usually accompanied by hesitation. students attention focusses on difficulties, hard to make a promise. it can also make a lack of confidence and painful to accept the friendliness from others. the mood of their feelings generally contradicts the atmosphere of the sanguine feeling, and it is less able to see the pleasure in others. the following is a description of the difficulties of metacognition of students who have a melancholic personality [4]. at the stage of understanding the problem of students who have melancholic personality types, they will experience metacognition difficulties when understanding problems and solving problems. at the step of creating a problem-solving plan, students have difficulty in considering strategies and realizing the usefulness of using strategies. at the stage of carrying the plan, students have difficulties in solving problems. in the stage looking back result, students experience difficulties in writing things on the matter. it is because pupils do not know the concept and practice of questions about static fluid material where students only focus on the methods that have used when solving problems. although the problem is different from the previous problem, lack of confidence of students, lack of interest and motivation in physics because the mindset of students considers that physics is a difficult subject to understand. the questions raised in the problem-solving test are shown in figure 3 as follows: figure 3. problem-solving skill melancholic personality types from figure 3, the types of melancholic personality experienced by students explained: in case 1 student experience a misunderstanding in the material of hydrostatic pressure on solid objects where students assume that if the surface area is large then the resulting pressure is also high if the small surface area of influence is poor, being an object that has a large cross-sectional area that will damage other objects it is working on. as for the correct concept, "the magnitude of the pressure is inversely proportional to the surface area of the base of an object. the greater the surface area of an object, the smaller the pressure that caused". in the case of 2 students only from guessing letters that are in the picture, do not know what they mean but after interviewing the students, it turns out that students assume that if the cross-sectional area contained in the pipe is different then the resulting pressure is different. in case 3 for the hydrostatic pressure on the liquid, the student's answer is fixed on the top point because the pressure is very high because influenced by external air pressure. 2. students who have sanguinis personality types analysis of metacognition difficulties students who have a sanguinis personality type based on the metacognition process in four problemsolving steps according to polya (2004) namely: (1) understanding the problem, (2) making a problemsolving plan (devising a plan), (3) carry out the plan and (4) check the results (looking back). setyawati et al. analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates... indonesian review of physics, volume 1, number 2, 2018 46 according to the theory, students have the sanguine type of personality have a sense of feeling full of hope. everything at one time seen as important, but a moment later they do not think about it anymore, feel happy when helping others, gentle and cheerful, in general, they are not coward, but if guilty it is hard to regret. the following is a description of the difficulties of metacognition of students who have a sanguinis personality [4] at the stage of understanding the problem, students who have a sanguinis personality type experience difficulties in reviewing the problem. at the stage of making a problem-solving plan (devising a plan), students have difficulty in considering strategies and realizing the usefulness in using strategies. at the stage of carrying out the plan students have difficulties in solving problems. at the stage of looking back. in this case, because the students do not understand the concept and practice the exercises wherein the learning process, students focus on similar questions that often done so that in solving the problem, it is difficult. as for the questions submitted in the problem-solving test asfollowing: figure 4. problem-solving skill sanguinis personality types from figure 4, the types of sanguine personality experienced by students explained: in case 1 student experience a misunderstanding in the material of hydrostatic pressure on solid objects where students assume that if the surface area is large then the resulting pressure is also large if the small surface pressure area is small, being an object that has a large cross-sectional area that will damage other objects that it is working on. as for the correct concept "the amount of pressure is inversely proportional to the basic surface area of an object. the larger the surface area of an object, the smaller the pressure that caused". in the case of 2 students do not answer because students assume that on the pipe, it is difficult to determine the biggest pressure at which point. in case 3 for hydrostatic pressure on a liquid, the student's answer is correct, but the student does not know the reason why if the highest pressure is at the base of the liquid. 3. students have phlegmatic personality types analysis of metacognition difficulties of students who have a phlegmatic personality type based on the metacognition process in four problemsolving steps according to polya namely understanding the problem, making a problemsolving plan (devising a plan), implementing the plan (carrying out the plan), and looking back. according to theory, students with phlegmatic personality types do not like to be careless / to be calm, difficult to influence, loyal. the following is a description of the difficulties of metacognition of students who have a phlegmatic personality [4]. at the stage of understanding the problem, students can understand the problem when looking at the problem and then make an illustration can change information into physical form. students have phlegmatic personality types have no difficulty in the stage of making a problem-solving plan (devising a plan ), students have problems, but these difficulties can be resolved by understanding their concepts. at the stage of carrying out the plan, students can realize the difficulties when working on the problem so that students can use different strategies. as well as looking back, in withdrawing the results obtained by students, they can give conclusions appropriately and adjust the answers to an actual phenomenon. 4. students who have the choleric personality type analysis of metacognitive difficulties of students have the choleric personality type based on the metacognition process that is on four steps of problem-solving according to the policy, namely understanding the problem (understanding the problem), making a problem solving plan (devising a plan), carrying out the plan (carrying out the plan), and re-examine the results obtained (looking back). some literature explains that students with choleris personality type are not flammable but are also calm, without hating, their actions are fast. but not constant, always busy, but in their busy life, he prefers to govern rather than work alone. his lust especially is pursuing honor, likes to be busy in the eyes of many people and likes to be praised openly, likes to be generous and protect, in dressing is always careful and neat, because then he appears more scholarly than he is [4]. at the stage of understanding the problem (understanding the problem) students have the choleric personality type experience difficulties, setyawati et al. analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates... indonesian review of physics, volume 1, number 2, 2018 47 this caused in the study of the problem. at the stage of making a problem-solving plan (devising aplan), students have difficulty in considering strategies and difficulties in realizing the usefulness of using strategies that are like what. in the carrying out the plan phase, students have difficulty in solving problems. at the stage of re-examining, the results obtained (looking back) students have difficulty writing down the things listed on the question. in this case, because students do not understand the concept and lack in working on the practice of the problem in the learning process where students fixated with only the same type of problem that often done so that when solving problems often feels difficult. based on the description above, there are differences in the ability of students' metacognitive thinking processes. it confirmed by previous research conducted by iswahyudi (2012), which states that students with gender differences and mathematical abilities have different metacognition activities [12]. another research is camelina fitria's (2016) research which states students with different types of guardian, artisan, rational and idealist types that have different thought processes in solving problems. two linear variables are not equal [13]. v. conclusion based on the results of the study showed that the causes of metacognition difficulties of students of solving problems in fluid material and the thinking process of students in solving problems in static fluid material, can be explained as follows: the cause of the difficulties of metacognition of students caused by the lack of understanding the concepts of physics, knowing the symbols, formulations, notations, and calculations in each problem solving, and lack of understanding of strategies in solving problems. students who have a melancholic, sanguine, choleric personality type have metacognitive difficulties when understanding questions and solving problems, having difficulty in considering strategies and having difficulty realizing the usefulness of using strategies. students who have a phlegmatic personality type can understand the problem by looking at the problem then making an illustration so that they can convert information to a form of physics. reference [1] karwono and 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[2] d.sulisworo.conceptual model identification of the personal learning environment.international seminar on education innovation and development in teaching and learning, 2014, pp. 37-41. [3] bsnp. standar isi dan standar kompetensi lulusan sma/smk. jakarta: kemdiknas. 2016. [4] t. r. astuti,deskripsi kemampuan pemecahan masalah matematis siswa sma negeri 4 purwokerto (ditinjau dari tipe kepribadian tipologi hippocratesgalenus), dissertation, universitas muhammadiyah purwokerto, 2016. [5] j. a. livingston, metacognition: an overview, education resources information center, 1997. [6] g. polya, howto solve it, princeton university press electronic book, 2004. [7] z. c. ozcan, assessment of metacognition in mathematics: which one of two methods is a better predictor of mathematics achievement?an international online journal of educational sciences, vol. 6, no. 1, 2014, pp. 49-57. [8] p. a. tippler. physics for science and engineering vol. 1, erlangga, 2010. [9] d. oktaviyanti. remediasi miskonsepsi siswa menggunakan pembelajaran learning cycle 3e pada materi fluida statis di man. jurnal pendidikan dan pembelajaran universitas tanjung pura pontianak. vol.5, no.12, 2016 [10] sugiyono. educational research methods quantitative, qualitative approach and r&d, alphabet bandung, 2010. [11] e. setyawati. pengaruh strategi konflik kognitif dalam pembelajaran fisika terhadap pemahaman konsep siswa xi ipa. dissertation,universitasmuhammadiyah metro, 2012. [12] g. iswahyudi, aktivitas metakognisi dalam memecahkan masalah pembuktian langsung ditinjau dari gender dan kemampuan matematika. prosiding snmpm, 2012. pp.88-102. [13] f. camelian, analysis of student metacognition difficulties in solving the problem of two-variable linear inequality systems in terms of guardian, artisan, rational and idealist personality types in class x of smk 1 jombang. electronic learning mathematics journal, vol.4, no.9, 2016, pp. 824-835. indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 8 13 doi: 10.12928/irip.v4i1.3327 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 8 carbon dots synthesized from tofu pulp for liquid tofu waste photodegradation yosi nurohman, elisabeth pratidhina, emi kurnia sari, wipsar sunu brams dwandaru* department of physics education, faculty of mathematics and natural sciences, universitas negeri yogyakarta, indonesia email: wipsarian@uny.ac.id article info abstract article history received: dec 30, 2020 revised: may 15, 2021 accepted: jun 5, 2021 this study was aimed to prepare and characterize carbon dots (cds) from tofu pulp for liquid tofu wastes photo-degradation. the tofu pulp was dried, heated in an oven for an hour at 250 oc, mashed into powder, weighted as much as (g) 1; 2; 3; 4; and 5, dissolved into 100 ml distilled water, filtered, and characterized using uv-vis, pl, and ftir. the photo-degradation experiment was conducted for pure waste, waste + cds, and waste + cds + uv light, then the bods were measured. the cds reduced the wastes to 14.29% and 53.90% without and with uv light, respectively. the pure wastes, wastes + cds, and wastes + cds + uv light produced bod values of (mg/l) 385; 200; and 135, respectively. the decrease in bod showed that cds with and without uv light successfully restore dissolved oxygen in the wastes. this is an open-access article under the cc–by-sa license. keywords: carbon dots liquid tofu wastes photo-degradation tofu pulp uv light to cite this article: y. nurohman, e. pratidhina, e. k. sari, and w. s. b. dwandaru, “carbon dots synthesized from tofu pulp for liquid tofu waste photo-degradation,” indones. rev. phys., vol. 4, no. 1, pp. 8–13, 2021, doi: 10.12928/irip.v4i1.3327. i. introduction carbon dots (cds) are new carbon-based materials that have attracted attention due to their optical properties. unlike other carbon-based materials, cds have strong fluorescence properties. compared to other fluorescence materials like semiconductor quantum dots, cds have advantages such as biocompatibility, low toxicity, easy functionalization, chemical inertness, and water solubility [1]. cds have been used for various applications, such as bio-imaging [2], sensing [3], light-emitting diode [4], biomedicine [5], and catalyst [6]. the synthesis of cds is relatively simple and requires cheap raw materials. there are two main types of cds synthesis, i.e., physical and chemical methods [1]. the physical method includes laser ablation and arc discharge. the chemical method includes electrochemical, hydrothermal, carbonization, and combustion. materials that contain carbon elements can potentially be used as raw materials or precursors to produce cds. due to their high carbon content, bio-mass waste has been exploited for synthesizing cds. cds have been prepared from fast food waste [7,8], coconut shell [9], rice husk [10], banana peels [11], orange peels [12], coffee [13], and seeds [14]. one application of cds that has been a current research topic is for waste treatment. cds have been used for carbamazepine removal from water [15], dyecontaining wastewater treatment [16], and removing heavy metals such as cd2+ and pb2+ in drink water [17]. since cds can be synthesized from carbon waste and can be used for waste treatment, a new concept called for waste by waste is emerging [18]. tofu is a popular food in asia. the tofu production process produces by-products, such as pulp and liquid wastes. many traditional tofu industries in indonesia directly release liquid waste to the environment and cause water pollutions [19]. the liquid waste from tofu production is high in organic substances, such that the biochemical oxygen demand (bod) ranges from 6000 8000 mg/l and the chemical oxygen demand (cod) ranges from 7500 14000 mg/l. due to the high content of organic substances, liquid waste of tofu production causes pollution in the surface and groundwater. the solid waste or pulp contains 20.93% protein, 21.43% fiber, 10.31% crude fat, 0.72% calcium, 0.55% phosphor, and 36.69% other compounds [19]. pulp waste of tofu production is carbonous material, which can be used as a precursor for cds. in this work, we are putting an effort to http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3327 http://journal2.uad.ac.id/index.php/irip mailto:wipsarian@uny.ac.id http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 8 13 9 nurohman, et al. carbon dots synthesized from tofu pulp for liquid …. p-issn: 2621-3761 e-issn: 2621-2889 conduct the “for waste by waste” concept by utilizing the pulp as a raw material to synthesize cds and then use the cds for liquid tofu waste treatment. ii. theory cds cds are new emerging zero-dimensional (0d) carbon-based nanomaterial. typically, the cds diameter is less than 10 nm [20]. cds consist of two main parts, i.e., core and surface states. cd core has mainly consisted of c=c bonding. meanwhile, the surface state can consist of various functional groups such as -cooh, -oh, and -nh2 [21]. cds are known for having strong optical properties. the strong optical properties are due to the quantum confinement effect and surface effect. mostly, cds pose strong optical absorption at the wavelength of 230 nm to 320 nm. the peak at around 230 nm is associated with the π→π* electronic transition related to the c=c bonds in the core of cds. a shouldering peak sometimes appears at a wavelength of around 300 nm. it is ascribed to the n→π* electronic transition of c=o bonds or other functional groups of the surface state [20]. biochemical oxygen demand (bod) bod is an indicator of the organic pollution of water. traditionally, bod is estimated in a five-day period. the parameter is defined as the amount of oxygen divided by the system’s volume, taken up through the respiratory activity of microorganisms growing on the organic compounds present in the sample when incubated for a certain period at a certain temperature. in brief, bod measures the organic pollution of water that can be degraded biologically. the unit of bod is milligrams o2 per liter. bod is usually used to indicate wastewater discharge criteria and determine the waste treatment method [22]. photo-degradation organic pollutants can be degraded using light and o2 under ambient conditions. the process is called photodegradation. the photo-degradation process can be applied to eliminate organic pollutants from water. in the photo-degradation process, catalysts can accelerate the reaction between organic pollutants and o2. the catalysis process lowers the energy barrier of the degradation reaction [23]. cds can be used appropriately for this purpose. iii. method cds preparation the main material for the cds was pulp waste from the tofu production process. the pulp waste was obtained from a local traditional tofu industry in yogyakarta, indonesia. cds were prepared using carbonization or a simple heating method. the pulp wastes from tofu production were placed in an oven at 250 oc for an hour. this process produced black carbon charcoal. the charcoal was then mashed with a porcelain mortar into powder. the powder was weighed for (g) 1, 2, 3, 4, and 5, and then each of them was mixed with 100 ml distillate water. hence, we get 5 samples with concentrations (in g/ml), i.e.: 0.01; 0.02; 0.03; 0.04; and 0.05, which were then filtered using filtering papers, producing samples of cd a; b; c; d; and e, respectively. cds characterization the as-prepared cds were characterized using photoluminescence (pl), uv-vis spectrophotometer (uv-vis), and fourier-transform infrared (ft-ir) spectroscopy. the uv-vis spectroscopy was conducted with a shimadzu uv spectrophotometer. the pl spectroscopy was carried out using a custom-configured device with an ocean optics usb4000 spectrometer. the ft-ir analysis was conducted using ftir thermo nicolet avatar 360. liquid tofu waste treatment to investigate the possible application of cds for liquid tofu waste treatment, three samples were prepared, i.e., pure liquid tofu waste (sample i), liquid tofu waste added with cds (liquid tofu waste + cds, sample ii), and liquid tofu waste added with cds and exposed by uv light (liquid tofu waste + cds + uv light, sample iii). all samples (i, ii, and iii) are left alone for seven days (one week). especially for sample iii, the mixed solution of cds c with liquid tofu waste was illuminated with uv light for 2 hours per day (for a total of seven days). the bods were then measured for all samples. iv. results and discussion the absorption spectra of cds are investigated using a uv-vis spectrophotometer. the uv-vis spectra of synthesized cds are presented in figure 1. the cd a sample does not feature any clear absorbance peak. meanwhile, cd b to cd e samples obtained from the precursor concentrations of (in g/ml) 0.02; 0.03; 0.04; and 0.05 produce an absorbance peak at wavelengths of 206 nm, 215 nm, 220 nm, and 226 nm, respectively. hence, the absorbance peak shifts to longer wavelengths as the precursor concentration increases (red-shift), according to the study in [24]. it may also be observed that a higher absorbance value is obtained with higher precursor concentration as more cds are produced. there is also a weak shouldering peak at around 250 nm for all cd solutions. this shouldering peak shows π→π* electronic transitions associated with c=c bonding of the cds’ core. moreover, another shouldering peak occurs at a wavelength of 320 nm for all cd samples, showing the cds’ surface state. this indicates the n→π* electronic transitions of oxygen functional groups. therefore, the presence of both of these absorbance peaks indicates the formation of cds, which is in agreement with dai et al. [25]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 8 13 10 nurohman, et al. carbon dots synthesized from tofu pulp for liquid …. p-issn: 2621-3761 e-issn: 2621-2889 figure 2 shows the pl spectra of prepared cds samples. the maximum pl intensity occurs at different wavelengths for different cd samples. under the excitation wavelength of 410 nm, the maximum pl emission wavelength appears at 499.173 nm; 499.173 nm; 507.988 nm; 511.686 nm; and 523.553 nm for cd a; b; c; d; and e, respectively. hence, all cd samples have cyan emission because the range of cyan luminescence is around 485 nm to 500 nm. according to the qualitative test, these pl results show all cd samples emit cyan luminescence under uv laser (see figure 3). as the precursor concentration increases, the emission peaks occur at a longer wavelength, and the intensity gets stronger. hence, the pl intensity depends upon the concentration of the cds [20]. a higher intensity peak in the sample with higher precursor concentration is because more cds are in the samples. this is again following the pl results in [25]. a possible underlying argument behind the dependence of the pl peaks upon the concentration of the cds is the different particle sizes that occur in the cds [20]. figure 4 shows the ft-ir spectra of cd samples with precursor concentrations of 0.01 g/ml (cd a); 0.03 g/ml (cd c); and 0.05 g/ml (cd e). for all samples, absorption bands appear at around 3400 cm-1; 1600 cm-1; and 600 cm1, corresponding to o-h; c=c; and c-c bonds. the existence of the c=c bonds indicates the core of the cds, hence confirming the formation of cds following the uvvis results. moreover, there are no significant differences between the bands of the cds samples, which means that the precursor concentration does not affect the functional groups in the cds. the ft-ir result is comparable to the ft-ir results in [26]. it can also be observed that the ftir spectrum of cd c is lower than cd a. this may be caused by the smaller amount of the cd c sample being characterized than the amount of the cd a sample. the prepared cds from the tofu pulp production are used to treat the tofu production’s liquid waste. bod tests are carried out for three samples. the sample i is a pure liquid waste of tofu production. sample ii is a mixture of liquid waste from tofu production and cds (wastes + cds). finally, sample iii is the same solutions as sample ii but illuminated by uv light for two hours each day for seven consecutive days (wastes + cds + uv light). the amount of the liquid waste is the same in samples i, ii, and iii. the bod test result can be seen in table 1. table 1. bod test results. samples bod (mg/l) i 385.00 ii 200.00 iii 135.00 based on table 1, sample i has the highest bod, i.e., 385 mg/l. the bod reduces to 200 mg/l in sample ii. in sample iii, the bod is reduced up to 135 mg/l. the maximum bod permitted by the indonesian ministry of environment, especially for liquid tofu wastes, is 150 mg/l [27]. the bod value of sample i is above the permitted value. however, treating the liquid tofu waste using the cds with uv light successfully reduces the bod value under the permitted value. hence, this result indicates that the cds synthesized from the solid waste of tofu can reduce bod in the liquid waste of tofu production. the cds act as catalysts for photo-degradation of the liquid tofu wastes. moreover, we also find that the photo-degradation can be enhanced under uv-light radiation, which produces the lowest bod in sample iii. under visible light, it can be observed that sample i looks cloudy (murky) and produces sediments. on the other hand, sample iii is seen clearer and contains fewer sediments than other samples (see figure 5). figure 1. uv-vis spectra of the synthesized cd samples. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 8 13 11 nurohman, et al. carbon dots synthesized from tofu pulp for liquid …. p-issn: 2621-3761 e-issn: 2621-2889 figure 2. pl spectra of prepared cds samples. figure 3. cds with precursor concentrations of 0.01 g/ml (a); 0.02 g/ml (b); 0.03 g/ml (c); 0.04 g/ml (d); and 0.05 g/ml (e) exposed to uv/violet laser. figure 4. ft-ir spectra of cd samples. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 8 13 12 nurohman, et al. carbon dots synthesized from tofu pulp for liquid …. p-issn: 2621-3761 e-issn: 2621-2889 figure 5. solution comparison of sample i (a), sample ii (b), and sample iii (c). v. conclusion in this study, we have synthesized cds from the pulp of tofu productions. the cd samples produce two shouldering peaks at 250 nm and 320 nm from the uv-vis characterization. based on the pl characterization, the synthesized cds show a peak at wavelengths of 499 nm to 523 nm, which means that the cds emit cyan luminescence. the functional groups of the cds obtained from the ft-ir test are c=c, oh, and c-c bonds. the cds have been applied as catalysts for photo-degradation of liquid tofu wastes. the bod in the liquid waste is reduced significantly by adding cds with uv light. vi. acknowledgment the authors would like to thank the physics education department, universitas negeri yogyakarta, for supporting this work. references [1] j. mondal and s. k. srivastava, “green synthesis of carbon dot weak gel from pear juice: optical properties and sensing application,” chemistryselect, vol. 3, no. 29, pp. 8444–8457, aug. 2018, doi: 10.1002/slct.201801383. 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review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 14 19 doi: 10.12928/irip.v4i1.3862 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 14 the ground state energy of helium using hartree-fock roothaan with six expansion terms of gaussian type orbital (gto-6g) nurlina1*, fitriah bidalo2 1 department of physics education, faculty of teacher training and education, universitas sulawesi barat, indonesia 2 department of physics, faculty of mathematics and natural science, institut teknologi bandung, indonesia email: nurlina@unsulbar.ac.id article info abstract article history received: mar 17, 2021 revised: jun 05, 2021 accepted: jul 03, 2021 an implementation of the hartree-fock roothaan with six expansion terms of gaussian type orbitals (gto-6g) is described and used to study the helium atom’s ground state accurately. the objective of this research is to calculate the ground state energy of the helium atom. the analysis was conducted using the numerical method using matlab 2017b. by using the hartree-fock roothaan method, the complexity of hartree-fock in integrating the differential equations of eigenvalues for each electron is repeatedly successfully overcome by expressing hartree-fock orbitals in the form of linear combinations, known as sto (slater type orbitals) and gto (gaussian type orbital). the hartree-fock roothaan approximation procedure begins by assigning an initial guess value to the elements of the density matrices and then constructing the first fock matrix from these matrices. the calculation is performed using the various iterations in multiples of 50, show that the error value expressed in relative uncertainty is getting smaller at the 150th iteration, which is around 1.84%. compared with some literature, the relative uncertainty value is still within tolerance (below 5%). the contribution of theoretical implications in this study can be used as input for other researchers to review the hartree-fock roothaan method and improve accuracy. this is an open-access article under the cc–by-sa license. keywords: gaussian type orbital hartree-fock roothaan helium six expansion ground-state energy to cite this article: nurlina and f. bidalo, “the ground state energy of helium using hartree-fock roothaan with six expansion terms of gaussian type orbital (gto-6g),” indones. rev. phys., vol. 4, no. 1, pp. 14–19, 2021, doi: 10.12928/irip.v4i1.3862. i. introduction one of the important in the study of an atom is the determination of the ground state energy. many methods can be used to determine the ground state energy of an atom. it can be done by solving the schrodinger equation. however, this tends to be very difficult in atoms with many electrons because it involves a fairly complex equation [1]. helium is an atom with two electrons and two protons. it has more than one particle, called a many-body system [2]. in such a system, there are various problems to study. one of those is the calculation of the helium ground state energy. the helium ground state energy calculates using the perturbation theory [3]. the variational technique, commonly known as the rayleigh-ritz method, is one of the approximation methods suited for handling such problems. the variational method helps determine upper-bound values for the energy eigenvalues of a system whose hamiltonian is known. in contrast, its eigenvalues and eigenstates are not known. it helps figure out what the ground state is. determining the energy levels of excited states becomes extremely difficult [4]. previously, this variational method was used to determine the ground state energy of berillium atoms with two parameters. the variational method with two parameters is well for explaining the properties of the ground state of an atom [5]. the ground state energy of the atom can be performed analytically and numerically. we can calculate the ground state energy with analytical calculation. however, this calculation has limitations, especially in atomic systems with many electrons. a method is designed to approach the exact value to solve this problem, namely the numerical method. the hartree-fock approach, with a slater determinant as the trial function, is a well-known http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3862 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 14 19 15 nurlina et al. the ground state energy of helium using …. p-issn: 2621-3761 e-issn: 2621-2889 classical example. the hartree-fock approximation has been the starting point for most electronic structure computations since hartree publicized the independent particle model and fock's addition of antisymmetry. designing a numerical solution for multi electronics atoms was extraordinary due to the absence of computational resources at the time [6]. hartree-fock also contributed to developments in approximate density functional theory [7], [8]. however, a theoretical estimate of how far the hartree-fock energy deviates from the correct conclusion in this scenario is impossible [9]. in the late 1920s, hartree presented self-consistent field (scf) methods to explore the electronic structure of atoms with more than one electron, which slater, fock, and others further developed. these hartree-fock methods are commonly used to compute the properties of atomic, molecular, and solid. some difficulties must be faced in finding a solution of the hartree-fock equation numerically because, in the process, the integration of the differential equations of eigenvalues for each electron must be repeatedly integrated. placing arbitrary constraints on the wave function makes hartree-fock theory more difficult to understand than the exact solution in many ways [10]. the complexity of this technique was overcome by roothaan, who proposed the critical idea of expressing the hartreefock orbital in the form of a linear combination of a complete set of previously known before, for example, the slater type orbital (sto) and gaussian type orbital (gto) [11], [12]. this method employs the principle that each electron’s movement can be described as a single particle function. in this research, the hartree-fock roothaan method is implemented on the helium atom to calculate the ground state energy. helium atoms are composed of an atomic nucleus with two protons and two protons, accompanied by two electrons surrounding the core [13]. in contrast to the hydrogen atom case, the hamiltonian of the helium atom involves the interaction terms between electrons that do not have closed solutions or are expressed in elementary function through analytical calculations. the solution of the case must be done numerically [14]. tjia and sutjahja [11] have also carried out this related research, but the calculations use sto type (slater type orbital) expansion terms. the hartree-fock roothaan method is implemented in this research with six expansion terms with the gto type (gaussian type orbital). the results obtained from this calculation are compared to other numerical and analytical results. ii. theory the atomic orbitals in slater’s determinant are described according to roothaan in equation (1). cn ni i i  =  (1) theoretically, as long as the basis i is complete, the translation in equation (1) can be justified in principle. only the accuracy of the choice of basis itself will affect the accuracy of the computation results and the convergence speed of the iteration process. the primary meaning of applying roothaan’s ideas expressed by equation (1) is the result in reducing the integration problem of the differential equations for atomic orbitals to the simultaneous algebraic equation for the linear combination coefficients {cni}. ( ) 0nf c   − = (2) the fock matrix n  is the diagonal matrix of the eigenvalues (orbital energies), which can be solved by matrix algebra. the algorithms used in this study is determining the basic gto function. we take ( )r an orbital (depending on the spatial orbital only) shared by the two electrons. we bring ( )r as a linear combination of four fixed, real basis functions (both ci and i  are real): ( ) ( ) 6 1 r c r i i i  =  = (3) with, ( ) 2r ir ei   − = (4) then, determine the six exponential coefficients using equation (5) [15]. 1 0.0366871 0.23872622 0.72458673 1.2425670 4 5.2829480 5 38.474970 6       →                                   (5) determination of the matrix elements of the overlap matrix for the orbital basis, s pq (p,q = 1, 2, …, 6), |s pq p q = (6) 3 2 pq p q s      =    +  (7) determination of the hamiltonian, 1 22 2 h pq p q r  = −  − (8) 1 2 22 2 h pq p q p q r r    = −  − + (9) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 14 19 16 nurlina et al. the ground state energy of helium using …. p-issn: 2621-3761 e-issn: 2621-2889 h t vpq pq pq= + (10) determination of the matrix elements of the kinetic energy, ( ) 3 231 2 52 2 p q tpq p q p q        = −  = + (11) determination of the matrix elements of the coulomb energy, 2 4 pq p p p q v r      = − = + (12) after that, iteration of the self-consistency field (scf). the matrix equation for the unknown prefactor coefficient vector c = {c1, c2, c3, c4, c5, c6}. calculation of the density matrix ρ, 2 occ c crs nr ns n  =  (13) calculation of the matrix g, 1 , 2 g pq rs pr qspq rs p q    = −     (14) with, 1 (1) (2) (1) (2) 12 pq rs p r q s r    = (15) 1 3 3 (1) (2) (1) (2) 1 2 12 pq rs d r d rp r q s r    =  (16) the fock matrix elements have the form, f h gpq pq pq= + (17) found the lowest eigenvalues of the secular equation, ( )det 0f s− = (18) update c from the roothaan equation, ( ) 0f s cpq n pq qn q − = (19) loop up to c is stable (scf is reached), we calculate the ground state energy as, 2e c c h c c c cpq pqrsp q pq p q r s= +  (20) in the end, we compare the energy with a reference value, using the modified hartree-fock with gaussian type orbital [16], 2,8616790e hartree ref = − (21) iii. method this research is a numerical method using the hartree-fock roothaan method with six expansion term to get the ground state energy of helium which closes to the reference value. the hartree-fock roothaan method allows the schrodinger equations for multiple particle systems to be solved relatively easily. the hartree-fock roothaan method is an iterative calculation so that the solution can be calculated with a computer. the software used in working on the research was the 2017b version of matlab software. the algorithm used in this study is generally summarized in a flow chart, as shown in figure 1. figure 1. hartree-fock roothaan flow chart iv. results and discussion one of the most critical problems in quantum chemistry is predicting the ground state energy of manyelectron [17]. the hartree-fock method is a widely used basic theory of electronic structure and the basis of the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 14 19 17 nurlina et al. the ground state energy of helium using …. p-issn: 2621-3761 e-issn: 2621-2889 molecular orbital theory, which provides data that the movement of each electron can be explained in terms of a particle function that does not depend on the direct movement of another electron. in 1993, roothaan applied the scf (self consistency field) concept to find an eigen solution to the hartree-fock method problem. furthermore, this method is better known as the hartreefock roothaan method. this concept is necessary to get knowledge in quantum mechanics, electromagnetic theory, and linear algebra. the hartree-fock roothaan function has been expanded in the sto term. studies about hartree-fock roothaan reported significantly improved results using a base set of gto. the gaussian type orbital (gto) is also known as the primitive gaussian function, which can be served in a cartesian coordinate system or a spherical coordinate system. it should be noted that, unlike the sto function, the gto function does not present a cusp shape at the location of the atomic nucleus for the radial part of the two types of atomic orbitals. this means this function provides a less realistic representation of the electron distribution for small r values. however, this gto function is more widely used in numerical computations because the exponential function, which depends on r2 allows for more efficient calculations of molecular integrals with its more straightforward formulation. this efficiency factor will reduce the cost of implementing sizeable numerical computation programs. we offer the findings of our computations in this part and compare them to those already published in the literature. the calculations are performed using the various iterations in multiples of 50. the results are shown in figure 2. it can be seen that the error value expressed in relative uncertainty is getting smaller at the 150th iterations, which is around 1.842%. the greater iteration is carried out, and the smaller deviation will be generated, which means that the ground state energy produced will be closer to the reference value [16]. (a) (b) (c) figure 2. the results of energy calculations use (a) 50 iterations, (b) 100 iterations, and (c) 150 iterations http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 14 19 18 nurlina et al. the ground state energy of helium using …. p-issn: 2621-3761 e-issn: 2621-2889 the primary limitation to the generalization of these results is we obtained the smallest of ground state energy compared to other studies using the other method like references [18–22] because our calculation was restricted to the 150th iteration, we just wanted to find out if this method was efficient enough at determining the ground state energy of the helium atom. table 1 shows the result of energy calculation using the various iterations. compared with some literature, the relative uncertainty value is still within tolerance (below 5%), which means implementing the hartree-fock roothaan with six expansion terms of gaussian type orbitals (gto-6g) is entirely accurate in determining the ground state energy of helium atom. overall, comparisons against the literature are shown in table 2. table 1. the calculation result of the ground state energy using the various iterations iteration eground (hartree) relative uncertainty (%) 50 -2.74482 3.939 100 -2.79519 2.323 150 -2.80896 1.842 table 2. the calculation result of the ground state energy of the helium atom author year method energy (hartree) ludeña [18] 1978 hartree-fock -2.86164 buendia et al. [16] 1997 modified hf-gto -2.86170 tsubono [19] 2009 bohr’s theory -2.90320 ekong et al. [20] 2015 quantum monte carlo casino-code -2.90369 purwaningsih et al. [21] 2019 hylleraas trial function expansion -2.90150 tjia and sutjahja [11] 2012 slater type orbital (sto-2g) -2.86200 doma et.al. [22] 2014 variational monte carlo -2.90377 this study 2021 gaussian type orbital (gto-6g) -2.80896 v. conclusion in this study, an implementation of the hartree-fock roothaan with six expansion terms of gaussian type orbitals (gto-6g) is described and used to study the helium atom's ground state accurately. setting an initial estimate value for the density matrix elements is the first step in the hartree-fock roothaan approximation procedure; with these matrices constructed the initial fock matrix. the calculation is performed using various iterations. it shows that the relative uncertainty is getting smaller at the 150th iteration, around 1.84%. the helium ground state energy produced in this study is close to the results of previous research. in the end, we presented a detailed comparison of our energy results to those of other methods showing that the relative uncertainty value is still within tolerance. this proves that the hartree-fock roothaan with six expansion terms of gaussian type orbitals (gto-6g) is very suitable in explaining the properties of the ground state energy of an atom, like helium atom. references [1] d. j. griffiths and d. f. schroeter, introduction to quantum mechanics, 3rd ed. u.k: cambridge university press, 2018. 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[15] a. e. feiguin, “phys 5870: modern computational methods in solids,” northeastern university, 2012. [16] e. buendía, f. j. gálvez, and a. sarsa, “hartree–fock wave functions with a modified gto basis for atoms,” int. j. quantum chem., vol. 65, no. 1, pp. 59–64, 1997, doi: 10.1002/(sici)1097-461x(1997)65:1<59::aidqua6>3.0.co;2-%23. [17] y. chen, l. zhang, h. wang, and w. e, “ground state energy functional with hartree–fock efficiency and chemical accuracy,” j. phys. chem. a, vol. 124, no. 35, pp. 7155–7165, sep. 2020, doi: 10.1021/acs.jpca.0c03886. [18] e. v. ludeña, “scf hartree–fock calculations of ground state wavefunctions of compressed atoms,” j. chem. phys., vol. 69, no. 4, pp. 1770–1775, aug. 1978, doi: 10.1063/1.436710. [19] y. tsubono, “calculation of helium ground state energy by bohr’s theory-based methods,” arxiv prepr. arxiv0903.2546, 2009. [20] s. a. ekong, m. t. oloyede, and d. a. oyegoke, “ground-state energy calculation of helium atom using quantum monte carlo casino-code,” adv. phys. theor. appl., vol. 46, pp. 1–6, 2015. [21] s. purwaningsih, p. nurwantoro, and a. hermanto, “calculation of ground state energy of helium using hylleraas trial function expansion,” int. j. eng. res. technol., vol. 12, no. 8, pp. 1178–1182, 2019. [22] s. b. doma, m. o. shaker, a. m. farag, and f. n. elgammal, “ground states of helium atom and hydrogen negative ion in the presence of magnetic field using variational monte carlo technique,” acta phys. pol. a, vol. 126, no. 3, pp. 700–705, aug. 2014, doi: 10.12693/aphyspola.126.700. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1007/s11182-019-01608-z https://doi.org/10.21468/scipostphys.6.4.040 https://doi.org/10.1002/(sici)1097-461x(1997)65:1%3c59::aid-qua6%3e3.0.co;2https://doi.org/10.1002/(sici)1097-461x(1997)65:1%3c59::aid-qua6%3e3.0.co;2https://doi.org/10.1021/acs.jpca.0c03886 https://doi.org/10.1063/1.436710 https://doi.org/10.12693/aphyspola.126.700 p-issn 2621-3761 e-issn 2621-2889 irip irip (indonesian review of physics) is a journal of physics and physics education research. it is compiled with a commitment to enhance quality of the research. indonesian review of physics (irip) 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model based on problems of physical learning achievements by students of class x science in sma 6 denpasar academic year 2017/2018 ni putu nadia nikki utami, i wayan santyasa, iwan suswandi the effect of the microsoft excel based interactive learning media on the physics problem solving irnin agustina dwi astuti, yoga budi bhakti the penetration of mobile technology and its implementation on learning in indonesian high school dwi sulisworo, muqoyyanah muqoyyanah architecture of atwood machine props with sensor-based passive infrared delia achadina putri, dandan luhur saraswati measurement eccentricity the moon’s orbit with image analysis technique by using tracker software ricka tanzilla, ishafit jauhari, yudhiakto pramudya published by universitas ahmad dahlan irip vol.1 no.1 pp. 1-25 yogyakarta, juni 2018 p-issn 2621-3761 e-issn 2621-2889 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/243 http://journal2.uad.ac.id/index.php/irip/article/view/243 http://journal2.uad.ac.id/index.php/irip/article/view/249 http://journal2.uad.ac.id/index.php/irip/article/view/249 http://journal2.uad.ac.id/index.php/irip/article/view/244 http://journal2.uad.ac.id/index.php/irip/article/view/258 http://journal2.uad.ac.id/index.php/irip/article/view/258 p-issn 2621-3761 e-issn 2621-2889 table of contents regular papers: the influence of blended learning model based on problems of physical learning achievements by students of class x science in sma 6 denpasar academic year 2017/2018 ni putu nadia nikki utami, i wayan santyasa, iwan suswandi universitas pendidikan ganesha, bali, indonesia 1 the effect of the microsoft excel based interactive learning media on the physics problem solving irnin agustina dwi astuti, yoga budi bhakti universitas indraprasta pgri, jakarta timur, indonesia 7 the penetration of mobile technology and its implementation on learning in indonesian high school dwi sulisworo1, muqoyyanah2 1universitas ahmad dahlan, yogyakarta, indonesia 2universiti pendidikan sultan idris, malaysia 12 architecture of atwood machine props with sensor-based passive infrared delia achadina putri, dandan luhur saraswati universitas indraprasta pgri, jakarta timur, indonesia 16 measurement eccentricity the moon’s orbit with image analysis technique by using tracker software ricka tanzilla, ishafit jauhari, yudhiakto pramudya universitas ahmad dahlan, yogyakarta, indonesia 20 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/253 http://journal2.uad.ac.id/index.php/irip/article/view/243 http://journal2.uad.ac.id/index.php/irip/article/view/243 http://journal2.uad.ac.id/index.php/irip/article/view/249 http://journal2.uad.ac.id/index.php/irip/article/view/249 http://journal2.uad.ac.id/index.php/irip/article/view/244 http://journal2.uad.ac.id/index.php/irip/article/view/258 http://journal2.uad.ac.id/index.php/irip/article/view/258 indonesian review of physics, volume 2, number 2, 2019 67 characterization of activated charcoal oil palm (elaeis guineensiss jacq) shell waste using sem and ftir: effect of activation temperature rasyid syidiq1*, la ode yusran2, muhammad anas1, suritno fayanto3 1 department of physics education, universitas halu oleo 2 department of master in physics, institut teknologi sepuluh november surabaya 3 program studi magister pendidikan fisika, universitas ahmad dahlan 1 jl. h.e.a. mokodompit, kendari sulawesi tenggara, 93231, indonesia 2 jl. raya its, keputih, surabaya, indonesia 3 jl. pramuka, no.42 umbulharjo, yogyakarta, 55161, indonesia email: *syidiq17121997@gmail.com abstract this study aims to determine the structure of morphology and functional groups from activated charcoal for palm oil waste with variations in activation temperature. the process of two stages: the carbonation and activation stage. carbonation process using a pyrolysis reactor at a carbonation temperature of 200oc -400oc for 6 hours. then, the sample activated at a temperature of 700 °c, 750oc, 800oc, and 850 °c. the samples were characterized using sem and ftir. the sem analysis results show that the largest pore size at a temperature of 850 oc with a diameter of 48.3 nm, and the lowest temperature was 700 °c with a pore size 35.9 nm. activated charcoal from oil palm shell waste at mesopore size. the ftir analysis results show wave numbers 2165,18 cm-1, 1554 cm-1, 1030,76 cm-1 dan 424,11 cm-1. the removal of some absorption bands and the formation of new absorption bands, caused by the activation temperature. keywords: activation temperature, sem, ftir, charcoal oil palm i. introduction one of the most effective adsorbents is activated charcoal, it is a multifunction material, and could be used to vanish the pollutant of gas and contaminated fluid flow as it has a large capacity of the absorption, a high surface area, suitable to develop porous structure, rapid kinetic absorption and good mechanical [1]. the charcoal surface is still covered by hydrocarbon precipitation that inhibits its activity. the while the surface of activated charcoal is relatively free of deposit and able to absorb as the surface area and has open pores [2]. the use of activated charcoal to overcome intoxication has been recognized since 1830 by a french chemist, bertrand. activated charcoal commonly produced through the pyrolysis process of material containing carbon and activated by oxidation with high-temperature vapor [3]. activated carbon produced from different precursors, including coal from a different structure, and lignocellulose materials, with physical or chemical activation process [4]. most of the material used to create activated carbon is organic materials that contain a lot of carbon [5]. therefore, the development of a method to reuse organic waste materials like activated carbon is hugely recommended to solve an environmental problem. agricultural waste and waste of factory production such as corn cobs, palm bunches, and palm oil shells, sawdust, cashew shells unusual to be used for activated carbon materials as it belongs to lignocellulose materials that have a high content of carbon [6]. palm oil with the latin name elaeis guneensis jacq is one of the natural resources which is very rich in indonesia. global production of palm oil has increased more than nine times since 1980 to 45.1 million tons in 2009 where indonesia and malaysia lead as the producer contributes for about 85% of all palm oil production in the world [7]. for a palm oil factory production to produce raw palm oils (cpo), it provides a considerable amount of solid waste and syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 68 wastewater, which has a high impact on the environment in 2015, the produce solid waste is about 17,7 million tons [8]. one of the waste is palm oil shell. palm oil shell is the final product of the palm oil manufacture process [9]. palm oil is the recommended raw material candidate to produce activated carbon with developed priority and surface area under several reasons: high carbon content and price, which is relatively inexpensive. it shown that palm oil shell has 55,7% carbon content compared to palm oil fiber (49,6%), coffee bark (50,3%), and bagasse (53,1%)[10]. the research aims to discover the effect of activated temperature variation toward surface morphology and functional group of activated carbon from palm oil shell. based on the description and data above, researchers are interested in researching the title of characterization of activated charcoal oil palm (elaeis guineensiss jacq) shell waste using sem and ftir ii. theory the process of making active charcoal activated charcoal made of several materials containing carbon, both derived from animals, plants, and minerals. these materials include wood, wood sawdust, coal, coconut shells, grain shells, rice husks, animal bones [11]. activated charcoal making process consists of three stages:. a. drying phase: this stage is the stage of the water removal process. the material dried in the sun or heated material to ± 170 ℃ b. carbonancy phase: this stage is the process of breaking down organic materials into carbon. this process is a process to convert organic material into charcoal by heating without the presence of oxygen so that the complex compounds that make up organic material decompose into charcoal with high carbon content. temperatures above 170 ℃ will produce co, co2, and acetic acid. at a temperature of 275 ℃ decompositions produces tar, methanol, and charcoal formation at a temperature of 400-600 ℃ [12]. c. activation phase: this stage gave a treatment of charcoal which aims to enlarge the pore, namely by breaking the hydrocarbon bonds or oxidizing surface molecules so that they experience physical changes, both chemical properties and physical properties with a larger surface area and effect on absorption [13]. activation method commonly used in the manufacture of activated charcoal there are two types of physical activation, and chemical activation described as follows: (1) this activation is the process of breaking carbon chains from organic compounds using chemicals. activator used is chemicals such as koh, nacl, h2so4, hcl, and h3po4. (2) this activation is the process of cutting carbon chains from organic compounds with the help of heat, water vapor, co2, or n2. the quality of the surface of activated charcoal produced is very dependent on the raw material, activating material, temperature, and method of activation. the main effect of activating charcoal with hot steam is to create and expand the charcoal pore. it is clear that hot steam activation not only removes unmanaged material but is also quite useful in forming and widening micropores with rising temperatures. increasing the temperature from 750 0c to 800 0c increases the volume of activated charcoal micropore. at a specific limit temperature increases, it will decrease the volume micropore [14]. activated carbon mass is affected by the activation temperature. the higher the activation temperature, the lower the mass of carbon activated carbon. in addition, the higher the activation temperature of activated carbon, the more water content evaporates, which affects the quality of activated carbon [15]. it explained that temperature greatly affects the quality of activated charcoal. scanning electron microscope (sem) scanning electron microscopy (sem) is a type of electron microscope that uses electron beams to describe the surface shape of the material analyzed. electrons interact with atoms that make samples produce samples that provide information about the surface topography of the sample, composition, and other properties such as electrical conductivity. sem can produce high-resolution images from a sample surface, capture in full with a size of about 1-5 nm, and produce the desired image sem has a considerable focus width usually 25-250000 magnification [16]. the working principle of sem consists of electron optics and electron coulomb console. sem sample is placed in a specimen chamber in the electron optical column with a high vacuum level of about two � 105 torr. electron beam generated by an electron gun will supply such as to specimen/sample. this electron beam will pass through an optic column that serves to focus the electron beam up to the sample [17]. fourier transform-infrared spectroscopy (ftir syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 69 fourier transform-infrared spectroscopy (ftir) is an analytical technique used to identify organic matter. this procedure measures the absorption of infrared radiation by sample material versus wavelength. infrared absorption groups identify molecular components and structures. when a material irradiated with infrared radiation, absorbed radiation usually excites molecules into a higher vibration state. the wavelength of light absorbed by specific molecules is a function of the energy difference between the state of vibration at rest and excited wavelength absorbed by the sample is a characteristic of its molecular structure. ftir spectrometers use interferometers to modulate wavelengths from broadband infrared sources. the detector measures the intensity of light emitted or reflected as a function of wavelength. the signal obtained from the detector is an interferogram, which must be analyzed by computer using the fourier transform to obtain the infrared spectrum of a single ray. ftir spectra usually presented as a plot of intensity versus wave number (in cm-1). intensity plotted as a percentage of light transmission or absorbance at each wavenumber [18]. figure 1. michelson interferometer design[19] ftir usually based on the michelson interferometer experiment setup, an example shown in figure 1. the interferometer consists of a board splitter, a framed mirror, and the mirror that translates back and forth, very precise. the beam splitter made of special material that transmits half of the radiation struck and reflected the other half. radiation from the source hits the beam breaker and separates into two beams. one beam transmitted through a beam divider to a fixed mirror and the second reflected from the beam divider to the moving mirror. fixed and moving mirrors reflect radiation beams to the breaker. again, half of the repeated radiation transmitted and half reflected at the beam splitter, producing a passing beam and a second detector to go back to the source [20]. iii. methodology raw materials this study uses materials that are oil palm shells taken from plasma jaya village, polinggona district, kolaka regency. the tools used in this study include glass tools, oven, 100 mesh sieve, carbonation tube, infrared thermometer, electric furnace, and mortar. characterization sample using (scanning electron microscope and fourier transform infrared spectroscopy). preparation and characterization of charcoal oil palm the oil palm shell that will sample cleaned and washed with water until it is clean and then dried in the sun for 24 hours. next, the sample is carbonated using a pyrolysis reactor for 5-6 hours with a temperature of 400 °c – 500 °c. then the sample is crushed using a mortar and sieved using a 100 mess sieve. furthermore, charcoal activated by steam of carbon dioxide (co2) or oxygen (o2) using an electric furnace at temperature variations of 700 °c, 750 °c, 800 °c and 850 °c for 60 minutes and the last sample characterized by using scanning electron microscope (sem) and fourier transform infra red (ftir). iv. results and discussion the effect of activation temperature variations on activated charcoal surface morphology the active charcoal of oil palm shell that activated with varying temperatures of 700ºc, 750ºc, 800ºc, and 850ºc analyzed using scanning electron microscope (sem) with 5000x enlargement as shown in figure 2. syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 70 (a) (b) (c) (d) (e) figure 2. active charcoal of oil palm that is the characterization results by sem (a) without activation; (b) activation of 700 ºc; (c) activation of 750 ºc; (d) activation 800 ºc; (e) activation of 850 ºc. based on figure 2, the results of the sem characterization show that the surface structure of activated charcoal morphology shows differences in pore size images at each activation temperature. in this confirmed from the results of imagej analysis that shows differences in pore size distribution at each temperature activation (table 1). jawad said that the pore activation process has a different surface structure with features of rough and irregular surfaces with heterogeneous cavities that are distributed randomly throughout the pore surface [21]. in figure 2e with an activation temperature of syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 71 0 10 20 30 40 50 60 no activation 700 ºc 750 ºc 800 ºc 850 ºc p o re s iz e (n m ) activation temperature 400 800 1200 1600 2000 2400 2800 3200 3600 4000 t ra n sm is si o n (% ) wave number (cm-1) no activation 700 oc 750 oc 800 oc 850 oc 850 ºc showed an apparent pore size of 48.3 nm pore size than the activation temperature of the others. because of the effect of activation temperature, which resulted in the evaporation process of volatile matter from the raw material of the activation process [22][23]. the activation temperature has caused the elemental composition reduced and produces some gas products such as co, co2, and hydrogen and methane [24]. for more details on the differences in the pore size of any activation, temperature difference presented in table 1 and figure 3. table 1. the average pore size of active charcoal determined on image-j analysis activation temperature pore size (nm) no activation 35.3 700 ºc 35.9 750 ºc 38.4 800 ºc 39.0 850 ºc 48.3 table 1 provides information that affects the activation temperature effect on the pore size distribution at each temperature activation. table 1 interpret that as temperature increases resulting activation of the pore size the higher (figure 3). in this line with the expression nurdiansyah and diah that the higher the activation temperature of the activated carbon produced diminishing of the number of impurities that cover the surface of the pores so that the resulting pore sizes getting bigger[25]. next, quach et al. explained that there was an increase in pore surface size on carbon xerogels at activation temperatures 700 ºc-1000 ºc [26]. figure 3. the effect of the activation temperature on the activated charcoal oil palm pore the results of characterization by sem analyzed using image-j showed that the best pore surface area was at temperatures of 850ºc (figure 2e) with a pore surface area of 48,262 nm. in this because the activation process can enlarge the pores by breaking hydrocarbon bonds or surface oxidizing surfaces that change the properties of activated charcoal, both physically and chemically and can increase the size of the surface area [27]. from the results of the analysis of the active pore size of oil palm shells in the mesoporous category (table 1), in this based on the mesopore size scale, which ranges from 2-50 nm [28]. margaret et al. and herawan et al. suggest that the average pore size for palm oil active charcoal samples is in the micropore and mesopore categories[28][29]. the influences of activation temperature on the function cluster activated charcoal ftir analysis aims to find out the number of particles in a material, as shown in figure 4. ftir shows the pattern of ir absorption in the graphical form of the connection between wave numbers and the quantity of ir transmissions. with the intake on the particular wavenumber domain, it shows that there is a vibration of function cluster. figure 4. ir spectrum of activated charcoal from palm shells with activation temperature variations syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 72 ftir absorption pattern figure 4 shows that the charcoal of oil palm tree (non-activation) there is absorption in the wavenumber domain of 2165,18 cm-1, which suspected as cluster vibration of alkyne. the absorption in wavenumber domain of 1554 cm1 which is allegedly caused by the vibration of c=c (aromatic), absorption in wavelength domain of 1030,76 cm-1 which is reportedly caused by c-o (secondary alcohol) and absorption in wavenumber domain of 424,11 cm-1 which suspected as cluster vibration of c-h. the identification results of ftir show that the charcoal of oil palm tree (nonactivation) contains function cluster of alkyne, c=c, c–o, and c-h. while, the activated charcoal of oil palm tree for variation of activation temperature suspected of containing function cluster of acetylene, c–h (alkyne), c=o, c=c, co, and c-h. in this expected due to heteroatoms (in this case, the oxygen atoms of carbon dioxideenriched atmosphere during the activation process) on the sheet or in a cluster of aromatic carbon [30]. the charcoal function cluster of oil palm shell with a variety of activation temperatures seen in the following table 2. table 2 charcoal functional cluster and activated charcoal in oil palm shell activation temperature wave number (cm-1) no activation 2165,18 1554 1030,7 424,11 700 oc 2188,34 1515 1037 427,18 750 oc 2286,07 1521 1038 411,21 800 oc 2324,04 2051,26 1981,59 1511 1026 444,75 850 oc 2323,83 2050,16 1980,05 1576 1027,0 428 cluster functions c2h2 acetylene cc  alkuna hcc  alkuna c=o carbonyl c=c aromatic c-o secondary alcohol c-h changes in functional groups did not occur at 700 oc and 750 oc activation temperatures. however, there was a decrease in absorption intensity in secondary alcohol groups. it is because the higher the activation temperature will weaken the bond or vaporize the group, which causes the vibration frequency to decrease. inactivation temperature of 800 oc and 850 oc, there is a friction of absorption pattern toward the wavelength domain of 2323 – 2424 cm-1 which suspected as c2h2 (acetylene) cluster. furthermore, the appearance of the new absorption band in the wavelength domain of 2050-2051 cm-1 which alleged as the vibration of c-h (alkyne) and in the wavenumber domain of 1980 cm-1 which assumed as c=o (carbonyl) cluster. this possibility caused by the interaction between activated charcoal with free radicals compounds from outside (h2o) when the process of temperature activation is in progress [31]. while swaidan (2013) argues that the rise due to the carbonyl group of the cellulose in plants itself, the statement was proven by the writings of maulina and iriansyah that the high cellulose content in oil palm charcoal was 31.5% compared to lignin content (14%) and hemicellulose (19.2%) [32]. the ftir analysis results pada tabel 2 show that the heat treatment or activation temperature variation can permute the function cluster. yashim et al. reported that changes in the functional groups of the surface treated with the activation and carbonized at high temperatures[33]. it is seen in the friction of absorption pattern, the loss of some absorption pattern, the formation of new absorption pattern, and the reduction of absorption intensity. carbonization and activation process has also formed a bond of c=c aromatic in approximately 1511-1576 cm-1. it shows that carbonization and activation to be activated charcoal will increase the aromatic compound [34]. this compound is the composer of charcoal hexagonal structure and activated charcoal. the higher activation temperature it will reinforce the aromatic cluster v. conclusion activation temperature has a significant effect on activated charcoal morphology and activated charcoal functional groups of oil palm shells. the higher of activation temperature, the more active charcoal pore area of the oil palm shell formed, the included in the mesopore category. palm shell charcoal has alkuna functional groups, c=c (aromatic), c-o and c-h, while charcoal activated in temperatures of 700 ̊c, 750 ̊c, 800 ̊c, and 850 ̊c undergoes functional group changes followed by atomic realignment carbon that viewed in shifting absorption bands. in addition, the higher activation temperature will strengthen the aromatic compounds; the compound is a constituent of charcoal and activated hexagonal structures syidiq, et al. characterization of activated charcoal oil palm (elaeis guineensiss jack)… indonesian review of physics, volume 2, number 2, 2019 73 acknowledgment our thanks to head of laboratory of the department in physics education universitas halu oleo and head of laboratory of terpadu universitas islam indonesia which has facilitated researchers so that this research completed reference [1] a. r. hidayu, n. f. mohamad, s. matali, and a. k. sharifah, “overview of mercury removal from flue gas using activated carbon,” business engineering and industrial applications colloquium, 2013, pp. 69–72. 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[34] j. park, i. hung, z. gan, o. j. rojas, k. hun, and s. park, “bioresource technology activated carbon from biochar : influence of its physicochemical properties on the sorption characteristics of phenanthrene,” bioresource technology, vol. 149, pp. 383–389, 2013. indonesian review of physics, volume 2, number 1, 2019 15 investigating the effects of activation temperature on the crystal structure of activated charcoal from palm bunches (arengga pinnata merr.) vivi hastuti rufa mongkito1*, muhammad anas2, wisda puspita bahar3 123department of physics education, universitas halu oleo 123jl. h.e.a mokodompit kendari southeast sulawesi 93231, indonesia email: vivi.hastuti@uho.ac.id abstract this research aims to determine the effect of activation temperature the crystal structure of activated charcoal. the material used activated charcoal bunches (arengga pinnate merr). the process of making activated charcoal divided into two, namely the carbonization stage at a temperature of 250 400 oc and the activation stage at a temperature variation of 600 800 ̊c. to find the crystal structure, the sample characterized by x-ray diffraction. the results of analysis the dominant elements diamond before activation with a percentage of 90.2% and an orthorhombic crystalline structure, where the lattice parameter a = 4.12700 å; b = 4.93700 å; c = 4.81900 å. peak carbon has a hexagonal crystal structure in all temperature variations. peak graphite an orthorhombic crystal structure and at a temperature of 700 oc a hexagonal crystal structure formed. therefore, giving temperature variations the activated charcoal of the bunches affects the structure of the formed crystal. wherein increasing the activation temperature, the crystal structure that forms look more amorphous marked by a widening diffraction peak intensity decreased crystals. keywords: crystal structure, temperature activation, xrd, bunches of palm i. introduction bunches of the palm is a plant with many stems, which measure about two feet. all filled with fruit that is green when young and yellowish brown when ripe. then, empty bunches where fruits used to process into food (indonesia names kolang-kaling) usually left dry or used as firewood. according to [1] his research component of chemical compounds included in waste palm bunches lignin is 27.74%, 68.11% (hemicellulose), 33.79% (α-cellulose), 11.10% water content extractive, so palm bunches are very high potential to be used as active charcoal. bunches of palm production function produces a variety of commodities that have high economic value and potentially serious export if cultivated, such as palm stems produce flour if palm sugar not intercepted and palm wood used as raw material for making furniture. all parts of the sugar plant have a production function and the function of conservation highly effective one to reduce characterization directly into the ground to prevent erosion [2]. some researchers have examined active charcoal made from palm bunches. some of them [1] arguing that the activated charcoal of aren bunches consists of α-cellulose isolation elements from palm bunches about 20-26% and 16-21.33% microcrystalline cellulose, with microcrystalline structures consisting of particles with a form irregular, odorless, white, tasteless, with ph 7.4 and drying shrinkage 8.6%. microcrystalline cellulose powder of palm bunches has good flow properties, with a resting angle of 20.47 ha, hausner index of 1.19, and compressibility index of 18.6%. moreover, hafiz et al., inform that microcrystalline cellulose pulp derived from oil palm empty fruit bunches filtered at room temperature and then dried in a vacuum oven at 105°c to constant weight reached. siemens difraktometer d5000 used to study the crystallinity of composite samples. xrd results explained that microcrystalline cellulose has its own or single cellulose structure with an 87% crystallinity index and a relatively high index of crystallinity with oil palm empty fruit pulp [3]. the yield of palm sugar leaves more bunches of sugar palm into the garbage. the trash from aren bunches is often considered useless and only becomes trash which turns out to have many mongkito et al. investigating the effects of activation temperature on the crystal structure… indonesian review of physics, volume 2, number 1, 2019 16 benefits for the community because its utilization to date only limited to tapping flower bunches for processing palm sugar juice. one of the benefits of palm bunches rarely known the public it can use as activated charcoal or briquettes which can be used to absorb the waste solids dissolved in water, remove odors, absorption of dyes, purification agents [4]. utilization of palm bunches intended in addition to tackling the buildup of waste and palm bunches expected to produce products that safe and environmentally friendly [5]. research on activated charcoal from palm bunches is very rarely found in various literature because currently the most developed is research on active charcoal from oil palm bunches, although palm bunches made into charcoal as a raw material for making activated charcoal. however, the activation process technology to produce activated charcoal to the characteristics of the crystalline structure of the corresponding standards still faces many obstacles. by knowing the crystal structure of an element, it will get a little information about the origins of the elements, physical properties, and mechanical. one of them is the method of x-ray diffraction (x-rd) where samples will be shot using x-rays with wavelengths a ̇ scale corresponding to the lattice spacing of a material that is the measurement result is a diffractogram — considering the importance of knowing the information about the structure of the activated charcoal crystal. so that researcher interested in researching with the title "effect of activation temperature on the crystal structure of activated charcoal from palm bunches." this research aims to learn the effect of activation temperature on the crystalline structure of activated charcoal formed from palm bunches. ii. theory the process of making activated charcoal activated charcoal making process made employing carbonation pyrolysis method. pyrolysis is a heating process in the absence of oxygen [6]. [7][8] stated that the pyrolysis is a process of incomplete combustion of a carbon-containing compound that not oxidized to co2. primary pyrolysis divided into a slow process at a temperature of 150 ̊c-300 ̊c which produces charcoal, h2o, co and co2, and a fast process, transpires at temperatures of 300 -400 , which produces charcoal, gas, and h2o [9]. after pyrolysis occurs at temperatures above 600 which produce carbon monoxide, hydrogen gas, and hydrocarbon gases [10][11]. next, [12] said states that when fast pyrolysis used (fast pyrolysis), heating for 0.1–0.5 seconds at a temperature of 400 – 600 . authoring or carbonization process divided into four stages: (a) the evaporation stage of water, which occurs at temperatures of 100 150 ; (b) stage of decomposition of hemicellulose and cellulose at a temperature of 200 -240 into pyrogenic solution which a low boiling point organic acid such as acetic acid, formic acid, and methanol; (c) the stage of depolymerization and termination of c-o and cc bonds, at a temperature of 240 -400 . in addition, the lignin begins to decompose to produce tar, decreasing the pyroglinat and co solution and increasing co, ch4, and hydrogen gas; (d) the stage of forming an aromatic layer, which occurs at temperatures more than 400 and lignin, continues to decompose to a temperature of 500 , whereas at temperatures over 600 there is a process of enlarging the surface area of charcoal. furthermore, charcoal can be purified or turned into activated charcoal at a temperature of 500 -1000 [13][14][15]. the crystal structure crystalline structure is a condition or condition in which a typical arrangement of atoms in a crystal arranged specially and periodically repeats in three dimensions on a crystal lattice due the heating process resulting in more regular changes in the atomic structure [16]. the arrangement occurs because of geometric conditions that must meet the permanence of trending atomic bonds and tight arrangement. for knowing the crystal structure of an element, it will get a little information about the origins of the elements, physical properties, and mechanical. ideally, the most stable arrangement of polyhedra coordination is one that allows minimum energy per unit volume. this situation achieved if: a) electricity neutrality fulfilled; b) discrete and directed covalent bonds fulfilled; c) the repulsion force of ions becomes minimal; d) the arrangement of atoms as close as possible [17]. lattice is an arrangement of points in three-dimensional space in which each point has a similar environment. the point with a similar environment named the lattice points. knot lattice arranged only in 14 different configurations, named lattice bravais. based on the theory of the higher temperatures will increase the mongkito et al. investigating the effects of activation temperature on the crystal structure… indonesian review of physics, volume 2, number 1, 2019 17 degree of crystallinity carbonized charcoal because of the high temperature capable of breaking the carbon chains that increasingly disordered arrangement of carbon atoms [18]. the degree of crystallization seen from the peaks of xrd which viewed from the value of the microcell origin/match three software iii. methodology this research conducted at the physics education laboratory universitas halu oleo and xrd sample characterization at the energy laboratory of the sepuluh nopember institute of technology. the materials used are arenga pinnata merr and using xrd (x-ray diffraction) characterization tools. the research stage divided into two stages, namely the carbonation stage at temperatures of 250-450 ̊c and the activation phase of the sample starting from 600 800 ̊c. the result of the analysis xrd in the form of an image of the activated crystalline charcoal structure of each bunch tested based on a comparison of temperature variations and a graph of the relationship of intensity and angle 2θ contained in each sample. the stages of the research described in figure 1. figure 1. research procedure iv. results and discussion result in this study to determine the crystal structure of the activated charcoal from palm bunches before heated, 600 ̊c-800 ̊c analyses by xrd, the source used cu with a wavelength of λ = 1.54060 ǻ. the direct information obtained from the xrd test of palm bunches for various temperature variations the form of a spectrum or graph between scattering angles (2θ) taken at a scattering angle of 5˚-60˚. the diffractogram graph of the xrd results seen in figure 2. figure 2. graph of the relationship of intensity and 2θ in the characteristics of samples of arsenic without activation and temperature of 600 ̊c to 800 ̊c characterization of samples using xrd sample carbonation in the form of palm bunches (250-450 ̊c) crushing and sieving use (100 mesh sieve) the process of activating the sample using a furnace at various activation temperatures of 600 ̊c, 650 ̊c, 700 ̊c, 750 ̊c, and 800 ̊c analysis of the results of the sample characterization using software match 3 result mongkito et al. investigating the effects of activation temperature on the crystal structure… indonesian review of physics, volume 2, number 1, 2019 18 figure 2 shows the change in diffraction peak as the activation temperature increases. a crystal structure assumed with a peak image where the position of the diffraction peak provides information about the lattice parameter, the shape of the crystal, while the relative intensity of the diffraction peak provides information about the position of the atom in a unit cell. to see the relationship between angles 2θ and counts, match three software used, which then analyzed the peaks formed. from match 3 software results obtained in the form of structure or shape of crystals, elements contained, percentage of content and lattice parameters (å). the results of the analysis of match-three software seen in table 1. table 1. results of testing by the method of x-ray diffraction (xrd) analysis using software match temperature (oc) crystal structure component persentase 2 the lattice parameter (å) without activation orthorhombic diamond 90,2% 28,35o a= 4.12700 å b=4.93700 å c=4.81900 å orthorhombic graphite 5,7% 25,70o a= 4.52500 å b=5.33400 å c=5.92500 å hexagonal carbon 4,1% 23,12o a= 4.89000 å c=3.88000 å 600 orthorhombic diamond 38,1% 24,23o a= 4.87000 å b=5.56500 å c=4.40600 å orthorhombic graphite 15,8% 30,07o a= 4.57500 å b=5.30400 å c=5.63500 å hexagonal carbon 46,1% 43,67o a= 2.52210 å c=12.35570 å 650 orthorhombic diamond 57,4% 40,54o a= 4.96400 å b=5.16300 å c=4.38700 å orthorhombic graphite 21,4% 30,02o a= 4.52500 å b=5.33400 å c=5.92500 å hexagonal carbon 21,1% 22,66o a= 4.89000 å c=3.88000 å 700 orthorhombic diamond 49,3% 28,34o a= 4.12700 å b=4.93700 å c=4.81900 å hexagonal graphite 8,7% 26,69o a= 2.45600 å c=6.69600 å trigonal carbon 42,0% 44,58o a= 2.52210 å c=43.24500 å 750 orthorhombic diamond 66,3% 47,31o a= 4.12700 å b=4.93700 å c=4.81900 å orthorhombic graphite 7,0% 30,22o a= 4.57500 å b=5.30400 å c=5.63500 å hexagonal carbon 26,7% 42,86o a= 2.52210 å c=8.23710 å 800 orthorhombic diamond 84,6% 24,23o a= 4.87000 å b=5.56500 å c=4.40600 å orthorhombic graphite 12,5% 30,09o a= 4.52500 å b=5.33400 å c=5.92500 å hexagonal carbon 2,9% 31,20o a= 4.89000 å c=3.88000 å furthermore, the characteristics of the crystalline material determined by atomic bonds in the crystal, the orientation of the crystal plane. the distance between the crystal plane and the crystal system. the typical arrangement of atoms in crystals called a crystal system or crystal structure. diffraction is the process of x-ray scattering by crystal material. the xrd method uses an x-ray which diffracted as a ray reflected from each plane, formed with crystal atoms from the material each sample with different temperature variations, it will produce a different diffraction pattern from the samples. figure 3. diffractogram samples palm bunches on pre-heating and temperature of 600 ̊c-800 ̊c mongkito et al. investigating the effects of activation temperature on the crystal structure… indonesian review of physics, volume 2, number 1, 2019 19 based on the graph (figure 3) of measurement results with the xrd with the assisted of software match 3 before heated, 600 ̊c, 650 ̊c, 700 ̊c, 750 ̊c, 800 ̊c shows that the resulting diffraction peak contains diamond elements, graphite, and carbon which not periodic and the actual diffraction peaks formed leads to crystalline graphite. although the higher the activation temperature diffraction peaks, more dominant amorphous form characterized by irregular peaks generated. crystal diffraction peaks formed at each temperature change the intensity of the diffraction peak, either increasing or decreasing. discussion this study aims to determine the description of the crystalline structure formed in activated charcoal bunches using xrd (x-ray diffraction). the results of the analysis explain that there is a shift in the diffraction peaks towards the angle 2θ higher near the peak of graphite (26o) and new peaks appear around the 30o and 40o angles (figure 3). peak 26o and 40o characterize graphite in a flat plane (planar l), whereas at angle 27o-28o is a graphite crystal structure in the vertical plane. at different temperatures, the diffraction peak of the crystal formed at an angle of 28o still appears, what changes is the intensity of the peak diffraction. manocha argues that the arrangement of activated carbon particles is allotropic, which can change from one crystal cell unit structure to another at a specific temperature [19]. the statement confirmed from the analysis of the samples sixth graph, the crystal structure changes, and the angular position of each element, obtained as a result of the given temperature. after the search software match 3, on active charcoal samples, bunches of palm-based diffractogram (figure 2) with different temperature variations arise diffraction peaks typically. the highest diffraction peak around the corner 2θ: 28.390 from the peak formed seen that in some of the top structure already shows the crystal structure although not periodic. the second known that the crystal structure has energy peaks sharp and narrow and at some of the top chart above shows the characteristics mentioned crystal structure located around the corner 28,35o, 30o, 40,54o. although a relatively small diffraction intensity showed, an amorphous structure is more dominant than the crystal structure. the crystal structure formed at a temperature of 700 oc more transforms the diffraction peak shifts due to the vibration of atoms where the graphite element forms a hexagonal crystal structure which initially at a temperature of 650 oc with an orthorhombic structure. it evidenced by the percentage of graphite content from the sample before heated, which is 5.7% to 15.8% at a temperature of 600oc and increases to 21.4% at a temperature of 650oc, but the decline in temperatures 700°c is 8.7%. this data reinforced from the study of [20-21] that on x-ray investigation showing that microscopic crystalline activated charcoal is similar to graphite structure, where graphite consists of some plates arranged in parallel, and each plate has a hexagonal system with six carbon atom. with increasing temperatures given, the type of the element at some angle 2θ obtained will vary from one temperature to another temperature. other materials also have a hexagonal crystal structure is cdse or compounds of cadmium and selenium that widely used in solar cell technology. in the study [22-23] the thin layer of cdse formed a polycrystalline crystal with a hexagonal crystal system. changes in crystal structure with different materials have also studied [24] stated that the transformation of pyrolusite minerals with a tetragonal structure a cubic bixbyite structure than to tetragonal hausmannite occurred due to increased sintering temperature causing structural changes in manganese seeds. based on xrd analysis (figure 2) when this diamond element fitting process found at the angles of 2θ (28o and 40o), but further research is needed to see if in certain circumstances diamonds can be amorphous or vice versa and still need to be verified by the existence of diamonds with other characterizations such as raman spectroscopy. the principle of raman spectroscopy is the interaction between light and the sun that uses a beam of monochromatic light such as a laser. scattering through the sample cause the frequency shift and yielding information on vibration, rotation, or other low-frequency transition in the molecule and capable of providing a fingerprint where the molecules identified. because generally the making of diamond elements not easy, so other proofs needed with different characterizations. based on research conducted by [25] regarding the raman spectroscopy study of diamond and graphite in ureilite and the origin of diamonds explain that raman spectroscopy is a useful and non-destructive tool for checking the properties of carbon materials. raman spectroscopy studies to obtain information about diamond and graphite properties in ureilite. graphite quickly produced with diamonds when the proportions of h2 and mongkito et al. investigating the effects of activation temperature on the crystal structure… indonesian review of physics, volume 2, number 1, 2019 20 ch4 change slightly. notably, high ch4 content seems to support the growth of graphite. graphite in ureilite is well arranged compared to carbon material in chondroitin carbon. domain dimensional graphite is estimated at 45-110 a ̇. shifting the position the diamond peak to higher wave numbers seem to support the chemical vapor deposition of diamond origin ureilite containing carbon matrix. its silicon coarse-grained (millimeter) and regarded as the accumulation of magma ultrasonic or partial melting residues. however, impressive results appear where at a temperature of 700oc at an angle of 30.38o, the diffraction peak does not experience a decrease in intensity after the diffraction peak temperature of 650oc widens. the decline in the intensity of the diffraction peaks are clues to start the formation of aromatic compounds [26]. the compound is a constituent of hexagonal crystalline charcoal and activated charcoal structures. in smallman's and [27-28] explained the effect of heating on the structure of minerals that formed is that the properties of the material will change if given treatment such as heating on the resources of manganese seeds. these events can be explained by physics when seed manganese samples heated at a precise temperature, the mineral structure changes in manganese ore samples into a new mineral which is also beneficial for the industry. changes in the structure of manganese ore minerals can occur due to temperature sintering. the changing structure of the material due to the temperature also caused when a material is heated; there will be an increase in energy, which allows the atoms vibrate at interatomic distances higher [29]. the higher the energy applied, the distance between atoms would be getting away. for a certain level of energy (temperature), atoms can get away from each other more quickly and are more difficult to suppress. the influence of energy on the distance between atoms, namely the more significant the energy yielded, the distance between atoms will be further away. changing the spacing between atoms will affect the structure of the material. v. conclusion from the results of the analysis of sugar palm bunches samples with six types of temperature treatment obtained by the dominating element is diamond found in the sample without activation with a percentage of 90.2% with an orthorhombic crystal structure. giving the heating temperature variation or activated charcoal palm bunches affect the structure of the crystals formed. where the temperature of activation increases, the structure of the formed crystal is more amorphous, which is characterized by the irregularity of the resulting peak. acknowledgment our thanks to physics education laboratory universitas halu oleo and energy laboratory sepuluh nopember institute of technology for all assistance and facilities provided to the author so that this research completed references [1] sumaiyah, b. wirjosentono, and karsono, "utilization of microcrystalline cellulose of sugar palm bunches (arengapinnata (wurmb) merr.) as excipients tablet direct compression," international journal of pharmtech research, vol. 9, no. 7, pp. 130–139, 2016. 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[29] v. vlack and l. h, ilmu dan teknologi bahan. jakarta: erlangga, 1995. vivi hastuti rufa mongkito1*, muhammad anas2, wisda puspita bahar3 keywords: crystal structure, temperature activation, xrd, bunches of palm references indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 70 75 doi: 10.12928/irip.v4i2.5265 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 70 stem iscit learning tools to improve integrative scientific thinking dian artha kusumaningtyas1*, dwi sulisworo2, jumadi3, edi istiyono4 1 department of physics education, universitas ahmad dahlan, indonesia 2 postgraduate program of physics education, universitas ahmad dahlan, indonesia 3 postgraduate program of physics education, universitas negeri yogyakarta, indonesia 4 department of physics education, universitas negeri yogyakarta, indonesia email: dian.artha@pfis.uad.ac.id article info abstract article history received: aug 26, 2021 revised: dec 14, 2021 accepted: dec 14, 2021 learning in the era of the new university regulations experienced a revolution in students’ learning style and teachers’ teaching style because this situation caused many changes in the learning system. different types of learning alternatives are carried out to achieve learning that meets these conditions. integrative stem was selected as one of the learning models in the new order era. however, inclusive stem learning is difficult to do without support or learning tools, especially in distance learning. based on these needs, this research was carried out to develop support devices for the integrative stem model in university physics class students. this research is research and development (r&d). the development model used uses a 4d development model. the 4d model is synonymous with definition, design, development, and dissemination. in this study, an assistive device model was developed in an integrative mint learning device. the analysis results show that the development of integrative learning tools based on stem for students is rated as good, with an average of 80%. this is an open-access article under the cc–by-sa license. keywords: integrative scientific thinking learning media stem iscit the new normal to cite this article: d. a. kusumaningtyas, d. sulisworo, j. jumadi, and e. istiyono, “stem iscit learning tools to improve integrative scientific thinking,” indones. rev. phys., vol. 4, no. 2, pp. 70–75, 2021, doi: 10.12928/irip.v4i2.5265. i. introduction covid19 has become widespread, so the government decided to close schools and universities by switching to distance education [1]. several initiatives have been taken to ensure that learning activities continue. the sudden shift from classroom teaching to distance education at home also indicates the need for increased teaching skills [2], [3]. one type of pjj is online learning. the online learning system is a learning system without direct contact between teachers and students, but online through the internet [4]. this condition also requires teachers to innovate in learning [5], to be more creative in the design of learning that can be implemented online to foster students’ independence and thinking skills [6]. the implementation of innovative, pedagogical, and communicative learning can be done by selecting the learning methods used and optimizing technology, pedagogy and content. to achieve the learning objectives according to the level of difficulty of the material, the teacher tries to implement different learning models [7]. most of the learning models that are attempted are studentoriented learning models. one of the models some teachers focus on is a learning model that builds science, technology, engineering, and math (stem) content. according to li et al. [8], an interesting learning model to examine the integration of tpc is the mint approach since this mint-based learning method can solve phenomena through the simultaneous application of knowledge and skills. research suggests that the mint learning model focuses the educational process on solving real everyday problems by developing various aspects of attitudes, knowledge, and skills and increasing critical thinking and the ability to form logic [9]. another study found that the stem learning model could empower students to solve problems and stated that the stem learning model could empower children to get used to finding solutions [10]. in addition, it can stimulate the ability to convey information easily, have patience, teamwork, and various mental skills that can be applied to individuality and daily life. another benefit of stem is http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 70 75 71 kusumaningtyas, et al. stem iscit learning tools to improve integrative …. p-issn: 2621-3761 e-issn: 2621-2889 that stem-based learning empowers students’ thinking skills. however, the cause of stem learning was not optimally achieved because teachers still failed to gain full student engagement and critical thinking and promote communication skills [11], [12]. furthermore, literacy among students in understanding concepts and facts remains limited. furthermore, inclusive learning prepares students to recognize their abilities and make appropriate decisions [13]. deep knowledge of science, technology, and mathematics is a prerequisite for making the right decisions, good analytical skills, accurate data collection methods, and excellent communication skills [14]. the analysis results suggest that the future needs of teacher training candidates include the integration of mastery of pedagogical and professional competencies, mastery of tpc skills in the presentation of learning materials, and the ability of students to perform well. critical thinking skills, proper decision-making, and competition in mediation require data. based on preliminary studies and studies, it is interesting to study studies on the development of stem learning models to improve pedagogical and professional skills [12], [15]. additionally, researchers will also work with integrative scientific thinking (iscit) in stem learning. then the stem integrative scientific thinking (stem iscit) learning model is developed. during stem learning, learning tools are needed to support the learning process. building on the importance of devices in stem learning, this study was conducted to develop integrated stem-based learning tools in universities for physics students. ii. theory stem stem education means providing practical strengthening of education in stem fields separately and further developing an educational approach that integrates physics, technology, engineering, and mathematics by focusing the educational process on solving real problems in everyday life or professional life [12]. stem will aid education in indonesia since both education and stem aspire to enhance students’ higher-order thinking skills, such as creative and critical thinking. stem is an integrated learning approach that connects real-world applications with classroom learning that includes four disciplines: natural sciences (physics), technology, engineering results, and mathematics. the stem approach connects learning with four teaching components: science, technology, engineering, and mathematics [16]. in line with this, the stem approach can be implemented at the level of formal education/in the classroom and at the level of non-formal units/outside the classroom. stem in recent years has been widely applied in several countries, such as in taiwan. in indonesia, stem has also been used in recent years [10]. learning using the stem approach is expected to be able to build and develop physics education students so that they not only memorize concepts but are also guided to be able to integrate physics, technology, engineering, and mathematics so that they can improve critical thinking skills in physics education students towards learning materials. to be applied to teach science, especially physics because studying physics does discuss not only mathematical formulas but also uses other components, such as technology and engineering to understand the material. students in physics education may benefit from a stem approach that aims to improve skills, such as problem-solving and investigational skills. [17]–[19]. these skills are important to help improve human resources. learning media learning tools are items that teachers must prepare before conducting instruction [20]. learning is a process or method of causing people to learn [21]. devices are tools or equipment, but learning is a process or method of causing people to learn. learning devices are tools or equipment that allow instructors and students to carry out processes to carry out learning activities. teachers can use learning tools to help them carry out learning in the classroom, laboratory, or outside the classroom. the preparation of learning resources is part of learning planning, according to permendikbud no. 65 of 2013 concerning standards for primary and secondary education. a syllabus and lesson plans that conform to topic standards are used to plan to learn. learning scenarios and the production of learning media and resources, assessment tools, and learning scenarios are all part of the learning planning process [22]. iii. method the development procedure needs to involve product testing, and research implementation is carried out systematically to achieve an expected result. therefore, this research development procedure uses 4d [23]. the following is a research flow chart shown in figure 1. figure 1. research flowchart http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 70 75 72 kusumaningtyas, et al. stem iscit learning tools to improve integrative …. p-issn: 2621-3761 e-issn: 2621-2889 define this step is carried out to determine and define development needs. this definition analyzes development needs, research, and models suitable for product development and product development tailored to user needs. analysis can be done through literature searches or preliminary studies [24]. design the design stage (planning) makes the initial product (prototype). the prototype is the initial model (pre-model) developed during development. the development stage aims to produce a supporting device for the iscit stem learning model. the development of learning support devices begins with designing a model supporting device. the device developed is a supporting device for the iscit stem learning model. the device was developed based on syntax (stages), namely a description of the implementation of the model in the field in teaching and learning activities. the syntax can be described as a systematic process of learning activities related to the implementation of the model. develop the development stage can be divided into evaluation by experts and development testing [24]. assessment by experts is a method for validating or evaluating the feasibility of a product design. experts in each field assess these activities. the suggestions are used to improve the teaching materials and prepare learning designs. the validation results are used to improve the product. after the product is repaired, it is retested to achieve effective results. disseminate the dissemination stage can be divided into three activities: verification testing, packaging, dissemination, and recruitment. the product modified in the development stage is deployed to the actual target in the validation testing stage. the implementation also measures the achievement of goals. this measurement is carried out to ensure the validity of the developed product. after the product is implemented, the developer must see the results of achieving the goals. the last activities in the development stage are packaging and distribution. this procedure is done to make the product available to others. the field test at the disseminate stage involved 60 physics education students. in this test, research is carried out using products that have been developed and refined. iv. results and discussion define preliminary analysis based on the literature study carried out, the initiative is carried out to ensure that the activity takes place. the change from face-to-face methods in the classroom to distance learning at home indicates the need to increase teaching capacity [1], [2]. one type of pjj is bold learning. the bold learning system is without direct face-to-face interactions between teachers and students, but online using the internet network [3]. this condition also requires teachers to make innovations in learning [4], to be more creative in designing learning that can be applied boldly to foster student independence and thinking skills [5]. based on the importance of students’ critical thinking and the need for students to be associated with science, technology, mathematics, and engineering in learning, the application of stem learning in higher education is carried out [5], [6]. learning devices are needed to support the learning process in the stem learning process. task analysis task analysis is carried out to analyze the main tasks that the subject must master to achieve minimum competence. the analysis is done by making achievement indicators for each competency improved. the indicators created are product feasibility indicators and user responses. concept analysis conceptual analysis consists of a concept map that is used to achieve a certain ability to determine the main parts of the study material systematically. from the results obtained, the material that will be used to develop integrative stem learning devices on magnetic material and electromagnetic induction with the product to be made is an integrative stem learning device. formulation of learning objectives analysis of learning objectives is carried out to determine material analysis and curriculum analysis indicators. based on the material analysis and curriculum analysis, the manufacture of integrative stem learning tools on magnetic material and electromagnetic induction is carried out. design the design stage (planning) makes the initial product (prototype). the product developed is an integrative stem learning tool. planning is done by making a draft for further validation and testing on the subject. the design is made using a microscope office. development the development stage is divided into two activities, namely: expert evaluation and development testing. expert evaluation is a technique to verify or evaluate the feasibility of a product design. the evaluation is carried out by experts in their respective fields. the suggestions given are used to improve the teaching materials and designs that have been prepared. development testing is a product design testing activity aimed at the actual target object. based on expert test data analysis, it can be seen that the product produced through this research has been declared very feasible, with several suggestions for improvement (see figure 2). http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 70 75 73 kusumaningtyas, et al. stem iscit learning tools to improve integrative …. p-issn: 2621-3761 e-issn: 2621-2889 figure 2. summary graph of expert consensus on integrative stem learning tools based on figure 2, the integrative stem learning device developed is very feasible. validation data were obtained from three experts: physics education experts, instructional experts, and learning technology experts. from the aspect of title formulation, it can be seen that the average obtained is 100% that the model book made in the aspect of title formulation has an effective and efficient short title formulation, does not cause double interpretation, the display is legible (size and typeface are appropriate), and the suitability of the color composition selection already well. from a review of aspects of language clarity and terminology/components, it can be seen that the level of expert consensus on the feasibility of the book model has reached 100%. this shows that the experts agree that the clarity of language and terminology is suitable for formulating the developed book model. clarity of language and terminology are terms used in simple, clear models, will not cause misunderstanding and can be understood by readers, as well as the use of common foreign languages and applicable terms of use. in addition, in terms of the systematic aspects/components of the model, the level of expert consensus on the developed integrative stem learning tools has reached 100%. this means that experts agree that the system model compiled is suitable for being used as part of the integrative stem learning tool. expert opinion is based on evaluation, showing that the documents developed in the model book: systematics according to indicators that are consistent and interesting to the reader (readability), systematics according to consistency between projects, systematics according to intervention design, and systematics based on research and theory development (basic equipment). another aspect is the formulation of the definition of the expert consensus model, which reaches the 75% level, indicating that the student activity designs that have been prepared are feasible to use. this feasibility is based on evaluation results showing that the toolkit has: clear and understandable sources, current or contemporary (containing visionary elements), comprehensive compilation, and elements that fit the model and definition. they are prepared comprehensively, objectively, and decisively. among the four experts, only the material expert gave an unworthiness rating or percentage (75%) in this regard, and the other two experts gave a very good level of consensus. this is because the material experts are of the opinion that the model book in the definition section of the development model is not following the development model. furthermore, the model book was improved based on input from material experts to be further validated without being reassessed. judging from the formulation and hypotheses of the philosophical review, it can be seen that the average consensus level of experts has reached 88%, which indicates that the planned teaching activity plan is declared feasible as part of the teaching activity. philosophical comments and hypotheses are used. this level of consensus is based on the evaluation results, namely that the developed model book has considered the formulation and assumptions of philosophical comments as useful. the breadth and depth of the philosophical hypotheses and commentaries are drawn up with cultural backgrounds in mind. the formulation of philosophical and hypothetical reviews is designed according to the context of life and the development of science and technology. the formulation of philosophical reviews and hypotheses is generalized to specific (already coherent). as in the formulation of the model definition, in the formulation of hypotheses and this philosophical review, the material also provides the least appropriate level of consensus (50%), while the other three experts think it is very feasible. because, according to material experts, both the breadth and depth of philosophical interpretation need to be slightly improved. furthermore, the model book was improved based on input from material experts to be further validated without being reassessed. from the following aspects, namely problem identification, the consensus of experts has reached an average level of 100%, which indicates that the evaluation system designed is considered very suitable as part of the problem identification system. this feasibility is based on the evaluation results which show that the resulting model book covers the existing problems, namely the demands of the world of education and identification of problems based on the needs of the development of science and technology. as the dynamics of the world of work, problem identification is based on the need to improve the efficiency and effectiveness of the education/learning process, and problem identification is based on a comprehensive needs analysis. another aspect of the expert’s evaluation of the effectiveness of the model book is the determination of the type of product. from this aspect, it can be seen that the consensus of the experts has reached 100% which indicates that it is very suitable as an expert. the way to do a field trial is to test the product made on 60 physics education students. the results obtained have a good perception of 45.55 from a score of 56 and a percentage of 79% of the developed framework. based on figure 2, it can be concluded that the developed framework is categorized as good. rationality, supporting theory, social system, reaction principle, support system, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 70 75 74 kusumaningtyas, et al. stem iscit learning tools to improve integrative …. p-issn: 2621-3761 e-issn: 2621-2889 instructional impact, accompaniment impact, instructional implementation instructions, learning environment, management tasks, and assessment are among the characteristics that are evaluated. figure 3. student response data to the integrative stem learning tool this study was used to determine the feasibility of stem iscit products used in distance learning. in addition, it can be used as reference material in learning about magnetic electricity. this product is equipped with teaching materials, learning media, lesson plans, and learning evaluations v. conclusion the stem iscit learning tool to improve integrative science thinking has been created. the results of the data obtained show that this device is suitable for supporting the stem iscit model in the new normal era. this study has limitations, namely that it is only used to determine the effectiveness of the iscit stem learning device to improve integrative scientific thinking on magnetic electricity. suggestions for further research are to conduct expanded research and add learning tools to other materials. vi. acknowledgment we express our deepest gratitude to all those who have assisted during this research process. to the lpp uad, validators, physics education students uad and uny. references [1] h. d’orville, “covid-19 causes unprecedented educational disruption: is there a road towards a new normal?,” prospects, vol. 49, no. 1–2, pp. 11–15, oct. 2020, doi: 10.1007/s11125-020-09475-0. 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https://doi.org/10.26858/publikan.v10i1.12172 https://doi.org/10.21744/irjmis.v5i3.667 https://doi.org/10.29408/kpj.v4i2.2666 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 39 45 doi: 10.12928/irip.v4i2.4920 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 39 synthesis of calcium phosphate from cockle shell loaded by silver nanoparticle and its antibacterial activity evaluation yuant tiandho1, rahmad lingga2, evi.j3, rifqi almusawi rafsanjani4, and fitri afriani5* 1,3,5 department of physics, universitas bangka belitung, indonesia 2 department of biology, universitas bangka belitung, indonesia 4 department of physics, universitas indonesia, indonesia email: fitri-afriani@ubb.ac.id article info abstract article history received: sept 25, 2021 revised: dec 15, 2021 accepted: dec 27, 2021 this study aimed to synthesize calcium phosphate loaded with silver nanoparticles and evaluate its antibacterial activity. we used cockle shells waste as raw material to prepare calcium phosphate. x-ray diffraction analysis showed that the constituent phases of calcium phosphate consist of hydroxyapatite (ha) and β-tricalcium phosphate (β-tcp). the incorporation process of silver nanoparticles on calcium phosphate was carried out in colloidal silver nanoparticles via the green-synthesis method using citrus x microcarpa bunge peel extract. the presence of colloidal silver nanoparticles through the green synthesis method was identified using uv-vis spectrophotometer by the peak of the absorption band that occurred at 468 nm. the incorporation of silver nanoparticles into calcium phosphate did not significantly change the crystalline properties of ha and β-tcp. evaluation of the antibacterial activity showed the silver nanoparticles had a strong antibacterial effect against staphylococcus aureus, which also occurs in calcium phosphate loaded by silver nanoparticles. after being incorporated with silver nanoparticles, calcium phosphate generally has no antibacterial effect. after being incorporated with silver nanoparticles, an inhibition zone with a diameter of about 9.8 mm can form. these results indicated that the method proposed in this study could be an alternative for developing calcium phosphate, which requires self-sterilization properties. this is an open-access article under the cc–by-sa license. keywords: calcium phosphate silver nanoparticles antibacterial green-synthesis to cite this article: y. tiandho, r. lingga, e. evi.j, r. a. rafsanjani, and f. afriani, “synthesis of calcium phosphate from cockle shell loaded by silver nanoparticle and its antibacterial activity evaluation,” indones. rev. phys., vol. 4, no. 2, pp. 39–45, 2021, doi: 10.12928/irip.v4i2.4920. i. introduction the calcium phosphate ceramic family is a widely used material for biomedical and tissue engineering purposes [1]. various types of calcium phosphate have good biocompatibility properties and do not show toxic effects for humans. among various types of calcium phosphate ceramics, hydroxyapatite (ha) and β-tricalcium phosphate (β-tcp) are often used as bone substitution materials, dentistry, and orthopedics [2][3]. it is because both materials are biocompatible and biodegradable [4]. one novel application of calcium phosphate ceramics is used as a mask filtration material [5]. in addition to being biocompatible, the porous calcium phosphate has superior air filtration performance [6]. however, the use of calcium phosphate as a mask filtration medium and in orthopedics is often constrained by its antibacterial activity. calcium phosphate is known to be unable to form a zone of inhibition in bacterial culture and has no antibacterial effect. one potential solution to raise the antibacterial effect in calcium phosphate is through substitute silver nanoparticles in its structure. silver nanoparticles have high antibacterial activity and are biocompatible [7][8]. this work synthesizes calcium phosphate-loaded silver nanoparticles mediated by citrus x macrocarpa bunge (c. x macrocarpa bunge) peel extract. we modified the green-synthesis method that utilizes biological objects such as plant extracts to substitute silver http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 39 45 40 tiandho, et al. synthesis of calcium phosphate from cockle …. p-issn: 2621-3761 e-issn: 2621-2889 nanoparticles into calcium phosphate. it aims to minimize the use of chemical compounds that are toxic and not environmentally friendly. we used the c. x microcarpa bunge peel extract because of its phytochemical compounds, which can act as a reducing agent and capping agent in synthesizing nanoparticles and its abundance in the bangka belitung islands. the fruit of c. x microcarpa bunge is used by local people to source a sour flavor in various foods. in addition, in preparing calcium phosphate, we use cockle anadara granosa (a. granosa) shells as the raw material. cockle shells contain high amounts of calcium carbonate to be used to synthesize calcium phosphate ceramics [9]. the utilization of raw materials derived from natural materials avoids toxic contaminants and maintains their sustainability. ii. theory calcium phosphate is a group of minerals that contain calcium together with orthophosphate (po4 3), metaphosphate (po3 -), or pyrophosphate (p2o7 4-), and sometimes with hydrogen ions or hydroxide ions. two phases of calcium phosphate, which are very prominently applied in tissue engineering, are ha (ca10(po4)6(oh)2) and β-tcp (ca3(po4)2). this is because both are biocompatible, non-toxic, and biodegradable [1][10]. the crystalline properties of ha and β-tcp are presented in table 1 and table 2. ha and β-tcp can be synthesized by reacting calcium materials, for example, cao, with a phosphate source such as h3po4 or (nh4)2hpo4. therefore, there have been many studies on the synthesis of ha and tcp using natural materials rich in calcium, such as eggshells [11], bovine bones [12], and fish bones [13], in recent years [14]. silver nanoparticles are widely known materials to have vigorous antibacterial activity [15]. in summary, the mechanism of antibacterial activity of silver nanoparticles can occur based on the following steps: (i) the presence of silver nanoparticles damages the cell walls and cytoplasmic membranes of bacteria; (ii) ribosome denaturation occurs and inhibits protein synthesis; (iii) interfere with bacterial atp production because silver ions entering the bacterial system will inhibit the respiratory system; (iv) silver nanoparticle ions and reactive oxygen bind to dna so that cell replication and multiplication processes cannot occur; (v) the membrane denaturation process occurs, and (vi) perforation of the bacterial membrane occurred as indicated by the ability of silver nanoparticles to pass through the cytoplasmic membrane and destroy cell organelles [16]. there are many methods to synthesize silver nanoparticles. however, considering that silver nanoparticles will be applied in the biomedical field, the main problem in the synthesis process is to avoid using toxic chemical compounds. therefore, the green-synthesis method using natural sources such as plant extracts is proposed as a promising alternative solution [17]. various phytochemical compounds from plant extracts containing phenolic compounds can reduce particle size. this is because phenolic compounds have hydroxyl aromatic ring groups that can act as ligands to prevent agglomeration during the synthesis process [18]. table 1. crystalline properties of ha [19]. space group : p 63/m lattice parameter : a (å) : 9.41844 b (å) : 9.41844 c (å) : 6.88374 atomic coordinates x y z ca (1) : 0.3333 0.6667 0.0016 ca (2) : 0.2460 0.9923 0.2500 p : 0.3980 0.3680 0.2500 o (1) : 0.3275 0.4841 0.2500 o (2) : 0.5869 0.4649 0.2500 o (3) : 0.3436 0.2580 0.0705 o : 0.0000 0.0000 0.1975 h : 0.0000 0.0000 0.0540 table 2. crystalline properties of β-tcp [20]. space group : r 3 c lattice parameter : a (å) : 10.417 b (å) : 10.417 c (å) : 37.329 atomic coordinates x y z ca(1) : -0.2766 -0.1421 0.1658 ca(2) : -0.3836 -0.1775 -0.0336 ca(3) : -0.2721 -0.1482 0.0606 ca(4) : 0.0000 0.0000 -0.0850 ca(5) : 0.0000 0.0000 -0.2658 p(1) : 0.0000 0.0000 0.0000 p(2) : -0.3109 -0.1365 -0.1320 p(3) : -0.3465 -0.1537 -0.2333 o(1) : -0.2736 -0.0900 -0.0926 o(2) : -0.2302 -0.2171 -0.1446 o(3) : -0.2735 0.0053 -0.1523 o(4) : -0.4777 -0.2392 -0.1378 o(5) : -0.4031 -0.0489 -0.2211 o(6) : -0.4246 -0.3056 -0.2152 o(7) : 0.1814 -0.0805 -0.2233 o(8) : -0.3696 -0.1748 -0.2735 o(9) : 0.0070 -0.1366 -0.0136 o(10) : 0.0000 0.0000 0.0400 iii. method preparation of calcium phosphate from cockle shells the cockle shells (a. granosa) used in this study were collected from the pangkalpinang city market, bangka belitung islands, indonesia. the cockle shells were washed and dried in the sun to eliminate macro dirts. the cockle shells were calcined at 1000 ℃ to decompose calcium carbonate compounds as given in the following reaction [21]: 3 2 caco cao+co→ (1) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 39 45 41 tiandho, et al. synthesis of calcium phosphate from cockle …. p-issn: 2621-3761 e-issn: 2621-2889 afterward, calcined cockle shells were dissolved into 100 ml of distilled water. as a phosphate source, we added h3po4 solution at a ca/p ratio of 1.5. precipitation was carried out using a magnetic stirrer at a temperature of 50 °c for 2 hours. the residue was sintered at 1000°c for 7 hours, thus considered a stock calcium phosphate for synthesis. preparation of c. x microcarpa bunge peel extract we used c. x microcarpa bunge fruit waste from bangka regency, bangka belitung islands, indonesia. we grounded the peel using a blender to obtain a coarse powder to facilitate the extraction process, as shown in figure 1. afterward, we used the maceration method to produce the extract by mixing two gr of peel powder with five ml distilled water as a solvent. the extract preparation process was carried out using a magnetic stirrer at a temperature of 100ᵒ ℃. the extract was filtered and stored at 4℃ for further use. synthesis of calcium phosphate loaded with silver nanoparticles about 12 grams of agno3 was dissolved in 400 ml of distilled water and stirred for 30 minutes. afterward, 100 ml of c. x microcarpa bunge extract was added and stirred for 48 hours. as an accelerator, we added naoh until ph = 7 was reached. the synthesis of calcium phosphate loaded with silver nanoparticles was carried out by adding calcium phosphate to 100 ml of silver nanoparticles in the extract and stirring for one hour. in this study, we varied the concentration of calcium phosphate by 3 grams (cp3/ag) and 5 grams (cp5/ag). the powder was filtered and dried using an oven at 110℃. schematically, the calcium phosphate synthesis route containing silver nanoparticles in this study is shown in figure 2. figure 1. (a) c. x microcarpa bunge fruit and (b) the grounded peels figure 2. schematic diagram of calcium phosphate synthesis (top) and calcium phosphate loaded silver nanoparticles synthesis (bottom) routes material characterization and antibacterial activity to investigate the crystalline properties of the synthesized calcium phosphate, in both pure calcium phosphate and calcium phosphate loaded by silver nanoparticles, we used x-ray diffraction (xrd). we analyzed the xrd data using the rietveld method. the presence of colloidal silver nanoparticles formed in the green synthesis was indicated by the absorption band using a uv-vis spectrophotometer in the range of 200 nm – 900 nm. the absorption peak that appears is related to the surface plasmon resonance of the silver nanoparticles. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 39 45 42 tiandho, et al. synthesis of calcium phosphate from cockle …. p-issn: 2621-3761 e-issn: 2621-2889 antibacterial activity was conducted against staphylococcus aureus (s. aureus) bacteria by disc paper diffusion method. the bacterial growth medium we used in this study was nutrient agar (na), and microbial inoculation was done by streaking the bacterial suspension on the na medium. furthermore, the disc paper that had been dipped in a mixture of calcium phosphate loaded with silver nanoparticles was placed on na medium and incubated for 24 hours at 37°c. the experiment was repeated three times, and the antibacterial activity was indicated by the average diameter of the inhibition zone. iv. results and discussion figure 3 shows the xrd pattern of the calcium phosphate synthesized in this work. after the refinement process, it is known that the types of calcium phosphate formed are ha and β-tcp. the goodness of fit coefficient value (χ2) of 0.205 indicates that the refinement has good quality. the three highest peaks associated with ha are indicated by peaks 52.97°, 30.97°, and 31.09°, and these peaks correspond to orientations 0 4 14, 0 2 10, and 2 1 7. crystal structure of the synthesized ha is hexagonal with space group p 63/m and has cell parameters: a = b = 9.3893 å and c = 6.8839 å. the three highest peaks associated with β-tcp are at positions 31.05°, 34.39°, and 27.82° and correspond to orientations 0 2 10, 2 2 0, and 2 1 4. the crystal structure of the synthesized β-tcp is trigonal with space group r 3 c. the cell parameters of βtcp are a = b = 10.431å and c = 37.3858 å. the cell volumes of ha and β-tcp were 525.58 å3 and 3522.81 å3, respectively. refinement calculations show that the molar percentages of ha and β-tcp are 12.98% and 87.02%, respectively. it indicates that calcium phosphate synthesized is dominated by β-tcp. it occurs because the ca/p ratio of h3po4 used is close to the ca/p ratio of βtcp. the diffraction pattern of β-tcp synthesized in this study is similar to other studies such as afriani et al. (2015), who synthesized tcp from eggshell [11], and kang et al. (2017), who synthesized β-tcp from abalone shell [22]. by substituting cell parameter data and atomic coordinates of ha and β-tcp, the crystal structure of both phases is presented in figure 4. figure 5 shows the color change of the c. x microcarpa bunge extract after agno3 was added from initially orange to black. the color change indicates that silver nanoparticles have started to form in the mixture. this transformation can also be observed through the absorbance band of the uv-vis spectrophotometer in figure 6. the absorbance peak of the extract of c. x microcarpa bunge occurred at wavelengths of 276 nm and 320 nm. the absorbance peak is related to the characteristics of the abundant citric acid in this plant [23]. after mixing with agno3, an absorbance peak was formed at a wavelength of 468 nm. the absorbance peak indicates that silver nanoparticles have been formed in the mixture. this is because noble metals have unique optical properties due to their surface plasmon resonance (spr) properties. spr is a collective oscillation of the conduction electrons under resonance conditions with the wavelength of the illuminating light. the type, size, and shape of the nanoparticles affect the spectral position of the plasmon band absorption. in various studies, it is known that spr of silver nanoparticles occurs at a wavelength of 400-500 nm [24]. figure 3. xrd pattern of calcium phosphate synthesized from cockle shell waste. the + symbol indicates the experimental data (obs), and a solid line indicates the calculation (calc) of the refinement. the lower trace is the difference between experiment and calculation (diff). the vertical lines mark the position of the calculated bragg peaks for an ha and β-tcp, respectively. figure 4. structure of: (a) β-tcp and (b) ha; color code: ca atoms in brown, p atoms in turquoise, o atoms in red and h atoms in blue. image created with vesta [25]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 39 45 43 tiandho, et al. synthesis of calcium phosphate from cockle …. p-issn: 2621-3761 e-issn: 2621-2889 figure 5. visual changes in the extract: (a) before and (b) after mixed with agno3 figure 6. uv-visible spectra of c. x microcarpa bunge skin extract and silver nanoparticles synthesized by green synthesis method figure 7 presents the refinement results of the xrd pattern of calcium phosphate loaded with silver nanoparticles. the xrd pattern in figure 7(a) is the xrd pattern for the cp3/ag, and the xrd pattern in figure 7(b) is the xrd pattern for the cp5/ag. the refinement for the xrd pattern belonging to cp3/ag has a goodness of fit coefficient value (χ2) of 0.457. the three compounds correlated with the xrd pattern were ha, β-tcp, and silver nanoparticles. after loading the silver nanoparticles, there was no significant change in ha and β-tcp type of crystal structure, each still in the space group p 63/m and r 3 c. the cell parameters of ha were a = b = 9.3394 å and c = 6.888 å while the cell parameters of β-tcp are a = b = 10.4818 å and c = 37.4468. the cell volumes of ha and β-tcp were 520.3 å3 and 3563.01 å3, respectively. compared with the initial conditions, the volume of ha cells slightly decreased while the volume of β-tcp cells expanded slightly. the cell parameters of silver nanoparticles in cp3/ag are a = b = c = 4.0973 å with a cell volume of 68.78 å3. based on the calculations, the molar percentages of ha, β-tcp, and silver nanoparticles in cp3/ag are 12.53%, 85.81%, and 1.66%, respectively. through refinement, as shown in figure 7(b), which has a goodness of fit coefficient (χ2) of 0.867, it is also known that the xrd pattern of cp5/ag is related to the ha, βtcp, and silver nanoparticles phases. the three phases have the same space group as in cp3/ag, namely ha in p 63/m, β-tcp in r 3 c, and silver nanoparticles in f m 3 m. cell parameters of ha, β-tcp, and silver nanoparticles are a = b = 9.3387 å and c = 6.8935 å; a = b = 10.4781 å and c = 37.424 å, a = b = c = 4.097 å, respectively. the cell volumes of the three phases are 520.64 å3, 3558.33 å3, and 68.75 å3. through refinement calculations, the molar percentages of the ha, β-tcp, and silver nanoparticles phases were 12.55%, 85.79%, and 1.66%, respectively. there was no significant difference between the molar percentages of cp3/ag and cp5/ag. it indicates that adding 3 grams of calcium phosphate and 5 grams to 100 ml of prepared colloidal silver nanoparticles can contain the same amount of silver nanoparticles. it occurs because the amount of colloidal silver nanoparticles is still above the loading capacity of calcium phosphate. figure 7. xrd pattern of calcium phosphate loaded by silver nanoparticles: (a) tcp3/ag and (b) tcp5/ag. the + symbol indicates the experimental data (obs), and a solid line indicates the calculation (calc) of the refinement. the lower trace is the difference between experiment and calculation (diff). the vertical lines mark the position of the calculated bragg peaks for an ha, β-tcp, and silver nanoparticles, respectively figure 8 shows the inhibition zone of calcium phosphate loaded with silver nanoparticles and pure silver nanoparticles. based on these results, it appears that calcium phosphate loaded with silver nanoparticles has an inhibition zone indicating an antibacterial effect. the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 39 45 44 tiandho, et al. synthesis of calcium phosphate from cockle …. p-issn: 2621-3761 e-issn: 2621-2889 inhibition zone of cp3/ag and cp5/ag was (9 ± 4) mm and (10 ± 3) mm, respectively. it appears that the two calcium phosphates loaded with silver nanoparticles have no significantly different inhibition zones. it can happen because, based on xrd analysis, the molar percentage of silver nanoparticles in calcium phosphate does not have a significant difference. as shown in figure 8(c), the silver nanoparticles synthesized in this study had the widest inhibition zone with (22 ± 2) mm diameter. the high activity of silver nanoparticles is because silver nanoparticles, through the presence of ag+ ions, can damage the cell walls and membranes of s. aureus and then interact with s and p-containing compounds, inhibiting the process of respiration replication and inactivating proteins. figure 8. inhibition zones of (a) cp3/ag, (b) cp5/ag, and silver nanoparticles against s. aureus. v. conclusion this study successfully synthesized calcium phosphate from cockle shell waste. we also incorporated silver nanoparticles into the calcium phosphate structure to obtain an antibacterial effect through the green synthesis method. xrd pattern analysis showed that the calcium phosphate produced was composed of two calcium phosphate phases, namely ha and β-tcp. the use of c. x microcarpa bunge peel extract in green-synthesis of silver nanoparticles also showed satisfactory results. through the uv-vis absorption band pattern related to the surface plasmon frequency of silver nanoparticles, it has been indicated that colloidal silver nanoparticles can be formed through the green-synthesis method. the synthesized silver nanoparticles had a strong antibacterial effect against s. aureus. therefore, investigations on the antibacterial activity of calcium phosphate loaded with silver nanoparticles also showed an antibacterial effect. thus, the method offered in this research can be used in the future to develop calcium phosphate-based biocompatible materials that have self-sterilization properties. vi. acknowledgment this research was funded by the institute for research and community services (lppm) universitas bangka belitung through hibah penelitian unggulan scheme in 2021 (no.: 17.29/un50/pp/iii/2021). references [1] n. eliaz and n. metoki, “calcium phosphate bioceramics: a review of their history, structure, properties, coating technologies and biomedical applications,” materials (basel)., vol. 10, no. 4, 2017, doi: 10.3390/ma10040334. 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[4] revealed that the flores region has the potential for tectonic earthquakes and generates tsunamis. the earthquake catalog noted that flores was hit by an earthquake and tsunami with mw > 7 in 1992 [9]. okal [10] explains that the 1992 flores earthquake and tsunami were caused by an underwater landslide and resulted in an extreme run-up as high as 26 m. pranantyo and cummins [11] added that this phenomenon causes a change in ground level with a lift of 1.1 m and a drop of -1.6 m. the results of field observations explained that after the tsunami occurred, there were no traces of buildings found on babi island, flores [12], and the destruction of most of the north coast of flores. this phenomenon also caused 1,952 dead and http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i2.6706 http://journal2.uad.ac.id/index.php/irip mailto:husnaniazmi@gmail.com http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 66 72 67 khusnani, et al. utilization of seismic data as a tsunami vulnerability review p-issn: 2621-3761 e-issn: 2621-2889 500 people to go missing [13]. other findings revealed that the damage caused by tsunami waves came from two directions with different magnitudes and deposited sand on the north and south coast [14]. the disaster that occurred in 1992 was destructive. progress in tsunami research is that there has been a decrease in the number of victims affected [15]. however, the tsunami warning system has not been able to reduce the number of victims affected by the tsunami. therefore, carrying out a tsunami risk assessment is crucial, especially in coastal areas [16]. a tsunami risk assessment can be in the form of conducting a tsunami risk mapping. sengaji and nababan [17] conducted tsunami risk mapping using earthquake distribution data from 1900 to 2007. however, on december 14, 2021, bmkg (badan meteorology, climatology, and geophysics) noted that an earthquake with an earthquake of mw 7.4 scale occurred, which resulted in a small tsunami with a height of 7 cm [18]. due to the flores area's significant potential for earthquakes and tsunamis, it is necessary to update the analysis of the vulnerability level. the current results are expected to be used as a reference input for stakeholders in disaster mitigation. based on the description above, the purpose of this study is to analyze seismic data, which is then made into an infographic to map the level of tsunami hazard in sikka district. ii. theory flores earthquake review based on geological data, handayani [9] explained that flores island is in an active tectonic area, where several plate boundaries bound the region. the plate boundary in the area is the eastern end of the subduction of the indo-australian plate towards eurasia, with the plate length extending from java to sumatra. the australian continental plate and the banda plate collide at the western boundary. the northern coastal area of flores island (as per figure 1) is the flores back thrust that extends along the island and is connected to the wetar thrust in the east. figure 1. active fault in flores island (https://geologi.esdm.go.id/geomap/) based on the study of earthquake history over 30 years, two earthquakes had mw > 7. on december 12, 1992, an earthquake with an mw of 7.8 occurred near babi island. people in the eastern half of flores island and the surrounding islands can feel the earthquake. in addition to an earthquake with a large magnitude, this earthquake caused a tsunami with inundation reaching a distance of 30 m to the west, a depth of 20.4 km, and a run-up measured at ilepadung – east flores of 11 m, babi island, sikka district 5.5 m, and wuring sikka 2.4 m [13]. the next earthquake occurred on december 14, 2021, in flores with a strike-slip mechanism causing a new fault [19]. if tracing the past earthquake (50 years) in the area, there was an earthquake in 1997 with mw 8.3 and 1995 with mw 6.5. based on the previous description, wiens [20] explained that a giant earthquake that occurs will be accompanied by aftershocks, which are related to changes in the polarity of the displacement waveform. meanwhile, another explanation was put forward by goes et al. [21] the fault mechanism changes in the mainshock and aftershock, caused by the strike-slip component of the mainshock consistent with the clockwise rotation of the slab material in an east-west direction to north-south. the study's results follow the surface structure modeling in figure 2 [22]. the modeling in figure 3 corresponds to setiadi [23]. the relocation results showed a significant decrease in the hypocenter to the north of about 640 km. he found a gap of earthquake activity along the subduction plate at the hypocenter of 300 400 km due to the partial melting of rocks in the mantle layer. figure 2. 3d modeling of subsurface structures in the region [22] figure 3. image of a three-dimensional model of the relocation of teletomo dd [23] tsunami a tsunami is a series of ocean waves with a large wavelength. tsunamis occur due to the movement of a substantial volume of water. this event can be caused by an earthquake or ground shaking in the sea [24]. in addition, a tsunami can be characterized by a sudden drop http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://geologi.esdm.go.id/geomap/pages/preview/peta-patahan-aktif-indonesia indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 66 72 68 khusnani, et al. utilization of seismic data as a tsunami vulnerability review p-issn: 2621-3761 e-issn: 2621-2889 in sea level followed by a substantial increase in seawater volume towards the coast and a vertical tsunami [25]. tsunami disasters can sometimes be global, originating from one place and destructive at a distance of thousands of kilometers from the source. if you trace the history of the tsunami that occurred, it can be seen that the process of tsunami occurrence has different events based on the cause of its occurrence. tsunami run-up tsunami run-up is the height of sea water waves calculated from the absolute limit of tsunami wave inundation from the zero point of sea level or mean sea level. the run-up height and tsunami height depend on the earthquake magnitude, seafloor morphology, and the shape of the coast. the magnitude of an earthquake affects the energy that causes a tsunami. therefore, the upper runup limit is an important parameter to determine the beach profile. difficulties that are often encountered when predicting run-up are sea wave transformation and wave reflection. land run-up speed can reach 25-100 km/h. the return of water to the sea after reaching the wave crest (run down) is also destructive because it drags everything back into the sea [26]. when the tsunami approaches the shoreline/land, the shallow part of the seabed serves to break or reduce the bottom wave propagation speed. therefore, the closer you get to the beach, the slower the speed of the lower sea waves, while the speed of the upper waves is still high, the higher the sea wave height or amplitude and the shorter the wavelength. likewise, the faster the friction between the waves and the beach bottom, the slower the bottom wave propagation speed, but the higher the maximum wave amplitude (run-up) will be greater. iii. method the research was carried out in sikka district, east nusa tenggara, which is located between 12155'40''12241'30'' east longitude and 0822'-0850' south latitude. the earthquake data was used on december 14, 2021, using data from the iris (incorporated research institutions for seismology) earthquake browser (https://ds.iris.edu/ieb/). in the analysis stage, two stages are carried out. the first stage analyzes seismic data, and the second is eq energy. eq energy is the cumulative seismic energy released by an earthquake. the eq energy value was obtained using iris data. this analysis will focus on the cumulative energy growth of the earthquake impact. the following analysis is tsunami risk mapping by determining tsunami hazards in areas with the potential for a tsunami to occur. tsunami-prone areas are mapped by mapping tsunami height point data or run-up analysis based on the data for the tsunami in flores on december 14, 2021. the tsunami run-up analysis is beneficial to determine the area's vulnerability to the potential for a tsunami, with the criteria for exposure according to table 1 [17]. iv. results and discussion seismic analysis of the flores area the flores sea area is seismically active, following figure 4 shows seismicity data from 1970-2022 with mw 5.0. based on the earthquake's depth analysis during this period, the depth values varied from 0-33 km in purple to 800 km in red (figure 4b). seismicity studies say that the zone classification in the flores region is divided into five parts. the category is the flores back arc thrust zone in the north of the island with shallow to medium thrust, shallow and medium thrust zones in timor through, and intermediate depth thrusts in the sawu basin and normal in the east, between sumbawa island and flores with strike-slip and subduction earthquakes [9], [27]. the new findings suggest that the flores back arc thrust has extended along the southern boundary of the java sea from alor in the east to east java in the western java sea [11], [28]. pranantyo et al. [2] pointed out that, in the flores region, there had been a tsunami phenomenon in the preinstrumental period (in 1815, 1818, 1820, and 1836) and the period after the 1992 pre-instrumental with mw 7.8. this phenomenon relates to flore's back arc thrust tectonic activity [2], [13]. in the earthquake phenomenon, the magnitude of the magneto plays a significant role in tsunami generation. it is because the emergence of an earthquake can be followed by other phenomena [29]. the reappearance of the december 14, 2021, earthquake has great potential to release energy. based on bmkg data, the spectral acceleration analysis noted that the ground acceleration value based on the accelerograph sensor showed a variable value between 0.16 to 74.44 gals. the study results from the nearest station (lfti), about 91.99 km from the earthquake's epicenter, recorded a maximum ground acceleration of 24.45 gals. however, compared with the ibti seismic station, the ground acceleration of 74.44 gals can be felt in ile boleng, east flores, with a distance from the epicenter of about 120.6 km. so, based on this analysis, it will impact the cumulative energy if it is reviewed based on the arrival time of the p wave (figure 2). table 1. relationship of tsunami run-up height, tsunami risk, and level of damage run-up height (m) damage risk level (r) scale > 16 very big very high risk 5 6-16 big hight risk 4 2-6 intermediate medium risk 3 0.75-2 small low risk 2 < 0.75 very small very low risk 1 the earthquake on december 14, 2021, with mw 7.4, resulted in a small tsunami with a height of 7 cm [18]. when viewed based on the energy generated. figure 5 is the result of eq energy for mw 7.3 flores sea by iris. based on figure 5 for the cumulative energy plot for earthquake data on december 14, 2021, it is determined that this phenomenon is at a high frequency of http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://ds.iris.edu/ieb/ indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 66 72 69 khusnani, et al. utilization of seismic data as a tsunami vulnerability review p-issn: 2621-3761 e-issn: 2621-2889 0.5-2 s and a wideband range of 0.5-70 s. the black vertical line (91 s) represents the inflection point determined by the crossover between near-constant growth and highfrequency energy, then marks the approximate burst duration [30]. at this point, the cumulative energy is determined for high frequency (ehf = 6.46 × 10 14 j) and broadband (ebb = 5.48 × 10 15 j). the high-frequency energy values are equivalent and assume only 1/5 of the energy is available in the selected higher pass band. (a) (b) figure 4. seismic activity in the flores region for the period 1970-2022, (a) distribution of seismic activity, and (b) distribution of earthquake activity based on depth and magnitude figure 5. eq energy for mw 7.3 flores sea http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 66 72 70 khusnani, et al. utilization of seismic data as a tsunami vulnerability review p-issn: 2621-3761 e-issn: 2621-2889 while figure 6 is a hemispheric visualization event that is taken regularly at a distance of 25 degrees to 80 degrees. it is done to avoid triplication and energy bias calculations when there is a dense collection of stations. it is taken from the initial station collection using a minimum distance between stations of 5 degrees sampled from available broadband stations. the seismicity data analysis shows that sikka district has the potential for an earthquake accompanied by a tsunami; this can be seen in the 1992 flores earthquake, with the most severely affected area in maumere, sikka district. it is crucial to map tsunami-prone locations. common mistakes include subscripts; for instance, the quant. analysis of the tsunami hazard level of sikka district determination of the level of tsunami susceptibility aims to determine the potential tsunami area. figure 7 is a map of the tsunami hazard area in the sikka district. the area's vulnerability level to possible tsunami is in table 1, where high vulnerability with run-up > 6-16 m is in the alok subdistrict and part of the talibura subdistrict. furthermore, moderate exposure with run-up height > 2-6 m covers almost the entire northern coastal area, namely the magepanda subdistrict, alok subdistrict, waigete subdistrict, and talibura subdistrict. meanwhile, the lowest vulnerability with run-up > 0.75-2 m is in the kewapante subdistrict. the coastal area is an area that is directly nearby the sea and has the potential to be affected by a tsunami [31]. the high level of vulnerability in figure 7 indicates that the area has a high potential for a tsunami. based on the analysis results, it can be claimed that the overall vulnerability level of the sikka district is low; this is because the sikka district area is dominated by hilly regions (figure 8). however, many people live in coastal areas. for example, in the 1992 flores tsunami phenomenon, it was found that most of the victims were in the alok subdistrict, where the population lives in the wuring and beru areas, which coincide with the coastal areas with a very high vulnerability level (figure 9). (a) (b) figure 6. hemispheric visualization, (a) bb (0.5-70 sec), and (b) hf (0.5-2 sec) figure 7. tsunami hazard map based on tsunami run-up data for coastal areas http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.2, december 2022, pp. 66 72 71 khusnani, et al. utilization of seismic data as a tsunami vulnerability review p-issn: 2621-3761 e-issn: 2621-2889 figure 8. tsunami hazard map of sikka district figure 9. map of settlements in the coastal area of alok subdistrict (https://www.google.com/maps/) v. conclusion the seismic data analysis shows that the flores area has the potential for earthquakes with tsunamis, which is indicated by the number of earthquakes with a scale of mw 5 from 1970-2022. it plays a critical role in tsunami generation. in addition, the flores sea has a history of earthquakes accompanied by tsunamis from the preinstrumental period and after the pre-instrumental period. based on the eq energy analysis caused by the december 14, 2021 earthquake, it is known that the value of ehf = 6.46 × 1014 j and ebb = 5.48 × 10 15 j. furthermore, the analysis of the level of tsunami vulnerability based on the tsunami run-up height in sikka district indicates that the coastal area of the northern coast of flores has diverse potential, with the highest level of exposure in the subdistrict of alok and parts of talibura. meanwhile, the area with the lowest potential is in the kewapante subdistrict. there is a potential for a tsunami on the north sea coast of flores, so research on simulating inundation due to a tsunami will be very supportive as a mitigation effort. vi. acknowledgment the researcher would like to thank the indonesian ministry of education, culture, research and technology for providing research funds through the 2022 beginner lecturer research grant scheme (pdp). references [1] h. kurnio, t. naibaho, and c. purwanto, “review of submarine landslides in the eastern indonesia region,” bull. mar. geol., vol. 34, no. 2, pp. 63–76, dec. 2019, doi: 10.32693/bomg.34.2.2019.618. 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[31] m. a. marfai et al., “tsunami hazard mapping and loss estimation using geographic information system in drini beach, gunungkidul coastal area, yogyakarta, indonesia,” e3s web conf., vol. 76, p. 03010, jan. 2019, doi: 10.1051/e3sconf/20197603010. declarations author contribution : azmi khusnani is responsible for the entire research project. he also leads scriptwriting and collaborations with other writers. adi jufriansah participated in data collection and analysis. mulya afriyanto participated as a data supplier. all authors approved the final manuscript. funding statement : this research is funded by the government of indonesian ministry of education, culture, research and technology with the contract no. 1098/ll15/km/2022) conflict of interest : all authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.4217/opr.2015.37.2.091 https://doi.org/10.1051/e3sconf/202133107001 https://doi.org/10.1130/0091-7613(1997)025%3c0523:sospcb%3e2.3.co;2 https://doi.org/10.1007/s00024-020-02451-x https://doi.org/10.1144/sp501-2019-107 https://doi.org/10.29244/jitkt.v1i1.7938 https://vsi.esdm.go.id/index.php/gempabumi-a-tsunami/kejadian-gempabumi-a-tsunami/3868-analisis-geologi-kejadian-gempa-bumi-merusak-di-laut-flores-tanggal-14-desember-2021 https://vsi.esdm.go.id/index.php/gempabumi-a-tsunami/kejadian-gempabumi-a-tsunami/3868-analisis-geologi-kejadian-gempa-bumi-merusak-di-laut-flores-tanggal-14-desember-2021 https://vsi.esdm.go.id/index.php/gempabumi-a-tsunami/kejadian-gempabumi-a-tsunami/3868-analisis-geologi-kejadian-gempa-bumi-merusak-di-laut-flores-tanggal-14-desember-2021 https://vsi.esdm.go.id/index.php/gempabumi-a-tsunami/kejadian-gempabumi-a-tsunami/3868-analisis-geologi-kejadian-gempa-bumi-merusak-di-laut-flores-tanggal-14-desember-2021 https://doi.org/10.1785/0320220015 https://doi.org/10.1029/98gl00417 https://doi.org/10.1029/97gl01245 https://jurnal.stmkg.ac.id/index.php/pjg/article/view/260 https://doi.org/10.34126/jlbg.v9i1.149 https://doi.org/10.21009/jmt.3.1.2 https://doi.org/10.1016/j.joes.2021.10.004 https://doi.org/10.24843/bf.2022.v23.i02.p08 https://doi.org/10.1007/s00024-019-02390-2 https://doi.org/10.1007/s00024-019-02390-2 https://doi.org/10.1029/2019gl086472 https://doi.org/10.1007/s00024-019-02266-5 https://doi.org/10.1029/95jb01969 https://doi.org/10.1051/e3sconf/20197603010 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 46 54 doi: 10.12928/irip.v4i2.4803 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 46 comparison of euler and euler-cromer numerical methods for undamped and damped spring oscillation nurul miftakhul janah*1, fajrul falah2, ratnawati3, ishafit4, wipsar sunu brams dwandaru5 1,2,3,4 postgraduate program of physics education, universitas ahmad dahlan, indonesia 5 department of physics education, universitas negeri yogyakarta, indonesia email: nurul2007041009@webmail.uad.ac.id article info abstract article history received: sept 02, 2021 revised: dec 12, 2021 accepted: dec 12, 2021 this study aimed to numerically analyze damped and undamped oscillations of a spring using the euler and euler-cromer methods via spreadsheet software. the varied parameters in this study were the damping constant, namely 0.1 (damped) and 0.0 (undamped). various quantities analyzed in this study were position (x), velocity (v), kinetic energy (k), potential energy (u), mechanical energy (e), and phase space as a function of time (t). iteration was done in t < 60-time steps (seconds). the results of this study indicated that when the spring experiences damping, the numerical results of x, v, k, u, e, and the phase space decrease periodically to zero due to the damping force, both for the euler and eulercromer methods. meanwhile, for the undamped spring (zero damping constant), there was a difference in the results for the euler and euler-cromer methods. for the euler method, the resulting values of x, v, k, u, e, and the phase space increased periodically with time, which was not following the actual situation. according to the simple harmonic oscillation, the euler-cromer method values of x, v, k, u, e, and the phase space were stable over time. this is an open-access article under the cc–by-sa license. keywords: damped oscillation undamped oscillation euler method euler-cromer method to cite this article: n. m. janah, f. falah, r. ratnawati, i. ishafit, and w. s. b. dwandaru, “comparison of euler and euler-cromer numerical methods for undamped and damped spring oscillation,” indones. rev. phys., vol. 4, no. 2, pp. 46–54, 2021, doi: 10.12928/irip.v4i2.4803. i. introduction science and technology, especially in the field of electronics, have rapidly progressed. this has resulted in the rapid development of computational physics [1], which examines physics problems based on numerical and/or simulation studies. computational physics can provide accurate calculations of various physical phenomena to serve as a visualization tool [2] or simulation of physical phenomena [3]. computational physics can also provide solutions that can be compared with analytical results. one of the uses of computational physics is solving differential equations using computer software, e.g., spreadsheet. differential equations are a part of mathematics, especially calculus, which has a very important role in physics. various laws of physics can be expressed in the form of differential equations, including newton’s laws [4], maxwell’s equations [5], and the first law of thermodynamics [6]. these various differential equations need to be solved to obtain physical information. in the process, only a small number of differential equations have analytical solutions, especially linear differential equations that have been idealized. most differential equations that describe physical phenomena are non-linear and difficult to solve analytically. this is where one of the strengths of computational physics, i.e., computational physics offers numerical solutions to various differential equations that are difficult to solve, such as solving atoms with more than two electrons using the configuration weight functions method [7] and density functional theory [8]. vibration is the movement of a system that can be in the form of regular and repeated movements continuously or can also be irregular or random movements. when vibration or oscillation repeats itself (back and forth motion) on the same trajectory, then the motion is called periodic [9]. in this study, the damped and undamped oscillations are numerically studied. a study on damped oscillations has been carried out [10] that analyzed the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 47 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 oscillations of vertical springs in fluids using tracker software (https://physlets.org/tracker/). in addition, damped harmonic motion using high-speed video has been studied [11]. a computational analysis of damped harmonic motion on a vertical spring using a spreadsheet is performed [12]. however, the study is still limited to comparing positions (functions of time) for analytical and numerical results, comparison of damping parameters and spring constants. the numerical method used in this study is the euler and euler-cromer methods. these two methods have been used to discuss the physical properties of damped oscillators [12,13]. however, there has been no further study on the mechanical energy of oscillations and phase space, especially for damped and undamped oscillations. therefore, this study is aimed to analyze the damped and undamped oscillations of a spring using the euler and euler-cromer methods. meanwhile, as mentioned above, the software used is spreadsheet as used in [12,14]. the main advantages of using the spreadsheet are ease in data handling and flexible in data presentation. moreover, the various quantities being studied are position (x), velocity (v), kinetic energy (k), potential energy (u), mechanical energy (e), and phase space as a function of time (t). these quantities are essential in the mechanics of the spring system. as mentioned above, the aforementioned quantities are determined using the euler and eulercromer methods and finally compared. ii. theory a brief description of a spring system one law that has been successfully revealed by physics is that when energy is transferred or changed through any process, there is no increase (gain) or reduction (loss) of energy in that process. this is known as the law of conservation of energy. for the spring system, the potential energy is given as: 𝑈 = 1 2 𝑘𝑥 2 (1) where x is the spring’s displacement from its normal or unstretched length, and k is the spring’s constant. the kinetic energy of the spring can be given as follows: 𝑈𝐾 = 1 2 𝑚𝑣2 (2) where m is the mass of the object and v is the object’s velocity. if there is no friction or other forces acting on this system, then the principle of energy conservation produces the following equation: 𝑈1 + 𝐾1 = 𝑈2 + 𝐾2 (3) the subscripts 1 and 2 refer to the potential and kinetic energies at two points at different times. figure 1. oscillation of a spring. when an object vibrates or oscillates in the same trajectory, and each oscillation takes the same time, then the motion is periodic. suppose a spring is attached horizontally, as shown in figure 1, with an object of mass m sliding frictionless on a horizontal surface. the spring has an initial length where the spring does not exert a force on the object. the position of the object at this point is called the equilibrium position. if the object is pushed to the left, then the spring is compressed. on the other hand, if the spring is pulled to the right, then the spring is stretched. the spring exerts a force on the object in the opposite direction by pushing or pulling it to its equilibrium position. therefore, this force is called the restoring force, f (red arrow in figure 1). an oscillatory system with a restoring force directly proportional to the negative displacement can be given mathematically as: 𝐹 = −𝑘𝑥 (4) this oscillatory system is said to perform simple harmonic motion (shm). shm can also be modified by generating other forces that affect the system’s motion, namely damping forces. for example, a study in [15] shows the phenomenon of damped oscillations caused by a wooden rod given a magnet swinging near an aluminum rod. the damping is a function of the distance between the magnet and the aluminium that can produce underdamped, overdamped, and critically damped oscillations. this study investigates the phenomenon of damped and undamped oscillations of a horizontal spring (see figure 1). to stretch or compress a spring, work must be done. thus, the potential energy is stored in a stretched or compressed spring. if the damping force is directly proportional to the velocity, i.e., f’ = -bv, then using newton’s second law and equation (4), the differential equation for the spring system can be written as follows: �̈� = −𝜔0 2𝑥 − 𝑏 𝑚 �̇� (5) and 𝜔0 = √ 𝑘 𝑚 . (6) the damping parameter may be stated as  = b/(2m). therefore, the damped oscillatory system has a frequency of http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://physlets.org/tracker/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 48 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 𝜔 = √ 𝑘 𝑚 − ( 𝑏 2𝑚 ) 2 = √𝜔0 2 − 𝛽2 (7) for the underdamped condition where  < 0. in this study, equation (5) is the differential equation used to model the spring system using the numerical methods of euler and euler-cromer. euler and euler – cromer methods euler’s method is utilized for solving differential equations by utilizing the description of the taylor series. the initial step of deriving this method starts from the explicit relationship, 𝑑𝑦 𝑑𝑥 = 𝑓(𝑥, 𝑦) (8) equation (8) can be approximated using the finite difference form, i.e.: 𝑑𝑦 𝑑𝑥 = δ𝑦 δ𝑥 = 𝑦𝑖+1 − 𝑦𝑖 𝑥𝑖+1 − 𝑥𝑖 = 𝑓(𝑥, 𝑦) (9) by denoting  = f(x,y), equation (9) can be written as: 𝑦𝑖+1 = 𝑦𝑖 + φ𝑖 ∆𝑥 (10) the value of  is an estimate of the gradient for the extrapolation from yi to yi+1 with a distance of ∆x = xi+1 xi with i = 1, 2, 3, …, n. equation (10) can calculate the y step by step with linear extrapolation on ∆x grid. however, the euler method has a disadvantage, which is its error is relatively high, i.e., more than 60%, so that the numerical results may not be correct. hence, the euler method can be modified to the euler-cromer method via substituting φi to φi+1 in equation (10), that is: 𝑦𝑖+1 = 𝑦𝑖 + φ𝑖+1∆𝑥 (11) the model the physical model of the spring is based on the differential equation (5). substituting y and x for v and t, respectively, in equation (10), we obtain 𝑣𝑖+𝑖 = 𝑣𝑖 + φ𝑖 (𝑡𝑖+1 − 𝑡𝑖) (12) comparing equation (5) and equation (12), an euler numerical equation is obtained as 𝑣𝑖+𝑖 = 𝑣𝑖 + (− 𝑘 𝑚 𝑥𝑖 − 𝑏 𝑚 𝑣𝑖 ) (𝑡𝑖+1 − 𝑡𝑖 ). (13) another equation is obtained by substituting y and x in equation (10) with x and t, respectively. 𝑥𝑖+1 = 𝑥𝑖 + 𝑣𝑖 (𝑡𝑖+1 − 𝑡𝑖 ). (14) equations (13) and (14) are a pair of numerical equations based on the euler method used in this study. a modification of the euler method results in the eulercromer method by modifying equation (14) according to equation (11), namely: 𝑥𝑖+1 = 𝑥𝑖 + 𝑣𝑖+1(𝑡𝑖+1 − 𝑡𝑖). (15) equations (14) and (15) are a pair of equations for the euler-cromer method. the kinetic energy of the spring system of equation (2) can be modified according to equation (13), i.e. : 𝐾𝑖 = 1 2 𝑚𝑣𝑖 2. (16) similarly, the potential energy of the spring can be determined from equations (14) and (15) for the euler and euler-cromer methods, respectively, viz.: 𝑈𝑖 = 1 2 𝑘𝑥𝑖 2. (17) hence, the mechanical energy of the spring system can be obtained by adding equations (16) and (17), that is: 𝐸𝑖 = 𝐾𝑖 + 𝑈𝑖 . (18) finally, the momentum of the spring system can be calculated using equation (13), i.e.: 𝑝𝑖 = 𝑚𝑣𝑖 . (19) equation (19) is used to generate the phase space. iii. computational method this numerical study was conducted using a personal computer (pc) with the hardware of dell desktopfaodg3t and the inspiron 1.1 3000 series model. the processor used was intel(r) cpu n3&10@1.60hz with 400 gb ram. meanwhile, various software used in this numerical study were ms word and ms excel. the coding was based on the spreadsheet using the euler-cromer and euler methods. the coding steps for the euler-cromer method were given as follows: 1) opening the worksheet in spreadsheet (ms excel); 2) declaring the known parameters, namely: m, k, b, and t in cells (boxes) b22 to b25 as can be seen in figure 2; 3) creating a table consisting of 8 columns containing iterations (i), t, x, v, k, u, e, and p, as can be observed in figure 2. especially for iteration i = i + 1 starts from 1 in cell b32. 4) declaring the initial conditions, namely t = 0, x = 0, and v = 1, in cells c31, d31, and e31, respectively. the time step t = ti+1 ti used is 0.01 with the number of iterations t < 60-time steps (seconds). 5) writing the formula for iteration of vi based on equation (13) starting from cell e33, namely: = e32 + ((((b$23/b$22)*d32) ((b$24/b$22)*e32))*(c33 c32)); http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 49 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 6) writing the formula for iteration of xi based on equation (15) starting from cell d33, namely: =d32+(e33*(c33c32)); 7) writing the formula for the iteration of ki based on equation (16); 8) writing the formula for the iteration of ui based on equation (17); 9) writing a formula for the iteration of ei based on equation (18); 10) writing the formula for the iteration of pi based on equation (19). moreover, 11) plotting the graphs of v against t, x against t, k and u against t, k and e against t, and p against x (for the phase space). finally, 12) for undamped oscillation, steps 1) to 11) were carried out by setting the parameter b = 0. figure 2. display parameters and formulas on the spreadsheet using the euler-cromer method. the coding steps for the euler method were carried out by repeating steps 1) to 12) in the euler-cromer method in the cells that have been determined. for step 5) the formula used was =e27+((((-b$16/b$15)*d27)((b$17/b$15)*e27))*(c28-c27)). meanwhile, the formula in step 6) is changed to equation (14), namely: =d27+(e27*(c28-c27)). this can be seen in figure 3 figure 3. display parameters and formulas on a spreadsheet using the euler method. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 50 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 iv. results and discussion the numerical analysis of damped and undamped oscillations of the spring in this study uses two numerical methods: the euler-cromer and euler methods. furthermore, the various numerical results generated from these two methods are discussed. the first result obtained in this study is a graph of position versus time (x vs. t). this can be observed in figure 4. figure 4. position the spring concerning time (a) with damping and (b) without damping. figure 4(a) shows a comparison of the spring’s position as a function of time resulting from the euler method and euler-cromer methods for the damped oscillation. as time advances, the amplitude of the spring gets smaller. this means that the spring’s displacement is getting smaller and will become zero at the equilibrium position. thus, the spring undergoes a damped oscillation to decrease the spring’s oscillation. the damping may be caused by, e.g., the friction of the spring at the interface as applied in [16] or viscous fluid in the liquid-springmagnetorheological-fluid-damper system [17]. furthermore, the euler-cromer method produces a smaller oscillation amplitude than the euler method. on the other hand, the same oscillation phase is obtained between euler and euler-cromer methods, which means that both methods produce the same damping evolution. figure 4(b) shows the graph of the spring’s position for the euler and euler-cromer methods in the undamped condition, which is obtained by changing the parameter b to 0. it can be observed that the euler method gives the position of the spring, which the amplitude gets larger as time progresses. of course, this does not satisfy the law of conservation of energy. in contrast, the euler-cromer method produces stable amplitude, which is according to the shm system without damping. thus, the eulercromer method is more stable than the euler method in the spring vibrations without damping. figure 5. the spring’s velocity concerning time (a) with damping and (b) without damping. figures 5(a) and 5(b) show v vs. t graphs obtained from two methods, namely: euler and euler-cromer methods, for the damped and undamped oscillations, respectively. in general, the profiles of the velocity of the spring oscillation are not different from the position profile of the spring in figure 4. it can be observed that the velocity of the oscillation of the spring with damping decreases and eventually becomes zero at the equilibrium position, both for the euler and euler-cromer methods. meanwhile, the spring’s oscillation velocity without damping is stable for the euler-cromer method compared to the velocity of the spring’s oscillation obtained from the euler method. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 51 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 figure 6. the kinetic and potential energies for damped spring oscillation using (a) euler-cromer and (c) euler methods, and undamped using (b) euler-cromer and (d) euler methods. it can be shown from figures 6(a) and (c) that for the damped springs, k and u profiles decrease with time for both euler-cromer and euler methods. in this case, the law of energy conservation applies: when k is maximum, then u is minimum, and vice versa. furthermore, the k and u profiles obtained through the euler-cromer method undergo damping faster than the euler method. furthermore, figures 6(b) and (d) show the k and u profiles for undamped spring oscillation obtained from the euler-cromer and euler methods. via the euler-cromer method, k and u profiles are stable over time. meanwhile, in figure 6(d) k and u profiles are getting larger with time. figure 7. kinetic and mechanical energies for damped spring oscillation using (a) euler-cromer and (c) euler methods and undamped using (b) euler-cromer and (d) euler methods. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 52 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 based on figures 7(a) and (c), a relationship is found between the velocity and the total loss of mechanical energy in damped spring oscillation using the eulercromer and euler methods, respectively. with the increase of time, the value of the velocity of the oscillation gets smaller. this causes the mechanical energy produced to dissipate and eventually go to zero. this phenomenon of mechanical energy is a physical phenomenon and not due to computational calculations. the area with the highest change in the mechanical energy occurs when the slope is greatest on the graph. figures 7(b) illustrate the relationship between velocity and the mechanical energy of the undamped spring via the euler-cromer method. it can be observed that the oscillation velocity of the spring appears to be stable, while the mechanical energy of the system is also stable and shows the ripple effect. this is different from figure 7(d) obtained using euler’s method. in this case, it is obtained that the spring’s velocity increases periodically with time, while the mechanical energy also increases but appears smoother without any ripples. the phase space of the spring oscillation can be observed in figure 8. the phase space is the p vs. x graph. figures 8(a) and (c) show the damped spring oscillation phase space generated by the euler-cromer and euler methods, respectively. it can be observed that the spiral profiles move from the outside to the inside and are getting closer to the zero point value (origin). this means that the momentum and position of the damped spring oscillation decrease towards zero. the greater the damping parameter, the less number of spirals that occur because the faster the spring is damped. in addition, it can be observed that the damped spring oscillation phase spaces from the eulercromer [fig. 8(a)] and euler [fig. 8(b)] methods produce similar profiles. however, the phase spaces for the spring’s oscillation without damping show different profiles for the eulercromer and euler methods. this can be observed in figures 8(b) and 8(d). figure 8(b) is the phase space of the spring oscillation without damping from the euler-cromer method. it can be observed that this phase space is circular. this is because the phase space is stable, so there is no spiral, according to shm. on the other hand, figure 8(d) shows the phase space of a spring oscillation without damping based on euler’s method resulting in a spiral that is directed outward and gets larger with time. this is unrealistic because the spring dynamics by itself (without force) can’t produce larger values of momentum and position. figure 8. the phase spaces for damped spring oscillations using (a) euler-cromer and (c) euler methods, and undamped using (b) euler-cromer and (d) euler methods. the numerical results above show that the eulercromer and euler methods work equally well in the case of damped spring oscillations. this is due to the damping factor b, whose value is not zero so that the hamiltonians of the spring system via euler-cromer and euler methods obey the principle of conservation of energy. however, the performance of these two computational methods is different when faced with the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 53 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 hamiltonian case, which is independent of time, namely, in this case, the vibration without damping (b = 0). the two methods have different performances due to their numerical structure. especially euler’s method cannot maintain the principle of conservation of energy. in a spring without damping, the structure of euler’s numerical equation causes the oscillation to get larger. this results in all the quantities becoming increasingly large and unrealistic. on the other hand, changing the parameter vi in equation (14) to vi+1 in equation (15) causes the oscillation of the harmonic motion to become stable, and the principle of conservation of energy is fulfilled. thus, the euler-cromer method produces quantities that are more stable and idealistic. v. conclusion a numerical study of the spring oscillation with damping and without damping has been carried out. the numerical methods used in this study are euler and eulercromer. the quantities of x, v, k, u, e, and phase space produce the same profiles for the euler and euler-cromer methods for the spring oscillation with damping. moreover, the numerical results of x, v, k, u, e, and the phase space decrease periodically to zero due to the damping force. meanwhile, when the spring does not experience damping, there is a difference in numerical results from the euler and euler-cromer methods. for the euler method, the resulting profiles of x, v, k, u, e, and phase space increase periodically with time, not matching the ideal condition. then, on the profiles of x, v, k, u, e, and phase space from the euler-cromer method, stable profiles are obtained with time, according to the ideal condition of shm. this means that the euler method only works well for the spring oscillation with damping, whereas the euler-cromer method is good for spring oscillation with and without damping. hence, we recommend using this study's appropriate computational method for the spring oscillation. moreover, this study can be used as a part of physics learning for senior high school and undergraduate students. vi. acknowledgment the authors would like to thank the postgraduate program of physics education, universitas ahmad dahlan, for supporting this numerical study. references [1] r. f. martin, “undergraduate computation physics education: uneven history and promising future,” xxvii iupap, conference on computational physics (ccp2015) 2-5 december 2015, j phys. conf. ser., vol. 759, p. 012005, 2016. doi: 10.1088/17426596/759/1/012005. 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[16] s. li, p. xiang, b. wei, c. zuo, l. jiang, and w. he, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& 10.1088/1742-6596/759/1/012005 10.1088/1742-6596/759/1/012005 https://doi.org/10.1016/j.pepi.2019.106312 https://doi.org/10.1088/1361-6552/ac0159 https://journals.indexcopernicus.com/api/file/viewbyfileid/1222945.pdf https://journals.indexcopernicus.com/api/file/viewbyfileid/1222945.pdf https://doi.org/10.32604/cmc.2019.04567 http://31.220.4.173/index.php/ejpe/article/view/222 https://doi.org/10.1134/s0022476619010013 https://doi.org/10.21468/scipostphys.6.4.040 https://doi.org/10.15575/jotalp.v3i1.6549 https://doi.org/10.1088/0031-9120/48/6/782 https://eprints.uns.ac.id/1713/ https://doi.org/10.31002/jom.v3i2.3366 http://ojs.uho.ac.id/index.php/jaf/article/view/4141/3228 indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 46 54 54 janah, et al. comparison of euler and euler-cromer numerical methods for …. p-issn: 2621-3761 e-issn: 2621-2889 “interface friction effects on scaling a vertical springviscous damper isolation system in a shaking table test,” structures, vol. 33, pp. 1878-1891, 2021. doi: 10.1016/j.istruc.2021.05.046. [17] n. maus and f. gordaninejad, “a bi-diretional, liquidspring-magnetorheological-fluid-damper system,” frontiers in materials, vol. 6 (6), pp. 1-11, 2019. doi: 10.3389/fmats.2019.00006. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1016/j.istruc.2021.05.046 https://doi.org/10.3389/fmats.2019.00006 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.6, no.1, june 2023, pp. 10 16 doi: 10.12928/irip.v6i1.8115 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 10 a preliminary study on promoting contextual teaching and learning using smart water quality sensors dwi sulisworo1*, meita fitrianawati2, arsyad cahya subrata3, khairul shafee kalid4, wan fatimah wan ahmad5 1postgraduate program of physics education, faculty of teacher training and education, universitas ahmad dahlan, indonesia 2elementary teacher education department, faculty of teacher training and education, universitas ahmad dahlan, indonesia 3electrical engineering department, faculty of teacher training and education, universitas ahmad dahlan, indonesia 4,5 computer and information sciences department, universiti teknologi petronas, seri iskandar, malaysia email: dwi.sulisworo@uad.ac.id article info abstract article history received: may 20, 2023 revision: jun 16, 2023 accepted: jun 17, 2023 building awareness among students on the issues of natural environmental phenomena has always been a challenge due to the difference in location between the student and the observed phenomena. the issues of the natural environment have been a part of the curriculum in elementary schools. one of the lessons taught on the natural environment in elementary schools is related to the water condition in various areas filled with water, such as ponds, rivers, lakes, etc. currently, learning in the natural environment is based on text, images, and videos, and learning activities using real-time data is still rare. this study presents the development of an iot-based smart water quality application prototype. the prototype consists of conductivity, ph, oxygen levels, salinity, and turbidity sensors. the iot prototype can also be used to automatically monitor fish, shrimp, and other species in aquaculture ponds. using the iot-based smart water quality application prototype, teachers can enhance students' higher-order thinking skills by designing learning activities using real-time data to identify, compare, and classify various concepts or phenomena. this is an open-access article under the cc–by-sa license. keywords: critical thinking skills green economy internet of things science learning smart water sensors to cite this article: d. sulisworo, m. fitrianawati, a. c. subrata, k. s. kalid, and w. f. w. ahmad, “a preliminary study on promoting contextual teaching and learning using smart water quality sensors,” indones. rev. phys., vol. 6, no. 1, pp. 10–16, 2023, doi: 10.12928/irip.v6i1.8115. i. introduction in a green economy, business growth is carried out by public and private investment through economic activities, infrastructure, and assets that encourage the reduction of carbon emissions and pollution, increase energy and resource efficiency, and prevent the loss of biodiversity and ecosystems. green economy refers to an economic model that increases human well-being and social equity while significantly reducing environmental risks and ecological scarcity as mandated by the united nations conference on sustainable development (rios+20). this declaration affirms and supports the concept of the green economy in the form of job creation and skills development, to lift people out of poverty and build greater social cohesion [1]. the use of smart water sensors based on the internet of things (iot) technology aligns with the principles of the green economy in several ways. smart water sensors enable real-time monitoring and data collection of parameters such as ph levels, dissolved oxygen, turbidity, and pollutant concentrations in water bodies. by promptly identifying and addressing pollution issues, these sensors contribute to preserving and conserving water resources, which are vital for sustaining ecosystems and supporting various economic activities. this tool optimizes water management practices. by efficiently managing water resources, unnecessary wastage can be minimized, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v6i1.8115 http://journal2.uad.ac.id/index.php/irip mailto:dwi.sulisworo@uad.ac.id http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 10 16 11 d. sulisworo, et al. a preliminary study on promoting contextual teaching … p-issn: 2621-3761 e-issn: 2621-2889 reducing energy consumption and costs associated with water treatment and distribution. this optimization aligns with the principles of resource efficiency and sustainable resource management promoted by the green economy. developing, producing, and deploying these sensors create new job opportunities and drive technological advancements in environmental monitoring. as businesses and industries embrace these technologies, they contribute to the growth of a green tech sector, which plays a significant role in the transition to a more sustainable economy. this awareness can be built through education by integrating a structured green economy into the curriculum [2]. the obstacle faced in building awareness of this global issue is that it is still difficult to present real natural phenomena to students, particularly due to the distance between the location of students and the observed phenomena. so far, the learning material is based on text, images, and videos. furthermore, relatively few learning activities still use real-time data to gain actual experience. the limited availability of media causes the level of interaction of students with actual phenomena to be less than optimal. in line with this integration goal, iot-based devices can be used to experience a phenomenon in realtime in learning [3]. iot is a technology that can be used to observe and monitor phenomena using smartphone sensors anywhere and anytime in real time [4]. many studies confirm that iot brings good changes for educators in bringing phenomena into learning [4]–[7]. iot technology can be developed to build awareness of the natural environment. thus, it is crucial that iot is introduced to children at an early age in elementary schools. theories related to cognitive development explain that elementary school students are still in the stage of developing their concrete ways of thinking [8]. in the elementary school curriculum, the topics on the natural environment are covered in 3rd-grade elementary school [6], in which one of the activities relates to water conditions in various places such as ponds, rivers, or lakes. using the iot device as a learning tool, higher-order thinking skills at this level can be developed by designing activities that allow students to identify, compare, and classify various concepts or phenomena. teachers need to develop a learning module that includes iot technology; however, learning activities that include iot in learning the natural environment at the elementary education level are still lacking. this study attempts to address this issue by developing an iot-based smart water quality prototype that uses sensors to monitor water conditions by capturing data on the water's conductivity, ph, oxygen levels, salinity, and turbidity using sensors. the iot prototype can be used for automatic monitoring of fish, shrimp, and other aquaculture ponds. the learning activities that include using data captured by the iot device in real time could enhance students' critical thinking skills, thus, internalizing their awareness of the natural environment from an early age. ii. theory iot in learning iot is a technology that can be used to monitor various conditions using the internet network so that data can be obtained remotely using a smartphone or other device [9]–[11]. three characteristics state a technology using iot: being able to observe phenomena remotely in real-time, provide information quickly and accurately and display multiple data in one device [12]. iot can be used to help provide an explanation of abstract concepts for understanding a phenomenon. currently, iot is widely used in industry, games, medicine, and the military, while in education, it is still rarely used [12], [13]. there are many ways to use iot in learning. iot can be integrated with worksheets. the characteristic of a good worksheet is the existence of directed activities in independent learning. a good worksheet contains reading menus, assignments, exercises, and evaluations. iot in the worksheet can be inserted into the assignment activity. after reading the material, students will gain better prior knowledge. furthermore, in the assignment activity, students can monitor certain magnitudes of the observed phenomena and compare various conditions. teachers can create scenarios to compare places where iot has been installed. iot-based worksheets and learning outcomes iot is one of the technologies that developed rapidly in the era of the industrial revolution 4.0 [3], [11]. the potential of iot is widely used in various fields to increase productivity. in education, iot-based learning media, including worksheets, also influence learning practices [5]–[7]. the level of ability to present a condition remotely in real-time allows student interaction and the concepts being studied to be higher. iot can present various phenomena that are relatively difficult to present in the classroom due to various limitations. the level of interest in learning in certain fields can be increased by using more interactive media and explaining phenomena more concretely [9], [13]. iot-based devices can also be used in science to explain various concepts, including climate change. the provision of iot-based media that explains this phenomenon is an alternative to increasing understanding of global issues, one of which is water quality monitoring which triggers increased learning outcomes. in many research studies and theories, interest in learning can be used as a predictor for learning success. the more interested students are in the content being studied, the more students spend time and effort to master the material so that it has an impact on performance or learning outcomes [14]. conversely, when students lose interest in learning, it significantly affects learning outcomes negatively [15]. psychological studies also show that interest in learning can mediate learning outcomes [16], which can be explained by self-determination theory [17]. included in recent learning research using iot-based media also shows this relationship in various subject matters [18]. however, it is undeniable that there are concerns that this media only makes students interested in http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 10 16 12 d. sulisworo, et al. a preliminary study on promoting contextual teaching … p-issn: 2621-3761 e-issn: 2621-2889 the media itself because iot-based media is something new both at the interactive and technological levels. this concern is valid as students are not familiar with the use of iot technology in their learning. studies that discuss this relationship can provide information on integrating iot technology with suitable learning strategies to optimize the learning process. conceptual model based on theoretical studies and similar research results, the conceptual model for this research is shown in figure 1. figure 1. conceptual model iii. method research context various purposes can use this iot-based application. this can be seen in the sensors installed in the application. however, the focus of developing this application is to support learning, particularly relating to the natural environment with the ctl approach. the supporting tools for this research are hp core i3 laptops, android phones, various sensors, and blynk software. this study adopts design research as the research model with the stages of needs analysis and prototyping. needs analysis was carried out by conducting interviews and focus group discussions (fgds). student interviews were conducted to understand the characteristics of students as users. the fgds involved teachers, material experts, and learning experts to determine the appropriate level of using this tool in a learning environment according to learning competencies. the implementation has yet to be carried out at this stage in learning. several possible applications with multiple learning modes are discussed in the discussion section. system architecture figure 2 presents the block diagram of the iot-based smart water quality application. the iot-based application consists of four layers: sensor, control, cloud, and output. the sensor layer consists of all four sensors. these sensors capture the data from the water and send the data to the control layer. in the control layer, the microcontroller will read the data and sends the data to the cloud that resides in the cloud layer. in the output layer, the data will be visualized as a dashboard in the user's smartphone through the mobile application. the mobile application was developed using blynk software. blynk is used to manage communication between iot devices and smartphones. the software was downloaded from http://j.mp/blynk android or http://j.mp/blynk ios. the blynk platform controls the iot device and displays, stores, and visualizes the data. iot device is equipped with a microcontroller board and sensors. figure 2. iot block diagram table 1 presents the microcontroller board, sensors, and indicators measured on iot devices. the bnc ph sensor module with ph probe and msp340 sensor measure the water ph levels. the total dissolved solids (tds) in the water are measured using the tds probe with sen0244. the tds is used to measure the conductivity, that is, the cleanliness of the water. the turbidity probe with the sen0189 sensor was used to measure the water's clarity. the ds18b20 sensor is used to capture the temperature data of the water. tabel 1. sensors and indicators indicator device name/ sensor water ph bnc ph probe + msp340 tds tds probe + sen0244 turbidity turbidity probe + sen0189 temperature ds18b20 iv. results and discussion results this section presents the design of the iot-based smart water quality application prototype. figure 3 presents the iot-based smart water quality application schematic diagram. the diagram shows the four sensors and their respective probes connected to the arduino board. figure 4 shows the probe sensors used to measure the water. the ph level, conductivity, turbidity, and temperature probes are put into the water. the probes sensor captures the data from the water and sends the data to the cloud through the arduino board for the blynk application to process and display the data. smart water quality sensor using student worksheet environment problems and issues contextual teaching and learning http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://j.mp/blynk http://j.mp/blynk indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 10 16 13 d. sulisworo, et al. a preliminary study on promoting contextual teaching … p-issn: 2621-3761 e-issn: 2621-2889 figure 3. schematic of iot-based smart water quality application figure 4. the probes used to capture data in learning, this iot-based device can be used anywhere because of its small physical size with dimensions (7cm × 10cm × 4cm) with several sensor probes. users can download and activate the application using a barcode. when the probe enters the water, the water condition triggers the sensor and sends data to the blynk cloud, which is read on the smartphone. users can monitor changes in this data and use it as needed. water condition data readings captured by iot devices are monitored through the blynk application. users can see this application on their smartphones with an installed interface. figure 5 shows the user interface of the monitoring dashboard. the dashboard interface consists of water ph, tds, water turbidity, and temperature indicator. figure 5. water quality indicators dashboard discussion iot devices use sensors to capture data and send the data to the internet using certain communication standards and protocols. the data this device reads can be accessed by all users anywhere and anytime. the advantage of using iot in the classroom is that it can be used as an alternative to collaborative learning. students from different locations can view the state of the water at certain locations in realtime. different data representing the quality from various water sources becomes a source of learning to improve critical thinking skills. teachers can apply problem-based learning with collaborative activities to solve problems related to water quality as part of learning about the natural environment. other activities can be developed that are in line with the subject matter. furthermore, these strategies that utilize this technology can encourage the development of more activities for stem-based learning. the data related to the water quality can be obtained from the water source in real-time and directly measured in class. the data is stored on the cloud, thus making it accessible to other students from different schools. students from different schools can do the same or different activities using the same or different data sets. this encourages flexibility in the student's learning. students can learn about water quality with or without iot. learning with iot has its benefits. students can observe the water quality directly and predict the environmental factors that affect water quality. any discussion regarding water quality, environmental impact, actions to be taken to improve water quality, and others can be conducted onsite. students near water-filled areas such as rivers, ponds, lakes, and others have this advantage. students located far away from the water-filled area will benefit from using iot. the iot-based smart water quality application enables students to monitor water quality from anywhere. in this setting, students in the tropics can access water http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 10 16 14 d. sulisworo, et al. a preliminary study on promoting contextual teaching … p-issn: 2621-3761 e-issn: 2621-2889 quality data in sub-tropical or polar regions. the data captured by the sensors attached to the device is stored in the cloud, making the data accessible to students from different schools. this promotes collaborative learning as students from schools located in various locations can jointly observe the water quality data in real time and perform activities that use these data collaboratively. in a nutshell, many possible learning strategies based on contextual teaching and learning can be developed because there is no time and place limit in observing the surrounding environment. teachers can design activities that allow students from other schools to collaborate. groups can consist of students from one school or different schools using various online learning features. students use digital worksheets to carry out activities that the teacher has designed. based on the findings, students discuss solving real problems collaboratively. data that is diverse and associated with observed natural conditions can encourage the development of higher-order thinking skills. this strategy can also be carried out at various levels in the school by determining the level of complexity of learning activities. this complexity is related to the depth of data analysis obtained from smartphone sensor readings. for low-grade students (1 to 3), the teacher can provide activities to compare the conditions of various water sources from different sources. the teacher can also ask about the cause of the difference in water quality. for high-grade students (4-6), the teacher can provide more advanced activities by tracing the causes of poor water quality, looking for other supporting data to strengthen arguments, or manipulating data from various data to gain new understanding and, for example, analyzing river water conditions at various points from downstream to upstream. see if there is a difference, what is the cause of this difference, what is the impact of this difference, and what are the solutions if a problem occurs. teachers can develop many activities that encourage the search for solutions to various environmental problems. learning activities using iot have also been confirmed by many researchers related to the issue of climate change and its impact on life at various levels of education and various types of subjects with different levels of depth of analysis [14], [18], [19]. the flexibility of data that different students can read allows teachers to develop various alternative learning activities that encourage the exploration of real conditions. students can be confronted with environmental problems and perform analyzes of varying degrees of complexity. this choice is adjusted to the student's level of thinking. this learning strategy was developed concerning the theory of learning connectivity, social learning, and others [20]–[22]. implementation of this strategy with various approaches has also been carried out by other researchers with significant results [6], [13]. users of these iot devices are not only teachers but also the public for various purposes. data read from sensors can trigger other devices to perform certain actions. this means that iot devices can be combined with other devices to provide a wider range of performance. as an example of use in fisheries, the ph sensor can be connected to other devices that can change the ph of the liquid. so that the sensor reads a change in ph, the ph regulator will be activated to pour certain substances at a certain level so that the ph is as expected. thus, this tool can be used in various sectors in education and other fields, especially in agriculture, fisheries, and livestock [23]– [27]. v. conclusion this research attempts to develop an iot-based smart water quality application prototype that can be used to monitor water quality in real-time from a smartphone. the iot-based prototype is equipped with sensors that read ph levels, temperature, and turbidity. teachers in elementary schools use the iot-based prototype as part of the student's learning activities on the topic of the natural environment. the iot-based prototype provides opportunities for students to collaborate within an integrative learning model such as problem-based learning. the tds sensors are used to measure the water quality. nonetheless, it is also widely used in agriculture, such as fish farming, shrimp, rice fields, etc. this provides opportunities for students to experience contextual learning related to problems that exist in society. the application of this prototype can be extended by integrating it with other tools for water quality regulation. there is also an opportunity to incorporate other relevant sensors to cater to potential future applications. vi. acknowledgment researchers from ahmad dahlan university and universiti teknologi petronas carried out the process of developing methods and analyzing 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https://doi.org/10.1007/bf03173109 https://doi.org/10.1016/j.jbi.2020.103383 https://doi.org/10.1038/s41893-020-0512-y https://doi.org/10.1016/j.iheduc.2017.12.002 https://doi.org/10.1016/j.jclepro.2019.04.053 https://doi.org/10.26782/jmcms.2019.10.00014 https://doi.org/10.1109/etncc.2015.7184801 https://doi.org/10.13031/aim.202001610 https://ettrends.etri.re.kr/ettrends/188/0905188006/36-1_54-63.pdf https://ettrends.etri.re.kr/ettrends/188/0905188006/36-1_54-63.pdf indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 10 16 16 d. sulisworo, et al. a preliminary study on promoting contextual teaching … p-issn: 2621-3761 e-issn: 2621-2889 declarations author contribution : dwi sulisworo took overall responsibility for the research project. meita fitrianawati authored the manuscript draft, while arsyad cahya subrata played a role in the prototype design. meita fitrianawati and khairul shafee kalid contributed to data collection, transcription, and analysis. wan fatimah wan ahmad meticulously revised and proofread the manuscript. finally, all authors approved the final version of the manuscript. funding statement : this research was funded by ahmad dahlan university through a research grant with contract number pd-035/sp3/lppm-uad/vii/2022. conflict of interest : all authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.6, no.1, june 2023, pp. 17 23 doi: 10.12928/irip.v6i1.7070 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 17 seawater lamp: utilization of seawater as an alternative energy source to generate electricity muh. ridwan kadir1, nurul afiqah arsyad2, syarifah nuraeni alaydrus3, wenny puspita4, sahrul5, muhammad nurkhalis agriawan6, hardi hamzah7* 1,2,3,4,6department of physics education, faculty of teacher training and education, universitas sulawesi barat, indonesia 5department of fisheries, faculty of animal husbandry and fisheries, universitas sulawesi barat, indonesia 7department of physics, faculty of mathematics and natural sciences, universitas cenderawasih, indonesia email: hardihamzah88@gmail.com article info abstract article history received: des 17, 2022 revision: jun 23, 2023 accepted: jun 30, 2023 fishermen are the main livelihood for coastal communities in west sulawesi. in fishing activities, especially at night, fishermen use lights to attract fish for a greater chance of catching fish. however, fishermen need a supply of electricity to turn on their lights when at sea. fishermen usually use batteries. this is a significant problem for fishermen because batteries require a relatively high operational level. researchers found the idea by developing a battery replacement tool to reduce high operating costs. this study aims to utilize seawater as an alternative energy source to overcome the problem of high operational costs for fishermen. the tool developed in this study uses two electrodes (zn and cu) placed vertically in a container and then filled with seawater. the two electrodes are connected in series, producing a high output voltage to light an led. after the initial measurement, the resulting output voltage is 5v and can turn on the led with a bright enough light. in periodic measurements for 96 hours with data collection every 4 hours, the voltage, current, and power do not decrease significantly, so the seawater lamp is suitable for coastal communities and fishermen's use as lighting when going to sea at night. series and parallel combinations must be developed to achieve higher voltage and power values and obtain brighter light. the results of this research can be an alternative and renewable energy source that can be widely used. this is an open-access article under the cc–by-sa license. keywords: seawater electrolytes renewable energy electrical energy to cite this article: m. r. kadir et al., “seawater lamp: utilization of seawater as an alternative energy source to generate electricity,” indones. rev. phys., vol. 6, no. 1, pp. 17–23, 2023, doi: 10.12928/irip.v6i1.7070. i. introduction electrical energy is a fundamental societal need and supports all aspects of life and national development [1]. as time goes by and technological developments, people's dependence on electrical energy increases [2]. fuel oil (bbm) and gas fuel are non-renewable energy sources that people use daily [3]. the need for electrical energy continues to increase and demands the availability of alternative sources of electrical energy from renewable energy. generally, electrical energy is generated from diesel, water, and geothermal energy. however, in its development, there are still many obstacles. therefore, another alternative is needed for developing renewable sources of electrical energy by utilizing available natural resources [4]. there are several ways to produce renewable electrical power, one of which is by using seawater. the utilization of seawater as a source of electrical energy has yet to be optimal. the existence of electricity sourced from seawater is a potential and inexpensive solution for electricity needs around the coast and for fishermen. however, the electrical energy generated from renewable sources is always smaller than that from non-renewable sources. this problem must be addressed if renewable energy is expected to replace conventional energy [5]. many countries have widely used seawater in this modern era as an alternative energy source and a material http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v6i1.7070 http://journal2.uad.ac.id/index.php/irip mailto:hardihamzah88@gmail.com http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 17 23 18 m. r. kadir, et al. seawater lamp: utilization of seawater as an alternative … p-issn: 2621-3761 e-issn: 2621-2889 that can be used to make something useful. if used on a large scale, this seawater will have great potential to provide good sources of electrical energy in society to meet the needs of electrical power [6]. the energy crisis has become a protracted problem in indonesia and other countries, including malaysia, for people living in remote areas [7], [8]. energy needs will continue to increase along with technological advances and population growth. therefore, the use of seawater is beneficial for overcoming the electrical energy crisis that has hit various countries [9]. marine energy is a "renewable" alternative energy that contains abiotic resources that have the potential to be developed. the sea is not only a food source but also has various energy sources, and its existence is becoming increasingly important as fossil fuel energy runs out. the potential of the sea is estimated to be four times the world's electricity demand, and it is not surprising that various developed countries are competing to utilize this energy [10]. seawater can generate electrical energy by utilizing electrochemical processes [10]. electrochemistry is a change in chemical energy into electrical power due to two electrodes and an electrolyte as a conductor of electrons [11]. the type of electrochemical cell used is a voltaic cell to produce electrical energy. the voltaic cell, an electrolyte of seawater, is given two metals as electrodes connected and has a potential difference that makes electrical power. electrolytes are solutions that decompose into ions, then become electrical conductors [12]. ions are charged atoms. electrolytes can be water, acid-base, or other compounds. electrolytes are generally acids, bases, or salts, and certain gases can act as electrolytes under certain conditions, such as high temperature and low pressure [13]. research on the use of seawater to generate electricity has been carried out by several previous researchers, such as that carried out by sastromidjojo, by flowing 2 liters of parangtritis seawater to the anode and cathode circuits in the form of graphite and zinc, which produce electrical energy with a voltage of 1.6 volts [14]. raphael and aisa mijeno made a series of led lights with a glass of water and two spoons of salt [14]. many countries carry out research and development of new energy potential. several studies have been conducted, including research on the analysis of the utilization of salt water as an alternative energy source using used battery carbon electrodes; the potential of this research is very good for development [15]. utilization of seawater electrolyte as a source of electrical energy for batteries with copper–aluminium electrodes the seawater battery developed succeeded in turning on led lamps and household lamps, with a generated voltage of 1.31 v and an electric current of 13.56 ma. 2-3 batteries arranged in series produced 2.55 v and 3,6 v [16]. in line with this research, the study entitled "seawater battery with al-cu, zn-cu, and gal-cu electrodes for fishing lights" obtained a maximum power of zinc electrodes of 704.17 mw, not much different from galvalume's 726.41 mw. in comparison, the aluminum electrode produces 175.75 mw of power. this shows that the anode electrode material strongly influences the performance of the seawater battery. the best anodes to use are zinc or galvanium. further development of seawater batteries with dc/dc converters and dual in-line package (dip) leds suits innovations in effective and efficient fishing lights for lift net fishing [17]. however, from previous research, the resulting voltage is still minimal, ranging from 1.6 to 3.6 volts. in this research, a seawater lamp will be developed, which fishermen can use when fishing at night with greater voltage, current and electric power. this research was carried out to produce a higher voltage by connecting several power sources in series. this study also used a series of leds with a size of 5×5 cm, input voltage of 3.75v, and 8 watts of power, with 16 leds connected in one circuit. natural resources, such as coal, oil, and gas, are abundant in indonesia. however, it has yet to be utilized effectively and is still dependent on petroleum as the primary energy source [3]. because of this, the government issued a renewable energy source policy stipulated in law no. 33 of 2007 at 20 paragraph 4 concerning energy supply and meeting people's energy needs by seeking alternative energy sources to replace petroleum [18]. west sulawesi is one of the provinces surrounded by an endless seawater supply. most people work as fishermen who need electrical energy in their daily activities, including fishing at night. some people use diesel generators and kerosene lamps, posing health risks and damaging coastal and marine ecosystems. this study generally aims to determine the potential for utilizing seawater batteries as an alternative source of lighting energy and a renewable energy source for fishermen. this study uses the electrolysis solution of two electrodes (zn and cu) with seawater. this seawater battery series is connected to leds arranged in parallel to produce bright light. the data measured are the electric power (w), voltage (v), and current (ma) generated by the seawater lamp to determine the durability of the seawater lamp before fishermen use it. water covers as much as 70% of the earth's surface, with 97.5% seawater. this makes it possible to develop seawater lighting products that can be renewable alternative energy sources. the result of this project is a saltwater-powered lighting product prototype to provide a stable supply of electricity, especially in rural areas enabling a better quality of life. ii. theory sea water seawater is a mixture of 96.5% pure water and 3.5% salt, dissolved gases, organic matter, and insoluble particles. the salt content in seawater is influenced by mineral salts in rocks and soil, for example, sodium, potassium, calcium, and others. the salinity of seawater is 3.5%, meaning that 1 liter (1000 ml) of seawater contains http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 17 23 19 m. r. kadir, et al. seawater lamp: utilization of seawater as an alternative … p-issn: 2621-3761 e-issn: 2621-2889 35 grams of salt [19]. the physical properties of seawater, such as density, compressibility, freezing point, and temperature, are greatly influenced by the salt content in seawater. two properties primarily determined by the sea's salt amount are electrical conductivity and osmotic pressure. the main salts contained in seawater are chloride (55%), sodium (31%), sulfate (8%), magnesium (4%), calcium (1%), potassium (1%), and the rest less than 1% consists of bicarbonate, bromide, boric acid, strontium, and florida [19]. seawater contains an electric current when it contains a high element of sodium chloride (nacl) which breaks down into na+ and cl-. in the fact of these free-charged particles, an electric current arises. the emergence of an electric current by these charges can be used as a cheap and environmentally friendly source of electrical energy using the voltaic cell method [20]. seawater battery a voltaic cell consists of two electrodes, namely the anode and cathode (see figure 1). the cu electrode serves as the cathode, and zn is the anode. the cathode is the positive electrode, where the reduction reaction takes place. meanwhile, the anode is the negative electrode where the oxidation reaction occurs [21]. in the reduction process, some ions or molecules on the positive electrons (cathode) receive reduction and electrons. some ions and molecules give electrons on the negative electrons (anode), causing the oxidation process. figure 1. seawater battery electrochemical cell electrical motion and resistance in batteries in figure 2, if the voltage is measured before being connected to the load resistance, "rl," then the voltage shows "e" volts. after the battery is connected to the load resistance and the voltage is measured, it will show "v" volts lower than the initial voltage. in figure 3, the voltmeter will show an open voltage of "e" volts before the "s" switch is connected, the ammeter will show that there is an electric current flowing across the load resistance, and the clamp voltage of the battery is shown by the voltmeter "v" volts after the switch is connected. the difference in electric voltage between v and e is caused by the electric current issued by the battery. the electric current must pass through the battery resistance before starting the load resistance. the battery resistance is called internal resistance, mainly found in the existing electrolyte material. the rest is on the plate and the end of the connection and marked "r" figure 2. measuring battery voltage and current [22]. figure 3. flow chart for measuring battery voltage and current [22]. in the battery there is internal resistance caused by electrolyte materials and the plates and connections in the battery, so the voltage loss on the battery is 𝑉𝑏, as in equation 1. 𝑉𝑏 = 𝐸 − 𝑉 = 𝐼 . 𝑟 (volts) (1) resistance in battery: 𝑟 = 𝑉𝑏 . 𝐼 = 𝐸 − 𝑉. 𝐼 (ohms) (2) voltage and current maximum in battery in figure 3, when the "s" switch is connected, the overall system in the battery will work, in the circuit there is a load resistance "rl" and an internal resistance "r". the decrease in current in the circuit is influenced by the internal resistance of the battery. the electric power generated by the battery is the sum of the power lost in the battery and the power generated by the load resistance. the amount of electric power that the battery will completely release follows equation 3. 𝑃 = 𝑃𝑏 + 𝑃𝐿 = 𝐸 . 𝐼 (watts) (3) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 17 23 20 m. r. kadir, et al. seawater lamp: utilization of seawater as an alternative … p-issn: 2621-3761 e-issn: 2621-2889 if the battery is short-circuited, the load resistance becomes zero, and the amperage released is: 𝐼 = 𝐸𝑟 (ampere) (4) iii. method this section describes the experimental procedure used for this research and the parameters to be studied, such as voltage, current, and electric power generated by seawater lamps. details of the experimental procedure for each parameter to be studied will be explained in this section. materials and instruments the research used seawater as an electrolysis solution and two zn and cu electrodes placed in an acrylic container with a size of (14×7.5×16) cm. characterization of seawater light overall the voltage and electric current are measured using a multimeter connected to a series of seawater lamps (figure 4). measurements were made using a multimeter connected to zinc and copper plates as the anode and cathode—voltage measurement. figure 4. electrolysis seawater experiment data collection, types, and sources the research method used is a laboratory scale experiment. the test was carried out by assembling seawater battery units in series and giving a load of a series of led light units. experiments were carried out by measuring the voltage and current on the seawater battery and the rate of decrease in light intensity produced by the led lights. the voltage generated by a seawater battery is affected by the type of electrode material used [23]. the data is used to estimate the durability of seawater battery components as a source of electrical energy. seawater lamp construction this experiment used seawater as an electrolysis solution with a specific volume and put it into an acrylic container. one electrode of each metal with dimensions of 3×3 cm is inserted into the container at a distance of 4 cm from each other. the electrode area affects the battery capacity. battery capacity is expressed by the number of active electrode materials that can produce electrical energy through electrochemical reactions. the wider the electrode, the greater the battery capacity. the wider the electrode used, the more active material that can accommodate electrons to produce more electrical energy. [24]. a copper wire is connected to each electrode at one end, and the other is connected to alligator clips. two similar devices are made for current production and electrochemical characteristics. seawater lamp durability the open circuit voltage is measured by connecting the positive and dangerous electrodes. a digital multimeter for four days (96 hours) measured current, volts, and electric power. this experiment aims to measure the electrode's durability in a seawater solution. to achieve this goal, voltage, current, and resistance changes are recorded every 4 hours. this corresponds to the ideal time used by fishermen when fishing at night. iv. results and discussion this seawater lamp voltage source circuit consists of two voltage source circuits connected in series to obtain a stable voltage gain. figure 5. seawater lamp voltage measurement the seawater lamp prototype that was successfully developed (figure 5) uses zn and cu electrodes. using 67 ml of seawater as the electrolysis solution. the zinc anode is an electrode with a higher zn content than aluminum, resulting in a higher output voltage than aluminum [25], [17]. the high zn content causes the oxide layer to react more quickly with chloride ions (cl-) in seawater. voltage measurements are made by connecting a voltmeter to the seawater lamp output (figure 6). the developed seawater lamp was tested by connecting it to an led (figure 7) and successfully lit it. subsequent tests use three series of leds arranged in parallel to produce a bright enough led flame (figure 8). http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 17 23 21 m. r. kadir, et al. seawater lamp: utilization of seawater as an alternative … p-issn: 2621-3761 e-issn: 2621-2889 figure 6. seawater lamp connected to the led figure 7. seawater lights connected to 3 led circuits figure 8. seawater lights connected to 3 led circuits after measuring for 96 hours with a range of data collection every 4 hours under normal room conditions, the results are shown in figure 9. figure 9. voltage-time relationship curve based on the obtained time-voltage relationship curve, the generated voltage decreased not significantly from the first to the second day, but from the third to the fourth day, the induced voltage did not change (figure 9). based on the current-time relationship curve, the electric current generated in the seawater lamp series decreased significantly on the first day. on the second day, it decreased but not significantly, but from the third day to the fourth day, the generated voltage did not change (see figure 10). figure 10. current time relationship curve based on the power-time relationship curve obtained, the generated electric power decreased drastically on the first day. on the second day, it decreased but not significantly, but on the third day, the generated power did not change, and on the fourth day, the electric power decreased, which was insignificant (see figure 11). figure 11. the curve of the relationship of electric power against time the decrease in voltage and current generated by the battery is also caused by the reduced concentration of nacl in the seawater used. the high nacl element by h2o is broken down into na+ and cl-; an electric current appears from this process. nacl has an ionization degree of 1, or close to 1, and nacl is a robust electrolyte solution and can be completely ionized in water [26]. the dimensions of the electrodes and the electron solution (salt) significantly affect the magnitude of the current and voltage generated by an electrochemical cell. this means that to restore the voltage and current of a seawater battery, one of the conditions is to replace the electrolyte solution [27]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 17 23 22 m. r. kadir, et al. seawater lamp: utilization of seawater as an alternative … p-issn: 2621-3761 e-issn: 2621-2889 after testing the durability of seawater lamps and obtaining excellent and durable results, fishermen can use seawater lamps when fishing at night. after researching seawater lamps, the results of this tool were that it could become a very efficient source of renewable energy if used by coastal communities and fishermen. after the trial results were obtained, this seawater lamp could last up to 96 hours. besides that, seawater can be a solution to replace fuel oil or diesel fuel because of the free particle charge of nacl salts contained in seawater [12]. fe and al can produce electric potentials up to 1.2 v, while zn, al, and fe and zn produce electric potentials below 1.2 v [14]. this shows that cu and zn can make better prospects than other electrode pairs. another study used cu and zn electrodes, adding 1000 ml of water and 100 grams of salt to produce a potential of 0.52-0.53 volts [28]. redox reaction resulting in increased electron flow. the ability of seawater batteries to generate electrical energy is also influenced by the effective surface area of the electrodes used, the rate of electron transfer, and external resistance [29]. the potential for electrical energy is higher at lower salt concentrations, and this is due to a large amount of free space for moving ions and the lower corrosion rate in water with low salt content [30]. developing this seawater lamp device is easy and can be reproduced using simple equipment. for future applications, this prototype can be used by fishermen to assist in fishing activities at night. these unit cells can be connected in series combinations to achieve higher circuit voltages. v. conclusion seawater lamp can last for more than 96 hours nonstop and produces an initial output voltage of 4.23 v with an initial power output of 6 watts, using 67 ml of seawater. after connecting with led lights and measuring using a multimeter, the highest voltage on the led is 2.56 v, and the voltage drop is only 0.04 v. meanwhile, the highest current test on the led is 2.4 ma and only decreases. recent is about 1.8 ma. and in the power test, it was obtained that the highest power on the led was 6 watts, and it experienced a decrease in intensity of 4 watts. this seawater lamp is suitable for coastal communities and fishermen's use as lighting when going to sea at night. the combination of series and parallel needs to be developed to achieve higher voltage and power values and obtain brighter lights. this research has significantly contributed as a source of renewable energy and alternative electrical energy for fishermen. however, empirical testing has not been carried out. therefore, further research needs to examine the further development of seawater lamps by considering the corrosion rate of the electrodes used and studying the most effective electrodes for use. vi. acknowledgment the research team would like to thank kemenristekdikti through the directorate general of belmawa (directorate general of learning and student affairs) and the university of west sulawesi for funding the pkm (student creativity program) activities. references [1] i. kholiq, “pemanfaatan energi alternatif sebagai energi terbarukan untuk mendukung subtitusi bbm,” j. iptek, vol. 19, no. 2, pp. 75–91, 2015, doi: 10.31284/j.iptek.2015.v19i2.12. 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[30] e. morabet, k. r. a., k. a. r., and a. m., “saltwater a viable source of energy for sustainable rural development,” in 16th international conference on environmental science and technology, 2019, pp. 205– 206, [online]. available: https://cest2019.gnest.org/sites/default/files/presentation_f ile_list/cest2019_00205_oral_paper.pdf. declarations author contribution : muh. ridwan kadir and hardi hamzah are in charge of the entire research project. he also leads the creation and data capture of research in collaboration with all authors. nurul afiqah arsyad, syarifah nuraeni alaydrus, wenny puspita and sahrul participated in delaying data collection, transcription and analysis. he also revised the manuscript. muhammad nurkhalis agriawan is responsible for the creation and design of the media as well as in the preparation of manuscripts and analysis of research data. all authors approved the final manuscript. funding statement : this research is the output of the program kreatifitas mahasiswa (pkm) which is funded by the kementrian pendidikan, kebudayaan, riset, dan teknologi (kemdikbud ristek) through the directorate general of belmawa. conflict of interest : all authors certify that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.20527/flux.v14i1.3777 https://openlibrarypublications.telkomuniversity.ac.id/index.php/engineering/article/view/8089 https://openlibrarypublications.telkomuniversity.ac.id/index.php/engineering/article/view/8089 https://jurnal.ensiklopediaku.org/ojs-2.4.8-3/index.php/ensiklopedia/article/view/958 https://jurnal.ensiklopediaku.org/ojs-2.4.8-3/index.php/ensiklopedia/article/view/958 https://doi.org/10.31851/sainmatika.v19i2.9583 https://doi.org/10.20508/ijrer.v7i4 https://jurnal.polsri.ac.id/index.php/austenit/article/view/3259 https://doi.org/10.23960/jemit.v3i1.88 https://jurnal.untan.ac.id/index.php/jteuntan/article/view/34942 https://jurnal.untan.ac.id/index.php/jteuntan/article/view/34942 https://doi.org/10.4236/jsbs.2016.61002 https://jurnal.unpad.ac.id/jmei/article/view/10959 https://doi.org/10.20508/ijrer.v7i1.5506.g7018 https://doi.org/10.1016/j.memsci.2022.120449 https://doi.org/10.31961/eltikom.v6i2.577 https://doi.org/10.24198/jiif.v5i1.31282 https://doi.org/10.1002/cssc.201501328 https://cest2019.gnest.org/sites/default/files/presentation_file_list/cest2019_00205_oral_paper.pdf https://cest2019.gnest.org/sites/default/files/presentation_file_list/cest2019_00205_oral_paper.pdf indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.1, june 2022, pp. 25 31 doi: 10.12928/irip.v5i1.4804 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 25 effect of sintering temperature on crystal structure and conductivity of the caco3-doped li4ti5o12 anodes from blood clam shells (anadara granosa) marhan ebit saputra1, megawati ayu putri2, eka febrianti1, and widodo budi kurniawan1* 1 department of physics, engineering faculty, universitas bangka belitung, indonesia 2 department of chemistry, engineering faculty, universitas bangka belitung, indonesia email: widodokurniawan1@gmail.com article info abstract article history received: sept 3, 2021 revised: apr 26, 2022 accepted: apr 26, 2022 caco3-doped li4ti5o12 was synthesized by solid-state method with sintering temperatures at 750 °c, 800 °c, and 850 °c. the source of caco3 was used from blood clam shells (anadara granosa) with a content of 97.67%. the influence of sintering temperature on crystal structure and conductivity of caco3-doped li4ti5o12 are extensively studied. xrd results show there is no caco3 phase found, which indicates that the doping of li4ti5o12 with caco3 has been successful. the smallest crystallite size was obtained at a sintering temperature of 800 °c, which is 46.49 nm, which is beneficial for shortening diffusion length and facilitating the electron and ion transport, causing an increase in anode conductivity. the most optimal conductivity was obtained in samples with a sintering temperature of 800 °c with a conductivity of 2.46 x 10-4 s/cm. when the sintering temperature is increased to 850 °c, the particles tend to agglomerate and deteriorate the electrochemical properties. this is an open-access article under the cc–by-sa license. keywords: blood clam shell conductivity li4ti5o12 sintering temperature to cite this article: m. e. saputra, m. a. putri, e. febrianti, and w. b. kurniawan, “effect on sintering temperature on crystal structure and conductivity of the caco3-doped li4ti5o12 anodes from blood clam shells (anadara granosa),” indones. rev. phys., vol. 5, no. 1, pp. 25–31, 2022, doi: 10.12928/irip.v5i1.4804. i. introduction the development of lithium-ion (li-ion) batteries is an interesting research focus as it is very useful in various applications such as mobile phones, computers, and other electronic devices [1]. recently, many efforts have been made to improve its application to hybrid electric vehicles (hev) and effective energy storage systems [2]. the anode is one of the important components that play a role in creating the characteristics of li-ion batteries [3]. li4ti5o12 (lithium titanate oxide) is a potential material as an anode for li-ion batteries as it has several advantages over commonly used anode materials such as graphite, including during insertion/extraction of li+ ions does not change the structure (zero strain), high operating voltage (1.55 v) ensure safe operation of li-ion batteries and long lifetime [4][5]. however, the poor conductivity of li4ti5o12 (< 10 -13 s/cm) is a problem that can limit its rate performance [6]. many methods have been developed to improve the performance of li4ti5o12, including coating with a conductive material and atomic doping such as ta, n, br, ag, ca, cu, zr, and f [7]–[16]. subhan et al. [3] synthesized ca-doped li4ti5o12 using chicken egg shells as ca source by solid-state method, delivering li3.9ca0.1ti5o12 had better electrochemical properties than the li4ti5o12 sample. priyono et al. also prepared cadoped li4ti5o12 with various concentrations of dopant and explored the ca2+ doping can significantly improve the electrochemical performance of li4ti5o12 [17]. in this research, caco3 from blood clam shells (anadara granosa) was used as doping which had the same ca content as chicken egg shells. it is known that the dominant content in blood clam shells is ca [18]. the synthesis method and steps will affect the performance of the anode material, leading to various particle sizes and crystal structures [19]. several methods can be used to synthesize li4ti5o12 such as microwave, molten salt, hydrothermal, sol-gel, electrospinning, and solid-state method [20]–[29]. in this study, the solid-state method was chosen because the process is simple, lowhttp://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i1.4804 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 25 31 26 saputra, et al. effect on sintering temperature on crystal structure …. p-issn: 2621-3761 e-issn: 2621-2889 cost, and does not require many precursors [1]. the formation of phase and crystal structure is strongly dependent on process parameters, especially sintering temperature and holding time. in the present study, caco3-doped li4ti5o12 was synthesized by a solid-state method with various sintering temperatures. the influence of sintering temperatures on crystal structure and conductivity of caco3-doped li4ti5o12 was investigated systematically. ii. theory anadara granosa or known as blood clams are a type of shellfish in the family mollusca and are commonly found in asia, such as indonesia [30]. this shellfish has a high level of productivity and can be processed into various products. in the province of the bangka belitung islands, especially the west bangka region, it is known that the total production of blood clams was 445.13 tons/year in 2015 [31]. the high consumption of blood clams produces a lot of shell wastes. clam shells are useful in many applications such as adsorbent, catalyst, and hydroxyapatite [32]–[34]. in addition, blood clams are natural ingredients that are abundantly available and economical. li4ti5o12 or lithium titanate oxide (lto) in an anode is known as “zero strain material” because it has negligible structure change during lithium-ion intercalation/deintercalation [35]. the structure of li4ti5o12 is face-centered cubic (fcc) spinel with lattice parameter sizes ranging from 8.352 to 8.370 å [36]. the performance of li4ti5o12 is known to have a good specific capacity and density of 175 mah/g and 3.5 g/cm3, respectively. in addition, it also has a long life cycle of more than 10000 cycles [37]. iii. method materials the precursors used in the synthesis of li4ti5o12 were lioh.h2o and tio2. blood clam shells or anadara granosa (see figure 1) were used as caco3 sources for doping. as a binder, the material used was polyvinylidene fluoride (pvdf), n-methyl-2-pyrrolidone (nmp) was applied as the solvent, and acetylene black (ab) was used as the conductive carbon. preparation of caco3 powder first of all, the blood clam shells are cleaned with water and then dried in the sun. after that, clam shells were ground and sieved through a 200 mesh sieve. to ensure that the sample is completely dry, the white powders were heated in an oven at 100 °c for 12 hours. finally, the caco3 powders were obtained and characterized using xray fluorescence (xrf) analysis to determine the chemical composition of materials and x-ray diffraction (xrd) analysis for phase identification. synthesis of caco3 powder caco3-doped li4ti5o12 were synthesized via the solid-state method. 0.1 mol of caco3 was used for doping. firstly, the precursors material which includes lioh.h2o and tio2 were grounded to pass through 200 mesh. a mixture of lioh.h2o, tio2, and caco3 was mixed by mortar until homogeneous. the mixture was calcined at 700 °c with a holding time of 2 hours. afterward, sintering was performed at temperature variations of 750 °c, 800 °c, and 850 °c with the same holding time for 4 hours. as a result, the caco3-doped li4ti5o12 was obtained and then characterized using xrd for crystal structure analysis (see table 1) fabrication of caco3-doped li4ti5o12 anodes to fabricate the anodes, caco3-doped li4ti5o12 powder, pvdf, and ab (80%: 10%: 10%) were uniformly mixed in nmp solvent. the resulting mixture is put into a mold container and heated in an oven at 50 °c until dry. for the eis measurements, the anode samples were made into squares with a side length of 1.5 cm. electrochemical impedance spectroscopy (eis) analysis was used to determine the conductivity value of caco3-doped li4ti5o12. iv. results and discussion characterization of caco3 from blood clam shells xrf and xrd analyses were used to show the characteristics of caco3 from blood clam shells. the elemental compositions of prepared caco3 from blood clam shells were evaluated using xrf as shown in table 2. figure 1. blood clams or anadara granosa table 1. sample code of caco3-doped li4ti5o12 formulation sintering temperature (°c) sample code li3,9ca0,1ti5o12 750 l-1 800 l-2 850 l-3 table 2. elemental composition of caco3 powders chemical element concentration (%) ca 97.67 ag 0.91 sr 0.35 al 0.34 other elements 0.73 http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 25 31 27 saputra, et al. effect on sintering temperature on crystal structure …. p-issn: 2621-3761 e-issn: 2621-2889 figure 2. xrd patterns of caco3 from blood clam shells figure 3. (a) xrd patterns of caco3-doped li4ti5o12 at different sintering temperatures. (b) enlarged (111) plane of samples xrf analysis showed the main component of blood clam shells is ca, with a percentage content of 97.67%. the amount of impurities (ag, sr, al, and other elements) is very low when compared to the ca content, which proves that the blood clam shells have high purity. the results of this study were also proven by several studies that showed ca content of blood clam shells in the range ≥ 90% [38]–[40]. the xrd pattern of caco3 from blood clam shells is shown in figure 2, the analysis using software match 2! results show that the phase obtained from the sample is aragonite (caco3). the major diffraction peaks are observed at 2θ values such as 26.31°, 33.21°, 37.98°, 45.95°, and 52.51° with miller index of (111), (012), (112), (221), and (113), respectively. all of the diffraction peaks are well agreed with the reference patterns of caco3 (cod no. 4001361). in addition, the highest peaks of 26.31° correspond with the previous study showing the highest peaks at 2θ of 26.22° [18], and 26.10° [41] crystal structure analysis of caco3-doped li4ti5o12 figure 3(a) shows the xrd patterns of caco3-doped li4ti5o12 with sintering temperatures at 750 °c, 800 °c, and 850 °c. the results of analysis using match 2 software shows that the dominant phase in the sample is li1.33ti1.67o4 (or spinel of li4ti5o12). the planes at (111), (113), and (004) confirmed that li4ti5o12 has a cubic structure and perfect accordance with corresponding cod no. 10111098. there is no caco3 phase found, which indicates that the doping of li4ti5o12 with caco3 has been successful. however, there was catio3 phase formation in the samples marked at 2θ values of 33.35° for l-1, 33.33° for l-2, and 33.35° for l-3. the presence of the catio3 phase is caused by ca2+ ions that exceed the maximum http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 25 31 28 saputra, et al. effect on sintering temperature on crystal structure …. p-issn: 2621-3761 e-issn: 2621-2889 doping amount, following the previous study by priyono et al. (2019) also has a catio3 peak at 2θ of 33.21° [17]. figure 3(b) shows an enlarged (111) plane at different sintering temperatures. it can be observed that the (111) peak shifted to a lower angle with increasing the sintering temperatures, which is indicating an increase in lattice parameters [42]. to analyze the effect of sintering temperature on the crystal structure, several crystal parameters were calculated including average crystallite size, lattice strain, lattice parameters, and unit cell volume. the average crystallite size of caco3-doped li4ti5o12 is calculated by using debye-scherrer’s equation: 𝐷 = 0.9 𝜆 𝛽 𝑐𝑜𝑠 𝜃 (1) where β is full width at half maximum (fwhm) and λ is the wavelength of cukα. table 3 shows the increase in sintering temperature will affect the enlargement of the lattice parameters and unit cell volume. this is because, during the sintering process, some ions are converted, leading to an increase in lattice parameters as the sintering temperature increases [43]. furthermore, an increase in the sintering temperatures also leads to a decrease in crystallite size. the sintering temperature is proportional to the amount of energy the atoms receive which affects the crystallite size and atomic bonding [44]. at higher temperatures (850 °c), this facilitates diffusion and agglomeration, causing the crystallite size of l-3 samples to become larger than those of l-1 and l-2. the size of crystals gives space for the atoms in the crystal [45]. at larger crystallite size, the atoms are close together, so the lattice strain becomes smaller, as shown in table 3. conductivity analysis of caco3-doped li4ti5o12 further analysis of electrochemical properties of caco3-doped li4ti5o12 was performed by eis. the eis measurement aims to determine the conductivity of the anode. in the eis measurement, using an ac voltage source of 1 v and test range frequency of 4 hz to 5 mhz. figure 4 represents the nyquist plot of the samples and equivalent circuits used for eis data analysis. the value of charge transfer resistance (rct) was obtained by fitting the nyquist plot with the simplified randless cell model using zview software. in the nyquist plot, it can be observed that the spectrum consists of semicircle patterns. the radius of the semicircle indicates the rct of caco3-doped li4ti5o12. the smaller the diameter of the semicircle, representing lower rct, the better the conductivity of samples [46]. figure 4 shows the order of semicircle patterns from smallest to largest for l-2, l-1, and l-3, respectively. this indicates that l-2 has the highest conductivity among the others, which is approved by the conductivity data obtained from the fitting nyquist plot shown in table 4. according to table 4, the sintering temperature can affect the conductivity of the caco3-doped li4ti5o12, in samples l-1 and l-2 the conductivity value increases, while in sample l-3 the conductivity value decreases. for higher temperatures (850 °c), agglomeration occurs in the sample so that crystallite size increases. the enlarged size of the crystallite increases the diffusion length and decreases the conductivity value [47]. figure 4. nyquist plot of caco3-doped li4ti5o12 table 3. crystal parameters of caco3-doped li4ti5o12 table 4. the conductivity of caco3-doped li4ti5o12 sample code rct (ω) conductivity (s/cm) l-1 289 2.20 x 10-4 l-2 269.7 2.46 x 10-4 l-3 481.4 1.06 x 10-4 sample code 2θ (°) lattice parameter (å) unit cell volume (å3) lattice strain (10-3) average crystallite size (nm) l-1 18.58 8.26 563.73 0.39 46.49 l-2 18.56 8.27 566.11 0.41 41.25 l-3 18.49 8.30 572.75 0.31 55.14 http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 25 31 29 saputra, et al. effect on sintering temperature on crystal structure …. p-issn: 2621-3761 e-issn: 2621-2889 v. conclusion the effect of sintering temperature on crystal structure 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[47] a. bouhamed, a. al-hamry, c. müller, s. choura, and o. kanoun, “assessing the electrical behaviour of mwcnts/epoxy nanocomposite for strain sensing,” compos. part b eng., vol. 128, pp. 91–99, 2017, doi: 10.1016/j.compositesb.2017.07.005. declarations author contribution : marhan ebit saputra was responsible for the entire research project. he also led the writing of the manuscript and the collaboration with the other author. megawati ayu putri and eka febrianti participated in the data collection and analysis. widodo budi kurniawan participated in transcription and revised the manuscript. all authors approved the final manuscript. funding statement : this research is funded by directorate general of higher education, ministry of education, culture, research, and technology through the scheme of exact research student creativity (pkm-re) 2021 with the contract no. 1949/e2/km.05.01/2021/ conflict of interest : all authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12962/j24604682.v11i3.1067 https://doi.org/10.1166/jnn.2019.16668 https://doi.org/10.1016/j.compositesb.2017.07.005 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.1, june 2022, pp. 1 7 doi: 10.12928/irip.v5i1.5816 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 1 magnetodeposited nickel on cu substrate with the angle variation of magnetic field moh. toifur1*, effilia allun jaladri1, efi kurniasari1, yuni latifah1, m taufiqurrahman2 1 magister of physics education, faculty of teacher training and education, universitas ahmad dahlan, indonesia 2 dea malela modern international islamic boarding school, indonesia email: toifur@mpfis.uad.ac.id article info abstract article history received: mar 06, 2022 revised: may 15, 2022 accepted: jun 15, 2022 the performance of a thin layer of cu/ni as a cryogenic sensor is produced by electroplating at various angles with the aid of a 200g parallel magnetic field. liquid nitrogen (ln2) is a low-temperature medium with temperatures varying from 0oc to -200oc. the characterization includes the sensor voltage range, sensor resistance, and sensor sensitivity. thermocouple tca-bta -200oc to 1400oc is used as a temperature calibrator. the results showed that all sensors could measure the ln2 temperature in the range of 20 oc to -200oc corresponds to the thermocouple's ability to measure up to -200oc. each sensor has its advantages, but the sensor produced from coating each 3 minutes sample with an angle of 90o has the largest output voltage range up to 0.058 v, and the coating at an angle of 0o with the sensitivity level as a function of t is s(t) = 0.0051 0.002t, while the 3 minutes coating sensor with an angle of 60o has the smallest voltage range of 0.0439 v and sensitivity (1.88 ± 0.05) v/oc. this is an open-access article under the cc–by-sa license. keywords: cu/ni sensor electroplating magnetic field plating angle sensor performance to cite this article: m. toifur, e. a. jaladri, e. kurniasari, y. latifah, and m. taufiqurrahman, “magnetodeposited nickel on cu substrate with the angle variation of magnetic field,” indones. rev. phys., vol. 5, no. 1, pp. 1–7, 2022, doi: 10.12928/irip.v5i1.5816. i. introduction the use of sensors is needed in almost all fields, including medicine [1], computer technology [2], and smoke detectors [3]. the development of sensor technology in health, agriculture, education, military, and civil engineering, is still ongoing. one sensor that continues to be developed is a low-temperature sensor [4], [5]. research to find variants of low-temperature sensors has also been widely carried out. the need for lowtemperature storage units below -150oc (cryonic temperature) is required for food preservation, organ storage [6], [7], and storage of cow semen for artificial insemination [8]–[10]. a thermometer measuring low temperature is also needed in line with the need for a low-temperature sensor. the characteristics of a low-temperature thermometer are different from room temperature or high-temperature thermometers because they include two things, namely changes in material properties when exposed to temperatures, especially low temperatures, and the design of the sensor material. one of the sensors that can be used is a resistance temperature detector (rtd). rtd sensor materials are generally made of metal in a coil, a thin layer, or thin-film [11], [12]. the working principle of rtd is utilizing resistance changes influenced by temperature [13], [14]. some materials often used as temperature sensors are pt, cu, ni, co and their combinations [15]. one of the good metal materials used in manufacturing thin films on rtd elements is platinum (pt) because platinum has oxidation resistance, high accuracy, and good stability [16], [17]. however, platinum is a metal that is quite expensive. therefore, to make a thin layer on rtd, other alternatives are used, namely copper (cu) and nickel (ni) [18]–[20]. cu has the potential to be a temperature sensor [21], but cu is still less sensitive to temperature changes. this is because the resistivity possessed by cu tends to be very low [22], as well as the nature of cu, which is easily oxidized. therefore, the sensitivity of cu can be increased http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i1.5816 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 1 7 2 m. toifur, et al. magnetodeposited nickel on the magnetic field angle variation …. p-issn: 2621-3761 e-issn: 2621-2889 by synthesizing it with ni, which has better resistivity to form a thin layer of cu/ni. another advantage of ni is that it can attract dissimilar molecules better than pt, making film deposition easier [23]. likewise, thin films were chosen because thermocouples have a limited ability to measure temperatures [24] to about -200oc. previous research on cu/ni thin films as lowtemperature sensors produced by electroplating at various coating times assisted by a 200g magnetic field in the transverse direction to the cu surface. the coating time varies from 0 to 45 seconds. liquid nitrogen (ln2) from 0°c to -200°c was used as the low-temperature medium under test. characterization was carried out on the voltage and sensitivity range. the cu/ni sensor of the coating in the 25 s time range has the largest voltage range of 128.48 mv and has a sensitivity (s) which has a linear relationship with temperature (t) according to s(t) = 0.287 0.002t [25]. several attempts to reduce hysteresis are carried out with the help of the use of a magnetic field (b) in the direction parallel to the ion current during coating, which is known as ppmf (permanent perpendicular magnetic field) [26]. the interaction between ni ions moving in the electrolyte towards the cathode under the intensity of the magnetic flux will cause a lorentz effect which can deviate ni ions from the original direction, which is perpendicular to b, and the velocity of the ni ion. by attaching the electrodes to a distance of about 4 cm, it is hoped that the lorentz effect will only produce an oblique path to the ni ion. this effect can improve the morphology of the ni layer attached to the cu substrate [27], [28] so that it is possible to obtain a homogeneous layer, having a denser and more regular arrangement of ni atoms, capable of filling the porosity of the layer which is microscopically invisible from the surface of the media and appears only in an oblique direction. also, using magnetic fields during the plating process can increase ionic currents [29], [30], thus speeding up the coating process [31]. in fact, in the use of this magnetic field, as stated by yue [32], there are several other forces involved besides the lorentz force (fl), namely the electrokinetic force (fe), the magnetic field force (fb), the magnetic damping force (fd) and the paramagnetic force (fp). the five forces compete with each other depending on the intensity of the magnetic field. the field intensity is not that big, and only two forces play an important role, namely fl and fe. too large a magnetic intensity will reduce the thickness of the layer and limit the current density [33], [34]. therefore, this study used the magnetic field intensity of 200g and variations of the coating angle from 0o, 30o, 60o, and 90o to produce variations in ni thickness. the layer thickness and the microscopic structural conditions of the deposit will play a role in determining the quality of the low-temperature sensor. ii. theory magneto hydro dynamics (mhd) mhd is a process of ion movement in an electrolyte solution due to an external magnetic field. mhd combines elements of electromagnetism and fluid mechanics to describe the electrical flow of liquids. convection of mhd is considered one of the characteristic phenomena in the magneto-electrochemical process. five magnetic forces occur, namely the paramagnetic force, field gradient force, lorentz force, magnetic damping force, and electrokinetic force. in this experiment, the force studied is the lorentz force. convection is induced by electromagnetic interactions (lorentz force). convection can increase the ionic mass transfer rate to increase the coating current. the direction of the magnetic field related to the electric field in the electroplating process is the current efficiency, composition, and layer morphology. the mass transport is increased, thereby changing the electroplating layer [35]. also, the lorentz force can affect the surface layer morphology and the thickness of the layer. electroplating electroplating or electroplating is a process of coating/depositing a desired protective metal on top of other metals using electrolysis. the provision of direct current into the solution causes a reduction process at the cathode and anode. faraday's law of electrolysis serves as the foundation for the electroplating process. the thickness of the produced layer can be estimated if there is a difference in the sample's mass after and before electroplating [36]. sensitivity. sensitivity is the ratio between the output signal (sensor response) and the input change (measured variable). the sensitivity indicates the temperature sensor's sensitivity to the quantity being measured. some temperature sensors can have a sensitivity expressed in volts per °c (v/°c), which means that a one-degree change in temperature at the input results in a change in voltage of several volts at the output. if the response is linear, then the sensitivity is the same for the entire measurement range. voltage range. one of the criteria for selecting a sensor is the ability or range to respond as needed. the sensor has a wider range, and it can be said that it performs better. a temperature sensor with a wider range can be used to measure the temperature range over a large range. resistivity resistivity (ρ) is the ability of a material or medium to inhibit its electric current. the resistivity value for each type of metal is different depending on several things such as porosity, constituent minerals, permeability, etc. resistivityassociated with electrons in electric current by the microscopic structure of the material. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 1 7 3 m. toifur, et al. magnetodeposited nickel on the magnetic field angle variation …. p-issn: 2621-3761 e-issn: 2621-2889 iii. method material specifications for coating conditions are given in table 1. substrate preparation at this stage, copper and nickel plates are prepared (10 × 1.3 cm2), and the lithography design uses a cutting sticker, fecl3, and acetone. the copper plates are cleaned by rubbing the surface with an autosomal metal polish in the same direction. the next step is to print the lithography design on the substrate by dissolving it with fecl3 for about 10 hours and cleaning it with acetone. after the printed design is cleaned by rubbing the surface with autosomal metal polish and smoothing the surface with toothpaste in the same direction, then rinsing with distilled water and alcohol in an ultrasonic cleaner. then the substrate is dried with a hairdryer and stored by wrapping it on a tissue, placing it on a plastic clip, and then storing it in the dry box. preparation of cu/ni coating before plating is carried out, a nickel solution (watt's nickel) is prepared to consist of niso4 260 g, nicl2 60 g, h3bo3 40g, and h2o 1000 ml. the ingredients are stirred using a magnetic stirrer for 3 hours. cu plates as substrate were weighed using ohaus-pa214 balance and recorded as mcu. a cu plate is attached to the cathode and a ni plate to the anode at a distance of 4 cm. electroplating is carried out at a voltage of 4.5 v by varying the coating angle of 0o, 30o, 60o, and 90o; the electrolyte temperature is 60oc, for 3 minutes. a 200g magnetic field is installed in a direction parallel to the direction of the electric field. after finishing, the sample is removed, then rinsed with distilled water and dried using a hairdryer. after drying, the sample was weighed again and recorded as mcu/ni. experimental design the experiments were carried out according to the procedure, as shown in figure 1. liquid nitrogen is a lowtemperature medium (ln2) [37]. this medium is filled in a 10 liters volume container where the temperature can be varied from 0°c to -200°c based on the location of the depth in the container. locations close to the container lid have a higher temperature than those close to the bottom of the container. ln2 temperature near the cover 20°c. characterization of the sensor following the standard test of immersion in liquid or gas [38]. to avoid the effect of leakage of voltage on the connecting cable between the sensor and the vp-bta voltage probe, the sensor is composed of a transducer circuit [39]. then the cu/ni sensor and the tca-bta thermocouple as a calibrator were slowly put into the container. slow motion on the sensor is intended so that the sensor can measure in an orderly manner any moderate temperature changes. the output of the cu/ni sensor is in the form of voltage and time data, while the thermocouple output is in the form of temperature and time data. both of these outputs can be observed on a computer screen with the help of mini labquest and loggerpro 3.8.6, two software in the numeric and graphic display. furthermore, the data is then analyzed on the sensor voltage range, resistance, and sensitivity [40]. table 1. specifications in the electroplating process specifications in the electroplating process cathode : cu anode : ni electrode spacing : 4 cm electrolyte : h3bo3 (40 gr), niso4 (260 gr), nicl2 (60 gr), and h2o (1000 ml). electrolyte temperature : 60c deposition time : 3 minutes transverse magnetic field : 200 g. cu / ni film specifications long : 15.40 cm wide : 2 mm big : 7.61 cm form : square wave cu layer thickness : 17 m ni layer thickness : (27.09 149.44) m http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 1 7 4 m. toifur, et al. magnetodeposited nickel on the magnetic field angle variation …. p-issn: 2621-3761 e-issn: 2621-2889 figure 1. schematic of low-temperature sensor performance research cu/ni iv. results and discussion resistance figure 2 shows the response of the cu/ni sensor to the temperature of liquid nitrogen when the temperature is lowered from 20oc to -200oc and then increased to 20oc again. in general, the output voltage signal still contains ripples. this is related to the microscopic structure of the cu/ni sensor when an electric current is applied. for a fine layer with a regular crystal structure and uniform grain size, an electric current can smoothly pass through the coating surface so that the output signal is smooth. however, for the cu/ni layer, which has a coarse microstructure, irregular crystal structure, and nonuniform grain size, the electric current will encounter many constraints resulting in ripples in the output signal. another thing that can be seen in figure 3 is the shape of the curve, which is gentle at the top and steep at the bottom. this is related to different responses to changes in temperature. likewise, the position of the peaks projected on the x-axis looks different. this shows the variation in the time it takes for the sensor to reach a temperature of 200oc. from the data (v, t) and (t, t) as the logger pro output, especially for the temperature drop, it is possible to create a vt curve where the slope curve shows the sensitivity of the sensor in responding to temperature changes. furthermore, the sensitivity was analyzed from the temperature-slope (vt) curve. the vt curve is not linear, so the data (v,t) are assigned according to the order of the polynomial 2. sensitivity (s) is determined by the slope of the dv/dt curve. here, because the sensitivity still depends on the temperature, but for the curve v(t), a larger slope indicates that the sensor is more sensitive. stability is obtained from the relative sensitivity error. voltage range the voltage range is the difference in the minimum output voltage when the sensor measures the lowest ln2 temperature (v-200 o c) to the maximum output voltage when the sensor measures ln2 20 oc (v-20 o c) temperature. v-20 o c is obtained when the sensor is placed near the mouth of the container, while v-200 o c is obtained when the sensor is placed on the surface of the ln2 in the container. the variation of each sensor's highest and lowest voltage shows figure 2. cu/ni sensor response figure 3. the response of the cu/ni sensor to the decrease and increase in temperature of ln2 0 10 20 30 40 50 60 70 80 90 0.65 0.70 0.75 0.80 0.85 v o lt a g e ( v ) degree () 0 () 30 () 60 () 90 () 0,0525 v 0,0445 v 0,0439 v 0,0580 v figure 4. cu/ni sensor output voltage range in response to ln2 temperature http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 1 7 5 m. toifur, et al. magnetodeposited nickel on the magnetic field angle variation …. p-issn: 2621-3761 e-issn: 2621-2889 figure 5. (a) sensor sensitivity and (b) cu/ni sensor sensitivity level the amount of cu/ni sensor resistance as a function of temperature t. from here, the sensor from the coating at a 90o angle has the lowest v-200oc compared to other sensors at 0.69 v, while the largest voltage is 0.87 v corresponds to the coating sensor at a 60o. the difference between the highest and lowest voltage is the voltage range. the large voltage range makes the sensor more accurate at displaying moderate temperatures. the largest voltage range of 0.058 v corresponds to the sensor resulting from a 3 minutes deposition at 90o. sensor sensitivity figure 5 shows a voltage-temperature curve. sensitivity can be seen from the slope of the curve, which shows the change in the output voltage to changes in ln2 temperature. the vt curve for all sensors tends to be curved so that the sensitivity is different at each temperature. mathematically, the equation for the vt curve can be approximated by a polynomial of second-order [25]. 2 0 1 2 v b b t b t= + + (1) while sensor sensitivity is a derivative of voltage to temperature. 1 2 ( ) 2 dv t b b t dt  = = + (2) the adjustable sensitivity curve from -200oc to 0oc is shown in figure 5. from this figure, it can be seen that the lower the medium temperature, the sensor sensitivity increases. thus, it can be concluded that the cu/ni sensor is more suitable for use as a low-temperature sensor. for example, a sensor that results from coating at an angle of 60o has a sensitivity of 0.128 v/oc at -100oc, whereas when used at -200oc, the sensitivity increases to 0.188 v/oc. also, the sensor resulting from coating at an angle of 0o has the highest slope compared to other sensors, so even though it has varying sensitivity levels, the lower the temperature, the more sensitive it is. at -100oc the sensitivity is 0.205 v/oc while at -200oc the sensitivity rises to 0.405 v/oc. the sensitivity of this sensor is two times increased from the sensitivity of the sensor from coating at an angle of 60o, whereas when compared to the sensor resulting from a 60o coating, when it is used to measure a temperature of -200oc, the sensor from the coating at an angle of 0o has a sensitivity of 2.2 times almost 2.5 times. therefore, sensors from 0o plating are suitable for selecting low-temperature sensors. about eq. 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[40] b. garnier and f. lanzetta, “in situ realization/characterization of temperature and heat flux sensors,” in advanced spring school “thermal measurements & inverse techniques,” 2015, pp. 79–87. declarations author contribution : moh. toifur was responsible for the entire research project. he also led the writing of the manuscript and the collaboration with the other authors. effilia allun jaladri, efi kurniasari, yuni latifah, and m. taufiqurrahman participated in the data collection and analysis. all authors approved the final manuscript. funding statement : this research is funded by the universitas ahmad dahlan with the contract no conflict of interest : all authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1016/j.electacta.2007.04.054 https://doi.org/10.1016/j.electacta.2003.04.009 https://doi.org/10.1007/s10008-006-0210-3 https://doi.org/10.4028/www.scientific.net/amr.1112.353 https://doi.org/10.1016/s0924-4247(01)00759-2 https://doi.org/10.1016/s0924-4247(01)00759-2 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 20 26 doi: 10.12928/irip.v4i1.3783 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 20 student self-regulated in remote learning with the implementation of local virtual lab based on online tutorial (lvl-bot) pariabti palloan1, sri rahmadhanningsih2, sparisoma viridi3, jainuddin4, ahmad swandi5* 1 department of physics, faculty of mathematics and natural sciences, universitas negeri makassar, indonesia 2,3 department of physics, faculty of mathematics and natural sciences, institut teknologi bandung, indonesia 4,5 department of physics education, faculty of teacher training and education, universitas bosowa, indonesia email: ahmad.swandi@universitasbosowa.ac.id article info abstract article history received: mar 05, 2021 revision: may 16, 2021 accepted: aug 05, 2021 this study aims to measure the level of self-regulated learning (srl), conceptual understanding and identify an increase in conceptual understanding after using lvl-bot. this type of research is pre-experimental with one-group pretestposttest design. the research sample consisted of 37 students from physics classes who took modern physics courses. students’ level of self-regulated learning is administered using a questionnaire, and understanding of concepts is administered using a test. based on the analysis results, the percentage level of self-regulated learning is at a value of 87.7%, which is included in the very high category. there is a significant difference between the mean pre-test and post-test mean. the ngain values of photoelectric effect and black body radiation are 0.47 and 0.57, respectively. this shows an increase in student’s conceptual understanding, which is “enough” after using lvl-bot. this is an open-access article under the cc–by-sa license. keywords: concept understanding remote learning self-regulated learning virtual lab to cite this article: p. palloan, s. rahmadhanningsih, s. viridi, jainuddin, and a. swandi, “student self-regulated in remote learning with the implementation of local virtual lab based on online tutorial (lvl-bot),” indones. rev. phys., vol. 4, no. 1, pp. 20–26, 2021, doi: 10.12928/irip.v4i1.3783. i. introduction the coronavirus pandemic has had a significant impact on human life in all fields, especially in education. learning that was initially carried out face-to-face is now being carried out online to cut the spread of the coronavirus. at present, all educational institutions are trying to find suitable models and methods. distance learning does not interfere with student learning, and the concept remains easy to understand even though it is done online. the separation of physics between students and lecturers is a characteristic of far-reaching education [1]. this impacts the lack of interaction between students and lecturers. of course, it has a negative effect on student learning outcomes. lecturers cannot control student activities during the distance learning process. there are still many lecturers who do not teach due to limited skills in operating computer technology. besides that, lecturers are also not used to developing online-based teaching materials. for this reason, it is necessary to use technology to support broader interactions and activities for students and lecturers [2]. this technology is also expected to present engaging, easy, and meaningful learning and the ongoing impact of the covid 19 pandemic and advances in network-based information and communication technology (ict) in education. so, ict in supporting distance learning is a must, and the government, educational institutions, and lecturers need to develop appropriate models, methods, and technology media. in addition, one indicator in seeing the achievement of distance learning objectives is the level of understanding of students’ concepts. learning achievement has a relationship with the student’s srl http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3783 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 20 26 21 palloan, et al. student self-regulated in remote learning …. p-issn: 2621-3761 e-issn: 2621-2889 level. students with a low level of learning independence tend to have an inadequate understanding of concepts and vice versa [2], [3]. srl is closely related to students’ planned thoughts, feelings, and actions, significantly affecting their learning and motivation. distance learning in various majors or courses is undoubtedly different. in social learning, the material presented in presentation slides or learning videos is sufficient. this is different from the science and mathematics majors, especially physics. physical phenomena that can be understood by mastering mathematical concepts first become quite difficult. they must be trained how to solve problems with a good understanding of mathematics. in addition, physics students must understand and observe directly existing physical phenomena and study these phenomena with correct mathematical concepts. learning like this will be more interesting, not dull, and increase student activity. therefore, physics learning should involve direct experimentation [4], [5]. however, not all physical phenomena can be observed by conducting experiments because some abstract material and invisible [6], [7]. in addition, the implementation of the experimental method is currently not possible due to several factors, such as (1) during the pandemic, which requires learning to be carried out in individual homes; (2) the availability of equipment in the laboratory that students in their homes can use is minimal [6], [8]; (3) the absence of practicum guidelines developed by lecturers that can direct students to make observations self-regulated is also a big problem for physics learners during the pandemic [9]. students who use distance learning are autonomous learners who have freedom of behavior and the learning system they will do [2]. they have broad autonomy to determine when they learn, where and how to organize their learning process and what learning resources should be used. this is different from face-to-face learning, where the lecturer can regulate the teaching and learning process in the classroom. in addition, because the characteristics of each student are different in the distance learning process, their ability to manage the learning process both in distance classes and additional learning is of particular concern for the teaching staff. choosing the suitable physics learning method during the distance learning class is expected to increase student motivation and activity in learning. this will also significantly affect their independence in learning physics. self-regulated learning (srl) for students in distance learning is very important. they must be able to control and regulate the learning process. they are also expected to direct their learning positively [2], [10]. the use of communication technology is expected to be more widely used in accessing information and learning resources. therefore, the role of lecturers in this matter is very much needed. the types of technology and teaching materials provided by the lecturers certainly affect their learning independence. lecturers who do not understand the technology and cannot use it either in developing learning media or the teaching and learning process will affect distance learning. it is necessary to have technologybased teaching materials that can achieve learning objectives. there need to be learning techniques that can direct students to explore abstract concepts even though learning is carried out online to solve this problem. this technology is also expected to increase students’ understanding of these concepts, reduce misconceptions and improve skills in analyzing graphics, numbers, or complete with mathematical concepts. this technology can replace the use of physics practicum tools, is easy to use, and has no risk even though it is used outside the supervision of a lecturer or tutor. one of the right technologies to solve this problem is implementing a local virtual laboratory based on online tutorial (lvl-bot). various previous studies have used virtual laboratories as a substitute for experimental activities in the classroom. however, there is still very little to do in online learning because the virtual laboratory needs to be developed to be used easily by students wherever they are. so that with the additional application, it can direct students in using teaching materials. the problem in this study is how students’ level of learning independence and increased understanding of concepts before and after using lvl-bot. ii. theory a local virtual lab is a developed application tool capable of describing a real laboratory environment. this application is stored in technology devices such as computers, laptops, or smartphones that the user can access offline. several studies on the use of virtual laboratories have been conducted. according to yusuf and widyaningsih [11], virtual laboratories can improve critical thinking skills. in addition, students’ activities and perceptions of learning physics with virtual laboratories are very good. swandi et al. [12] also stated that virtual laboratories positively affected problem-solving skills and student learning outcomes. in addition, student activity observation is in the very high category, above 80% when learning with the experimental method using a virtual laboratory [6]. most students also strongly agree with virtual laboratories because they feel invisible phenomena become visible even though they will never be seen [7]. students who use virtual media such as virtual laboratories as learning media have a higher ability to understand and present the studied material [13], [14]. a similar conclusion was also put forward by magyar and žáková [15] in their research, which stated that students’ http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 20 26 22 palloan, et al. student self-regulated in remote learning …. p-issn: 2621-3761 e-issn: 2621-2889 motivation to be more active in participating in learning and developing various skills could be increased by using virtual laboratories. figure 1 is an example of a virtual laboratory developed by swandi et al. [12]. figure 1. local virtual laboratory equipment on the compton effect concept. the photons emitted from the x-ray tube then collide with free electrons on the surface of the gold. as a result of this collision, electrons will bounce off with various changes in angle, and photons will experience a change in magnitude. the change in magnitude after the collision is observed from the detectors that surround the compton effect circuit. various facilities can be used in this virtual experiment, such as changes in incident angle and photon wavelength to determine the relationship between the incoming photon wavelength and the angle of the electron after the collision, the relationship between the incoming photon wavelength and the photon wavelength after the collision, the photon wavelength shift after the collision, and the kinetic energy of the electron after the collision. although virtual laboratories have been widely developed and used by previous researchers, these studies indicate that virtual laboratories are used in the classroom (face-to-face between lecturers and students), which means there is still extensive and direct interaction between lecturers and students. this is different if learning is carried out remotely where students cannot meet directly with the lecturer. without prior explanation by the lecturer, virtual laboratory learning will be very difficult to do. therefore, lecturers need to develop virtual laboratory teaching materials that students can download with online tutorials to overcome this. this is important so that virtual laboratories can still be used without direct instruction from lecturers or tutors. in addition, virtual laboratories are also supported by online learning platforms through applications such as websites or e-learning. so that even though lecturers and students are separated, they can still interact even through the application. students would benefit immensely from using instructional materials and media like this since professors provide instructions or video tutorials and a distance learning platform. when students have questions, they can quickly ask the lecturer [16]. figure 2 shows the stages of learning using lvlbot. figure 2. learning stages using local virtual lab based on online tutorial two things distinguish lvl-bot from virtual labs that have been widely used before. the first is the lvlbot supported by a video containing instructions from the lecturer. with this video, students easily follow instructions to make observations and collect data, then analyze the results and conclusions. the second advantage is that lvl-bot is accessed with an online learning platform. this makes learning more interactive. the interaction between teachers and students can still be done supported by e-learning facilities. in addition, teachers easily evaluate the learning process that has been taking place [17]. lvl-bot, which is rich in interactive simulations, allows students to carry out experimental activities independently whenever and wherever they are [18], [19]. an exciting simulation can show physics concepts and phenomena through visualization. students can see how physical parameters influence or interact with a concept or theory [20]. iii. method this research is pre-experimental research where there are still external variables that influence students’ conceptual understanding and learning independence. this is due to the absence of control variables, and the sample was not randomly selected. the sample in this study was 37 physics education students who took modern physics http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 20 26 23 palloan, et al. student self-regulated in remote learning …. p-issn: 2621-3761 e-issn: 2621-2889 courses at makassar state university. this study uses the one-group pretest-posttest design, as shown in table 1. table 1. research design [21] pattern information o1 x o2 o1 = initial test scores before being given treatment o2 = final test scores after being given treatment students are first given a preliminary test before students are treated with virtual laboratory teaching materials assisted by e-learning in distance learning. then, after being given treatment, students were again given the post-test. thus the results of the treatment can be known to be more accurate because it can compare with the previous situation. experts have validated concept understanding test instruments and self-regulated learning questionnaires to assess construct and content validity. the test instrument is in the form of essay questions with ten questions related to the concept of the photoelectric effect and black body radiation concepts. meanwhile, to promote self-regulated learning consists of 40 questions with five indicators, namely (1) initiative in online learning; (2) responsibility for assigned tasks; (3) confidence in the results of work; (4) independence in working and making decisions; and (5) independence in using knowledge and experience by situations and conditions. improved understanding of concepts after using a virtual laboratory based on video tutorials and assisted by e-learning is reviewed based on the average post-test score minus the average pre-test score. improved learning outcomes were analyzed using n-gain, student learning independence data were analyzed descriptively through percentage techniques. iv. results and discussion at the end of the lesson, with the application of a virtual laboratory based on online tutorials on black body radiation and photoelectric effects, students are asked to complete a self-study questionnaire according to their opinion of themselves during the lesson. the questionnaire was filled out online via google form and then analyzed using ms. excel in a quantitative descriptive manner to calculate the percentage of responses. the results of the self-learning questionnaire analysis for each indicator are presented in table 2. based on table 2, in general, the percentage of selfregulated learning is at a value of 87.7%, which falls into the very high category. the indicator of self-regulated learning, namely student initiative in online learning, had the highest percentage, 92.4%. at the same time, the lowest is the indicator of self-confidence towards work results, namely 80.4%. for the other three indicators, the score is above 80%. in addition, it can be concluded that the percentage for all indicators of self-regulated learning of students is in the very high category. table 2. indicators of student self-regulated learning aspect percentage (%) initiatives in online learning using lvlbot 92.4 responsibility for assigned tasks 91.6 confidence in the results of work 80.4 behave in a disciplined manner 91.8 independence in using knowledge and experience by situations and conditions. 82.3 average 87.7 the high percentage of student initiative in online learning is due to adequate online learning support facilities. all students have laptops and smartphones that can access teaching materials and virtual laboratories based on online tutorials. however, some students complained about the availability of their internet data packages and their unstable network. because to access and download all teaching materials and virtual laboratory applications, a large data package is required. some students have also prepared learning materials before the lecturers provide virtual laboratory teaching materials. most of the students had studied the material beforehand with books and references from the internet. almost all students do assignments and collect on time. the task given is in the form of conducting experiments with a virtual laboratory. each student studies the teaching materials provided, makes observations, collects data, analyzes, discusses, and draws conclusions. students are happy with assignments that are quite clear and systematic. so they no longer need to ask the lecturer about completing the assignment. they also strongly agree with the task collection system that uses e-learning. the lecturer quickly checked the assignments that were entered then students were asked to correct them if there were deficiencies. however, a small proportion of students are still indifferent and cannot complete assignments selfregulated. they still need help from friends for the process. students find it easy to work and study with sufficiently complete teaching materials such as books, worksheets, and virtual laboratory manuals. online tutorial-based virtual labs are beneficial for them. they argue that this is equivalent to face-to-face learning because a lecturer guides them to work on a project even though it is in the form of audio and not video. the learning material is also presented in audio format so that the explanation is obvious and can be repeated if there are things that are not understood. some students who do not http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 20 26 24 palloan, et al. student self-regulated in remote learning …. p-issn: 2621-3761 e-issn: 2621-2889 understand the explanation can also directly ask questions through the e-learning used. some students also thought that their memory ability of the concepts they learned through virtual laboratories was better. this aligns with jagodzinski and wolski’s research that learning using virtual laboratories positively impacts teaching efficiency. students also experience an increase in remembering information and show greater resilience in remembering information (concepts material) [22], [23]. however, even though distance learning is becoming more attractive, many students still lack confidence in their results. even in a pandemic, students are encouraged to enhance their activities at home, which includes studying. for some students, this is not an issue. they argue that although face-to-face learning in class is different from distance learning, they have great freedom [24]. supported by online tutorial-based virtual laboratory teaching materials, they can easily download and access teaching materials, manage when and wherever they study, repeat lessons repeatedly, and ask lecturers directly using elearning without noticing other students. therefore, it can be concluded that the application of online tutorial-based virtual laboratories is very suitable to support distance learning and increase student independence in learning. several previous studies have shown that the application of laboratory-based teaching materials can improve student learning activities, attitudes, and motivation in learning physics [25], [26]. amin et al. [5] also stated a positive relationship between the application of a virtual laboratory with problem-solving skills and science process skills for physics students. palloan and swandi [27] state that using virtual simulations with active learning strategies can increase student activity in observing abstract concepts. after the students filled out the self-regulated learning questionnaire, they were then asked to take a final test related to black body radiation and the photoelectric effect. concept understanding test scores were then analyzed to determine the average score on the pre-test and the final test, and then the intervals were determined. the results of comparing the results of the students' concept understanding test results before and after being treated in the form of the online tutorial-based virtual laboratory teaching materials on the photoelectric effect and black body radiation materials are described in figure 3. from figure 3, it can be seen that there is an increase in the average understanding of students’ concepts before and after learning using virtual laboratories for photoelectric effect material and black body radiation. for the photoelectric effect material, the difference between the final test and the pre-test is around the value of 27. for the black body radiation material, it is in the range of value 13. although the difference between the final test and the pre-test is not too significant, it can be concluded that there is an enhancement of student concepts understanding using lvl-bot. categories of increasing students’ conceptual understanding are tabulated in table 3. figure 3. comparison of pre-test and post-test table 3. the value and category of enhancement concept understanding unit n-gain value category photoelectric effect 0.47 enough black body radiation 0.57 enough from table 3, it can be seen that there is an increase in student learning outcomes after using the lvl-bot both on the concept of the photoelectric effect and black body radiation. at the same time, the increase is in the ”enough” category. these results are in line with several studies conducted by several researchers. research conducted by yusuf and subaer [28] and amin et al. [7] show that there has been an increase in student learning outcomes and science process skills after using virtual laboratories inside. according to nurrokhmah and sunarto [29], learning with a virtual laboratory makes learning activities more enjoyable. students’ interest and enthusiasm for learning can be increased by using virtual laboratories. furthermore, this learning paradigm encourages students to be more engaged to absorb better the concepts being taught. athaillah et al. [30] also stated an increase in student’s conceptual understanding, marked by the n-gain category in the experimental class and the control class for dynamic electricity material. likewise, there is an increase in conceptual understanding for chemistry learning, especially in understanding, cognitive, and application after learning using a local virtual laboratory based on online video tutorial (lvl-bot). although there is an increase in student’s conceptual understanding after learning using lvl-bot, it cannot be concluded that the application of the lvl-bot on conceptual understanding. this is because the form of research used is only pre-experimental, which does not limit other influencing variables. 0 20 40 60 80 100 pre-test post-test interval photoelectric effect black body radiation http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 20 26 25 palloan, et al. student self-regulated in remote learning …. p-issn: 2621-3761 e-issn: 2621-2889 v. conclusion based on the study results, it can be concluded that the level of student self-regulated learning in distance learning physics after using the lvl-bot learning device is at an average percentage of 87.7%, which falls into the ”very high” category. in addition, based on the analysis results before and after the use of lvl-bot, there was an increase in conceptual understanding of both the photoelectric effect material and black body radiation, each of which was in the “adequate/enough” category. however, it cannot be said that using the lvl-bot learning tool is both on self-regulated learning and on conceptual understanding. this is because the research design used does not limit other variables that may have an effect. therefore, other researchers need further research that can be carried out by other researchers using experimental research designs such as the use of pre-test and post-test in two classes, namely the experimental class and the control class. further research can also be carried out to see whether there is an effect of the application of lvl-bot on learning independence and conceptual understanding or learning independence on conceptual understanding. therefore, the use of research methodologies must be appropriate. references [1] g. flanagan, “teaching and learning at a distance — foundations of distance education,” internet high. educ., vol. 3, no. 3, pp. 219–222, jul. 2000, doi: 10.1016/s1096-7516(01)00034-3. 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[30] athaillah, i. khaldun, and mursal, “peningkatan pemahaman konsep siswa melalui laboratorium virtual pada materi listrik dinamis di sma negeri 1 sukamakmur aceh besar [improving student concept understanding through virtual laboratories on dynamic electrical materials at sma negeri 1 sukamakmur aceh besar],” j. pendidik. sains indones., vol. 5, no. 1, pp. 114–119, 2017. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.24252/jpf.v9i1.20519 https://journal.unismuh.ac.id/index.php/jpf/article/view/5107 https://doi.org/10.1177/1054773816666280 https://doi.org/10.33225/pec/14.61.46 https://doi.org/10.15294/jpfi.v13i2.9234 https://doi.org/10.1119/perc.2020.pr.wilcox https://doi.org/10.30870/educhemia.v2i2.1608 https://doi.org/10.26740/jpps.v2n2.p191-197 https://doi.org/10.1088/1742-6596/1157/3/032016 https://doi.org/10.1088/1742-6596/1157/3/032016 https://journal.unnes.ac.id/nju/index.php/jpii/article/view/2722 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 32 38 doi: 10.12928/irip.v4i1.3980 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 32 the analysis of students’ critical thinking and scientific literacy skills fatma zuhra1*, nurhayati2, fitria arifiyanti3 1 department of primary school teacher education, faculty of teacher training and education, universitas almuslim, indonesia 2 department of mathematics education, faculty of teacher training and education, universitas almuslim, indonesia 3 doctoral school of education, university of szeged, hungary email: fatma.zuhra34@gmail.com article info abstract article history received: apr 19, 2021 revised: aug 2, 2021 accepted: aug 4, 2021 this research aimed to determine critical thinking and scientific literacy skills for the tenth-grade students of bireuen public high school 2 (sman 2 bireuen). this research used a quantitative approach with a descriptive research design. there were 27 tenth-grade students of the second science class who selected samples through the purposive sampling technique. descriptive analysis is a research type that does not provide the treatment, manipulation, or modification on the independent variables, but it describes an actual condition. the instrument used in this research was a test adapted from pisa questions. the results showed that the critical thinking and scientific literacy skills of tenth-grade students of sman 2 bireuen were in the fair category. therefore, it is necessary to apply learning approaches/models that can train students’ scientific literacy skills to get used to carrying out scientific activities, solving scientific problems, providing explanations for a phenomenon scientifically, and using scientific evidence to explain a fact. this is an open-access article under the cc–by-sa license. keywords: critical thinking scientific literacy students’ achievement to cite this article: f. zuhra, nurhayati, and f. arifiyanti, “the analysis of students’ critical thinking and scientific literacy skills,” indones. rev. phys., vol. 4, no. 1, pp. 32–38, 2021, doi: 10.12928/irip.v4i1.3980. i. introduction the development of science and technology becomes a challenge in the educational field, making human resources more qualified and competing. this can happen if it is supported by good quality education. the rapid development of science and technology today is one of the impacts of globalization. the mindset of human resources is increasingly critical [1]. education is one aspect of life that affects the development of science and technology. science and technology education is essential in preparing students to think critically, logically, creatively, and responsively to issues developing in everyday life [2]. then, wirnati et al. [3] it states that science education is a process that can shape human resources to think critically and creatively. the development of science and technology education requires sensitivity in analyzing various problems in life. human resources are needed to have reading, writing, counting, and scientific literacy [4]. based on oecd 2014 obtained the domain of scientific literacy consists of context, knowledge, competence, and attitudes [5]. the pisa assessment assesses students’ knowledge and science skills from school and applies them in everyday life. therefore, pisa scientific literacy questions only focus on situations related to the individual, social, and society in general. indonesia’s involvement in participating in the program for international student assessment (pisa) is an effort to compare the development of educational programs in indonesia with other countries in the world. this is very important for indonesian children in developing educational programs to compete with other countries. indonesia, from 2000 to 2018, has had the program for international student assessment (pisa). the results obtained are that indonesia is still very far from the expected results, so it takes effort and hard work to get better results, especially in critical thinking skills and science. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3980 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 32 38 33 zuhra et al. the analysis of students’ critical thinking …. p-issn: 2621-3761 e-issn: 2621-2889 in general, students at this time still have not been able to develop skills in reasoning such as reading while thinking so that they can receive information clearly in solving various problems. critical thinking, logical thinking, and adaptation to various changes and developments can teach students scientific literacy skills [6], [7]. based on this, it can be assumed that critical thinking and scientific literacy skills have an attachment. critical thinking skills play an essential role in science education because they involve solving problems, making decisions, analyzing, and conducting various studies. critical thinking skills in science learning are fundamental to be mastered. students are trained in expressing opinions, making decisions, or becoming experts in studying the sources used. furthermore, scientific literacy is a thinking process that includes problem-solving or critical thinking [8]. scientific literacy can also be expressed as a skill to understand a concept or principle and thought process in solving problems that occur in everyday life [9], [10]. students’ scientific literacy includes the skills of analyzing, predicting, and applying various concepts. there are several studies related to critical thinking skills and scientific literacy. research from fatah et al. [11] showed a significant effect of the argument-driven inquiry learning model on cognitive skills and scientific literacy on the concept of plant tissue in the experimental class. then, research from rahayuni et al. [12] pointed out such things as; a strong correlation between critical thinking and scientific literacy skills, and the science technology community model is better than the learningbased model to improve critical thinking and improve students’ scientific literacy skills. furthermore, juhji and mansur [13] showed that critical thinking and scientific literacy skills affect the mastery of basic concepts of biology, which obtained a value of 56.8%. this shows the importance of developing critical thinking skills and scientific literacy skills in science learning activities. furthermore, research from azrai [14] reported that critical thinking and scientific literacy skills have a close relationship, where critical thinking skills can contribute 19.9% to the scientific literacy process. based on the previous description, this study explores critical thinking skills and scientific literacy skills at bireuen public high school 2 (sman 2 bireuen). ii. theory science learning science learning seeks to increase students’ interest in developing various knowledge and improving skills and abilities to think about the universe. science learning contains facts, theories, and concepts that must be mastered and memorized and includes various activities that use reason and scientific attitudes to study these aspects. the process must be carried out thoroughly in science learning because if it only contains facts, concepts, and theories, the learning process is incomplete. science learning includes three critical components: scientific attitudes, scientific processes, and scientific products. the form of the incomplete science learning process is often used in the science learning process. as a result, the achievement of the scientific literacy process as a science learning goal is hampered. this is contrary to science learning objectives, where success or failure in achieving it depends on the learning activities that occur in the classroom and are experienced directly by students. science learning has complex characteristics because it requires critical thinking skills in analyzing a problem. critical thinking is a result that can be produced from science learning because the nature of science learning is not only focused on remembering material and understanding concepts. however, science learning must provide direct and meaningful learning experiences to students to be applied in everyday life. meaningful learning in science learning can be done by applying scientific literacy to be helpful in the problem-solving process in students’ lives [15]. critical thinking skills critical thinking skills in the learning process can make students understand themselves, the world, and others. students who can think critically will quickly analyze their thoughts so that their decisions are accurate [16]. critical thinking skills can be obtained through the science learning process or other learning. many studies on critical thinking skills have been carried out. salbiah [17] stated that students’ critical thinking skills at public high school in west java on colloidal material were classified as very good. however, this contradicts the research results by susilowati et al. [9], which states that students’ average critical thinking skills at magetan islamic senior high school (man magetan) are in a low category. several things influence the quality of students’ critical thinking skills. for example, the selection of an inappropriate learning model, the lack of students’ skills in identifying problems, and students often find it difficult to develop strategies when faced with different difficulty levels. this is following the opinion expressed by several researchers. they stated that critical thinking skills were still low because students could not identify known variables, ask questions, and be given problem-solving strategies [18]–[20]. thus, it can be concluded that critical thinking skills are skills in thinking about things reflectively based on their experiences. the teacher's role is very influential in the process. critical thinking skills can show students' cognitive abilities and must continue to be developed because these aspects are directly related to everyday life. scientific literacy skills the skills of students’ scientific literacy in the learning process are to apply concepts from natural science and various natural phenomena that occur in life based on scientific activities, including identifying, collecting, and analyzing the concepts so that the conclusion can be http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 32 38 34 zuhra et al. the analysis of students’ critical thinking …. p-issn: 2621-3761 e-issn: 2621-2889 obtained based on their findings. in developing scientific literacy skills, teachers are expected to implement a learning process centered on student activeness in understanding concepts about the various problems. students need scientific literacy skills in analyzing problems and being able to relate to scientific facts in life. this is carried out to make decisions about problems related to various natural phenomena [21]. in the learning process, by applying scientific literacy, students’ skills are assessed using scientific knowledge and understanding, such as students’ skills to search, interpret, and analyze evidence. the program for international student assessment (pisa) tests the following aspects: recognizing scientific questions, identifying evidence, drawing conclusions, communicating conclusions, and understanding scientific concepts. furthermore, the assessment of scientific literacy skills is not only based on mastery of the material but also guided by thinking skills, life skills, and the skills to carry out scientific processes in everyday life. iii. method this research used a quantitative approach with descriptive research design, which meant the study did not provide treatment, manipulation, or alteration of the independent variables but described the actual condition. the population of this research was all students of the tenth grade of bireuen public high school 2 (sman 2 bireuen). the sample was 27 students of the tenth grade of second science class selected through the purposive sampling technique. the sample used in this study was selected by considering the inclusion and exclusion criteria. inclusion criteria are criteria or characteristics that each member of the population needs to be met that can be taken as a sample [22]. inclusion criteria include male or female students in class x at sman 2 bireuen and willing. exclusion criteria are characteristics of population members that cannot be taken as samples [22]. exclusion criteria in this study were not present at the time of data collection, were sick at the study, and were not willing to be respondents. the instrument used in this research included critical thinking and student scientific literacy skills test adapted from pisa questions. both were measured through six indicators. for the critical thinking skill test, the indicators consisted of interpretation, analysis, evaluation, inference and explanation, and self-regulation. for the literacy skills test, the indicators are: identifying valid scientific opinions, understanding research design elements and their impact on findings/conclusions, make good graphs based on data, being able to solve problems based on scientific phenomena, understanding and interpreting basic statistics, and being able to make inferences, predictions, and draw conclusions based on the data. the instrument used in this research has passed the process of content validity testing, test item difficulty level, distinguishing power, and reliability testing. the content validity test for critical thinking and scientific literacy skills test instruments was carried out by experts. the validation results of the instrument were 87.7% and 89.9% for each aspect, which indicated that the test instrument was valid. the validity test of the difficulty level was carried out to classify the criteria for easy, medium, and difficult questions and the distinguishing power to determine the questions that can be used or discarded. reliability test results also showed a good percentage. reliability for scientific literacy was 0.82, and for critical thinking skills was 0.78, which meant the test results were high so that the questions can be used for research. the data analysis technique in this research was descriptive with the percentage technique. this research was conducted to provide critical thinking and scientific literacy tests to 27 students of the tenth grade of second science class. this test was given within 2 hours of the school time lesson (2 x 45 minutes). the percentage of critical thinking and scientific literacy skills achievement was displayed descriptively based on the student learning criteria proposed by arikunto [23] as in table 1. table 1. interpretation of students’ critical thinking and scientific literacy skills no. percentage criteria 1. 80-100 very good 2. 66-79 good 3. 56-65 fair 4. 40-55 low 5. 30-39 very low iv. results and discussion students’ critical thinking skills critical thinking skills are skills that must be possessed by students, especially in high schools. in this research, critical thinking skill was measured through 6 indicators distributed in each question. details of questions for each indicator can be seen in table 2. table 2. distribution of questions about critical thinking skills no. sub concept no. item of question 1. interpretation 1, 3 and 5 2. analysis 2 and 12 3. evaluation 7, 11 and 14 4. inference 6, 9 and 13 5. explanation 4 and 10 6. selfregulation 8 and 15 table 2 shows that the number of questions for the critical thinking skills test are 15 questions. each indicator consists of 2-3 questions according to the items’ validity and reliability test results. the total achievement of critical thinking skills was obtained by calculating the average percentage of students who answered questions correctly on each critical thinking skill test indicator. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 32 38 35 zuhra et al. the analysis of students’ critical thinking …. p-issn: 2621-3761 e-issn: 2621-2889 table 3 shows the percentage of students’ critical thinking skills achievement. table 3. the average level of achievement of students’ critical thinking skills no. indicator percentage (%) category 1. interpretation 63.55 fair 2. analysis 55.78 fair 3. evaluation 57.98 fair 4. inference 57.77 fair 5. explanation 56.18 fair 6. self-regulation 60.18 fair average 58.57 fair table 3 shows that students’ critical thinking skills achievement was fair from six indicators used in the research. the average level of achievement of critical thinking skills was 58.57. among the six indicators of critical thinking skills, the interpretation indicator has the highest percentage, which was 63.55%. the inference is the skills to identify and obtain the elements required to make a logical conclusion [24]. with this skill, students can understand and state the meaning or purpose of experiences in various situations, data, events, decisions, conventions, beliefs, rules, procedures, or criteria. in addition, tenth-grade students of sman 2 bireuen also had good self-regulation skills with a percentage of 60.18%. self-control skills are related to a person’s awareness of controlling their mindset, especially by evaluating his skills to conclude the terms of questions, confirmations, validations, and corrections [9]. this finding is in line with the report of sari et al. [24]. they stated that several things caused the high student self-control indicator. for example, students can review results, explore material in-depth, and have other ways to obtain quality information. assagaf [25] stated that several factors caused the high self-regulation indicator. for example, trying to remember and repeat the material, dig deeper into the material, determine learning objectives, have strategies for obtaining information, and evaluate the quality of the work that has been completed. overall, the critical thinking ability of class x students of sman 2 bireuen is still low. it can be seen from the results of the student’s critical thinking ability test. this is because students are not used to solving critical thinking skill questions. students need more time to solve problems. critical thinking skills can be built when students are given a problem. the problems can make the students construct their knowledge to find the right truth to solve it [26]. one of the learning models that can lead to problem-solving learning is the problem based learning (pbl) model. pamungkas et al. [27] showed that the problem-based learning model improved students’ critical thinking skills. through the problem-based learning model, students can solve problems in a structured way [26]. in addition, alvionita et al. [28] stated that the problem-based learning model made students more active in solving the problems directly. students are more accessible in developing their critical thinking skills. critical thinking skills are needed to face the development of the industrial revolution 4.0. it trains the students to be independent and careful, logically and thoroughly [26]. critical thinking is a directed, clear and structured process used in solving problems, making decisions, and analyzing assumptions [2]. with critical thinking skills, students are trained to get used to facing various problems with logical and directed problemsolving skills. students’ scientific literacy skills six indicators are used to assess scientific literacy skills, which are described in fifteen questions. table 4 shows the distribution of questions for each indicator in detail. table 4. distribution of questions on students’ scientific literacy skills no. indicator of students’ scientific literacy skills no. item of question 1. identify valid scientific opinions 1 and 9 2. understand the elements of research design and their impact on findings /conclusions 7 and 12 3. make the graphics accurately from data 2, 6 and 15 4. be able to solve questions based on scientific phenomena 4, 8 and 14 5. understand and interpret basic statistics 3 and 10 6. be able to make an inference, predict, and draw conclusions based on data 5, 11 and 13 table 4 shows that each indicator of students’ scientific literacy skills consists of 2 and 3 questions. for indicators of identifying valid scientific opinions, understanding the elements of research design and their impact on findings/conclusions, and understanding and interpreting the basic statistics, each consists of 2 questions. for indicators of making graphs appropriately from data, being able to solve problems based on scientific phenomena, and making inferences, predictions, and drawing conclusions based on data, each consisting of 3 questions. as for the critical thinking skills, the total achievement of scientific literacy skills was obtained by calculating the average percentage of students who answered questions correctly on each indicator of students’ scientific literacy skills. analysis of the achievement of students’ scientific literacy skills can be seen in table 5. based on table 5, it can be seen that the scientific literacy skills of tenth-grade students of sman 2 bireuen were fair. among the six indicators measured, the indicators of solving questions based on scientific phenomena and understanding the elements of research design and their impact on findings/conclusions get the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 32 38 36 zuhra et al. the analysis of students’ critical thinking …. p-issn: 2621-3761 e-issn: 2621-2889 lowest percentage. this showed that students were still not able to explain occurred scientific phenomena to explain a fact. students were also not familiar with activities using scientific steps. thus, students have not used scientific steps to solve problems and communicate experimental results to prove a fact. table 5. the average level of achievement of students’ scientific literacy skills no. indicator percentage (%) category 1. identify valid scientific opinions 58.77 fair 2. understand the elements of research design and their impact on findings/ conclusions 56.86 fair 3. make the graphics appropriately from data 62.57 fair 4. be able to solve questions based on scientific phenomena 56.36 fair 5. understand and interpret basic statistics 59.00 fair 6. be able to make an inference, predict, and draw conclusions based on data 58.08 fair average 59.38 fair the students’ inability showed that the science learning (physics, chemistry, biology) at sman 2 bireuen had not been implemented according to the nature of science. this indicated that it is necessary to strengthen learning, especially science, to improve scientific literacy skills with a supportive learning approach. in general, the students' scientific literacy skills are still low. this can be seen from the results of students' literacy skills tests. students could only determine problems but could not explain the solutions to these problems scientifically. one of the factors that cause the low literacy skills of students is that students are not used to solving questions related to literacy skills, the questions related to science process skills, or problem-based questions, which are the main part of scientific literacy. based on the analysis of students’ scientific literacy skills at sman 2 bireuen, it is necessary to apply a learning approach/model to train students’ scientific literacy skills to do scientific activities. in addition, the practitioner can also practice scientific problem solving, explain phenomena scientifically and get used to using scientific evidence to justify a fact. one approach that can be applied is the scientific approach. asyhari and hartati [29] states that learning with a scientific approach improved students’ literacy skills in competence and knowledge. in line with what was conveyed by setiawan [30] that the scientific approach can be applied in learning to train students’ literacy skills. the scientific approach will encourage students to be active in learning [31]. in line with suryani et al. [32] who applied the 5e learning model integrated with a scientific approach to the reproductive system material. they succeeded in improving students' scientific literacy skills. according to saputro et al. [26], the results showed that the application of problem-based learning science literacy learning tools had a significant effect on students' critical thinking skills. v. conclusion this research shows that the critical thinking and scientific literacy skills of tenth-grade students of sman 2 bireuen are fair. this can be seen from the percentage of achievement in each indicator. the six indicators for each skill in this research showed that the average level of achievement of critical thinking skills was 58.57%, and the average level of achievement of scientific literacy skills was 59.38%. based on the results of the analysis of the scientific literacy skills of students at sman 2 bireuen, it is necessary to apply learning approaches/models that can train students’ scientific literacy skills so that students are accustomed to carrying out scientific activities, solving scientific problems, providing explanations of a phenomenon scientifically and are accustomed to using scientific evidence to explain a fact. references [1] n. nurhayati and f. zuhra, “analisis tingkat kepuasan mahasiswa matematika fkip universitas almuslim terhadap pemanfaatan e-learning di era pandemi covid 19 [analysis of the level of satisfaction of mathematics students fkip almuslim university on the utilization of e-learning in th,” j. ilm. pendidik. mat. al qalasadi, vol. 4, no. 2, pp. 83–90, dec. 2020, doi: 10.32505/qalasadi.v4i2.2184. 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[32] a. i. suryani, a. w. jufri, and d. setiadi, “pengaruh model pembelajaran 5e terintegrasi pendekatan saintifik terhadap kemampuan literasi sains siswa smpn 1 kuripan tahun ajaran 2016/2017 [the influence of the 5e learning model integrated scientific approach on the scientific literacy ability of smpn 1 kuripan students for the 2016/2017 academic year],” j. pijar mipa, vol. 12, no. 1, pp. 39–43, mar. 2017, doi: 10.29303/jpm.v12i1.339. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.23887/jisd.v3i2.17774 https://doi.org/10.46245/ijorer.v1i3.46 https://doi.org/10.24042/jpifalbiruni.v4i2.91 https://doi.org/10.31004/basicedu.v4i1.298 https://jbasic.org/index.php/basicedu/article/view/298 https://doi.org/10.29303/jpm.v12i1.339 p-issn 2621-3761 e-issn 2621-2889 irip irip (indonesian review of physics) is a journal of physics and physics education research. it is compiled with a commitment to enhance quality of the research. indonesian review of physics (irip) aims to provide a forum for researchers, lecturers, teacher and student on the topics related to physics and physics education. the journal was first published in 2018 and regularly published twice per year in june and december. editor in chief fatin aliah phang scopus id: 57192376607 universiti teknologi malaysia johor bahru, malaysia email: p-fatin@utm.my managing editor dwi sulisworo scopus id:55317003800 universitas ahmad dahlan yogyakarta, indonesia email: dwi.sulisworo@uad.ac.id advisory international editorial boards akihiko tomita scopus id: 7201880070 wakayama university japan atomita@center.wakayama-u.ac.jp hassan k. juwhari scopus id: 6503859673 university of jordan jordan juwhari@ju.edu.jo rungchatchadaporn vehachart scopus id: 6992533300 thaksin university thailand vahachart@hotmail.com butch o saulon nueva caceres university philippines butch.saulon@unc.edu.ph muhammad abdul hadi bunyamin scopus id: 57195100817 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review of physics) vol. 1 no.2, december 2018 regular papers: the content analysis of bisphenol a (bpa) on water in plastic glass with varying temperatures and contact times using uv-vis spectrophotometer bayu nugroho, yudhiakto pramudya, widodo widodo effectiveness of active learning method quiz team type on student learning outcomes in subject ohm law in sma negeri 1 pundong abu yazid raisal, nanang suwondo the development of worksheet based on guided discovery learning method helped by phet simulations interactive media in newton's laws of motion to improve learning outcomes and interest of vocational education 10th grade students arip nurahman, widodo widodo, ishafit ishafit, butch o. saulon analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates – galenus personality type eni setyawati, susilawati susilawati, dwi sulisworo signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring using arduino uno rev.3 rismawan rismawan, moh. toifur published by universitas ahmad dahlan irip vol.1 no.2 pp. 27-51 yogyakarta, december 2018 p-issn 2621-3761 e-issn 2621-2889 http://journal2.uad.ac.id/index.php/irip/article/view/716 http://journal2.uad.ac.id/index.php/irip/article/view/716 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/780 http://journal2.uad.ac.id/index.php/irip/article/view/780 http://journal2.uad.ac.id/index.php/irip/article/view/809 http://journal2.uad.ac.id/index.php/irip/article/view/809 p-issn 2621-3761 e-issn 2621-2889 table of contents regular papers: the content analysis of bisphenol a (bpa) on water in plastic glass with varying temperatures and contact times using uv-vis spectrophotometer bayu nugroho, yudhiakto pramudya, widodo widodo universitas ahmad dahlan, yogyakarta, indonesia 27 effectiveness of active learning method quiz team type on student learning outcomes in subject ohm law in sma negeri 1 pundong abu yazid raisal, nanang suwondo universitas ahmad dahlan, yogyakarta, indonesia 33 the development of worksheet based on guided discovery learning method helped by phet simulations interactive media in newton's laws of motion to improve learning outcomes and interest of vocational education 10th grade students arip nurahman1, widodo widodo2, ishafit ishafit3, butch o. saulon4 1,2,3universitas ahmad dahlan, yogyakarta, indonesia 4nueva caceres university, philippines 37 analysis of metacognition difficulties in problem-solving static fluid material in term of hippocrates – galenus personality type eni setyawati, susilawati susilawati, dwi sulisworo universitas ahmad dahlan, yogyakarta, indonesia 42 signal processing of c-rtd sensor output as the input to the instrument of low temperature monitoring using arduino uno rev.3 rismawan rismawan, moh. toifur universitas ahmad dahlan, yogyakarta, indonesia 48 http://journal2.uad.ac.id/index.php/irip/article/view/716 http://journal2.uad.ac.id/index.php/irip/article/view/716 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/776 http://journal2.uad.ac.id/index.php/irip/article/view/780 http://journal2.uad.ac.id/index.php/irip/article/view/780 http://journal2.uad.ac.id/index.php/irip/article/view/809 http://journal2.uad.ac.id/index.php/irip/article/view/809 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.1, june 2022, pp. 8 15 doi: 10.12928/irip.v5i1.5830 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 8 development of photoelectric effect learning media based on arduino uno hardi hamzah1, dewi sartika2, and muhammad nurkhalis agriawan3* 1 department of physics, faculty of mathematics and natural sciences, universitas cenderawasih. 2,3 department of physics education, faculty of teacher training and education, universitas sulawesi barat. email: muhammadnurkhalisagriawan@gmail.com article info abstract article history received: mar 11, 2022 revision: may 10, 2022 accepted: jun 14, 2022 this study aims to develop a photoelectric effect learning media based on arduino uno. the subjects in this study were students who took modern physics courses. the media development procedure uses the borg and gall model, which is limited to seven stages. the feasibility of the developed media refers to the results of the media expert's assessment, the level of practicality, and the effectiveness of the media. the test results show that the product's planck constant of 6.62 × 10-34 j.s corresponds to the theoretical value. three experts concluded that the learning media had a good level of feasibility to be used as an experimental tool. the level of practicality and effectiveness of the media showed good results. that is, practical and effective media to be used in experiments. so, it can be concluded that the arduino uno-based photoelectric effect learning media that has been developed is suitable for use in learning. this is an open-access article under the cc–by-sa license keywords: arduino uno learning media photoelectric effect to cite this article: h. hamzah, d. sartika, and m. n. agriawan, “development of photoelectric effect learning media based on arduino uno,” indones. rev. phys., vol. 5, no. 1, pp. 8–15, 2022, doi: 10.12928/irip.v5i1.5830. i. introduction physics is one of the sciences with many formulas, laws, and theories created by scientists from their discoveries [1], [2]. stigma about the difficulty of physics subjects has been embedded in most high school, and college students, so few students do not understand the concept of physics well [3]. one theory that is quite well known among physics students is quantum theory. in quantum theory, there is a discussion of the wave-particle duality, namely light as a particle and light as a wave. this will be discussed further in the physics curriculum, which is important for learning quantum theory, namely the photoelectric effect [4], [5]. abstract physical phenomena such as the photoelectric effect will be easier to understand with experiments. not all educational institutions have adequate experimental equipment facilities, one of which is the west sulawesi university physics education study program. the implementation of the photoelectric effect practicum has never been done independently due to the unavailability of photoelectric effect practicum tools. information and communication technology (ict) cannot be separated from the physics learning process in the digital era, especially in the laboratory. the use of information and communication technology is an effective and efficient way to convey information and has great potential to improve the quality of learning, especially in displaying physical phenomena [6]. one of the uses of a microcontroller in media development is to develop a sound level meter based on arduino uno [7], as well as the development of hooke law teaching aids based on arduino uno [8]. the study used the arduino uno microcontroller as an analog data processor for digital data [9]–[11]. in line with this, the use of various types of sensors to develop media has been widely carried out, such as the use of infrared sensors, magnetoresistance, sensor networks and pipelines, photodiode sensors, and giant magnetoresistance (gmr) sensors [12]–[14]. there is a fundamental physical constant in the concept of the photoelectric effect. this constant is used to explain various effects in quantum theory which is very important for determining the standard for measuring electricity and mass, namely planck's constant [15]. not a few think that planck's constant is an interesting thing to prove, so the measurement (h) in the international units system is used as an experimental effort to prove its existence [16]. many types of research on the photoelectric effect have been carried out using various research methods. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i1.5830 http://journal2.uad.ac.id/index.php/irip mailto:muhammadnurkhalisagriawan@gmail.com http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 8 15 9 h. hamzah, et al. development of photoelectric effect learning media based … p-issn: 2621-3761 e-issn: 2621-2889 the development of instruments to explain the occurrence of the photoelectric effect with its various developments has been the research subject in recent years. for example, garver [17] developed an economic photoelectric effect experimental apparatus using leds as a light source. the experimental results for determining the plank constant reached an uncertainty level of 7%. then risdiyanto [18] developed an experimental photoelectric effect using led as a light source and a 1p39 vacuum phototube type where the photoelectric effect occurs. umma and sucahyo [19] developed a microcontrollerbased photoelectric effect experiment tool with rgb leds as light sources and photodiodes as light sensors. this experimental tool can explain that the photoelectric effect is not affected by light intensity but is influenced by the frequency of a light source that illuminates a metal. in addition, the measured plank constant has an error of 3.8%. putri and ishafit [1] have developed a data acquisition system using arduino and labview for photoelectric effect experiments. this developed system allows the automation of data collection to minimize errors. the plank constant was measured using the capacitor discharge technique on the led. the acquisition system has been declared feasible by experts. the analysis results show the measurement error rate is less than 5%. the measured plank constant value is 6.67 × 10-34 j.s. based on previous research, the output or appearance of the photoelectric effect experiment is still manual. therefore, this study designed a tool that can directly display photoelectric effect events on a laboratory scale using an lcd. the light source used is an rgb led and a photodiode sensor as a variable for the light intensity value into a voltage value which will automatically be read on the lcd. the design of this tool uses arduino uno and arduino ide software as a controller of light intensity by the source and also a reader of the output voltage value from the sensor and uses a potentiometer as an rgb led color variable so that it can produce various types of colors. planck's constant can be measured 10% better using multiple leds ranging from 470 nm to 631 nm [10]. the rgb led is used as a light source in this study as an led that can emit three basic colors of light in one led unit. the advantage of this rgb led is that it can produce more data variations of up to six types of colors with the help of the arduino ide software. so that learning is more meaningful. another advantage of leds over sodium, sodium, and mercury lamps is that they are more energy-efficient and last longer, up to 50000 hours. in comparison, the mercury lamp is 10000 hours. led lamps are not hot and do not contain ultraviolet. the choice of photodiode sensor is because this sensor can explain the photoelectric effect. so, this study aims to develop a photoelectric effect learning media that is suitable for use on a laboratory scale. ii. theory learning media are all forms of physical equipment that are designed in a planned manner so that they can be used in learning and can be used by students [20]. learning media is a tool in the teaching and learning process to stimulate the thoughts, feelings, attention, and abilities or skills of the learner so that it can encourage the learning process [21]. based on this definition, learning media is a tool that is made in a planned manner to support the learning process. arduino is an electronic board that is open source so that it can make it easier for anyone who wants to create interactive and interesting projects [22]. the photodiode sensor is a light-sensitive diode. the photodiode sensor will experience a change in resistance when receiving light intensity and will flow forward electric current as a diode [23]. the photodiode is a semiconductor material where there is a p-n junction in it [24]. a photodiode sensor is a component that can be used to change the intensity value that is read from light into an electrical quantity, namely the voltage value. in the photoelectric effect, the effect of light on electrical properties is not only due to the nature of light as an electromagnetic wave but also the nature of light as an energy carrier. in the photoelectric effect experiment, measurements were made of how the emitted electrons' rate and kinetic energy depended on the light source's intensity and wavelength [25], [26]. the light intensity only affects the large value of the current that passes through the circuit. when a suitable light is applied to one of the plates, an electric current is detected in the wire. this occurs because electrons escape from one plate and go to another plate together, where one electron absorbs a quantum of energy. one quantum of energy absorbed by the electron is used to detach from the metal and move to another metal plate. since the electron with the highest energy cannot pass through the stopping potential, the measurement of the stopping potential or vs is a way to determine the maximum kinetic energy of the electron (see eq. 1). 𝐸𝑘𝑚𝑎𝑥 = 𝑒 𝑉𝑠 (1) where e is the electron charge (1.6 × 10-19 c), vs is the stopping potential in volts. the maximum kinetic energy value can be related to the frequency as shown in eq. 2. 𝐸 = 𝑊𝑜 + 𝐸𝑘𝑚 (2) ℎ𝑣 = ℎ𝑣𝑜 + 𝐸𝑘𝑚 (3) 𝐸𝑘𝑚 = ℎ𝑣 − ℎ𝑣𝑜 (4) equations 2 are called the einstein photoelectric effect equations. where wo is the energy threshold of the metal work function, vo is the threshold frequency of the metal, and v is the frequency of the light used, ekm is the maximum kinetic energy of electrons released from the metal and moving to another metal plates [27]. plank's constant can be determined experimentally using eq. 5. ℎ𝑣 = 𝐸𝑘𝑚 (5) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 8 15 10 h. hamzah, et al. development of photoelectric effect learning media based … p-issn: 2621-3761 e-issn: 2621-2889 ℎ 𝑐 𝜆 = 𝐸𝑘𝑚 (6) c is the speed of light (3 × 108 m/s), and 𝜆 is the wavelength of the light source used. equation 6 illustrates the relationship between the wavelength of light and kinetic energy. the greater the wavelength of light, the smaller the kinetic energy because the value of kinetic energy is inversely proportional to the wavelength. iii. method the types of research used are research and development, which is a method of research used to produce specific products and test the effectiveness of the product [28]. the development is carried out using a procedural model by adapting the borg and gall development model. product trials include product trial designs. the development procedure in this study adopted the seven steps of borg and gall, as shown in figure 1. figure 1. seven stages of the borg and gall development model the first stage: potential and problems. at this stage, identify potential problems in the physics education laboratory of the university of west sulawesi. potentials and problems are obtained by observing practical tools in the laboratory, especially the availability of learning media in modern physics courses. second stage: data collection. at this stage, collect reference sources that support the development of photoelectric effect learning media. the material for the photoelectric effect is because it is one of the materials that require practicum in learning. arduino uno-based learning media makes it easier for students to understand the photoelectric effect material. third stage: product design. the product developed is in the form of arduino uno-based photoelectric effect learning media. the learning media developed is adapted to the photoelectric effect material. the learning media created at this stage must be able to be a solution to the existing problems. fourth stage: product validity. the test was carried out using a questionnaire instrument that had been provided to obtain scores and expert validators' responses to the developing learning media. the validators consist of content experts, media experts, and design experts. the results of the assessment of the development of photoelectric effect media by experts are used to improve product quality so that it is suitable for learning. after validating the product, the next step is design revision. at this stage, we improve the product according to the advice of the experts. products that have been valid and revised will proceed to the product testing stage. sixth stage: product trial. the product is tested on a limited group of subjects at this stage. after being treated using arduino uno-based photoelectric effect learning media, users responded through a questionnaire. the last stage is to revise the product based on the suggestions at the product trial stage. the research was conducted at the university of west sulawesi. subjects in this study include experts and students of physics education as users. the data collected in this study is quantitative data obtained through polling as a research instrument. the results of the expert assessment were analyzed using the percentage technique. the quality criteria for the photoelectric effect learning media refer to table 1. table 1. value interval for media feasibility level interval (%) eligibility criteria 0 – 20 not very good 21 – 40 not good 41 – 60 less good 61 – 80 good 81 – 100 very good iv. results and discussion the physics laboratory of the university of west sulawesi has various kits or electronic components that can be used to develop photoelectric effect learning media, one of which is the arduino uno microcontroller. arduino uno is often used by physics education students in digital electronics practicum. arduino uno has been widely used in research on developing physics learning media [29]– [32]. in addition, using the arduino uno microcontroller in developing laboratory-scale learning media is relatively cheaper. this is the basis for using the arduino uno microcontroller as the main component in developing laboratory-scale photoelectric effect learning media. as a follow-up to the development of learning media, the arduino uno-based photoelectric effect learning media was designed. this design aims to produce learning media suitable for use in modern physics practicum material on the photoelectric effect in modern physics practicum courses. media is said to be suitable to be applied in learning if the obtained score is > 62.5% [28]. product design 1 at this stage, arduino uno is connected to several components such as photodiode sensors, rgb leds, 12x2 lcds, and potentiometers. on the photodiode sensor, there are three pins connected to the arduino uno: pin a0 connected to a0 on the arduino uno, the vcc pin connected to the 5v pin on the arduino uno, and the gnd pin connected to the gnd pin on the arduino uno. then the rgb led is connected to the arduino, the r leg on http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 8 15 11 h. hamzah, et al. development of photoelectric effect learning media based … p-issn: 2621-3761 e-issn: 2621-2889 the led is connected to pin 11 pwm arduino uno, the g pin on the led is connected to pin 10 pwm arduino uno, and the b leg on the led is connected to pin 9 pwm arduino uno, and the anode leg on the led is connected to the arduino uno. arduino uno's gnd pins. next, connecting the potentiometer with arduino uno consists of 3 potentiometers, potentiometer r is connected to pin a1 arduino uno, potentiometer g is connected to pin a2 on arduino uno, and potentiometer b is connected to pin a3 arduino uno. after that, connect a 12x2 lcd equipped with i2c, the vcc pin on the i2c is connected to the arduino uno 5v pin, the gnd pin on the i2c is connected to the arduino uno gnd pin, and the scl pin on the i2c is connected to the arduino uno scl pin, and the sda pin on the i2c is connected. the arduino uno's scl pin and the sda pin on the i2c are connected to the arduino uno's sda pin. the connection of each component is shown in figure 2. figure 2. photoelectric effect learning media design the initial design of this learning media was carried out with a rough design, namely with the help of a breadboard. the initial design of this tool was carried out at the physics laboratory of the university of west sulawesi as a starting place for developing photoelectric effect learning media based on arduino uno. this product design aims to test the components of the tool and calibrate the tool before making the tool perfectly. testing the components of this tool begins with making a series of learning media components based on arduino uno, with the help of photodiode sensors, rgb leds, breadboards, potentiometers, and jumper cables. then proceed with assembling the manufacture of a programming language on the arduino ide application. this programming language is a command given to arduino uno and the components used in this development. after this programming language is created, data collection is carried out in a dark room. data retrieval is performed ten times for each color emitted by the rgb led. the data from the voltage measurement generated by the photodiode sensor can be seen in table 2. after getting the frequency and kinetic energy values, the next step is to determine the slope of the graph between frequency and kinetic energy. the slope of the graph can be seen in figure 3. table 2. measurement data using photodiode sensor no color wavelength (nm) freq. (× 1014 hz) v (volt) ke (× 10-20 j) 1 red 630.00 4.76 0.18 2.92 2 red green 582.50 5.15 0.30 4.86 3 green 535.00 5.61 0.40 6.48 4 green blue 492.50 6.12 0.67 10.9 5 blue 480.00 6.67 0.98 15.9 6 redblue 380.00 7.85 1.20 19.4 figure 3. relationship between kinetic energy and frequency product design 2 after designing the tool and ensuring all components function properly, we perfected the learning media, starting by connecting arduino uno with several components such as photodiode sensors, rgb leds, jumper cables, and potentiometers. the next step is to build an arduino uno box. this arduino uno box is made of acrylic material. the arduino uno box is designed to be opened and closed to replace the arduino uno or other components in case of damage. the purpose of making this arduino uno box is to protect the arduino uno and its circuit. arduino uno box can be seen in figure 4. figure 4. photoelectric effect learning media kit box design when viewed from above, the acrylic box contains the arduino uno (see figure 5), photodiode sensor, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 8 15 12 h. hamzah, et al. development of photoelectric effect learning media based … p-issn: 2621-3761 e-issn: 2621-2889 potentiometer, rgb led, lcd, and jumper cables. the lcd on the component functions as an output to display the voltage value from the photodiode sensor, the potentiometer functions as an rgb led regulator to display various colors and the jumper cable functions as a connector for each component. validation the aspects assessed in the expert validation sheet on the media include: (1) the suitability of the tool with the concept of the material taught by the lecturer, (2) the ability of the tool to improve student competence, (3) ease of maintenance, (4) accuracy, (5) ease of operation of the tool, (6) construction is safe for users, and (7) has aesthetic value [33]. the results of experts' validation of the photoelectric effect learning media can be seen in table 3. based on table 3, the percentage of each aspect is in the range of 88% to 100%, including the very good criteria. the lowest percentage is in the first aspect, and the highest is in the second, fourth, and seventh aspects. after being analyzed as a whole, the average percentage of the quality of the learning media that has been developed is 96%, which is a very good criterion. so, the arduino unobased photoelectric effect learning media meets the elements of validity and is feasible to use. in line with this research, another study that developed a physics practicum module received valid criteria from three validators [34], [35]. product trial this trial was conducted at the physics laboratory of the university of west sulawesi. the trial was conducted on physics education students and lecturers of modern physics practicum courses. this trial stage is a research stage to determine the practicality and effectiveness of arduino uno-based photoelectric effect learning media. practicality level the practical value of product development refers to the product's condition, which is easy to use by users [36]. the practicality of the learning media was obtained from the questionnaire responses of course lecturers and students to the practicality of the arduino uno-based photoelectric effect learning media when used in practicum or learning in class. the practicality level indicated that the materials were easy to run by teachers. the analysis results show that the developed physics teaching materials are very practical [37]. after testing the arduino uno-based photoelectric effect learning media with students and implementing it in a modern physics practicum, the responses of lecturers who teach modern physics are shown in table 4. based on table 4, the rating ranges from 70% to 93%. the average assessment of all aspects of lecturer responses is 85%. because the large percentage obtained is 81%-100%, the arduino uno-based photoelectric effect learning media is included in the very practical category. figure 5. photoelectric effect learning media based on arduino uno table 3. validation results of each aspect by expert validators no rated aspect percentage (%) criteria 1 the suitability of the tool with the concept of the material taught by the subject lecturer 94 vg 2 the ability of the tool in improving student competence 100 vg 3 ease of maintenance 92 vg 4 accuracy 100 vg 5 ease of operation 98 vg 6 the construction is safe for the user 88 vg 7 has an aesthetic value 100 vg average 96 vg note: vg = very good table 4. the practicality of learning media is based on the lecturer's response. no aspect percentage (%) criteria 1 ease of use 93 vg 2 increase student interest and motivation when used individually or classically. 90 vg 3 possibility of being used for individual study by students and or teaching aids for lecturers 87 vg 4 encourage students to think critically and solve problems. 87 vg 5 contextuality with application in real life according to student characteristics 70 vg average 85 vg note: vg = very good testing of the arduino uno-based photoelectric effect learning media has been carried out to determine http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 8 15 13 h. hamzah, et al. development of photoelectric effect learning media based … p-issn: 2621-3761 e-issn: 2621-2889 student responses to the level of practicality. the results of student responses to learning media are shown in table 5. based on table 5, the average response from all aspects is 87%. because the large percentage obtained is in the range of 81%-100%, the arduino uno-based photoelectric effect learning media is included in the very practical category. effectiveness level the effectiveness of learning media is obtained by taking into account four aspects of the assessment, namely: (1) achievement of learning objectives, (2) student enthusiasm, (3) student involvement, and (4) clarity of learning media [38]. the test of the effectiveness of the media to students as users was reviewed based on student feedback or responses [39], [40]. after testing the arduino uno-based photoelectric effect learning media to students of the physics education study program as well as carrying out modern physics practicum. the results of the course lecturers' responses to learning media are shown in table 6. based on table 6, the average of all aspects of lecturer responses is 98%. because the large percentage obtained is 81%-100%, the arduino uno-based photoelectric effect learning media is included in the very effective category. the results of student responses to the effectiveness of learning media are shown in table 7. based on table 7, the average of all aspects of student responses is 88%. because the large percentage obtained is 81%-100%, the arduino uno-based photoelectric effect learning media is included in the very effective category. v. conclusion the development of arduino uno-based photoelectric effect learning media has been developed using the seven-stage borg & gall development model. based on the data analysis and product testing results, it is known that the learning media meets the elements of validity, practicality, and good effectiveness. the results of the plank constant test follow the theory. so, it can be concluded that the photoelectric effect learning media is feasible to be used as an experimental tool on a laboratory scale. this research has made a significant contribution to facilitating modern physics practicum. however, empirical testing has not been carried out. therefore, future research needs to examine how much improvement in student learning outcomes when using this learning media. table 5. the practicality of learning media is based on student responses. no aspect percentage (%) criteria 1 ease of use 93 vg 2 students are enthusiastic about to use 89 vg 3 giving new experience 90 vg 4 practical to use between other photoelectric effect learning media 89 vg 5 photoelectric effect learning media can be used independently 73 vg 6 learning media have the concept of the photoelectric effect 86 vg 7 have attractive design 86 vg average 87 vg note: vg = very good table 6. effectiveness of learning media based on lecturer's response no aspect percentage (%) criteria 1 achievement of learning objectives 100 vg 2 student enthusiasm 100 vg 3 student engagement 93 vg 4 clarity of learning media 100 vg average 98 vg note: vg = very good table 7. effectiveness of learning media based on student's response no aspect percentage (%) criteria 1 relevance 89 vg 2 interest 90 vg 3 satisfaction 91 vg 4 self-confident 84 vg average 88 vg note: vg = very good references [1] r. c. w. putri and ishafit, “pengembangan sistem akuisisi data 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interest : all authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.15294/jpii.v7i1.12718 https://doi.org/10.1088/1742-6596/1351/1/012064 https://doi.org/10.1088/1742-6596/1816/1/012107 https://doi.org/10.1088/1742-6596/1816/1/012107 https://doi.org/10.1088/1742-6596/1816/1/012109 https://doi.org/10.1088/1742-6596/1816/1/012109 https://doi.org/10.1088/1742-6596/1655/1/012073 https://doi.org/10.1088/1742-6596/1655/1/012073 https://jurnalmahasiswa.unesa.ac.id/index.php/5/article/view/29800 https://jurnalmahasiswa.unesa.ac.id/index.php/5/article/view/29800 https://doi.org/10.21009/03.snf2019.01.pe.25 https://jurnalmahasiswa.unesa.ac.id/index.php/17/article/view/26874 https://jurnalmahasiswa.unesa.ac.id/index.php/17/article/view/26874 https://doi.org/10.21831/jk.v1i1.10896 https://doi.org/10.15294/jpii.v7i2.14249 https://doi.org/10.15294/jpii.v9i2.23504 https://ejournal.unesa.ac.id/index.php/jurnal-pendidikan-teknik-elektro/article/view/19530 https://ejournal.unesa.ac.id/index.php/jurnal-pendidikan-teknik-elektro/article/view/19530 https://doi.org/10.15294/jpii.v6i1.7205 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.1, june 2022, pp. 16 24 doi: 10.12928/irip.v5i1.6073 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 16 analysis of land and sea temperatures trend during 1985-2021 period to understand local or global warming effect in bengkulu city arya j akbar, ashar muda lubis* department of physics, faculty of mathematics and natural sciences, universitas bengkulu, indonesia email: asharml@unib.ac.id article info abstract article history received: may 12, 2022 revision: jun 14, 2022 accepted: jun 15, 2022 global warming is a phenomenon where the earth's temperature rises drastically. the temperature increase causes negative impacts on the environment globally. bengkulu city, indonesia, is situated with a growing population and land-use change that may cause temperature rise. this research aimed to analyze the temperature change in the land and sea area of bengkulu city. to understand the local or global factors influencing temperature changes in bengkulu city, we also studied the correlation between land and sea temperatures. the temperature data were obtained from bmkg and noaa psl. firstly, we analyzed the temperature trendlines for the last 36 years. then we evaluated the coefficient determination (r2) value to determine the correlation between sea and land temperatures. the results show that during the last 36 years, the sea temperature is increased by 0.40 °c, while the land temperature is increased by 1.07 °c. moreover, we found a relatively weak correlation between sea and land temperature, with a 10.7% correlation. we argued that the increased temperature in bengkulu city land is associated with land change use and rising population in the last few decades, which means the local factor affected the land temperature changes. on the other hand, global phenomena (iod and enso) influenced sea temperature changes, which means the global factor affected the sea temperature changes. the rising land temperature is relatively high; hence it is necessary to understand better what parameters are causing temperature changes that may affect the physical environment in bengkulu, indonesia. this is an open-access article under the cc–by-sa license. keywords: global warming effect local warming effect land and sea temperature trendline to cite this article: a. j. akbar and a. m. lubis, “analysis of land and sea temperatures trend during 1985-2021 period to understand local or global warming effect in bengkulu city,” indones. rev. phys., vol. 5, no. 1, pp. 16–24, 2022, doi: 10.12928/irip.v5i1.6073. i. introduction land and ocean temperatures are critical factors in understanding the earth's weather behavior, such as the global warming phenomenon. recent studies show that human activities can contribute significantly to co2 emissions that may impact global warming, causing likely harm to ecosystems and humans [1]. moreover, rising temperatures may be associated with the occurrence of forest fires. for example, indonesia experienced forest fires covering more than 3 million hectares of land in five years (2014-2019) [2], affecting our oxygen supply besides burning fossil fuels that release large amounts of co2. climate change can impact biological growth, such as the production and growth of animals and plants, as well as the diversity of biological, physical, and chemical that may affect the sustainability of life on the earth. climate change also significantly impacts the growth of crops such as maize, wheat, and rice worldwide [3]–[5]. the temperature increase of the earth's surface temperature on a global scale augmented the indication of climate change due to global warming. the temperature and diurnal temperature range (dtr) are essential indicators for detecting recent climate change [6]–[8]. currently, the increase in temperature due to global warming is felt globally almost everywhere on the earth. the increase in temperature also becomes one of the indications of climate change where the earth's surface temperature increases on a global scale. the intergovernmental panel on climate change (ipcc) previously reported that the earth's http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i1.6073 http://journal2.uad.ac.id/index.php/irip mailto:asharml@unib.ac.id http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 17 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 temperature rose 0.99 (0.84 to 1.10) °c higher during the first two decades of the 21st century (2001-2020) compared to the period 1850-1900 [9]. the increase in temperature will have various destructive impacts on the environment. high temperature melts ice in the polar. melted ice causes sea-level rise, increasing the potential for flooding in coastal areas [10]. high temperatures cause extreme evaporation, resulting in high precipitation, which causes climate change and also increases the potential for flooding [11]. high temperatures can also cause droughts that trigger forest fires. research shows that every 1 degree celsius increase in temperature will increase the relative forest burned area by approximately 54.65% [12]. on the other hand, rising temperatures will indirectly affect the availability of food and clean water, settlements and public facilities, public health, and economic activities [13]. since indonesia is on and near the equator, monitoring the surface temperature is essential to detect global warming/global climate change exists or not. in addition, previous research has shown that indonesia is one of the countries that will experience a high-temperature rise in this century [14]. furthermore, on the west coast of indonesia, bengkulu province, located in sumatra near the equator, is also experiencing the impact of global warming. from satellite data, we know that bengkulu experienced a fairly high-temperature increase at the beginning of the 21st century [15]. temperature change in bengkulu may be related to increased industrial, mining, and plantation activities. for example: currently, as we may know, bengkulu is one of the palm oil producers in indonesia [16]. at the same time, oil palm plantations are one of the causes of global warming because oil palm plantations are a massive source of nitrous oxide (greenhouse gas) [17]. in addition, bengkulu is one of the largest coal mines in sumatra, with 3.02 million tons of coal mined in 2017 [18]. a mining activity such as coal mining causes an increase in temperature in an area due to land-use change [19]. furthermore, the use of coal as an energy source for the electric steam power plant (pltu) in bengkulu city since 2021 can produce greenhouse gases in the atmosphere. since the bengkulu area is at risk of the global warming effect, it is necessary to analyze the present trend of temperature change in bengkulu city. this study aimed to investigate temperature change on land and sea in bengkulu city over the last several decades. we also studied the relationship between land and ocean temperatures to understand the change better. this study will be beneficial as one indicator and benchmark for how local or global warming exists in indonesia, particularly bengkulu city. ii. theory global warming global warming is an increase in the earth's temperature globally. temperature increases in the atmosphere, sea, and land [20]. the presence of greenhouse gases causes global warming that retains heat from the sun's energy. the greenhouse gases include carbon dioxide (co2), sulfur hexafluoride (sf6), methane (ch4), nitrous oxide (n2o), and others [19]. human activities are the main factor in greenhouse gases’ high concentration nowadays [21]. regression analysis regression analysis is a method widely used in the world of science to determine the relationship between two or more variables [22]. regression analysis is used to understand a dependent variable. meanwhile, the independent variable is assumed to affect the dependent variable. linear regression can be used to see the trendline of a dependent variable [23]. data preprocessing data pre-processing is a technique to improve raw data [24]. raw data can be incomplete, contain outliers and have noise values [25]. data outliers are strange or unexpected data; missing data are records containing missing fields or blank data, whereas noisy data contain irrelevant or unnecessary data [26]. data pre-processing includes data cleaning and data reduction to reduce data errors in the data [27]. iii. method the data used in this study were daily temperature data from the bengkulu city area during the past 36 years (january 1985-august 2021) obtained from two sources. firstly, we accessed land surface temperature data from the bengkulu province meteorology, climatology, and geophysical agency (bmkg). the temperature data were obtained through thermometer measurements in a weather cage at an altitude of 1.25 m above the ground surface. the noaa sst v2 high-resolution dataset represented sea surface temperature data obtained from the noaa physical sciences laboratory page in *.nc format. the sea surface temperature data have a 0.25o latitude x 0.25o longitude resolution [28], [29]. figure 1 shows the land and sea surface temperature locations used in this study. figure 1. map of station and data point in the research area. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 18 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 next step, we applied data pre-processing for the temperature data obtained from bmkg and noaa. since the noaa data is in *.nc format, it needs to be changed to match the bmkg data format (.txt format). this step also included data cleaning and data reduction. the noisy data can later affect our analysis. hence it is necessary to pay attention to data quality, outliers, and missing data. data cleaning also needs to be performed for some data. we used linear trend analysis to investigate the trend temperature change in bengkulu city [30]. the trendline of temperature changes can be used to determine how the average temperature increased during the last 36 years. we used the least-squares regression method to see the trendline of temperature changes. the formula for the trendline is given by 𝑦̂ 𝑖 = 𝑎 + 𝑏𝑋𝑖, (1) where yi is ith temperature data, ŷi is predicted ith data value of temperature data, xi is ith time in the day, a is the intercept value, and b is a coefficient representing temperature change (increase or decrease). n is the total data, and the value of b represents the changes rate of temperature data over time [31], estimated from 𝑏 = ∑ (𝑋𝑖 − �̅�)(𝑌𝑖 − �̅�) 𝑛 𝑖=1 ∑ (𝑋𝑖 − �̅�) 2𝑛 𝑖=1 (2) we gained the intercept value by putting the average data value as ŷi and xi to equation (1). we obtained the average data with the formula �̅� = 1 𝑛 ∑ 𝑌𝑖. 𝑛 𝑖=1 (3) mean square error (mse) and root mean square error (rmse) are used to evaluate the accuracy of the data results. mse and rmse can be used to detect if any outlier data need to be clean in the data with the equations 𝑀𝑆𝐸 = 1 𝑛 ∑ (𝑌𝑖 − 𝑦̂ 𝑖) 2,𝑛𝑖=1 (4) 𝑅𝑀𝑆𝐸 = √ 1 𝑛 ∑ (𝑌𝑖 − 𝑦̂ 𝑖) 2,𝑛𝑖=1 (5) in the next step, we calculated the temperature data anomaly yi anomaly. data anomaly calculated by 𝑌𝑖 𝑎𝑛𝑜𝑚𝑎𝑙𝑦 = 𝑌𝑖 − �̅�. (6) the daily land and sea temperature data distributions were analyzed using a normal distribution. we used the normal distribution to see the accuracy of the processed data [33], which can be identified from the normal distribution curve and estimated by 𝐹(𝑌𝑖) = 1 𝜎√2𝜋 𝑒 −(𝑌𝑖−�̅�) 2 2𝜎2 ⁄ (7) we found the relationship between sea and land temperature rise by making a scatter plot of data anomaly. the value of r2 (coefficient of determination) determines how strong the correlation between land and sea temperatures is. r2 described by 𝑅2 = 1 − ∑ (𝑌𝑖−𝑦 𝑖) 2𝑛 𝑖=1 ∑ (𝑌𝑖−�̅�) 2𝑛 𝑖=1 . (8) the coefficient of determination value represents the variation of dependent variables explained by independent variables [34]. if the value is close to zero, the correlation is weak, whereas if the value is close to one, the correlation is strong [35]. iv. results and discussion during 1985-2021, the city of bengkulu experienced temperature changes, as illustrated in figures 2a and 2b. the average temperatures for 36 years were 26.459 °c based on air temperature on land and 29.035 °c based on sea surface temperature on the sea. the straight lines in figure 2 are the trendlines of daily temperature in bengkulu city. the trendlines represent the temperature changes for 36 years. the sea surface temperature changes show an increase in temperature in the sea around bengkulu city. the rise in temperature in the sea is 0.401 °c. the land temperature change depicted in figure 2b shows a significant boost for 36 years in the sea around bengkulu city with a relatively stable graph compared to sea surface temperatures. the increase of temperature on land is 1.071 °c. the temperature increases in both places are quite significant, so it is necessary to pay attention and prepare how to deal with the adverse effects of this rising temperature on society in the future. if we look at figure 2d, land temperature data are well distributed. most of the land temperature data are under the normal distribution bell. figure 2c shows that the sea temperature data are not as well distributed as the land temperature data because many data are outside the curve. the data outside the normal distribution curve are possible outliers [36]. although the data are conceivably outliers, we cannot remove the data because some conditions make outliers better not to remove. the requirements not to remove outliers are when there are many outliers, and the outliers are critical for analysis [37]. the values of the temperature data are still reasonable. in addition, the rmse value of land and sea temperature data are 0.86 and 1.04. due to these reasons, we kept the data outside the normal distribution curve for the following analysis. in order to understand the relation between sea and land temperature, it is necessary to see the temperature increases in the range of minimum and maximum value. figure 3 shows the sea and land temperature graph in monthly mean, maximum, and minimum temperature, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 19 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 figure 2. a graph of sea temperature rise from bmkg station data, b graph of the increase in land temperature from the noaa sst v2 high-resolution dataset noaa psl data, c normal distribution of sea temperature data, d normal distribution of land temperature data. figure 3. a graph of sea temperature monthly (mean, maximum, and minimum temperature), b graph of land temperature monthly (mean, maximum, and minimum temperature) where the dash lines describe the trendline. from figure 3a, it is observed for the last 36 years period that the monthly mean sea temperature increased by 0.401°c, the monthly maximum sea temperature fell by 0.005°c, and the monthly minimum sea temperature rose by 0.803°c. whereas figure 3b shows results for 36 years the monthly mean land temperature rose by 1.071°c, the monthly maximum land temperature rose by 1.071°c, and the monthly minimum land temperature rose by 0.937°c. the scatter plot in figure 4 shows the relationship between sea and land temperatures, where sea temperature is the fixed variable, and land temperature is the dependent variable. the linear regression lines show a correlation between both variables. from the coefficient determination (r2) value, we know that the daily data http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 20 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 figure 4. relation between land and sea temperature rise anomaly (a. daily data anomaly, b. mean monthly data anomaly, c. maximum monthly data anomaly, d. minimum monthly data anomaly) anomaly correlation is 10.7%, while the mean monthly data anomaly value correlation is 28.5%. the correlation of monthly data is higher because monthly total data is less than the total daily data; many data cause high variance and lower the correlation in this data. the maximum and minimum monthly data anomaly correlations in land and sea are 18.7% and 9.7%. the low correlation relates to the previous discussion, where different factors influence land and sea temperature. figures 2a and 2b show that land temperature increases much faster than the sea. the increase in land temperature is 2.5 times higher than the increase in sea temperature. the high increase in land temperature is due to the rapid development and population growth in bengkulu city. economy activities, land used for plantations and settlements, the high number of transportation, and a lack of awareness of the environment have certainly accelerated the increase in temperature on the land of bengkulu city [19], [38] based on statistics indonesia (bps) data, the population of bengkulu city rose from 96,383 people in 1986 to 373,591 people in 2020 [39], [40]. bengkulu city has the highest population growth rate in bengkulu province, with a 4.06% population increase yearly. figure 5 shows the bengkulu city population from 1986 to 2020 based on bps data, where the trend is positive as the temperature changes in bengkulu city [39]–[45]. the increase in population also affected the development of the residence and industry areas. based on landsat images from 2008 to 2018, the area built in bengkulu city increased from 3,383.51 ha to 5,485.10 ha. changes in the built area reached an increase of 5.0% per year [46]. significant changes happened between 2011 to 2017, when 439.19 ha of agricultural land and non-agricultural land became build-up areas in selebar subdistrict, bengkulu city [47]. high populations and the expansion of the area built increased the number of greenhouse gases in bengkulu city. figure 5. bengkulu city population from bps data (19862020) the increased number of greenhouse gases accelerated the temperature increase in bengkulu city [19]. the high greenhouse gas concentration on bengkulu city land caused the increased temperature on the land to be higher than the increased temperature on the sea. main human activities are on land and relatively far from the sea. because of that, the increased sea temperature is lower than the increased land temperature. the temperature increase in bengkulu city is similar to the global http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 21 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 temperature increase, where land temperature increases higher than sea temperatures globally [9]. the fact that land temperature increased higher due to the accumulation of greenhouse gases on bengkulu city land made the pattern of changes in sea temperature in figure 2a seems quite different from changes in land temperature values in figure 2b. at some points on the graph, the low point of sea temperature deviates very far from the trendline. figure 2c also describes that sea temperature data is not well distributed. the variations in sea temperature happen due to the influence of the el-niño southern oscillation (enso) and indian ocean dipole (iod). it is known from previous research that enso and iod correlate with sea temperature around the islands of the west part of indonesia [48]–[50]. from figure 6, low sea temperature occurred when iod positive phase happened (1994, 1997, 2006, and 2019). a previous study found that the west coast of sumatra island (bengkulu city) experienced a drastic temperature decrease when iod positive phase happened [49]. enso's significant impact on low sea temperature occurred around 2011 in the la nina phase [51]. the iod phenomenon has more impact on the sea temperature around bengkulu city than enso. the effect of iod and enso felt strongly on sea temperature due to the water movement from the indian and pacific oceans only touching seawater around sumatra island [48], [52]. from figure 3, we can see a range of variations in sea temperature. the monthly maximum sea temperature tends to be stable with almost no changes for the last 36 years, and the monthly minimum sea temperature experiences drastic positive changes. this kind of increase in temperature also happens in other places on the earth. for example, some nepal and egypt cities experienced a rise in temperature where the minimum temperature rose faster than the maximum temperature [53], [54]. by previous studies, the maximum sea temperature change is smaller than the minimum sea temperature change, while the mean sea temperature increases significantly are signs of climate change [6], [55]. on the other side, changes in monthly mean, maximum, and minimum land temperatures are relatively similar to each other, where all of them rose positively. this increase in land temperature is different from the increase in sea temperature. the monthly maximum and minimum temperatures rose simultaneously, with the monthly maximum temperatures slightly higher than the others. this kind of increase in temperature also happened in bangladesh [56]. the increase must be watched out for its future negative impact on the environment because the trendline and graph show that the temperature constantly changes in a positive trend. from the previous discussion, we speculate that bengkulu city's temperature rising on land affected by population growth and the expansion of area built that drive the greenhouse gases to high concentration. a previous study also shows that temperatures in sumatra island have high variation [15]. temperature increase in land affected by local greenhouses concentration means that the land temperature in bengkulu city is mainly affected by regional factors. on the other hand, global phenomena like iod and enso influence sea temperature around bengkulu city. different factors that influence the temperature in the sea and land cause sea and land temperature to have a low correlation. figure 6. iod and enso relation with temperature on bengkulu sea http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 16 24 22 a. j. akbar, et al. analysis of land and sea temperatures trend during 195-2021 … p-issn: 2621-3761 e-issn: 2621-2889 v. conclusion the increased temperatures in bengkulu province for the last 36 years are 1.071 °c for the land area and 0.401 °c for the sea area. increased temperatures yearly are 0.030 °c for the land area and 0.011 °c for the sea area. the land temperature rose higher due to many activities that emit greenhouse gases, such as fast population growth and used land changes in bengkulu city. enso and iod highly influenced the sea temperature around bengkulu city. from the analysis of the increase in monthly mean, maximum, and minimum temperatures, sea temperature showed signs of climate change where the maximum temperature rise lower than the minimum temperature, and the minimum temperature rose drastically. on the other hand, monthly mean, maximum, and minimum temperatures on land rose simultaneously. the correlations between sea and land temperature are weak. the values are only 10.70% for daily temperature data and 28.52% for monthly temperature data. these low correlations are different due to the factors that influenced the temperature in both places. the land temperature is mainly affected by regional factors such as high population numbers and the used land changes leading to increased greenhouse gas concentration. at the same time, the sea temperature was not affected by the concentration of greenhouse gases as high as on land because of low human activity on the sea. conversely, global phenomena like iod and enso highly influenced the sea temperature changes in bengkulu city. since there are high-temperature rises and signs of climate change in bengkulu city, all parties must make plans to protect the environment so that we can avoid the adverse effects of global warming. vi. acknowledgment the author would like to thank the department of physics, faculty of mathematics and 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[54] m. domroes and a. el-tantawi, “recent temporal and spatial temperature changes in egypt,” int. j. climatol., vol. 25, no. 1, pp. 51–63, 2005, doi: 10.1002/joc.1114. [55] m. d. martínez, c. serra, a. burgueño, and x. lana, “time trends of daily maximum and minimum temperatures in catalonia (ne spain) for the period 1975-2004,” int. j. climatol., vol. 30, no. 2, pp. 267–290, 2010, doi: 10.1002/joc.1884. [56] s. shahid, s. bin harun, and a. katimon, “changes in diurnal temperature range in bangladesh during the time period 1961-2008,” atmos. res., vol. 118, pp. 260– 270, 2012, doi: 10.1016/j.atmosres.2012.07.008. declarations author contribution : arya j akbar was responsible for the entire research project. he also led the writing of the manuscript and the collaboration with the second author. ashar muda lubis participated in the transcription and analysis. he also revised the manuscript. both authors approved the final manuscript. funding statement : this research is funded by department of physics, faculty of mathematics and natural sciences, bengkulu university with the contract no. 255.a/un30.12/fis/hk/2021. conflict of interest : both authors declare that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.3390/atmos12121683 https://doi.org/10.1002/joc.1114 https://doi.org/10.1002/joc.1884 https://doi.org/10.1016/j.atmosres.2012.07.008 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.5, no.1, june 2022, pp. 32 39 doi: 10.12928/irip.v5i1.4268 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 32 development of al-qur'an-based physics learning media applications to improve higher order thinking skills and spiritual attitudes for preservice physics teacher lailatul nuraini1*, firdha kusuma ayu anggraeni2, alex harijanto3, sri handono budi prastowo4, subiki5, bambang supriadi6, maryani7, sutarto8, and rayendra wahyu9 1,2,3,4,5,6,7,8 department of physics education, universitas jember, indonesia 9 freudental institute, utrecht university heidelberglaan, netherland article info abstract article history received: june 18, 2021 revision: may 18, 2022 accepted: june 11, 2022 this study aims to develop an android-based al-qur'an integrated physics learning media to improve preservice physics teachers' higher-order thinking skills and spiritual attitudes. the development of learning media uses the addie model. media and material experts assessed the feasibility of learning media through a validation questionnaire. the trial was carried out on 40 preservice physics teacher students. the validation results were analyzed using a descriptive technique. the analysis results show that the learning media developed is suitable for improving higher order thinking skills and the spiritual attitude of preservice physics teachers. so, the android-based physics learning media integrated with the quran can be implemented for preservice physics teachers. this is an open-access article under the cc–by-sa license. keywords: al-qur'an-based physics hots physics learning media spiritual attitudes to cite this article: l. nuraini et al., “development of al-qur’an-based physics learning media applications to improve higher order thinking skills and spiritual attitudes for preservice physics teacher,” indones. rev. phys., vol. 5, no. 1, pp. 32–39, 2022, doi: 10.12928/irip.v5i1.4268. i. introduction physics is a branch of science that studies natural events and processes. physics is not only studying facts but also studying how to think and work scientifically. understanding physics requires thinking logically [1], critically [2], [3], creatively [4], [5]. one of the goals of studying physics is for students to understand the greatness of god [6]. islamic teachings contain values that are influential in life that humans consider in determining decisions to act [7]. because in islam, natural science is discussed in a complex manner which is parsed through verses of the qur'an related to the phenomena of everyday life. by studying physics, students will understand that natural phenomena are the creations of allah swt that must be considered so that students can increase their moral awareness and devotion to the creator. however, in reality, there are still challenges in studying physics. these challenges include lessons considered less interesting, the direction of learning that tends to be rote, verbal, and unrelated to life, and the thought that learning physics does not contribute to positive thinking to glorify the power of allah swt [8]. based on these factors, efforts are needed to create students who are not only academically intelligent but also morally and spiritually intelligent so that national goals can be realized. steps that can be taken using technologybased learning media to support learning activities [9], develop academic abilities [10], [11], and create spiritual abilities [12]. learning media is used by incorporating religious values as verses from the qur'an. the purpose of inserting verses of the qur'an is to improve students' attitudes and spiritual understanding of the qur'an. understanding the qur'an must also be supported by an understanding of science. therefore, the two elements are interconnected. these efforts maintain science, especially physics so that students remain active in teachings that align with faith beliefs [13]. this is with the government's efforts in the field of education as stated in article 31, paragraph 3 of the 1945 constitution, which states that the government seeks and organizes a national teaching system, increases faith, piety, and noble character in the context of the intellectual life of the nation. one of the physics materials that can be related to the verses of the qur'an is the material of waves and optics. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v5i1.4268 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 32 39 33 nuraini, et al. development of al-qur'an-based physics learning media … p-issn: 2621-3761 e-issn: 2621-2889 the material on waves and optics are divided into several subjects, including geometric optics, diffraction and polarization, interference, and the spectrum of electromagnetic waves. geometric optics is one of the physical materials containing many abstract and complex concepts related to the reflection and refraction of light. this material requires a detailed and in-depth explanation of geometric ray diagrams and mathematical rules [14], [15]. the verse of the qur'an related to geometric optical materials is q.s. an-nur verse 35. another subject of waves and optics is the spectrum of electromagnetic waves. waves with the widest frequency distribution are called electromagnetic waves [16]. the resulting frequency is in the range of 102 hz to above 1023 hz. the smallest electromagnetic wave frequency is 1024 hz, which gives an approximate range of wavelengths and frequencies for various segments. the frequency and wavelength of electromagnetic waves can differ, but the relationship 𝑐 = 𝑓. 𝜆 in a vacuum is applied to every electromagnetic wave [17]. material about the spectrum of electromagnetic waves can be combined with one of the verses of the qur'an, namely q.s. yunus verse 5. geometrical optics, a part of optics and waves, is difficult because students are limited in drawing the image formation process on the plane, concave, and convex mirrors. thube and saligram [14] stated that students understand the existence of reflection or refraction events in the mirror. students have difficulty giving scientific and mathematical explanations about the process of forming shadow images. geometry optics material requires learning media to describe the process of reflection or refraction of light so that students can more easily understand the concepts of physics material. learning media has been understood as anything that can be used as a tool in educational activities to arouse students' interest, feelings, and attention [18]. learning media is also described as a tool, both physical and virtual, utilized by teachers to deliver lessons to pupils more efficiently and effectively so that educational resources are well received by all pupils and inspire them to learn more [19]. therefore, the two-way communication that occurs is precise and efficient. learning media must be interesting for students [20] and interactive [21] but does not reduce the importance of the material presented. the development of learning media is increasingly sophisticated with various technological advances. one form of learning media that is used is an android-based application. basic physics subject iii physics education at the university of jember, no teaching material or media integrates islamic values in physics. research on alqur'an-based physics learning has been carried out by nisa et al. [22]. they concluded that learning physics based on the qur'an is better than learning physics without integrating the qur'an. this research is also relevant to aslamiyah's [23] research, which explains that islamicbased physics learning media can integrate islamic values with the concept of physics to improve spiritual and intellectual abilities. in addition, the use of media can also increase students' reading interest. this is following the research of danaswuri et al. [24]. diani and hartati [25] also researched the integration of islamic values in physics learning media and found that islamic-based physics learning media could improve student learning outcomes in the "very good" and "very feasible" categories for use in learning. students need media that can be used for independent learning integrated with islamic values. the development of modules that follow islamic values, one of which can provide supporting facilities and infrastructure for the creation of students who excel in achievement and religion. it is expected that students are not only intellectually intelligent but also spiritually intelligent. technology-based learning media will increase students' interest in learning and motivation in understanding physics concepts integrated with the verses of the qur'an. in addition to spiritual attitude, high order thinking skills (hots) is one of the skills students need in dealing with life in the 21st century [26]. higher order thinking skills (hots) are aptitudes that are stressed globally and are now the main area of instruction in an increasing number of courses. by implementing hots in teaching and learning, teachers may encourage students' critical thinking and enhance classroom learning [27]. however, the reality is that student hots are still quite low. in the conventional learning process, students cannot experience independent experiences finding new learning concepts. using technology-based media such as computers or smartphones, students can adjust learning speed, interact, and make observations that foster greater curiosity about physics concepts in an event [28], [29]. learning media is one of the media used in learning. one of the advantages of learning media is that, in certain cases, it can represent the teacher in presenting the information taught to students. learning media is expected to facilitate higher-order thinking skills and students' spiritual attitudes. android-based digital learning media that has been developed can support the physics learning process well. various studies have reported the results of the development of android-based physics learning [30]–[33]. however, there are limited reports on developing androidbased learning media for those oriented toward higher order thinking skills and spiritual attitudes. therefore, this study aims to develop an android-based physics learning media oriented toward higher order thinking skills and spiritual attitudes. ii. theory physics learning media media is a communication and a good connector between two parties that function to convey information. the information can be ideas or opinions. learning media is a tool whose use is as a messenger of learning. learning media can facilitate the learning process, increase the efficiency of the learning process, and help students concentrate more on the learning process [34]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 32 39 34 nuraini, et al. development of al-qur'an-based physics learning media … p-issn: 2621-3761 e-issn: 2621-2889 the purpose of using media in the learning process is not only to complete the learning process itself and attract students' attention but also to facilitate the learning process, as well as to improve the quality of learning, and achieve learning objectives. in choosing media, accuracy is needed. thus learning outcomes are optimal, following what is desired by educators. educators need to consider various foundations. hence, the chosen media follow students' understanding, thinking, psychological, and social conditions. this is due to avoiding the non-optimal use of media in the learning process [35]. learning physics will be meaningful for students if the physical processes can be observed visually. more involvement of the five senses will further optimize student learning outcomes. generally, the characteristics of wave and optical matter are abstract. therefore, the development of technology-based physics learning media will bridge the activity of observing abstract physical processes on the wave and optical material. technologybased learning media also allows students to be actively involved because it involves several members of the five senses. higher order thinking skills thinking skills are skills in managing thoughts or cognitive systems consisting of knowledge, observation, and production. in addition, thinking skills also mean the ability to make decisions to solve problems based on information and experience. thinking activities aim to find meaning, understand something, look for ideas or creations, and make judgments [36]. thinking skills are divided into two types. these are low-order and high-order thinking skills [37]. both lowerorder and higher-order thinking are derived from bloom's taxonomy. bloom's taxonomy consists of six levels of cognitive thinking these are remembering (c1), understanding (c2), applying (c3), analyzing (c4), evaluating (c5), and creating (c6). low-order thinking skills (lots) are abilities that consist of c1 to c3, while higher-order thinking skills (hots) are abilities that consist of c4 to c6 [38]. higher order thinking has the characteristics of being able to think critically and creatively. critical thinking ability is an important ability in all aspects of life, including education. this ability can be used in various fields of study. students need to be trained to think critically so that they can solve problems that exist in the real world [39]. in comparison, creative ability is obtained by students by finding and using rational new ideas in participating in learning. this ability involves creativity to produce new products or combinations or developments of existing ones which are useful and can be accepted or understood [37] in education, the quality of learning must be improved to increase students' higher-order thinking skills. technological advances and curriculum changes are important in improving higher-order thinking skills [40]. advances in technology make it easier to obtain information in cyberspace. on the other hand, students need the ability to filter information so that the information obtained is good and valid. in ensuring the validity of information, the teacher's role is needed to clarify concepts in learning. it is important to create a suitable evaluation tool to measure learning achievement to gauge the level of students' higher-order thinking abilities. for example, essay questions, multiple choice, short entries, and other forms are arranged based on the domain levels c4 to c6 [41]. students' ability to solve problems can only be achieved when they can master how to analyze various alternative problem-solving views from various aspects [42]. spiritual attitude the word spiritual is closely related to almighty god and its relationship to the beliefs held by individuals [43]. spiritual attitude is the attitude that individuals have about the beliefs they hold. spiritual attitudes come in selfawareness as god's creatures, being grateful for the gifts and potential they have both physically and culturally [44]. based to hasanah et al. [43], the spiritual dimension consists of four aspects, namely: relating to something unknown or uncertain in life, finding meaning and purpose in life, realizing the ability to use one's resources and strength, and having a sense of attachment to oneself and god almighty. these aspects indicate the existence of human involvement that comes from feelings and knowledge. there is an ever-growing knowledge of discovering the unknown and finding meaning in life, but there is a sense of engagement with greater power. spiritual attitudes need to be possessed by students to create individuals who are faithful and pious. many studies have been conducted on integrating aspects of spiritual attitudes in learning. integrating the values of monotheism in learning materials will affect the quality of science. then, teaching materials integrated with spiritual values will encourage positive attitudes in students, such as gratitude, faith, piety, sincerity, and others, through the awareness that there is a relationship between the knowledge learned and the greatness of god's creation [45]. presenting religious values in science is a good way to understand scientific and spiritual concepts. integrating religious values with science is not only about finding arguments in the qur'an or hadith, nor is it the process of converting science to islam, but science acts as an intermediary for students to get closer to god. therefore, the preparation of teaching materials needs to be oriented to religious values as a step to produce students who have intellectual, emotional, social intelligence, and spiritual intelligence [46]. iii. method the research method used is research and development (r&d) with the addie development model [31], [47]. figure 1 shows the five stages of learning media development. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 32 39 35 nuraini, et al. development of al-qur'an-based physics learning media … p-issn: 2621-3761 e-issn: 2621-2889 figure 1. development stage in addie model the results of the development of the al-qur'anbased physics learning media application were tested on students who took the optical material iii basic physics course. participants in this study amounted to 40 students using the purposive sampling technique. data collection techniques used questionnaires, higher order thinking skill test questions, and questionnaires on students' spiritual attitudes. the data analysis technique used descriptive analysis. the percentage of the effectiveness of higher order thinking skills and students' spiritual attitudes is shown in table 1. table 1. category interpretation of effectiveness percentage (%) category < 40 ineffective 40 – 55 less effective 56 – 75 enough effective > 76 effective the learning media that has been developed is tested for validity. validity relates to the accuracy of the assessment tool against the concept to be assessed so as to assess what should be assessed [48]. experts, users, and audiences can test the validity [49]. this study uses expert validation. furthermore, the validation results are categorized. determine the validity category by matching the average total with the validity criteria, as shown in table 2. table 2. validity criterion validity range criterion 3.25 < va ≤ 4.00 very valid 2.50 < va ≤ 3.25 valid 1.75 < va ≤ 2.50 less valid 1.00 < va ≤ 1.75 not valid iv. results and discussion this research was conducted in the odd semester of the 2020/2021 academic year. the research begins by reviewing the curriculum in the physics education study program and the physics concepts that will be discussed. furthermore, developing the application of al-qur'anbased physics learning media. four materials on optics and waves have been developed: 1) geometric optics, 2) diffraction and polarization, 3) interference and 4) electromagnetic wave spectrum. an example of the development results is shown in figure 2. a. home of geometry optics materials b. home of diffraction and polarizing materials c. al quran verse integration http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 32 39 36 nuraini, et al. development of al-qur'an-based physics learning media … p-issn: 2621-3761 e-issn: 2621-2889 d. sample of quiz figure 2. example of display of learning media each al-qur'an-based interactive media application that has been developed consists of course learning outcomes (cpmk), learning objectives, materials on waves and optics (optical geometry, diffraction and polarization, interference, and electromagnetic wave spectrum), practice problems, simulation/animation, verses of the qur'an and evaluation/quiz. after compiling the results of developing an interactive media application based on the qur'an, validation activities were carried out. three experts carried out validation. the validation results show that the constructed aspect is 3.58 (very valid), the content aspect is 3.4 (very valid), and the linguistic aspect is 3.47 (very valid). the average validity for all aspects is 3.48, which is included in the very valid category. the validation results are shown in table 3. table 3. validation result of al qur'an based on learning physics no assessed aspect expert validating value average 1 2 3 1 construct 3,75 3,50 3,50 3,58 2 content 3,60 3,40 3,20 3,40 3 language 3,43 3,43 3,57 3,47 based on the average validation results shown in table 3, the resulting learning media is included in a very valid category and can be used in learning. this follows research conducted by ihwanudin et al. [50] which states that integrated science teaching materials integrated with the verses of the qur'an are classified as very valid categories. hence, they can be used as a media for science learning in the classroom. interactive learning multimedia with light material containing the qur'an that has been developed is suitable for use as a medium to support the learning process in muhammadiyah schools [51]. susilana and riyana [52] argue that learning media that has been validated undoubtedly can be used because it has gone through a scientific assessment process. media supports the learning process that can convey the material effectively and efficiently. the process of receiving abstract material will be faster using the media than lectures without tools [53]. by using the media, stimulation can be given. thus students are more motivated to learn something new [54]. the al-qur'an integrated physics learning media is effectively used in learning physics subjects for basic physics iii optics, according to table 1. this is based on the percentage obtained from the higher order thinking skill test results, which is 85% and in the effective category. values the higher order thinking skill obtained by students is 80.1 because, during the learning process, students show good enthusiasm and motivation to study physics in studying the concepts of waves and optics. some students ask questions and are active during learning if they do not understand waves and optical material. the results of students' spiritual attitudes after learning using the application of integrated physics learning media with the qur'an are in the very good and effective category, following table 1 with 89.8%. this is because when using this qur'an-based learning media, students can learn physics along with the verses of the qur'an related to the context and optical concepts being studied. during the learning process, there is no dichotomy between studying physical science and the context of the qur'an. therefore, students can glorify the creator's greatness, be more grateful for the blessings of faith and knowledge, and have a better spiritual attitude. this is in line with research conducted by cahyati and suseno [55], which states that learning media oriented to the value of the qur'an can direct and develop students' spiritual attitudes. the results of this study are relevant to the research reported by pratiwi et al. [56], which states that islamic values-based physics learning media can improve the quality of learning and get a positive response from lecturers and students. subsequent research by wati et al. [57] regarding learning media that integrates islamic values with the concept of physics shows that the media can improve learning outcomes, religious attitudes, and social attitudes. v. conclusion the al-qur'an-based physics learning media application that has been developed contains four waves and optics materials: 1) geometric optics, 2) diffraction and polarization, 3) interference and 4) electromagnetic wave spectrum. the feasibility test results show that the al-qur'an-based physics learning media is feasible and effective for developing higher order thinking skills and students' spiritual attitudes. this study has limitations, namely that it still focuses on waves and optics. however, the al-qur'an-based physics learning media can be one of the innovative solutions for preservice teacher students for online learning, especially amid the covid-19 pandemic. in future research, some suggestions that can be made are to develop a broader physics material, and the basic education level can be a concern. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.5, no.1, june 2022, pp. 32 39 37 nuraini, et al. development of al-qur'an-based physics learning media … p-issn: 2621-3761 e-issn: 2621-2889 references [1] r. rahmawati, n. y. rustaman, i. hamidah, and d. rusdiana, “the profile of cognitive style, logical thinking ability, and conceptual knowledge of electricity and magnetism topic based on prospective physics teachers’ grade level,” j. phys. conf. ser., vol. 1157, p. 032036, feb. 2019, doi: 10.1088/17426596/1157/3/032036. 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[57] l. wati, r. rahimah, e. w. nengsih, and m. mardaya, “media pembelajaran majalah fisika terintegrasi nilai keislaman [learning media integrated physics magazine islamic values],” j. ilm. pendidik. fis., vol. 5, no. 2, p. 192, jun. 2021, doi: 10.20527/jipf.v5i2.2731. declarations author contribution : lailatul nuraini was responsible for the entire research project. she also collaborate with other author for writing these article manuscript. firdha kusuma ayu anggraeni, alex harijanto and rayendra wahyu bactiar was responsible to check about how to develop these media. sri handono, bambang supriadi, subiki was responsible to check the quality theory of physics concept and media, maryani and sutarto was responsible to check the result and discussion. all of us is one team of research group in physics education study program, faculty of teacher training and education, university of jember. funding statement : this research is funded by the internal research group grant from research and community service institutions, university of jember. contract number: 11872/un25/lt/2020 conflict of interest : all of author declare that they have no conflict of interest. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1016/j.caeai.2021.100030 https://doi.org/10.1016/j.arth.2019.10.058 https://doi.org/10.1371/journal.pone.0233969 https://journal.unnes.ac.id/sju/index.php/upej/article/view/27674 https://ejournal.unsri.ac.id/index.php/jipf/article/view/5747 https://doi.org/10.24127/jpf.v3i2.252 https://doi.org/10.24042/ijsme.v2i3.4355 https://doi.org/10.20527/jipf.v5i2.2731 microsoft word 17_5-agustus-puspitawati-3.doc indonesian review of physics, volume 2, number 1, 2019 variation of mixed banana peel substrate and cow dung in biogas pressure as a learning source for renewable energy sources puspitawati1, riswanto2, and nyoto suseno3 1,2,3muhammadiyah university of metro jl. ki hajar dewantara 15 a iring mulyo kecamatan metro timur rumbiariswan@gmail.com abstract the supply of world energy resources is increasingly depleted. the abundance of cow manure and banana peel can cause environmental pollution. it can be used as raw material for biogas because both materials have a high methane gas ratio. this research is an experiment with six variations in the amount of mixture in each experiment. results of the research on gas pressure and the best biogas production results using 1-litre banana peel substrate and 4-litre cow dung. data shows that the gas pressure is faster and is greater when the ph of the mixture is acidic 6.2, the mixture is thick green and has a strong odour. gas pressure on day 20 is obtained by 106421 pascal. the average value of the results of the validation of the learning resources of the three aspects of an assessment is 82.3%; it shows that the poster can be used as a learning resource. keywords: banana peel substrate and cow dung, biogas, renewable energy source i. introduction this industrial era 4.0, humans are required to be able to compete in the world of technology in the use and development of modern technology that always develops well from small things to big things, so that future innovations that are useful for life are expected. energy is divided into renewable energy and non-renewable energy. most of the energy that has been used in everyday life is non-renewable energy in the form of fuel oil (bbm) and gas fuel. the world's energy inventories are increasingly depleted because of the need for innovations in developing advanced technology that should meet three aspects, including energy, economics, and ecology [9]. oil fuels include energy that cannot be renewed because the formation process takes thousands of years. humans must have the knowledge and ability to be able to use and use the energy in the right way. alternative energy sources that can be processed in the surrounding environment, namely sun, water, wind, biogas, and others. biogas is an alternative energy source obtained from the decomposition of organic matter with microorganisms in anaerobic conditions in a reactor. biogas is a mixture of gases produced by bacteria that occur in materials that can decompose naturally under anaerobic conditions. biogas is obtained from the fermentation of organic materials. methanogenic bacteria are found in organic materials that can produce methane or other gases [1]. indonesia is one country that has abundant natural resources such as oil, coal, gas, and even extraordinary natural attractions. unfortunately, indonesia is still dependent on petroleum energy sources, thus affecting indonesia's lack of independence in managing resources. nonrenewable natural resources are expected to run out in the coming decades. therefore the government is promoting the renewable energy movement. one of the renewable energies initiated by the government is home biogas. the government's efforts in optimizing its energy resources by making the following policies: law no. 33 of 2007 concerning energy in article 20 paragraph 4 contains that the provision of new energy and meeting energy needs in meeting people's needs is by finding alternative energy sources as energy substitutes petroleum [2]. metro lampung city has good potential in utilizing renewable energy sourced from biogas energy. the biggest potential of biogas material in metro city to be developed into biogas is cow dung (a1) with a percentage reaching 84%, goat manure (a2) 8%, buffalo dung (a3) 5% and chicken manure (a4) as much 3%. as for the potential of puspitawati et al. variation of mixed banana peel substrate and cow dung in biogas pressure… indonesian review of physics, volume 2, number 1, 2019 2 vegetable biogas (from plants) which has the highest percentage, namely in code b5, namely from rice straw while for other potential 13% is b3 (tofu waste) as much as 38% and b4 (banana peel) by 8% [3]. ii. theory organic matter can affect the biogas microorganism process. for example, water hyacinth can play a role in accelerating the process of biogas formation. the treatment of adding water hyacinth mixture to cow dung can accelerate the process of fermentation in biogas. this is evidenced based on data that on the first day the water hyacinth mixture showed changes in biogas pressure of 179.805 n / m2, whereas when compared with preliminary test data which only used cattle filth, the pressure change occurred on day 2 with a pressure value of 9, 81 n / m2 [10]. biogas composition and variation in three different biogas production plants were studied to provide information pertaining to its potential use as biofuel. methane, carbon dioxide, oxygen, nitrogen, volatile organic compounds (vocs) and sulphur compounds were measured in samples of biogases from a landfill, sewage treatment plant sludge digester and farm biogas plant. methane content ranged from 48% to 65%, carbon dioxide from 36% to 41% and nitrogen from <1% to 17% [11]. the other organic material which is quite abundant is banana peel. banana skin contains 68.90% water and 18.50% carbohydrate. most of the banana peel waste is still underutilized [4]. a small portion of banana peel waste is usually used for animal feed, and the rest is not utilized. the role of banana skin substrate in biogas production is to accelerate the reaction of methanogenic bacteria so that it can produce biogas faster. addition of banana skin substrate to livestock faeces in methanogenic fermentation can increase enzyme activity, but negatively affects vfa amount of biogas production, methane gas content and methane gas production (ch4) [5]. mixing banana skin substrate with cow dung is one way to increase carbon and nitrogen ratio. addition of a mixture of banana peels to cow faeces by 15 and 30% has not reached an optimal balance of the carbon and nitrogen ratio, the optimal balance of the carbon and nitrogen ratio in biogas production is in the range of carbon and nitrogen ratio 25 to 30 [5]. most of the biogas in metro city is biogas whose raw materials are only livestock manure both duck manure, chicken manure, cow dung, and others. cows are one of the livestock that is maintained by many people around the metro. cow manure is usually used as compost. excessive and untapped cow dung waste will hurt the environment such as soil, water, air pollution and the spread of infectious diseases. the content of carbon and nitrogen ratio of cow manure is around 24. high carbon and nitrogen ratio will accelerate methane bacteria to react. therefore cow dung has considerable potential if used as material for producing biogas [1]. anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel – the biogas [12]. the experiment the researchers had done was by making biogas from cow dung; the experimental results were that cow dung produced gas pressure. this research is an experimental study which aims: 1). to determine the effect of variations in the mixture of banana skin substrate and cow dung on the biogas pressure produced. 2). to produce appropriate learning resources, it is necessary to research biogas as an alternative energy source for renewable energy source material. 3). the community can respond well to the research poster iii. methodology this study uses an experimental method that is by varying the mixture of banana skin substrate to be used with cow dung. variation of the mixture of banana skin substrate and cow dung. the experiment was carried out 6 times with the number of mixtures in the first experiment namely banana skin substrate 0 litres and 5 litres of cow manure, the second experiment using 1 litre banana peel substrate and 4 litre cow manure, the third experiment used a 2 liter banana skin substrate and dirt 3 liters of cattle, the fourth experiment uses a 2.5 liter banana peel substrate and 2.5 liters of cow dung, the fifth experiment uses a 3 liter banana peel substrate and 2 liters of cow dung, and the sixth trial uses a 5 litre banana peel substrate and 0 litre cow manure. the process of taking biogas data is carried out in pekalongan, east lampung. in addition to biogas pressure, other parameters observed from the results of the study are ph, temperature, mix colour, odour, and air humidity. the testing process is carried out to obtain data by noting the gas pressure changes printed on the manometer. data collection was carried out for 20 consecutive days from the first day, the second day, the third day, the 4th day, the 5th day, until the 20th day. the results of this study are learning resources in the form of posters that are useful for reference as well as information in finding alternative energy sources. puspitawati et al. variation of mixed banana peel substrate and cow dung in biogas pressure… indonesian review of physics, volume 2, number 1, 2019 3 learning resources are learning media [8]. the feasibility percentage scale, as shown in table 1. table 1. category percentage scale no percentage scale (%) interpretation 1 81-100 % very worthy 2 61-80,9 % worthy 3 41-60,9 % enough 4 21-40,9 % not feasible 5 0,0-20,9 % very inappropriate learning resources are said to be feasible if the percentage of the feasibility of learning resources is 61%. but not all learning media can function as learning resources. learning resources generated in this study are poster resources. learning resources that have been made will be validated by several experts in terms of material coverage, graphics, and complexity. this validation aims to find out that the learning resources (posters) are feasible or not yet to be used or publicized. tabulation of data is used to calculate the percentage of average rating scores obtained using the formula [6]: information: : percentage sub variable s: sub variable total n: maximum total score criteria for percentage assessment and interpretation to find out the feasibility of learning resources as a reference for evaluating the data generated from the validator are in table 1. iv. results and discussion the experiments were carried out in 6 variations with a mixture of different ingredients. experiment 1 used cow dung and trials 2 to 5 used variations of the mixture of banana skin substrate with cow dung and experiment 6 only used a banana skin substrate. all experiments use an additional 5 litres of water, with the results, as shown in figure 1. figure 1. biogas pressure measurement chart results of the study, the amount of biogas pressure produced by the mixture with the volume of cow manure more than the volume of the substrate will produce greater biogas pressure. the fastest rising biogas pressure is found in experiment 2 with a variation of 1-liter substrate and 4-litre cow manure. figure 1 graph shows the results of biogas pressure measurements. the highest increase in biogas pressure was obtained from experiment 2 with a mixture of 1-liter substrate, 4-litre cow manure, and 5-litre water. the amount of biogas pressure on day 20 is 106519 pa. the lowest biogas pressure was found in experiment 4 with 2.5-litre substrate mixture, 2.5-litre cow manure and 5-litre water with 104363 pa biogas pressure. mixing water hyacinth with cow manure, biogas pressure changes happen on day 1 with the characteristic graph of a r2 = 0.976. this condition describes that the mixing of the water hyacinth and cow dung provides distinctions signifikant in accelerating the process of occurrence of biogas [13]. while for the effect of mixing banana skin substrate and dirt on biogas pressure will increase biogas pressure faster when the banana skin substrate volume is less than cow dung. the jump in biogas pressure on average occurs on day 14 and day 15. the jump illustrates the highest increase in biogas pressure from each experiment. the jump in biogas pressure is caused by an increase in reactions caused by microbes, so ideally, an increase in biogas pressure occurs on day 14 and day 15. during the fermentation process, air temperature and humidity do not affect the increase in biogas pressure because the increase or decrease in temperature and humidity are not far from the first day and the next day. the average increase in temperature and humidity is stable around 280c and 74% air humidity. the best biogas methane content is when conditioned ph 7.0 [7]. while the results of the research conducted show that the best ph to produce methane biogas is 6.2, this is because the highest puspitawati et al. variation of mixed banana peel substrate and cow dung in biogas pressure… indonesian review of physics, volume 2, number 1, 2019 4 rate of increase in biogas pressure is produced in a comparison of the mixture of banana peel substrate and contaminated with 1: 4. if the volume of cow manure increases, the ph value will be higher, and vice versa, if the cow manure is used less, then the ph value, will be lower. meanwhile, the learning source validation results in the form of posters which contain aspects of material coverage, aspects of graphics, and aspects of reusability. the learning source validation process was carried out by three experts, namely one lecturer one teacher and one community leader. table 2. percentage of average learning resource assessment no assessment aspects value 1 coverage of teaching material 82,75% 2 graphics 79,83% 3 usability 85,91% average 82,3% based on the table the average percentage of assessment of learning resources shows that from the three aspects of assessment of learning resources, namely aspects of assessment of usability get a greater value of 85.91%, aspects of material coverage 82.75% and lowest values found in aspects of graphic learning resources, 79, 83%. the results of the assessment obtained from the expert validation sheet are 82.3%. this shows that the percentage scale assessment of learning resources more than 60 with interpretations is very feasible to be used as a source of learning. v. conclusion there is an effect of variations in the mixture of banana skin substrate and cow dung on the amount of biogas pressure produced. the biggest biogas pressure is generated from treatment 1, which is a mixture of 1-litre banana peel substrate, 4-litre cow manure, and 5-litre water. the results of the research made in the form of posters have gone through a validation process and are declared very feasible as a source of learning. the material contained in the poster contained discoveries of alternative energy sources by utilizing additional banana skin substrates to accelerate the biogas production process. the community responded well to posters made from the results of the research. suggestion, for the community, the results of this study can be used as a reference for processing and utilizing banana peels as an addition to organic material in the manufacture of biogas using cow dung. for teachers, the learning resources that are made can be used as learning resources for renewable energy sources. this research is the manufacture of sensorbased reactors, efforts to minimize gas leakage from reactor tubes. reference [1] wahyuni, sri. 2008. biogas. jakarta: penebarswadaya [2] uu no 33 tahun 2007 tentang energi dalam pasal 20 ayat 4 [3] riswanto, r. (2017). pemetaan potensi biogas di kota metro. jurnal pendidikan fisika, 5(2), 126137. [4] setiawati, d. r., sinaga, a. r., & dewi, t. k. (2013). proses pembuatan bioetanol dari kulit pisang kepok. jurnal teknik kimia, 19(1). [5] triatmojo, s., & yusiati, l. m. pengaruh penambahan limbah kulit pisang (musa spp) terhadap produksi gas metan dalam fermentasi matanogenik kotoran ternak. buletin peternakan, 36(2), 87-94. [6] arikunto, suharsimi. 2010. manajemen penelitian. jakarta: rineka cipta [7] kurniawan, muhammad ilham.,kirom, m. ramdlan dan suhendi, asep. 2017. pengaruh nilai ph awal terhadap hasil produksi biogas pada reaktor anaerob.eproceeding of engineering.vol. 4.no. 3.halaman 39773984. [8] asyhar, rayandra. 2011. kreatifmengembangkan media pembelajaran. jakarta: gaungpersada press [9] kholiq, imam. 2015. pemanfaatan energi alternatif sebagai energi terbarukan untuk mendukung substitusi bbm. jurnal iptek. vol. 19. no. 2. halaman 75-91 [10] riswanto, r., & sodikin, s. (2019). pengukuran tekanan absolut biogas berbahan campuran eceng gondok dan kotoran sapi. jurnal pendidikan fisika dan teknologi, 5(1), 25-29. [11] rasi, s., veijanen, a., & rintala, j. (2007). trace compounds of biogas from different biogas production plants. energy, 32(8), 1375-1380. [12] holm-nielsen, j. b., al seadi, t., & oleskowicz-popiel, p. (2009). the future of anaerobic digestion and biogas utilization. bioresource technology, 100(22), 5478-5484. indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.6, no.1, june 2023, pp. 1 9 doi: 10.12928/irip.v6i1.6464 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 1 students’ computational thinking skills in physics learning: a case study of kinematic concepts rif’ati dina handayani*, albertus djoko lesmono, sri handono budi prastowo, bambang supriadi, nila mutia dewi physics education department, faculty of teacher training and education, universitas jember, indonesia email: rifati.fkip@unej.ac.id article info abstract article history received: aug 14, 2022 revision: jun 16, 2023 accepted: jun 17, 2023 physics learning provides a context for future careers in fostering ability in high-end logic with the 21st learning goals. applying computational thinking in schools is challenging and requires systemic transformation and teacher attention. this study aims to investigate the computational thinking of students in physics learning. this study used exploratory qualitative research. data were gathered through observation, interviews, and portfolio documents. the data are analyzed through six stages: preparing and organizing, exploring, building descriptions, representing the findings, interpreting the results, and validating the accuracy. the result indicated four primary computational thinking skills: decomposition, abstraction, simulation, and evaluation. the computational thinking skills in physics learning can develop students’ understanding and implementation of physics concepts based on data, not just mathematical formulas. computational thinking in physics learning gives students the opportunity and space to explore and develop their ideas and logical reasoning more deeply in problem-defining, solutions, and evaluation. students use their logical reasoning to solve the problem precisely. this study is expected to be used as a basis and support for physics teachers to integrate computational thinking into their learning classroom. this is an open-access article under the cc–by-sa license. keywords: computational thinking physics learning problem-solving 21st-century learning to cite this article: r. d. handayani, a. d. lesmono, s. h. b. prastowo, b. supriadi, and n. m. dewi, “students’ computational thinking skills in physics learning: a case study of kinematic concepts,” indones. rev. phys., vol. 6, no. 1, pp. 1–9, 2023, doi: 10.12928/irip.v6i1.6464. i. introduction computational thinking is widely studied in the 21st century as a new paradigm of thinking and developing science and technology. the 21st century has transformed various skills, knowledge, and competencies required in modern society [1]. research related to integrating computational thinking in learning is an exciting issue [2]. integrating computational thinking into the classroom is challenging and requires systemic transformation, teacher attention, and learning resources [3]. computational thinking is an essential thinking skill crucial in helping individuals solve problems [4]. computational thinking refers to systematically analyzing, investigating, and testing solutions to complex problems [5]. computational thinking is a cognitive process that involves a complex logical sense [6], [7]. providing the young generation with complex and challenging problem-solving skills will be significantly valuable in dealing with developments in an increasingly complex and dynamic future era [8]. applying computational thinking in schools is exciting and challenging. computational thinking is an essential skill that must be integrated and marked from early education to solve the problem effectively [9]. giving a complex problem increases the young learner’s capabilities to solve a dynamic situation [8]. computational thinking involves multiple-level abstraction processes used across multidisciplinary subjects and applied in the virtual and the complex real world [10]. also, it combines much cross-disciplinary knowledge such as science, technology, engineering, mathematics, social, and literacy [7], [11], [12]. computational thinking contains many high-level skills, such as creativity, critical thinking, algorithmic thinking, collaboration, and problem-solving [13]. students are http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v6i1.6464 http://journal2.uad.ac.id/index.php/irip mailto:rifati.fkip@unej.ac.id http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 2 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 expected to solve problems and be responsible, transform what is learned, analyze, interpret scientific data, and use technology appropriately [14]. skills related to creativity, curiosity, critical thinking, literacy, and technology are required for students’ existence in their future careers [15]. therefore, teachers must prepare students as the younger generation with computational thinking skills. physics education is crucial to encourage the workforce to compete in the industrial revolution 4.0. physics education supports technological development and prepares students to make advanced scientific progress and discoveries [16], [17]. physics provides a context for future careers promoting profound knowledge and boosting proficiency in high-end logic parallel with the twenty-first-century learning goals [16]. physics is a prerequisite for engineering and technology and is appropriate for all sciences. advancements in technology are commonly established on discoveries in physics and inventions based on new construction of current physics knowledge [18]. learning physics equips the required skills for scientific thinking, constructing knowledge, keeping track of developing technology, analyzing, and interpreting phenomena in nature [19]. physics learning helps students analyze complex problems and understand natural phenomena [17]. unfortunately, several students think physics learning is accustomed to conventional education by directly using mathematical formulas [20]. students are frightened to study physics because it has a standing as a complex and complicated subject [21]. particular considerations of physics that they uncover enormously include the need to realize various mathematical equations and figures and then be able to convert those concepts into actual life [22]. in addition, computational thinking research in physics learning is infrequently accomplished [21], [23]. this study aims to investigate students’ computational thinking skills in physics learning. the research question of this study is what are students’ computational thinking skills in physics learning? ii. theory computational thinking skills several researchers have proposed definitions of computational thinking. each researcher has a different interpretation. the variety of descriptions illustrates that computational thinking and its facets are not limited to computer-related practices but have a broader meaning [24]. xu and tu [25] also clarified that computational thinking skills universally involve various mental and thinking processes that reflect computer science and meaningful frameworks. computational thinking is a way of thinking, investigation, and action, which can be established using specific skills to assess performancebased computational thinking [26], [27]. it is a process of formulating problems and solutions that can be represented more effectively and efficiently [28]. alfayez and lambert [29] stated that computational thinking involves intellectual skill, practice, and methods to solve a complex problem. in other representations, the scope of computational thinking is broader and a complex process that can be described through the knowledge, attitudes, and general practices that supplement it [30]. table 1 represents some characteristics/facets of computational thinking. table 1. characteristics of computational thinking authors characteristics of computational thinking skills wing [31] abstraction, decomposition, problem reformulating barr & stephenson [32] abstraction, algorithm and procedure, decomposition, automation brennan & resnick [33] computational concept, computational practice, computational perspective aho [34] algorithm design and problem-solving technique grover & pea [35] abstraction, algorithm notation, automation, structured and logical problem solving, decomposition, iterative thinking, recursive and efficient weintrop et al. [36] practical data, modeling, and simulation practicum, computational problemsolving practice, systems thinking practice shute et al. [26] decomposition, abstraction, algorithm design, debugging, iteration, and generalization kale et al. [37] confrontation, decomposition, pattern recognition, abstraction, algorithm, automation, analysis lee & malynsmith [10] abstraction, algorithm, developing a program, data collection & analysis, modeling & simulation ehsan et al. [38] abstraction, algorithms and procedures, troubleshooting and debugging, pattern recognition, simulation computational thinking skill in education instruction and learning are becoming challenging due to technical and technological information development in the 21st century. exploring computational thinking in education is a fundamental skill that facilitates students to explore their ability to solve problems [10], [39]. integrating computational thinking requires many skills, from teaching strategies to utilizing computer knowledge to teach subject matter [37]. schools and teachers should collaboratively support the teaching of computational thinking skills to their students [40]. the academic perspective views that computational thinking skills will improve math and science content knowledge [7], [12], [41]. wing [42] stated that reading, writing, and arithmetic must add computational thinking skills to children. bringing computational thinking and practice to classroom learning will provide students with a more realistic and contextual interpretation [7], [43], [44]. computational thinking can effectively teach a more challenging and meaningful body of knowledge [12]. also, computational thinking skills can change the perspective and approach to understanding a subject matter [11], [45] http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 3 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 and help gain a more profound struggle to comprehend scientific concepts [18]. weintrop et al. [36] presented several advantages of integrating computational thinking in the classroom: familiarizing students with open-ended problems, persistent working with complex issues, confidence in dealing with the complexity, representing ideas in a more meaningful way, reframing into a more organized problem, assessing the strength or weakness of the data, compiling algorithmic solutions, and checking and rearranging ambiguities in the algorithm. iii. method participants the sample was determined using the purposive sampling method. purposeful sampling is widely utilized in qualitative research to identify and specify issues-rich cases associated with the topic of interest [46]. the participants in this study were 35 students taking introductory physics in the first semester, 29 females (83%) and six males (17%) aged 18-19 years old. the sample included relatively more female respondents than males since more females have become science-related majors in college in indonesia. the introductory physics courses are the basis for all subsequent studies in physics. research ethics have been carried out, and the results of this research do not affect the final assessment of students. research design this research used exploratory qualitative research to investigate students’ computational thinking skills in physics. a case study is a research method that emphasizes exploration more in-depth than a description [47]. exploratory case studies are designated to explore any phenomenon in the data which operates as a topic of interest [48]. the qualitative case method is widely used in preliminary engineering, science, and computer science learning research using a small sample [38], [49]. being boosted by the studies, the case study was chosen since this methodology emphasizes accurate findings to investigate students’ computational thinking skills profoundly with a small sample. furthermore, this study’s participants were split into eight groups (g1, g2, g3, g4, g5, g6, g7, g8), each composed of four to five students. this group distribution ensures that students actively collaborate and participate in physics classroom learning. collaboration promotes the input of thought, ideas, control, and reflection and provides constructive feedback to group members through rationalization and reasoning. the steps of physics learning in this study taken are 1) students are introduced to contextual issues related to kinematics problems, 2) the teacher gives examples of simple problem-solving together with students, 3) students are asked to solve the problems the teacher has passed and make simple simulation models using the microsoft excel program, 4) communicating accomplished solutions textually in portfolios and oral presentations. data collection data is gathered through observation, interviews, and portfolio documents. the observation was made through a recorded zoom cloud meeting because face-to-face classrooms cannot be implemented during the covid-19 pandemic. observation is an important research method in the qualitative because it is the primary step to getting actual data on the research [50]. in addition, the interviews in this study used open-ended interviews. open interviews were chosen to obtain in-depth information about students’ ideas and opinions without restricting the researcher’s viewpoint. interviews enable identifying more exact and in-depth information about an issue from the participants [50], [51]. the interview lasted approximately 30 minutes for each group. it aims to explore detailed information on the computational thinking of students. the last data source is a document. the documents collected are student project portfolios. documents are an excellent source of textual data in qualitative research. the written document is significant evidence of understanding what the students learn, accomplish, and value [52]. data analysis data analysis in this investigation utilized the approach of creswell [53], which consists of six stages: preparing and organizing data, exploring and coding, building descriptions and themes, representing the findings, interpreting the results, and validating the accuracy. first, all data are organized in file folders containing video recordings, interviews, and portfolio documents. interview data were transcribed into data text and grouped based on the similarity of issues and ideas. second, the documentary analysis was carried out by reading the students’ project portfolios with the purpose was to map the students’ thoughts and representations. the researchers repeatedly analyze all data, reading and observing, to get critical information about students’ computational thinking in physics. the primary purpose of this analysis stage is to generate a series of essential data. furthermore, the resulting critical information uses to build categories that provide a broader abstraction regarding students’ computational thinking. the researchers analyzed and re-analyzed to obtain valuable findings from the study and achieve the research objectives. the research data is carefully examined to determine what students’ computational aspects arise in physics learning. the analysis result indicates four main characteristics of students’ computational thinking in physics learning: decomposition, abstraction, simulation, and evaluation (table 2). these findings were further validated using triangulation, theory, and other research on computational thinking in the learning context, such as in table 1. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 4 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 table 2. characteristics of students‘ computational thinking skills in physics learning computational thinking skills indicators decomposition • problem identification • representing idea • formulate the problem • breaking down the problem abstraction • collecting the data • data analysis • pattern recognition • sketching/graphics simulation • iteration • making algorithm • manipulating data evaluation • verification • troubleshooting • validating • debugging iv. results and discussion results physics is intellectual knowledge and experience that inspires students to expand their understanding of nature and generates the basic knowledge required for future technological advancements. integrating computational thinking in physics learning trained students to learn from mathematic formulation and solve problems by looking at data pattern recognition. this study’s computational thinking skills contain multi-aspect builders that implicate cognitive complexity. the results of the data analysis of students’ thinking skills indicated that students were more focused on solving problems. decomposition decomposition is an essential step to comprehending the problem. the decomposition process appeared when students investigated the critical information in the kinematic issues. the students discuss in a group and present their ideas about the facts that arise in the kinematics problems. students looked for information based on their fundamental concepts of physics. they write down essential variables (independent and dependent variables), write the formula, and look for emerging points in the kinematics issues based on the arrangement of the ideas from their discussion. they simplify the problem by dividing it into more minor solvable problems or subpieces to understand the cases better. here are some examples of students’ response “we searched for relevant variables and categorized the potential element in order of axis, structure, and function of motion” (interview, g7_ne) “we break down the problem into simpler parts to find out which quantities and substantive elements need to solve first (interview, g5_ri) “we look at the issues given by the teacher step by step to find out the root of the problem.” (interview, g6_trk) the pieces of information that have been broken down are then grouped based on their structure, function, sequence, similarities, or characteristics and resolved in each group separately. for example (figure 1), students are grouping variables of the physical quantities in the projectile motion on the x-axis and y-axis. this activity showed students’ decomposition process. decomposition simplifies the problem by dividing it into smaller or simpler parts to make it easier to manage. decomposition helps them find solutions more efficiently and manageably. also, the process helps students clearly understand the goal or what they are attempting to achieve (criteria/regulations/constraints). figure 1. example of students’ answer in projectile motion abstraction abstraction is the method of describing the most fundamental aspect of problems. abstraction is more about significant issues that are essential and not essential. the results of the analysis data indicate that the abstraction process is carried out when students identify the main problems, such as when the ball reaches the highest position and the time needed to get to the farthest places in projectile motion. they conducted the exploration process through virtual experiments of air track simulators and the phet simulations program. “we used the phet simulations program to collect data virtually (interview, g1_fgl) “we utilized an air track simulator to gather data on time and distance (interview, g4_ff) “we describe every state of the ball and illustrate the velocity acting on the projectile motion” (interview, g2_ kn) students took data, analyzed it, and looked for patterns. they described the problems based on the data collected and their prior knowledge. the data collected is http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 5 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 then put into tables and analyzed to make it easier for them to get an overview or a big picture (figure 3). the abstraction process also appeared when the students looked for data patterns (pattern recognition). data pattern recognition is conducted by sketching graphs or compiling data in tables. some students argued that making table and graph visualization in physics is a strategic and appropriate method for analyzing information in visual display. we quickly understand patterns if data analysis results are presented visually, such as graphs or charts” (interview, g8_rts) graphics in physics are commonplace and are widely used to look for patterns (interview, g8_ik) figure 2. example of the student’s sketch of free-fall motion the abstraction skills force learner to focus on the critical and substantive elements and assist students analyse the extent of the problem to give the right solution. this activity illustrated the students’ abstraction process to understand the issues in a structured manner. in this study, students held that data and data analysis are the main points of the scientific method of physics learning. simulation modeling or simulation is not a new method in physics. students mainly utilize simulations to understand physics concepts. the data analysis showed that students used a simulation to solve the problem. they tried to imitate data by conducting simple algorithms and programs. students built codes and developed simple algorithms to represent data, recognize patterns, and describe physical models. they construct step-by-step instructions for solving the problem. students realized that programming is an elaborate process that involves complex thinking that conducts computational thinking processes. they attempted to simulate, visualize data, make inferences, and predict physics phenomena. some students stated that making simulations and models in physics pushes them to work harder. “made a physics simulation make our group work and think harder” (interview, g1_gp) “we made a simple simulation of projectile motion using excel” (interview, g8_ug) “we made a simple algorithm of the data so that the pattern of linear motion can be noticed obviously” (interview, g4_gbl) in addition, students conducted data management, such as arrangement of data, filtering data, and merging. manipulating data is undertaken to detect the pattern, assess, and prioritize tasks to find effective and efficient solutions. for example, students simulating threw a ball at different masses and angles in projectile motion. the students remarked that simulation is a way of accruing ideas, adequately building a structured thinking process, and drawing decisions appropriately in physics learning. students realized that the existing algorithms and simulations were suitable for representing physical models in the expression of computational thinking. figure 3 shows an example of students’ simulation code using the excel program. “we sort data and manipulate mass in projectile motion simulation to assess the problem and find the right, effective, and efficient solution” (interview, g2_gln) “making program algorithms drives us to think in a structured thinking process” solution (interview, g6_ar) “we are merging and tinkering data to detect patterns and find the appropriate result” (interview, g7_okn) figure 3. an example of a student’s algorithm program of projectile motion evaluation evaluation is a crucial stage in computational thinking skills. in this study, evaluation refers to testing, checking, and ensuring that the solutions align with the data observation and experiment results. the evaluation process enables the algorithmic solution to be usable under various possibilities and appropriate for completing the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 6 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 problem. in this study, evaluation is necessary to highlight the benefits and drawbacks of the solution. students’ challenge in the simulation program is accuracy in writing algorithm code. it requires checking and re-checking the code built before the running process. data analysis indicated that evaluation is carried out by testing the simulations. they pay attention to the execution of the solution during programming. students conducted this process to identify distinctions and appropriateness between the simulation program and the analytical data taken. this is a verification process. in addition, the student compares simulation results from other professional programs and another simulation of identical issues. testing is one of the ways to calibrate the simulation program. in detail, students check each code or algorithm created individually to look for possible errors (debugging). the debugging process aims to analyze the program workflow and find bugs (errors) or cracks in a computer program to work as expected. if the program has trouble, they discover why the code is not running well (troubleshooting). “we examine and check the lines per line of code that are created to look for errors in excel” (interview, g3_etr) “we try to run the program and compare the results with real/ analytical data” (interview, g5_aws) “we used analytic data and professional programs as a reference and framework in making conclusions” (interview, g8_so) furthermore, interview results indicate that students use personal experience and peers to check their programs. the ability to check individually or collectively is trained and improves the ability of students to identify and rebuild solutions in line with expectations. in short, the debugging process facilitates students to construct their knowledge and realize problem-solving strategies. “we check each code that has been accomplished sequentially step by step in a detailed process based on our personal experience” (interview, g1_fmt) “in the group, we check the code when an error occurs or the simulation program does not run properly” (interview, g6_has) “we compared our programs with other simulations” (interview, g7_ans) discussion within physics learning, conceptual understanding and problem-solving remain a current priority. the finding indicated four main characteristics of students’ computational thinking skills in physics: decomposition, abstraction, simulation, and evaluation. computational thinking reveals students’ ability to reframe problems through basic problem-solving skills such as formulating issues, presenting an idea, finding facts, and identifying relevant physical quantities. in this study, students accessed various representations of physics concepts and tried to communicate the multiple representations based on their knowledge and understanding. they attempted to reformulate the problem to construct a thinking system that simplifies solving kinematics problems. problem reformulation has been recognized as an initial problemsolving procedure before the beginning of computational thinking [54]. decomposition and abstraction are essential facets of computational thinking skills. based on the result, decomposition and abstraction help students understand and determine problem borders, restraint, purpose, and prerequisites in problem-solving. students utilized firstorder logic of thinking in defining problems based on existing facts. the decomposition and abstraction emphasize analytical logic thinking of students’ problemsolving. logical thinking enables students to construct the meaning of knowledge by analyzing and checking facts on problems clearly and precisely. rendering points through an open, rational, and precise mindset is a logical thinking process that involves rational and intellectual design, forecasting, confirming, decision-making, and conclusions [38]. a good understanding of the problem will produce an effective and efficient solution without losing critical information. based on the results, students make the simulation a way to analogies and modify similar issues to find the best solutions. analogies assist students in designing, constructing, and assessing problem solutions. students who use analogies and modifications provide solutions using their understanding and skills related to a problem already solved [37]. students constructed a simple simulation to explore kinematics deeply. visual models in science can be flowcharts, computer simulations, diagrams, equations, chemical formulas, and physical models. a simulation is a form of modification and visualization of the results of thinking to make solving problems easier to understand and recognize [52]. simulation is the expression of analytical data integrated with the ability to predict and interpret information. in this study, the simulation of a physics phenomenon trains students’ thinking in a structured, step-by-step manner in script coding and frameworks to visualize and analyze problems. also, it supports their conceptual, strategies, and procedural knowledge. irgens et al. [24] and sung and black [12] posit in their research that using modifications such as simulation program builds students’ thinking progress or frameworks. unfortunately, not all students in this study have the capabilities to create an excellent coding program. they have difficulty pouring their ideas into code. orban and teeling-smith [52] states that the correct set of regulations and simulation programs is often difficult for students. creating and running programs to model some physical phenomena by engaging intuition, http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 1 9 7 r. d. handayani, et al. students’ computational thinking skills in physics … p-issn: 2621-3761 e-issn: 2621-2889 understanding, and noticing physics sets are autonomous of a mathematical formula but an iterative connection among codes and data. furthermore, evaluation is the last aspect of students’ computational thinking skills in physics. an evaluation process is a form of reflection and validation of the program’s accuracy. the result noticed that a testing process conducts the evaluation process. testing involves multiple trials and errors to ensure and check the program. the student evaluates their solution like an iterative process. testing and debugging are crucial when creating an algorithm or working on a computer. debugging refers to identifying, fixing, improving solutions, investigating, and checking results. students who can solve problems in algorithms will be able to identify, analyze, and improve the solutions offered systematically and efficiently [55]. in this study, students’ systematic testing and debugging contributed to problem-solving, primarily when evaluating and considering potential solutions. evaluation in simulation programs reinforces and strengthens students’ idea that computer programs represent rational thinking of accuracy and reliability. integrating computational thinking in physics learning helps students construct their knowledge and allows them to determine the best solution to resolve the problem. bers et al [54] asserted that students could learn more deeply when constructing their knowledge through a project in a community of learners. students are trained in open-ended physics problems by examining various perspectives involving graphs, tables, and mathematics. open-ended problems have opportunities to utilize knowledge and skills comprehensively [56]. students have much experience finding solutions to the problem, such as simulation. computational thinking assists and develops physics students’ accuracy, structured thinking, brainstorming, and a framework of difficulties to obtain an effective and efficient solution. students use their logical reasoning when determining solutions. this logical reasoning is the key to solving a problem in physics learning. it helps them solve issues precisely based on data dan simulation. furthermore, this study has limitations; it only focuses on the kinematics concept and has a restricted number of participants. the challenge when integrating computational thinking skills in the school is teachers’ ability concerning computer science. teachers have to upgrade their computer science skills and knowledge. future research must investigate other physics concepts like waves, magnetism, and atoms. also, future studies need to follow up by considering the computational attitudes of students. v. conclusion the main point of computational thinking is problem-solving. this study indicated four primary characteristics of students’ computational thinking skills in physics: decomposition, abstraction, simulation, and evaluation. computational thinking improves students’ ability to problem understanding, identify problem boundaries constraints and set goals and prerequisites for problem-solving in physics learning. it develops students’ ideas and logical reasoning more structured when determining solutions and evaluating problem-solving frameworks. also, computational thinking skills in physics learning allow students to develop relevant ideas through their collaborative problem-solving experience. this study illustrates that to understand physics, students not only learn physics from a series of mathematical formulas but based on pattern recognition of the data. this research is expected to contribute to physics teachers integrating computational mental skills in their learning classroom. integrating computational thinking in learning will train students to be responsive to open problems and think logically and structurally. vi. acknowledgment the university of jember funded this research. references [1] t. palts and m. pedaste, “a model for developing computational thinking skills,” informatics educ., vol. 19, no. 1, pp. 113–128, 2020, doi: 10.15388/infedu.2020.06. 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[56] r. popping, “analyzing open-ended questions by means of text analysis procedures,” bull. méthodologie sociol., vol. 128, pp. 23–39, 2015, doi: 10.1177/0759106315597389. declarations author contribution : rif’ati dina handayanai as main author and research coordinator. albertus djoko lesmono as data processing, sri handono budi prastowo as data processing, bambang supriadi as develop research instruments, nila mutia dewi as collect data funding statement : the university of jember funded this research conflict of interest : no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. additional information : http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.1016/j.edurev.2014.10.002 https://doi.org/10.1007/s10639-012-9240-x https://doi.org/10.1145/1118178.1118215 https://www.learntechlib.org/primary/p/209807/ https://doi.org/10.1007/s10956-019-09794-8 https://doi.org/10.1007/s10488-013-0528-y https://doi.org/10.1007/s10488-013-0528-y https://doi.org/10.1186/1471-2288-11-100 https://doi.org/10.1007/s11251-016-9396-7 https://doi.org/10.1017/cbo9781107415324.004 https://doi.org/10.1119/1.5145470 https://doi.org/10.1016/j.compedu.2013.10.020 https://doi.org/10.1007/s10639-022-10921-z https://doi.org/10.1007/s10639-022-10921-z https://doi.org/10.1177/0759106315597389 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.6, no.1, june 2023, pp. 45 55 doi: 10.12928/irip.v6i1.6705 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 45 estimation of flores sea aftershock rupture data based on ai adi jufriansah1*, azmi khusnani2, yudhiakto pramudya3, and mulya afriyanto4 1mathematics education department, ikip muhammadiyah maumere, indonesia 2physics education department, ikip muhammadiyah maumere, indonesia 3postgraduate program of physics education, faculty of teacher training and education, universitas ahmad dahlan, indonesia 4meteorological, climatological, and geophysical agency (bmkg), sikka regency, indonesia email: saompu@gmail.com article info abstract article history received: oct 10, 2022 revision: jun 15, 2023 accepted: jun 20, 2023 the earthquake catalog notes that there have been earthquakes with mw > 7 that hit the flores area, three of which occurred in the flores sea in 1992, 2015, and 2021. revealed that the seismic activity of eastern indonesia is thought to be influenced by the isolated thrust fault segment of the island of flores and the island of wetar. the study of the rising fault segment on flores island and wetar island helps in further understanding the fault behavior, earthquake pattern, and seismic risk in the flores sea region. in earthquakes with giant magneto, an aftershock can occur due to the interaction of ground movements. this research analyzes and compares the data from the evaluation of the classification algorithm and the regression algorithm. the initial stages of this research include requesting iris dmc web service data. the data is then subjected to a cleaning process to obtain the expected feature extraction. the next stage is to perform the clustering process. this stage is carried out to label dependent data by adding new features as data clusters. the following procedure divides the validation value, which consists of training and test data. the estimation results show that the classification algorithm's evaluation value is better than that of the regression algorithm. the evaluation value of several algorithms indicates this, with an accuracy rate between 80% and 100%. this is an open-access article under the cc–by-sa license. keywords: aftershock flores sea earthquake machine learning classification algorithm regression algorithm to cite this article: a. jufriansah, a. khusnani, y. pramudya, and m. afriyanto, “estimation of flores sea aftershock rupture data based on ai,” indones. rev. phys., vol. 6, no. 1, pp. 45–55, 2023, doi: 10.12928/irip.v6i1.6705. i. introduction flores island, indonesia, is a seismically active area [1]. pranantyo et al. [2] revealed that the seismic activity of eastern indonesia is thought to be influenced by the isolated thrust fault segment of the island of flores and the island of wetar. the study of the rising fault segment on flores island and wetar island helps in further understanding the fault behavior, earthquake pattern, and seismic risk in the flores sea region. the data is collected through seismic modeling, which is able to make predictions about the potential for future earthquakes. with a better understanding of isolated rising fault segments on flores island and wetar island, disaster mitigation efforts can improve, especially with a more effective early warning system. this is an important step to protect the public and reduce the negative impact caused by the earthquake in the region.the earthquake catalog records earthquakes of > mw 7 that have hit the flores area, three of which occurred in the flores sea in 1992, 2015, and 2021. in earthquakes with a giant magneto, an aftershock can occur due to the interaction of ground movements [3]. it is caused by an increase in the deformation mechanism (increase in stress) for a fracture area which is quantified as a change in coulomb stress failure (cfs) [4]. changing earthquake stress will encourage or inhibit seismic activity in the area. this can be proven by calculating the coulomb stress, which helps predict the location of its increase in the future. based on this, the aftershock phenomenon will often occur in areas with positive changes in coulomb stress rather than negative coulomb stress [5]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v6i1.6705 http://journal2.uad.ac.id/index.php/irip mailto:saompu@gmail.com http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 46 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 because the flores sea frequently sees intense seismic activity, it is crucial to research the aftershocks in this region. aftershocks are earthquakes that happen immediately after the first shock and frequently have a smaller magnitude [6]. but aftershocks can wreak more harm and even present a risk to places already impacted by the preceding mainshock. by comprehending aftershock patterns in the flores sea, scientists and seismologists can more accurately evaluate risk [7]. they can identify areas that could be impacted, forecast the likelihood of aftershocks, and give the immediate area early notice. the flores sea aftershocks must be better understood in order to create a more reliable early warning system. one way that this technology can warn people before aftershocks happen is by using an artificial intelligence system. machine learning (ml) algorithms are machines that can learn like humans. ml studies the system's behavior based on dataset information without requiring prior knowledge [8]. several ml algorithms that have been studied in earthquake prediction and aftershock are grouped into regression and classification algorithms. various ml architectures are presented in (figure 1). wieland et al. [9] explained that the success of ml is shown by its success in identifying earthquake damage. it is clarified by the use of svm in the japanese earthquake data in march 2011. in addition, syifa et al. [10] once compared predictive data based on the accuracy value between svm and ann. so far, there has not been much research on the aftershock hazard in the flores sea using predictive models. so, it needs to be used as an evaluation material because three large earthquakes have historically hit the flores sea. furthermore, it is essential to study the aftershock study because it can provide new information about seismogenic processes, including the location of newly active faults. several studies have succeeded in comparing several classification and regression algorithms. the evaluation process is carried out by comparing several parameters, such as the estimated value. so, this research is considered necessary in the future as a time alarm and forecast in analyzing aftershock predictions. based on the description above, the purpose of this study is to determine the estimated value of the aftershock rupture data for the flores sea earthquake based on ai. the best estimation results will provide a correction value to be used as comparison data for further investigations regarding the prediction of aftershocks. the benefits of this research are as a hope in the geohazards field and predict earthquakes with a reasonable accuracy level. figure 1. ml architecture (a) svm algorithm classification process, (b) svr algorithm work procedure, (c) k-nn algorithm decision making process, (d) k-means algorithm principle work, (e) rf algorithm classification process, (f) dendrogram hierarchical clustering algorithm, (g) the decision-making process of the dt algorithm [11]. ii. theory this relevant applications of classification and regression algorithms exist in the analysis of earthquake data [12]. in this context, classification algorithms can be used to classify earthquakes into various categories, such as shallow, medium, or deep earthquakes, based on the profundity of their epicentre [13]. in the meantime, the regression algorithm can be used to simulate the relationship between certain features, such as earthquake magnitude, depth, or epicentre distance, and certain parameters, such as building damage or vibration intensity [14], [15]. in theory, classification and regression algorithms use a variety of mathematical techniques to classify and analyse earthquake data [16]. implementing the classification algorithm on earthquake data requires data preparation, the selection of pertinent features, and the configuration of a classification algorithm model, such as svm or decision tree [17], [18]. it is necessary to collect and organise quake data from multiple sources with care in order to meet the requirements of the analysis. important characteristics, such as magnitude, depth, epicentre location, and duration, should be chosen as model training attributes [19]. to obtain optimal model performance, it is also necessary to consider the hyperparameter settings, such as c in svm or maximum depth in the decision tree [20], [21]. implementing a regression algorithm on earthquake data, on the other hand, entails similar data preparation and http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 47 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 feature selection steps [22]. to predict continuous values, such as building damage or vibration intensity, a regression algorithm, such as linear regression or svr, may be implemented [23], [24]. the application of a classification algorithm to earthquake data can yield valuable information regarding the characteristics of a specific earthquake [25], [26]. by classifying earthquakes based on depth, for instance, seismologists can comprehend the patterns and behaviour of earthquakes at specific depths and identify potential dangers in certain regions [27], [28]. in addition, the classification algorithm can aid in earthquake risk analysis by classifying areas according to their potential hazard level, allowing for more precise mitigation measures [29]. applying the regression algorithm to earthquake data enables the prediction of continuous earthquake-related values [30]. using regression, we can, for instance, predict building damage or tremor intensity based on certain earthquake characteristics, such as magnitude and epicentre distance [31]. this information can be used to assess the potential damage and impact of an earthquake in a particular location, allowing for earlier implementation of mitigation measures and disaster response plans to reduce earthquake-related risks and losses. the application of classification and regression algorithms to earthquake data contributes to a greater comprehension of earthquake patterns, the characteristics of certain earthquakes, and the potential for disaster [32], [33]. the classification algorithm aids in classifying earthquakes based on certain attributes, allowing for the identification of risks and potential dangers in certain regions [34], [35]. on the other hand, the regression algorithm enables us to model and predict earthquake impacts, such as building damage and the intensity of vibrations, so that disaster mitigation and response actions can be more precisely directed [36]. however, the implementation of this algorithm encounters obstacles in the preparation of accurate and representative data, the selection of pertinent features, and the setting of the appropriate hyperparameters [37]. in addition, earthquake data can be highly dynamic and intricate, necessitating a vigilant and ongoing analytic approach to produce accurate and useful results [38]. iii. method this study uses real-time data on the aftershock rupture of the flores sea, east nusa tenggara, which was recorded from december 14, 2021, to march 20, 2022, obtained from iris dmc web service (https://service.iris.edu). the parameters used in this study consist of latitude, longitude, depth, and magnitude data, totaling 1403 data. this research analyzes to compare the data from the evaluation of the classification algorithm and the regression algorithm. the initial stages of this research include requesting iris dmc web service data. the data is then subjected to a cleaning process to obtain the expected feature extraction it is necessary to clean up data in order to get rid of errors. this entails eliminating unimportant signals or noise, such as interference from people or equipment. clean seismic data can be processed using techniques for filtering, blending, and outlier elimination. following the identification and separation of the crucial phases, feature extraction is done to explain the pertinent seismic properties. parameters like amplitude data, frequency data, duration, or wave speed are examples of possible features. to find and extract these features from seismic data, signal processing methods and statistical analysis might be applied the procedure of normalization is then carried out. data normalization may be used in specific circumstances to guarantee consistency and accurate comparison of extracted features. by altering the scale or range of feature values, normalization can be done to make them uniform and simple to compare. dimensionality reduction is frequently required in big seismic datasets to ease complexity and accelerate analysis. using methods like principle component analysis (pca) or factor analysis, one can reduce the dataset's dimensionality while still preserving important data. a robust foundation for additional research, such as seismic modeling, subsurface structure mapping, or earthquake prediction, is provided by appropriate data cleaning and feature extraction procedures. seismic researchers and scientists can examine seismic patterns, trends, and characteristics using well-extracted features. the clustering process must be done as follows: in this stage, new features are added to the data as data clusters to label the dependent data. latitude, longitude, depth, and magnitude data are the features that have been chosen for this section. the elbow approach, also known as wcss analysis, will be used to find the best elbow graph by utilizing the sklearn cluster import kmeans library function. the outcome is then merged with the concat command in the data frame to create a new label. the validation value, which comprises training data and test data, is divided by the subsequent process. this method compares 70% training data and 30% test data using a fitting model with training data and targets. the results of the examination of the comparative analysis of the accuracy value of the classification and regression algorithms are evaluated in the final stage. details are presented in figure 2. iv. results and discussion historically, earthquake predictions have been made since the 19th century. geller [39] reviewed earthquake predictions that were divided into different timescales and could explain precursors, which were recognized in the iaspei guidelines. in the same year, uyeda [40] revealed that the earth is a seismo-electromagnetic signal and developed the van method for short-term earthquake prediction. by strengthening his report that electrical signals are not enough to be said as earthquake precursors. one of the researchers who disputed this was sevgi [41], http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://service.iris.edu/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 48 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 who revealed that the seismo-electromagnetic signal still contains much noise data. another thing to note is the local characteristics of permittivity, permeability, and background noise. however, the discussion only shows the earth's electrical signal and has not demonstrated an earthquake prediction model based on historical data. huang et al. [42] added that earthquake precursors consist of several parameters, such as seismic, geo-electromagnetic, geodesic, gravity, and ground fluid. several other parameters are input parameters, such as satellite imagery and animal behavior. researchers have developed aftershock predictions using artificial intelligence [43]–[45]. karimzadeh et al. [46], has reviewed aftershock on distribution slip, coulomb stress change at source fault, and active fault orientation to predict aftershock pattern. this study provides promising results for predicting spatial aftershocks but has not answered the predictions for the time and depth of aftershocks. main shock review the mw 7.3 earthquake that occurred in the flores sea on december 14, 2021, was recorded using the australian array (au) station with 14 seismic stations (figure 3). the data was obtained based on a bandpass filter of 0.1 hz to 1.0 hz with the cross-correlation method to 18 seismic stations. the rupture characteristics are described in (figure 4) after filtering the waveform in the pass band range between 0.1 hz to 0.5 hz and 0.3 hz to 1.0 hz. it results in a p-waveform (figure 5) with a coherent and in-phase signal. figure 2. research flow chart figure 3. sesismogram based on distance from earthquake (1 degree = ~111 km) (a) bhz 0.1 – 0.5 hz (b) bhz 0.3 – 1.0 hz figure 4. alignment process using cross correlation method start data web service cleaning feature extraction cluster no data classification algorithm regression algorithm evaluation yes http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 49 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 (a) bhz 0.1 – 0.5 hz (b) bhz 0.3 – 1.0 hz figure 5. p-coda stack with long distance (dist =30-95*) review aftershock figure 6(a) is the dynamics of rupture data for the flores sea earthquake on december 14, 2021, shown with a blue circle pattern. while figure 6(b) is the aftershock data marked with a green circle pattern. the results of the figure show the distribution pattern after the main earthquake expanded unilaterally to the west and partly to the east. aftershocks are more common in areas with a depth of 5.0 km to 17.5 km below sea level (figure 6(c)). it shows that the pattern follows the area around the main earthquake. handayani [47] has reviewed the source of the flores island earthquake. from the results of this study, it is known that normal faults dominate the flores sea. it is clarified by maneno et al. [48] that the earthquake hypocenter in the northern part of flores was dominated by deep earthquakes associated with the flores thrust zone. the southern part is more overlooked by shallow to moderate earthquakes. so far, research on the flores earthquake has only been limited to earthquake mapping and relocation. kurnio et al. [49] only describe a review of underwater landslides with the result that the trigger for the 1992 earthquake in the flores sea was an underwater landslide. the same thing was also explained by pranantyo et al. [50] regarding seismic and non-seismic hazards in indonesia, especially in eastern indonesia. then handayani [47] clarified the seismic hazard, especially in the flores sea area, which had experienced seven significant earthquakes. supendi et al. [51] explained that the aftershock study provides new information on seismogenic processes and seismic hazards in indonesia, including the location of newly active faults. therefore, several parameters need to be considered when making aftershock predictions because these will affect the performance accuracy. (a) (b) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 50 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 (c) figure 6. (a) event mw 7.3 data, (b) aftershock data, (c) aftershock distribution data between magnitude and depth classification algorithm the classification process is carried out based on the aftershock rupture data, which was previously carried out before the data cleaning process was carried out to avoid missing data. this process involves several stages, such as feature extraction to label new data as dependent data with the cluster name. feature, while the dependent variable is cluster data.this process is carried out as an initial step in determining the validation value using the cross-validation method, which will divide the data into training and test data [52]. using the wcss tool with the elbow method, we get a cluster division of 3 clusters (figure 7), followed by a classification algorithm. figure 7. elbow method the elbow approach aims to select a small k number while maintaining a low withinss value [53]. the elbow method of cluster analysis is used in this study to determine the ideal number of clusters, taking into account the comparative value (from the sse calculation for each cluster value) between the number of clusters that will form an elbow at a point, such that the sse value will decrease as the number of clusters k increases [54]. the sse formula looks like in equation (1). 2 1 21 1 k k k x sk sse x c =  = −  (1) since there are 3 clusters based on equation (1) above, use equation (2) to calculate the distance between the two objects that are closest to one another. ( ) ( ) 2 2 , 1 n x y i d x y xi yi = = − = − (2) table 1 includes the results of computations made using the elbow technique. table 1. the elbow method is used in calculating the first five data latitude longitude depth magnitude cluster -8,55 121,9184 10 3,34 3 -7,53 121,5823 10 3,11 3 -7,36 121,2343 15 2,58 3 -8,02 122,406 10 3,41 3 -7,51 121,6354 10 2,64 3 -7,53 122,1766 19,3 3,33 1 banggut et al. [4] revealed that the classification method would place objects into categories. therefore, it will depend on each classification attribute in the new data [55], [56]. there are 982 data of training data after the train-validation split, while a lot of test data after the train-validation split 421 data. the training data consists of two variables: the independent variable using the magnitude. the complete comparison of the accuracy of the classification algorithm is presented in table 2. table 2. comparison of classification algorithm accuracy values algorithm accuracy logistic regression 0.99 support vektor machine (svm) 0.98 hyperparameter svm 1. svm linear 0.99 2. svm polynomial 0.99 3. svm rbf 0.98 decision tree 1.00 hyperparameter decision tree 0.80 naïve bayes 0.46 k-nearest neighbors 0.99 regression algorithm the regression process is carried out to determine the relationship between categories or labels. in this process, the algorithms that compare the evaluation values are the decision tree regressor and the random forest regressor. the results show that both do not meet the accuracy value because the error value is very large. it is also reinforced by using the convolution matrix method (figure 8), which shows a minimal value of the relationship between attributes. marhain et al. [47], [57] have investigated the application of ai for earthquake prediction in terengganu using ml. in the report, several algorithms are compared, such as svm, random forest (figure 9), decision tree (figure 10), and logistic regression. the limitation of this research is that the data information from each station is different. so the research http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 51 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 only focuses on one station to compare the accuracy and probability values and then analyze the results. in the same year, essam et al. [58] conducted a study in the same location by comparing the artificial neural network (ann) and random forest algorithms. this study succeeded in predicting ground motion parameters, namely earthquake acceleration, earthquake speed, and earthquake depth, based on four performance criteria that were successfully evaluated. these results indicate that the ann algorithm has accuracy compared to random forest. although the proposed model has an accuracy value, it has not answered the location point for the earthquake. other researchers who use svm are [55], [57], [59], [60]. in addition to svm, earthquake prediction algorithms are often used, namely random forest [61], and neural network algorithm [62]–[64]. figure 8. convolution matrix using spearman method figure 9. random forest regressor http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 52 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 figure 10. decision tree regressor deeper insight into fault behavior and possible seismic danger can be gained by analyzing patterns and trends in aftershock data. based on already available features, classification techniques can be used to categorize aftershocks. in this instance, by examining the resulting categorization decisions, it is possible to examine the observed patterns and trends in the aftershock data. you can check to see, for instance, whether there is a spatial pattern suggesting that stronger aftershocks are more likely to happen close to the mainshock or whether there is a temporal pattern suggesting that the frequency of aftershocks increases after a mainshock of a certain magnitude. it follows that this classification analysis can help with comprehension of aftershock characteristics and associated potential dangers. this can be used to improve comprehension of the spatial and temporal distribution of aftershocks and to offer guidance in the design of plans for mitigating earthquake risk. in order to examine trends and numerical patterns in aftershock data, regression algorithms might be applied. in this instance, the generated regression coefficients can be used to assess the pattern and observed trends in the aftershock data. a tendency toward increased aftershock frequency as time passes after the primary earthquake, for instance, may be indicated by a significant and positive regression coefficient for the time variable. this regression analysis's implication is that it can aid in more precisely simulating aftershock behavior. regression analysis data on numerical trends and patterns can be used to anticipate and better understand fault behavior and potential seismic danger. v. conclusion new scenarios in the field of earthquake prediction need to be seriously reviewed. it is crucial in risk assessment as prevention and early warning in the future. however, this will be difficult to do because data availability is influenced by several factors, such as noise data affecting earthquake detectors. so to do this, it is necessary to have an initial analysis that is useful in filtering noise data so that the sensor only captures earthquake data sources, not other data. the method is through an alignment process with cross-correlation, which can produce p-waves in a coherent and in-phase signal form. it is very useful when the detector is converted into a normalized value structure to determine the estimated value. the estimation results show that the classification algorithm's evaluation value is better than the regression algorithm. several algorithms' evaluation value indicates an accuracy rate between 80% and 100%. research utilizing svm, hp-svm, and pso-svm to predict earthquakes is a challenge that must be resolved by overcoming several limitations on prediction accuracy. data constraints, which pose a significant barrier to model creation, are the primary issue. however, data augmentation and synthetic data integration techniques can overcome this limitation. in addition, careful feature analysis is required to identify the most pertinent features and eliminate the possibility of features with minimal correlation. when using optimization techniques such as pso to improve svm performance, paying special attention to how non-stationary earthquake characteristics can be incorporated into the model is crucial. as a result of these issues, the study's recommendations include the use of multiple models, particularly the combination of svm with various optimization techniques. in addition, methods for addressing the issue of rare earthquakes and feature imbalances must be further developed to improve the accuracy of forecasts and ensure their dependability in real-world situations; thus, a comprehensive evaluation of various scenarios against earthquake spatial data sets is necessary. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 45 55 53 a. jufriansah, et al. estimation of flores sea aftershock rupture data … p-issn: 2621-3761 e-issn: 2621-2889 vi. acknowledgment the researcher would like to thank the indonesian ministry of education, culture, research and technology for providing research funds through the 2022 beginner lecturer research grant scheme (pdp) under grant no. 1098/ll15/km/2022. references [1] a. jufriansah, a. khusnani, y. pramudya, and m. afriyanto, “comparison of aftershock behavior of the flores sea 12 december 1992 and 14 december 2021,” j. phys. theor. appl., vol. 7, no. 1, pp. 65–74, 2023. 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http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.3390/diagnostics12020264 https://doi.org/10.3390/j2020016 https://doi.org/10.1007/s11589-009-0315-8 https://doi.org/10.1109/jstars.2014.2321972 https://doi.org/10.1007/s11069-021-04716-7 https://doi.org/10.1016/j.soildyn.2021.106826 https://doi.org/10.1007/s12559-019-09644-0 https://doi.org/10.1007/s12559-017-9542-9 https://doi.org/10.1007/s12559-018-9615-4 https://doi.org/10.1007/s12559-018-9615-4 https://doi.org/10.30630/joiv.2.1.106 https://doi.org/10.1109/kcic.2017.8228594 https://doi.org/10.1016/j.jksus.2011.05.002 indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 61 69 doi: 10.12928/irip.v4i2.3814 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 61 evaluation of stem-based physics learning on students' critical thinking skills: a systematic literature review winarti1*, dwi sulisworo2, narentheren kaliappen3 1 department of physics education, universitas islam negeri sunan kalijaga, indonesia 2 postgraduate program of physics education, universitas ahmad dahlan, indonesia 3 school of international studies, universiti utara malaysia, malaysia email: winarti@uin-suka.ac.id article info abstract article history received: jul 24, 2021 revised: dec 14, 2021 accepted: dec 27, 2021 this article discusses the importance of stem learning in optimizing critical thinking skills in physics learning. it presents an overview of stem learning to identify, train and improve students' critical thinking skills to assess misconceptions in the science education research literature since 2010. this study published articles in primary science education journals and indexed them in the leading research database to obtain data on stem-based physics learning and critical thinking skills. to identify relevant studies in the literature, we conducted a systematic search of the two databases with the document analysis method. the investigation was limited to indonesia's studies published between 2010 and 2020 for the most recent stem-based physics learning studies and critical thinking skills based on the most recent findings. this study summarizes stem learning at the high school and the undergraduate students. the implementation of the research related to stem-based physics learning with critical thinking skills variables was in various teaching materials, learning models, and learning media. teachers taught physics concepts using the stem approach to improve critical thinking skills, including optical tools, thermodynamics, temperature and heat, dynamic fluids, and sound waves. the findings of this study can be used as a reference in the development of stem learning patterns in the realm of science and physics education to improve students' critical thinking skills, which are the demands of skills in the 21st century that students must possess. this is an open-access article under the cc–by-sa license. keywords: physics learning stem-based learning critical thinking skills misconceptions in science to cite this article: w. winarti, d. sulisworo, and n. kaliappen, “evaluation of stem-based physics learning on students’ critical thinking skills: a systematic literature review,” indones. rev. phys., vol. 4, no. 2, pp. 61–69, 2021, doi: 10.12928/irip.v4i2.3814. i. introduction many reviews on stem (science, technology, engineering, and mathematics) arose in 1990 [1]. stem in the curriculum focuses on the notion of educating learners in four integrated disciplines. they are science, technology, engineering, and mathematics with an interdisciplinary and application approach [2]. stem is a science discipline and curriculum with science, technology, engineering, and mathematics. the acronym stem was introduced in 1990 by the science administrator of the national science foundation (nsf) of the united states of america [3]. previously, the organization used the term stem when referring to a particular discipline's career field or an integrated scienceskill curriculum. in 2001, an nsf's biologist, educational, and human resource director assistant named judith ramaley in america re-arranged words and created an acronym of stem [4]. since the moment, any stemfocused curriculum has widely spread outside of the united states of america. the curriculum has specifically developed programs based on the areas such as asia, australia, china, france, southern korea, taiwan, and english [5]. the findings of international studies, such as timss (trends in international mathematics and science study), are regularly researched on an international scale to compare mathematics competence and cognitive science achievement of fourth and eighth graders [6], [7]. on the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 61 69 62 winarti, et al. evaluation of stem-based physics learning on students’ …. p-issn: 2621-3761 e-issn: 2621-2889 other hand, pisa (program for international student assessment) promotes a three-year assessment of the cognition and skills of learners aged 15 years [8], [9]. the findings obtained by pisa have also been carried out by several researchers who researched the implementation of the stem learning approach among high school students. many high school students are still stuck in participating in integrated learning simultaneously by prioritizing aspects of science, technology, engineering, and mathematics [10]. moreover, each student has a dominant ability in only one aspect. however, this is not a significant problem in implementing stem-based physics learning for high school students. in studying physical phenomena, students must master mathematical abilities [11]. in addition, students also need to adapt to technology and engineering to solve any existing physics problems. that is, stem learning in physics can strengthen students' mathematical, technological, and engineering abilities [12]. it can also support the implementation of learning in other science groups such as chemistry and biology. chemistry and biology learning in the future will certainly be related to each other with physics, which must prioritize understanding mathematical concepts to discuss these phenomena [13]. the stem learning approach can optimize students' abilities in learning physical chemistry and physical biology by prioritizing strengthening mathematical abilities and mastering technology to help understanding and problem solving [14]. the stem approach does not significantly impact if its implementation is carried out on arts and socialhumanities learning whose scientific basis does not require students to understand mathematical abilities. however, the stem learning pattern that is carried out by combining several disciplinary approaches can also be used to optimize students' abilities in learning arts and humanities if the implementation of learning is integrated with similar branches of science [15]. thus, educators need to improve the implementation of learning that integrates several sciences or expertise so that students can grow various views in dealing with each problem. in physics learning, every educator and student needs to synergize in applying physics and mathematics learning simultaneously because mathematics cannot be separated from physics and as a step in implementing the stem approach according to learning objectives [16]. furthermore, some teachers integrate project-based activities that require cognitive and psychomotor implementation in certain areas, such as engineering. in some instances, extracurricular activities are included as team competitions. they can be added together or extended for a specific purpose. undergraduate students also have the opportunity to spend their time with stem experts regarding the availability of on-the-job training programs [17]–[20]. stem has often been studied to measure, improve, and train students' critical thinking skills [21]–[26]. in addition, teachers can apply stembased learning to train, improve, and measure students' creative thinking skills at various levels [27]–[30]. integrated stem learning can improve critical thinking skills [31]–[35]. this finding is also by the findings in physics learning which shows that physics learning carried out by integrating the traditional game-based stem approach can improve students' critical thinking skills [36]. this can happen considering that physics learning is fun for students. students feel enjoy during learning, and they actively question every physical phenomenon that occurs in real or virtual traditional games through simulations [37]. simultaneously integrating science, technology, engineering, and mathematics in physics learning raises student curiosity in responding to every physical phenomenon from various points of view and is properly accommodated [38]. students often question every narrow gap from every discussion of physics material delivered by the teacher. this is one of the indicators that physics learning is by the learning objectives and can grow students' critical thinking skills [39]. however, some findings show that the stem approach does not really contribute to optimizing students' critical thinking skills [40]. thus, the success factor in optimizing students' critical thinking skills through stem learning is not only from the draft learning guidelines that have been compiled. however, what is far more important is the teacher's ability to identify student needs, classroom mastery skills, physics and stem concepts mastery skills, and problemsolving skills by integrating various stem concepts. this review of contrasting findings is very important in stembased learning and the correlation of critical thinking skills in high school physics learning. this study chose critical thinking skills as a variable because stem learning is strongly correlated with skills to address each problem indepth and accurately. moreover, mastery of critical thinking skills by mastering technological advances, engineering, science, and mathematics is very much needed in the development of the 21st century [41], [42]. in its correlation with the critical thinking skill of physics lessons, stem has specific features. physics learning is strongly correlated with physics concepts with its mathematics language as the mean [41]-[43]. learners would understand the contextual process of physics concepts around their surroundings [44]–[46]. for example, learners that listened to accident news on the road. they might explain the accident using momentum and impulse concepts between two collided objects. another example could be a crashed object. teachers might apply mathematics calculation to identify which one was the victim. in the academic setting, students could create reconstructions optimally. thus, it is possible to improve learners' physics understanding and their learning achievements. furthermore, this study aims to examine the importance of stem learning to optimize students' critical thinking skills in learning physics. this article also presents an overview of stem learning to identify, train, and improve students' critical thinking skills to comparatively assess misconceptions in the 2010s science http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 61 69 63 winarti, et al. evaluation of stem-based physics learning on students’ …. p-issn: 2621-3761 e-issn: 2621-2889 education research literature. the significance of the research relates to its contribution to the literature by describing stem learning and critical thinking skills, especially in physics learning in indonesia. in addition, this study also briefly compares stem learning and critical thinking skills learning in general by considering indonesia's strengths and weaknesses. researchers apply stem correlation analysis and critical thinking skills to enrich the literature on stem-based physics learning, focusing on achieving student competencies in a comprehensive, focused, and based on actual needs. ii. theory stem stem learning combines elements of science, technology, engineering, and mathematics simultaneously in learning at the basic education level to higher education [47]. the implementation of stem learning is mostly done in the science family, such as physics, chemistry, biology, and science. although it is undeniable that the stem approach can also be carried out in social humanities learning if it still integrates the relationship between learning objects and real problems that occur in students' daily lives [48]. meanwhile, the stem approach is a learning approach that can teach two or more stem subjects related to holistic and comprehensive learning activities that can optimize students' critical thinking skills [49]. therefore, stem is a learning approach that is often used to optimize some students' abilities so that they can be more adaptive to the problems that occur that must be faced from various perspectives. stem education that is implemented in physics learning can make students more concerned about the physics material they are learning, which has an important role in solving every problem that occurs in everyday life [50]. implementing stem learning certainly requires effective strategies and patterns so that learning and students go hand in hand and foster meaningful learning for students [51]. furthermore, creating a strategic approach to integrating stem learning in physics requires resources, analysis of student needs, and a strong conceptual understanding of student characteristics, physics material, and stem learning patterns [52]. stem-based education could develop meaningful learning via systematic and integrated knowledge, concept, and skill [53]. it could also improve scientific literacy, motivation, investigation skill, experience, and critical thinking skills. stem emphasizes all aspects of learning. stem practice involves posting questions and defining problems. develop and use planning models and activities to promote research. analyze and interpret data with mathematics, information, and computer technology. interpret and design solutions, including evidence-based arguments, arrange conclusions, evaluate, and communicate the process [54]. meanwhile, the purpose of stem is to develop skills for students to be applied in various situations and various problems of everyday life. stem-based learning aims to create students with a balance of hard skills and soft skills. critical thinking skills several findings indicate that critical thinking skills have a relationship with problem-solving abilities. the findings state that problem-solving skills require students to think critically [55]. learners with critical thinking skills can actively solve problems [56]. realizing critical thinking skills in learning demands to explain, generalize, conclude deductively, and determine an accurate way. demands of students to solve a problem. demands students to understand how to find ideas, recognize the need for new knowledge, and determine possible steps applied to solving data collection and knowledge learning problems. requirements to promote fair and objective judgment [57]. critical thinking skills allow learners to analyze information, post arguments and supportive evidence, think widely with posting hypotheses, investigate to prove a phenomenon, and obtain new information [58]. furthermore, optimizing students' critical thinking skills in learning can help students understand themselves and understand their ability to think deeply about the narrow gaps of a problem or phenomenon that occurs [59]. students who are accustomed to always prioritizing critical thinking skills towards any phenomena or problems they face will become individuals who do not easily believe in news or information that has no clear evidence of clarity [60]. optimizing critical thinking skills in students is influenced by several things such as learning styles, implementation of learning, ability to understand concepts, and problem-solving abilities [61]. therefore, it can be concluded that critical thinking skills are deepthinking skills that can question and contradict all kinds of narrow gaps from every existing problem so that new insights that are full of accuracy emerge. iii. method in this case, the investigation took articles published in the science-education journal and indexed journal outlets. it was to obtain the data of stem-based and critical thinking skill learning on physics. the researchers applied systematic searches from two databases (google scholar and science direct) with a document analysis method to identify relevant literature studies. the two databases contain various scientific articles published by various reputable journals, especially scientific articles from indonesian researchers. in addition, the keywords that we used during the search for scientific articles were the stem approach in learning physics and the effect of stem on critical thinking skills in learning physics. the limitation search was on indonesian language studies published between 2010 until 2020. it was to get physics learning studies based on the latest stem and critical thinking skills. the multistage process was followed by reading each article. all information from the reports was identified and discussed with the experts. after placing http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 61 69 64 winarti, et al. evaluation of stem-based physics learning on students’ …. p-issn: 2621-3761 e-issn: 2621-2889 1940 articles with the applied keyword, abstract, only 116 articles revealed their focuses on stem in physics learning, the correlation to critical thinking skills, and the given treatment. there was an iterative process during the article searches. each obtained article reference list was added as a new reference source. the accepted articles were comprehensively investigated within physics learning based on stem and critical thinking skills. a general discussion about stem and critical thinking skills compares the articles' strengths and weaknesses. figure 1 illustrates the study flow of the searching and selecting processes. figure 1. research flow iv. results and discussion the researchers grouped the research article percentage based on the population levels and the learners' samples to determine the distribution of stem-based physics learning and its correlation toward critical thinking skills. considerations for selecting the population and sample in this study are the results of research that has been published in various national journals using populations and samples from high school students during physics learning using the stem approach with the main aim of optimizing their critical thinking skills. furthermore, table 1 shows the percentage of research results in stembased physics learning and critical thinking skills of indonesian students. table 1. the percentage of the stem-based physics learning research and critical thinking skills of indonesian students no. education level numbers percentage (%) 1 senior high school 71 61 2 undergraduate 45 39 table 1 shows that teachers have promoted stembased physics and critical thinking skill learning in indonesia in senior high schools (61%). it is higher than the university level, precisely the undergraduate degree (39%). physics lessons included a foundation of science and biology at the junior high school level. therefore, it was excluded from this research category. physics lessons had thematic learning and primary science and other studies discussions at the primary school level. it was excluded for this stem level category on this research review (it did not meet selected articles' criteria). physics learning at senior high school or university levels had been an integral part of a lesson or a course. it showed that teachers focused physics learning at the university level on specific and comprehensive physics discussions. there were widely many studies about stem at this education level. unconsciously, stem had existed in physics learning at university levels, such as fundamental physics (science), instrumentation (technology), laboratory praxis (engineering), and calculus (mathematics). at senior high school levels, physics learning was still following conservative curriculum patterns. the changes are due to the government policy revitalization. it promoted comprehensive research on stem-based physics and critical thinking skill learning at the senior high school level than the university level. similar-themed article findings from other countries supported indonesia's article review findings [3], [10], [12]. table 2 shows that stem-based physics and critical thinking skill learning in indonesia were mostly applied to learning models to teach physics (59%). the following result is stem-approach implementation on physics learning media based on stem with a percentage of 24% and the performance on stem-based physics teaching material with 17%. the stem approach implementation on the learning model could be purely applied or in an integrated manner. for example, the integrated applications of stem were project-based learning, problem-based learning, and 5-cycle of learning. the stem approach component implementations on learning materials were such as learners' worksheets. they were reflected on the lesson plan arrangement and observable during learning syntaxes. the stem approach implementation on learning media consisted of visual media (powerpoint) and audiovisual media (video). table 2. the implementations of stem and critical thinking skill approaches no. the implementations on the learning numbers percentage (%) 1 stem-based physics learning materials 20 17 2 the model of stembased physics learning 68 59 3 stem-based physics learning media 28 24 table 2 describe stem approach implementation that could be the basis of developing media, models, and learning material. the most frequent performance was on learning model development from one hundred sixteen http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 61 69 65 winarti, et al. evaluation of stem-based physics learning on students’ …. p-issn: 2621-3761 e-issn: 2621-2889 articles. the stem-based physics learning development could be a specific syntax (as the pure stem approach and syntax). on the other hand, it could be integrated with other existing models proven effective for learning physics. one of the researches was the integrated stembased learning model with project-based learning model. teachers facilitated learners to design and realize the projects based on the teachers' already taught physics concepts as facilitators. the learners should follow the stem-based learning syntax with the pjbl model. it made learners understood the essence of physics and the mathematics language instead of a mere physics concept and vice versa. learners who could work on mathematics-physics problems would be more able to analyze the contextual phenomena physically. their trained critical thinking skills were based on stem syntax [62]. investigations on stem-based physics learning and its pjbl integration to improve critical thinking skills in other countries supported this finding. han et al. [63] dan verma et al. [64] found that learners could be better motivated with pjblstem than those high-achievement learners with low critical thinking skills and achievements. a longitudinal study would allow researchers to get more data about the influences of stem-pjbl integration on learners' critical thinking skills. although teachers, as the facilitators, could not control each factor, the influential critical factor had significant influences on learners' learning achievements based on the improved critical thinking skills. various articles cited stem-based physics learning varied in terms of the levels, implementations, and physical concepts. in the first article in table 3, the researchers developed the learner worksheet with the stem approach on the learning flow and syntax to improve learners' critical thinking skills. the worksheet results based on the stem approach proved that it could improve the learners' critical thinking skills. the same results were found in the second until the fifth research shown in table 3. the stem approach could influence the critical thinking skill of the learners. the findings of stem-based physics learning, summarized in table 3, had the same objective. it was to improve the learners' critical thinking skills. however, they might have different implementations, such as the learners' worksheets, the integrated project-based learning and stem, and stem assisted by thinking map media on the guided inquiry learning model. table 3 shows the research varieties about stembased physics learning on physics concepts, such as optical instruments, sound waves, dynamic fluids, thermodynamics, temperatures, and heat. the first reference was the worksheet development based on the stem approach [65]. the developed worksheet could improve learners' critical thinking skills. the second and third references showed similar things. implementing stem-based learning could improve learners' critical thinking skills [15], [66]. the fourth research developed project-based learning with a stem approach. before the intervention, the learners' critical thinking skills were categorized low. however, after being intervened, the learners' critical thinking skills improved into a moderate category [62]. the fifth reference also obtained the same thing. the stem-based physics learning development assisted by thinking map media during a guided-inquiry model could improve the learners' critical thinking skills [67]. the findings of the articles in table 3 represent the findings of stem-based physics learning studies on physics concepts, such as temperatures and heat, thermodynamics, sound waves, dynamics fluids, and optical instruments. it showed that reviews about the theme had a diverse nature. stem learning was proven to have a better implication on physics learning's critical thinking skills in indonesia. it was in line with several types of research in other countries. they also summarized the stem learning for physics lesson [68]–[72]. stembased learning could improve learners’ critical thinking skills. table 3. stem-based physics learning reference to improve critical thinking skills no. physical concept research findings reference 1 optical instrument the learners’ worksheets with the stem approach could improve critical thinking about optical instruments. (lestari, astuti, & darsono, 2018) 2 sound waves implementing the stem learning approach could improve learners’ critical thinking skills. (khoiriyah et al., 2018) 3 dynamic fluids the findings showed the influence of stem learning on conceptual masteries and learners' critical thinking skills about dynamic fluid. (rivai, yuliati, & parno, 2018) 4 thermodynamics the results showed moderate improvement category of scientificcreative and critical thinking skills after being taught with project-based learning and stem approach. (cholisoh, 2019) 5 temperature and heat stem assisted by thinking maps on a guided-inquiry learning model significantly influenced the learners’ critical thinking skills about the materials. (wastiti & sulur, 2020) the syntax of stem-based physics learning is as follows. 1) planning and promoting class sessions by involving all learners actively, no matter how large the class was; 2) using the technology properly during face-tohttp://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 61 69 66 winarti, et al. evaluation of stem-based physics learning on students’ …. p-issn: 2621-3761 e-issn: 2621-2889 face, online, hybrid, and blended courses; 3) assessing the cognitive, psychomotor, and conceptual understanding performances of learners to learn the lessons, 4) facilitating learners to develop excellent problem-solving and communication skills, to develop creative thinking, critical thinking, cooperation, and autonomous learning; and 5) providing the stem learners with various attributes and broader background. educating learners with stem lessons (if the teacher taught correctly) could prepare them to engage with their future lives despite their preferred profession later. the findings could show learners the importance of critical thinking and creative thinking skills to solve problems. the skills are also important in their lives when they encounter challenges. the researcher also suggests applying stem-based contextual learning to solve 21stcentury challenges. thus, integrating stem and critical thinking skills are important to create meaningful and joyful learning. v. conclusion the multistage process of this research had eliminated 1940 articles about stem-based learning. they were initially identified based on the title, abstract, and keyword. at the end of the article selection based on the whole content, relevance, range of years from 2010 until 2020, limitation on physics learning, and indonesian language articles. the research consisted of 116 items that the abstracts showed research focuses on stem in physics learning and its correlation to critical thinking skills and the interventions. the findings showed the stem implementation at senior high school and the undergraduate levels, especially in indonesia. besides that, any related research about stem-based physics with critical thinking skills showed the performance of learning materials, learning models, and various learning media. teachers applied the physics concepts using a stem approach to improve the critical thinking skills on optical instruments, thermodynamics, heat and temperatures, dynamic fluids, and sound waves. this study still has several limitations, such as the main reference source used as the primary source of research is still limited from research results from indonesia. the research results from indonesia used in this article are also not entirely, or the majority have not been from reputable international journals. therefore, further research is needed that can overcome the problems of this research by increasing the variety of research results in terms of geography, such as comparisons with countries in the southeast asian region or asian countries. further researchers also need to use reference sources from scientific articles that have been published in various reputable international journals so that their usefulness can be applied universally. vi. acknowledgment universitas islam negeri sunan kalijaga, universitas ahmad dahlan, and universiti utara malaysia who facilitate the access of all reports. references [1] n. r. council, “successful k-12 stem education: identifying effective approaches in science, technology, engineering, and mathematics,” washington, dc, 2011. 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https://doi.org/10.12973/eu-jer.8.3.753 https://doi.org/10.1007/s10763-016-9723-0 http://dx.doi.org/10.1111/j.1949-8594.2012.00101.x microsoft word 4217 template indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.2, december 2021, pp. 76 86 doi: 10.12928/irip.v4i2.4217 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 76 meta-analysis of the effect of the discovery model in physics learning on critical thinking ability and knowledge competence of high school students annisa n*, asrizal, fatni mufit magister of physics educations, universitas negeri padang email: annisa.1754@gmail.com article info abstract article history received: jun 12, 2021 revised: dec 08, 2021 accepted: dec 14, 2021 21st century education requires students to have the competence and ability to think critically, especially in learning physics. so we need an appropriate learning model, one of which is the discovery model. in fact, there are still many teachers who cannot choose the right learning model, so students cannot develop their competence and critical thinking skills. the solution is to analyze the effect of the discovery model on students’ critical thinking skills and knowledge competencies in terms of the type of discovery model and physics material. the articles were analyzed from 16 relevant articles originating from international and national articles. based on the analysis that has been done, four research results were obtained. from the four research results, it is known that the discovery model in terms of the type of discovery model and physics material influences students’ critical thinking skills and knowledge competence. this is an open-access article under the cc–by-sa license. keywords: meta-analysis discovery model physics learning critical thinking ability knowledge competence to cite this article: a. n, asrizal, and f. mufit, “meta-analysis of the effect of the discovery model in physics learning on critical thinking ability and knowledge competence of high school students,” indones. rev. phys., vol. 4, no. 2, pp. 76–86, 2021, doi: 10.12928/irip.v4i2.4217 i. introduction the development of science and technology in the 21st century has greatly influenced education. 21stcentury education is a matter of knowledge, skills, attitudes, and mastery of science and technology integrated into education [1]. education in the 21st century is very important in ensuring students have the ability to think [2]. the ability to think is expected to be a provision in solving the problems they face as well as innovating and changing their mindset [3]. one of the thinking skills required in 21st-century education is the ability to think critically. critical thinking ability measures the level of achievement in managing students’ thinking in learning. critical thinking ability is an ability possessed by a person in scientifically solving difficult problems [4]. with critical thinking skills, students can examine the thinking process and evaluate implied thoughts from what they hear and read [5]. the ability to think critically is useful so that students can solve problems by digging up information about problems related to the real world [6]. critical thinking skills involve analysis, synthesis, evaluation, and concepts [7]. thus, students’ critical thinking skills need to be developed, especially in learning physics. physics studies are learning that is related to natural phenomena. by studying physics, students can understand concepts, solve problems independently, and relate to everyday life [8]. in learning physics, students can also develop critical thinking skills [9]. the learning model needs to be applied to achieve learning objectives [10], especially in improving students’ critical thinking skills. therefore, choosing the right learning model in learning physics is necessary. the discovery model is one of the learning models that can be used in learning physics. this discovery model is a learning model that improves students’ critical thinking skills [11]. by using the discovery model, students can build their knowledge with scientific experiment activities [12]. model discovery is divided into two types: the discovery learning model and the guided discovery model [13]. first, the guided discovery model is a model that requires the teacher’s role as a facilitator and guide during the learning process [14]. the model-guided discovery will actively involve students and provide opportunities for students to do it themselves, following a process, starting from observing, analyzing, proving, and drawing conclusions related to a problem [15]. but on the indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 77 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 guided discovery model, the teacher’s role is still very much needed. the role of the teacher here is as a guide and facilitator who can help direct students in solving problems and finding concepts [16]. second, the discovery learning model is a discovery model without any direction and instructions from the teachers so that students can solve their problems [17]. the discovery learning model refers to a confusing situation so that later students will be encouraged to analyze the problem and find the solution to the problem itself [18]. with the encouragement of curiosity about problems, students can develop thinking skills, improve their cognitive abilities, and form more complex knowledge later. in fact, several problems were found at school, which were obtained from several articles that were found. first, the teacher does not provide opportunities for students to be active so that students are less involved in the concept discovery process independently [19]. second, the lack of experimental activities in schools so that students are less than optimal in understanding the physics material that has been given by the teacher [20]. third, learning is not varied, which makes it difficult for students to develop their critical thinking skills [21]. from the problems that have been described, a solution can be found to overcome these problems. the solution is to analyze how much influence the discovery model in learning physics has on students’ critical thinking skills and knowledge competencies. to support this research, relevant sources are needed and come from international & national journals. the difference between this research and other studies is that this research was conducted by analyzing the effect size of the data from the research results of 16 relevant previous articles and summarizing them into one. it is useful to see the effect of the discovery model on students’ critical thinking skills and knowledge competencies. the analysis was carried out regarding the type of discovery model and physics learning material. the problem in this research is how is the effect of the discovery model on critical thinking skills in terms of the type of discovery model? how is the effect of the discovery model on knowledge competence in terms of the type of discovery model? how is the effect of the discovery model on critical thinking skills in terms of physics learning materials? and how is the influence of the discovery model on knowledge competence in terms of physics learning material. this research aims to determine the effect size of the discovery model’s influence on critical thinking skills in terms of the type of discovery model, the effect of the discovery model on knowledge competence in terms of the type of discovery model, the influence of the discovery model on critical thinking skills in terms of physics learning materials, and the influence of the discovery model on knowledge competence in terms of physics learning materials. for the research to be more focused and unidirectional, it is necessary to limit the problem. the limitation of the problem in this research consists of three limitations. first, the articles analyzed in this research are from 2016 to 2021. second, the moderator variable in this research is only limited to the type of discovery model and physics learning material. third, the related article contains the components needed to find the effect size, the t value, and the number of students or articles with an average value and standard deviation. ii. method meta-analysis one type of research that is included in the literature review is meta-analysis. meta-analysis is research that uses statistical methods to analyze research data [22]. meta-analysis is included in quantitative research [23]. meta-analysis itself can be interpreted as a quantitative analysis carried out on large amounts of data into a meaningful conclusion [24]. mets-analysis can also be defined as summarizing several relevant previous studies, then analyzing to conclude [25]. thus, meta-analysis can be an analysis on top of an existing analysis to draw a meaningful conclusion. meta-analysis has several purposes. first, it is useful to increase the statistical power of research results. second, to obtain an effect size to see the relationship or difference in terms of several moderating variables. third, overcome the uncertainty or differences in relevant research results [26]. therefore, meta-analysis can strengthen and clarify the different results of previous studies. meta-analysis consists of several steps. first, determine the research topic. second, choose the type of publication. third, collect relevant articles. fourth, record research data. fifth, calculate the effect size of each article and analyze the research results. sixth, summarize the research results and make a report [25]. this step makes the research more focused and structured. the meta-analysis also has advantages and disadvantages. the advantages of the meta-analysis are that it can combine several previous research results quantitatively, provide a good overview between research results, and minimize differences in relevant research results. the disadvantage of the meta-analysis is that the sample used must be large (> 10) and allows biased samples and unnecessary data [22]. thus, meta-analysis is only suitable for larger data and can reduce differences in the results of previous relevant studies. model discovery one of the learning models in 21st-century education is the discovery model. the discovery model is a learning model focused on a concept discovery [11]. the discovery model can be defined as directing students to find their knowledge independently [12]. model discovery involves students in direct discovery [11]. thus, the discovery model is student-centered to find knowledge and concepts independently. the discovery of the model is divided into two types. first, model-guided discovery. the guided discovery indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 78 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 model is a learning model that is carried out with the teacher’s guidance [15]. this model is defined as a model that can guide students in exploring information to build new ideas through a real experience [27]. this guided discovery model can also be interpreted as supporting students to obtain information to build their competencies and abilities and discover concepts and principles of a material with the teacher’s guidance [28]. therefore, this guided discovery model is one of the models that can construct the competencies possessed by students and is guided directly by the teacher. both models are discovery learning. discovery learning this model is a model that learns to explore its knowledge so that students can find and understand it themselves [5]. this model can support students in discovering knowledge that they do not know in depth [29]. thus, this model can support the encouragement of thinking skills and competencies possessed by students. the discovery learning model and the guided discovery model have their respective advantages. the advantages of the guided discovery model, which are obtained, are long-lasting and easy to apply to new conditions, improves students’ reasoning and thinking skills, and increases creativity and problem-solving skills [15]. the advantages of the discovery learning model are that students gain knowledge individually so that it is easy to increase motivation, increase student confidence, provide opportunities for students to develop according to their interests, and prepare mentally to explore real knowledge. thus, we must choose the right discovery model according to learning needs. the two discovery models have significant differences. in the guided discovery model, learning is carried out with the teacher’s guidance. this means that students’ competence and thinking skills are successful because of guidance from the teacher. while in the discovery learning model, learning is more centered on students seeking their knowledge [30]. therefore, the discovery learning model will challenge exploring student knowledge more than the guided discovery model. physics learning physics is one of the subjects studied in sma/ma. physics is a science whose aim is to study the components of matter and their interrelationships. physics can be said to be the foundation of science because physics includes basic knowledge from all fields of science [31]. physics can be interpreted as a science that provides a direct experience to understand the natural surroundings and develop their competence abilities [32]. based on some of these opinions, it can be said that physics is a part of natural science that examines the nature and characteristics of objects and phenomena in nature so that students can explore them directly to stimulate their competencies. physics learning is one of the lessons taught to high school/ma students. physics learning contains four components of knowledge that are explored through scientific activities to shape students’ thinking skills [33]. physics learning can be defined as obtaining information through empirical methods logically and systematically [34]. learning physics trains students to apply learning materials in everyday life. so, learning physics is learning that is carried out scientifically and systematically and contains the linkage of four aspects of knowledge related to natural concepts. knowledge competence the term competence will be familiar in the field of education. competence itself can be interpreted as a person’s ability to determine something [35]. competence can also be defined as an ability needed by someone to carry out learning [36]. competence is an ability that consists of three aspects, namely knowledge, skills, and readiness [37]. so, competence is a measure of a person’s ability to do something that includes attitudes, knowledge, and skills. one of the competency achievements that will be discussed is knowledge competence. knowledge competence is a level of achievement of student learning outcomes in terms of knowledge [37]. knowledge competence can be defined as an assessment to measure student achievement in the knowledge aspect of understanding a learning concept [36]. knowledge competence includes remembering, memorizing, understanding, applying, analyzing, and evaluating [38]. thus, the measurement of student knowledge competence needs to be carried out to see the limits of student achievement to master and understand the learning material. critical thinking ability one of the skills required in 21st-century education is the ability to think critically. critical thinking can be defined as rational, directed, and orderly thinking to analyze, evaluate, and make decisions in solving problems [32]. critical thinking is a complex thought that considers many aspects [39]. critical thinking can also be interpreted as a way for students to solve problems logically, systematically, carefully, effectively, and efficiently [40]. thus, critical thinking is a complex thought to solve a problem. critical thinking skills are highly demanded to solve problems, especially physics. with critical thinking skills, students can analyze problems systematically [39]. in addition, students can also determine the cause and effect of the problems found [5]. this happens because critical thinking skills involve higher-order thinking skills. critical thinking ability is not an innate ability, so this ability can be trained and developed through learning at school [41]. thus, students must face life problems and solve them to improve their critical thinking skills. critical thinking ability consists of several indicators. the indicators for critical thinking skills are formulating questions, answering questions with tentative assumptions, seeking solutions, providing further explanations regarding the solutions provided, and concluding [42]. therefore, students’ critical thinking indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 79 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 skills can be measured by referring to critical thinking indicators. iii. method this research is a type of meta-analysis research. the meta-analysis aims to measure how big the effect size of the discovery model is on students’ critical thinking skills and knowledge competence in learning physics. the metaanalysis data is quantitative and is carried out statistically by summarizing the results of many previous studies. in the process, the meta-analysis is carried out in several steps. first, determine the research topic to be raised. the topic in this research is a meta-analysis of the influence of the discovery model in learning physics on students’ critical thinking skills and knowledge competence. second, choose a publication that is accredited with sinta. this is because to support the demands of education in terms of the publication of sinta accredited journals. third, collect journals that are relevant to the research topic. fourth, record and process metaanalysis data and make reports. the articles in this meta-analysis came from international and national journals. the number of articles analyzed were 16 articles on the influence of the discovery model in learning physics on students’ critical thinking skills and knowledge competencies from 2016 to 2021. the identity of the articles can be seen in table 1. the variables in this research are divided into three. first, the independent variable is a discovery model. second, the dependent variable is in the form of critical thinking skills and student knowledge competencies. third, the moderator variable is the type of discovery model and physics learning material. the analytical technique used is a quantitative approach. the research data used was taken based on the data already in the article. the effect size calculations can be determined in the following statistical parameters. a. pretest-posttest mean and standard deviation. presd prexpostx es   (1) information: es = effect size x̄ post = average posttest x̄ pre = average pretest sd = standard deviation b. mean and standard deviation of two groups post-test only. csd cxexes   (2) information: es = effect size x̄ e = average of the experimental group x̄ c = control group average sdc = standard deviation of control class c. the mean and standard deviation of the two groups pre-posttest     postcsdpreesdprecsd cpre xpostxepre xpostx es    (3) information: es = effect size x̄ poste =average posttest experimental group x̄ pree =average pretest experimental group x̄ postc = mean posttest control group x̄ prec = control group pretest average sde =standard deviation of the experimental group sdc = standard deviation of the control group d. if the standard deviation is not known, it can be done with the t-test. cnen tes 11  (4) information: es = effect size t = t test result n e = number of experimental groups after the effect size is calculated based on the appropriate formula, then the effect size is categorized at the following levels in table 2: table 2. effect size criteria [54] no es category 1 2 3 4 5 es ≤ 0.15 0.15 < es <0.40 0.40 < es <0.75 0.75 < es <1.10 es > 1.10 can be ignored low moderate high very high iv. results and discussion the results of this research are grouped into four parts. first, the effect of the discovery model in learning physics on students’ critical thinking skills in terms of the type of discovery model. second, the influence of the discovery model in learning physics on the competence of students’ knowledge in terms of the type of discovery model. third, the influence of the discovery model in physics learning on students’ critical thinking skills in terms of physics learning material. fourth, the effect of the discovery model in learning physics on students’ knowledge competence in terms of physics learning material. the explanation of each research result is as follows. indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 80 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 table 1. article title and identity code article title identity ct[43] the effect of experimental skills toward senior high school students’ critical thinking abilities through discovery learning model author: laili komariah & mira karimah year: 2018 journal name: advances in social science, education and humanities research ct[18] the influence of the discovery learning learning model on critical thinking ability viewed from the learning style of class xi science students at sman 4 bantaeng author: andi fitriani hafrah, a. muhammad, a. kaharuddin year: 2021 journal name: makassar state university journal ct[44] the effectiveness of the discovery learning model with brainstorming on students’ critical thinking ability author: nurhasanah, & djukri year: 2019 journal name: educational journal ct[45] students’ critical thinking ability through discovery learning assisted with physics teaching materials based on scientific approach author: candra dewi, budi astuti, sunyoto eko nugroho year: 2018 journal name: unnes physics education journal ct[46] the effectiveness of physics learning online based on guided discovery models to improve critical thinking skill author: eko mhd ramadan, jumadi jumadi, dwi ulan rahmawati year: 2020 journal name: advances in social science, education and humanities research ct[47] effectiveness of web-based simulation integrated with guided discovery learning to enhance students’ critical thinking skills in physics author: riki perdana, riwayani, jumadi, & dadan rosana year: 2019 journal name: advances in social science, education and humanities research ct[48] application of the guided discovery model to improve critical thinking skills on heat material at khadijah high school surabaya author: adnin ulfa yunianti, setyo admoko year: 2016 journal name: journal of physics education innovation ct[49] application of guided discovery learning model to enhance critical thinking skills on secondary grades class of students sma n 9 pekanbaru in learning physics author: rahman bimantara, muhammad nasir, m. rahmad year: 2016 journal name: student online journal (jom) in the field of teacher training and education kp[16] application of virtual laboratory assisted discovery learning to improve physics competence of high school students. author: masril, hidayati, yenni darvina year: 2018 journal name: science education research journal kp[50] the effect of phet media assisted discovery learning model on physics learning outcomes of class xi students of sman 1 kediri academic year 2017/2018 author: hamidah lidiana, gunawan, muhammad taufik year: 2018 journal name: journal of physics and technology education kp[20] application of the discovery learning learning model to improve physics learning outcomes on business and energy materials for class x mia2 students at sma negeri 3 sampolawa even semester year 2018/2019 author: candra dewi, la tatang, muhammad yuris year: 2020 journal name: journal of physics education research kp[17] the effect of discovery learning model on students learning outcome at sma muhammadiyah 09 author: rahmi nazliah, et al year: 2020 journal name: international journal of innovative science and research technology kp[51] the effect of guided discovery learning models in improving student learning outcomes on the main material of straight motion in class x semester i sma negeri 3 binjai tp 2017/2018 author: setrie frimayri and abd.hakim s year: 2018 journal name: journal of physics learning innovation kp[52] guided discovery learning model to improve learning outcomes and scientific attitudes of learners in physics subjects class xi author: suciarsy year: 2018 journal name: journal of physics education, university of muhammadiyah makassar kp[15] the effect of guided discovery learning model on physics learning outcomes of class xi students of man 1 palu author: sugeng wibowo, h. amiruddin hatibe and marungkil pasaribu year: 2020 journal name: online creative journal kp[53] the effect of collaboration-based guided discovery learning model with flash media on science process skills and high cognitive learning outcomes of physics high school students author: erna pardede, motlan, retno dwi suyanti year: 2016 journal name: journal of physics education indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 81 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 the effect of the discovery model on critical thinking ability in terms of the type of discovery the first research results are the effect of the discovery model in physics learning on critical thinking skills in terms of the type of discovery model. the discovery model found in the article is divided into two types: a discovery learning model and the guided discovery model. of the 8 articles found, 4 articles used the discovery learning model, and 4 used the guided discovery model. the average value of effect size in terms of the type of discovery model is presented in table 3. table 3. the effect size of the discovery model on critical thinking ability viewed from the type of model discovery model type discovery journal code es average es information discovery learning guided discovery ct[43] ct[18] ct[44] ct[45] ct[46] ct[47] ct[48] ct[49] 1.98 1.13 0.52 0.84 1.67 0.83 0.40 1.01 1.12 0.98 high high based on the research data in table 3, it can be explained that the two types of discovery models have a significant effect on students’ critical thinking skills in learning physics. in learning physics, the use of the discovery learning model has a higher effect with an effect size of 1.12 with a very high category than the guided discovery model with an effect size of 0.98 with a high category. by using the discovery learning model, students can think critically and analyze problems to find answers to these problems [7]. the results of this research are in line with the research of dewi et al. [45]. they state that students’ critical thinking skills increase after applying the discovery learning model. by applying this model in learning physics, students will have more experience directly and provide opportunities to develop their critical thinking skills [29]. therefore, it can be said that the use of the discovery learning model in learning physics has more influence on students’ critical thinking skills compared to the use of the guided discovery model. the influence of the discovery model on knowledge competence in terms of the type of discovery model the result of the second research is the influence of the discovery model in physics learning on knowledge competence in terms of the type of discovery model. the discovery model found in the article is divided into two types, namely the discovery learning model and the guided discovery model. of the 8 articles found, four articles used the discovery learning model, and 4 articles used the guided discovery model. the average value of effect size in terms of the type of discovery model is presented in table 4. table 4. the effect size of the discovery model on knowledge competence in terms of the type of discovery model model type discovery journal code es average es information discovery learning guided discovery kp[16] kp[50] kp[20] kp[17] kp[51] kp[52] kp[15] kp[53] 0.48 0.72 1.25 1.52 0.24 1.93 1.16 0.33 0.99 0.91 high high based on the research data in table 4, it can be explained that the two types of discovery models have a significant effect on students’ knowledge competence in learning physics. both types of discovery models greatly influence students’ knowledge competence from the data obtained. however, if we look again at the use of the discovery learning model, it has a higher effect with an effect size of 0.99 than the guided discovery model with an effect size of 0.91. by using the discovery learning model, students will be more active in learning to analyze and solve their problems [17]. therefore, the learning that he finds himself will become new knowledge, so that his know-ledge competence will increase and the concepts will stay longer in his brain. the results of this research are in line with research by sitanggang and harahap, which states that the application of the discovery learning model can improve student learning outcomes with an average post-test of 67.57 [55]. by applying the discovery learning model in learning physics, students can learn to prove and find the relationship between concepts and physics equations through an experiment, discussion and question and answer to remember and understand the concepts being studied [56]. the discovery learning model also requires students to actively construct their knowledge to find a principle and their concept [57]. the direct involvement of students in the process of finding a concept will increase students’ knowledge competence [58]. so, it can be concluded that the use of the discovery learning model in learning physics has more influence on students’ knowledge competence than the use of the guided discovery model. the effect of model discovery on critical thinking ability judging from the physics learning materials the third research is the effect of the discovery model in physics learning on students’ critical thinking skills in terms of physics learning material. from the articles analyzed, there are several physics materials. the physics materials include dynamic fluids, static and dynamic fluids, kinetic theory of gases, heat, and spring forces. the effect size of each article based on physics learning materials can be seen in table 5. indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 82 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 table 5. the effect size of the discovery model on critical thinking ability in terms of physics learning materials journal code theory es informatio n ct[43]&[46] ct[18] ct[47] ct[48] ct[49] dynamic fluids static & dynamic fluids kinetic theory of gas heat spring force 1.41 1.13 0.83 0.40 1.01 very high very high high medium high based on the research data in table 5, it can be described that there are three categories of the effect size of the discover model on students’ critical abilities in terms of physics learning materials, namely medium, high, and very high. physics material that gives a moderate effect is heat material. physics material that gives a high effect is the kinetic theory of gas and spring forces. at the same time, the physics material that gives a very high effect is fluid. dynamic material applied in learning physics with the discovery model gives the highest effect on students’ critical thinking skills, compared to other materials with an effect size of 1.41. dynamic fluid material is a material that is closely related to everyday life. the discovery model integrated on dynamic fluid material will make it easier for students to find their concepts because they are related to the real world. students’ critical thinking skills will increase when faced with the real world. this is in line with the research of komariyah and karimah [43], which states that there is an increase in students’ critical thinking skills by applying the discovery model to dynamic fluid material. one of the criteria for good material to support students’ critical thinking skills is to relate theory to phenomena in everyday life [59]. physics learning with the discovery model on dynamic fluid material also follows the physical characteristics, namely inductive and centered on experimental activities [18]. in particular, conducting direct experiments on dynamic fluid material will encourage students’ experimental skills so that later it will stimulate students to use critical thinking skills [45]. therefore, it can be concluded that the dynamic fluid material applied in learning physics with the discovery model greatly influences students’ critical thinking skills. the influence of the discovery model on knowledge competence in terms of physics learning materials the fourth research is the effect of the discovery model in learning physics on students’ knowledge competence in terms of physics learning material. from the article’s analysis, there are several physics materials. the physics materials include glb & glbb, elasticity & hooke’s law, work & energy, and momentum & impulse. the effect size of each article based on physics learning materials can be seen in table 6. tabel 6. the effect size of the discovery model on knowledge competence in terms of physics learning materials journal code theory es informati on kp[16]&[51] glb & glbb 0.36 low kp[50] elasticity & hooke’s law 0.72 medium kp[20] work and energy 1.25 very high kp[15] momentum & impulse 1.16 very high based on the research data in table 6, it can be described that there are three categories of the effect size of the discovery model on students’ knowledge competence in terms of physics learning materials, namely low, medium, and very high. physics material that gives a low effect is glb & glbb material. physics material that gives a moderate effect is elasticity & hooke’s law. at the same time, the physics material that gives a very high effect is work & energy, and momentum & impulse. the work & energy material applied in learning physics with the discovery model gives the highest effect on students’ knowledge competence, compared to other materials with an effect size of 1.25. the matter of work & energy is one of the materials closely related to everyday life. learning physics, especially the matter of work and energy, has so many physical science concepts that are so difficult for students to understand theoretically so that an appropriate learning model is needed to realize it. the discovery model, integrated into the work & energy material, will help students develop their thinking skills, solve problems, and improve their knowledge competencies. this happens because the discovery model, which is integrated into the material, work & energy, is directly related to the real world. these results are in line with the research of dewi et al., which states that students’ learning outcomes in class x on work and energy materials taught using the discovery learning model have increased [45]. by applying the discovery model to the work and energy material, students can build mastery of concepts and knowledge better than applying other learning models because they are freed to explore their knowledge [20]. the discovery model carried out on the work and energy material focuses on students’ curiosity to solve everyday life problems [60]. this is in line with the research of turrahmah et al. [61]. they stated that the discovery model supports students to be directly involved in finding concepts and principles, especially in work and energy, by conducting direct experiments with the real world. therefore, it can be concluded that the work & energy material applied in learning physics with the discovery model greatly influences students’ knowledge competence. v. conclusion based on the data analysis that has been done, there are four research results. first, the discovery model that indonesian review of physics (irip) vol.4, no.2, december 2021, pp. 76 86 83 annisa, et al. meta-analysis of the effect of the discovery …. p-issn: 2621-3761 e-issn: 2621-2889 has the most influence on students’ critical thinking skills in learning physics is the discovery learning model with an average effect size of 1.12. second, the discovery model that has the most influence on students’ knowledge competence in learning physics is the discovery learning model with an average effect size of 0.99. third, dynamic fluid material applied in learning physics with the discovery model greatly influences students’ critical thinking skills with an effect size of 1.41. fourth, the work & energy material applied in learning physics with the discovery model greatly influences students’ knowledge competence with an effect size of 1.25. thus, it can be concluded that the discovery learning model has a significant influence on students’ critical thinking skills and knowledge competencies, especially on dynamic fluid material as well as momentum and impulses. references [1] w. widayat, “implementation of 21st century skills development through virtual class features of the learning house portal,” web, 2018. 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observatory at muhammadiyah university of north sumatera muhammad hidayat, arwin juli rakhmadi, abu yazid raisal development of interactive physics e-module using the sets (science, environment, technology, society) approach to improve science literacy dimension of content and process dimensions in fluid dynamics material eka syafutri, widodo widodo, yudhiakto pramudya analysis of students' understanding of concepts on momentum and impulse material using research-based learning (rbl) models nanda safarati, rahma rahma e�ect of deposition voltage on layer thickness, microstructure, cu/ni sheet resistivity of deposition results by magnetic field electroplating assisted technique willi anindita wijanarka, moh toifur implementation cooperative learning type stad assisted edmodo in improving students' critical thinking skills muhamad epi rusdin, widodo widodo, guntur maruto indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 19-22 doi: 10.12928/irip.v3i1.1944 http://journal2.uad.ac.id/index.php/irip 19 analysis of students' understanding of concepts on momentum and impulse material using research-based learning (rbl) models nanda safarati*and rahma department of physics education, universitas almuslim jl. almuslim, bireuen, aceh, indonesia *email: nandasafarati@umuslim.ac.id article info abstract article history received mar 21, 2020 revised may 17, 2020 accepted june 18, 2020 this study aims to analyze students' understanding of concepts in the material of momentum and impulses using research-based learning (rbl) models. this type of research is quantitative research with a descriptive approach. the population in this study were students of class xi of sma 3 bireuen, the subjects in this study were students of class xi2 of sma 3 bireuen as many as 30 students. the results of this study indicate that 30 students in class xi2. 53.3% of students in the category understood the concept, 20% students in the guessing category and 26.7% students in the don't understand the category. this shows students will better understand the concepts of momentum and impulses by using research-based learning models. keywords: concept understanding momentum and impulse research-based learning to cite this article: n. safarati and rahma, “analysis of students’ understanding of concepts on momentum and impulse material using research-based learning (rbl) models,” indones. rev. phys., vol. 3, no. 1, pp. 19–22, 2020. i. introduction education has an important role in a nation and is demanded to be relevant to the continued development of science and technology so that through education it is expected to be able to form people who have the skills to survive in the current globalization. according to mudyaharjo [1] education is all learning experiences that take place in all environments and throughout life. one of the goals of education is to facilitate students to reach an understanding that can be expressed verbally, in the form of numbers and positive thinking frameworks [2]. learning that requires understanding is learning to think at a high level because in it there is a concrete thinking process, namely the ability to think spiritually, think creatively, solve problems, and make decisions. according to alatas [3], understanding is the result of teaching and learning that has indicators and each individual can explain or define a piece of information in his own words. according to deviyanti [4], physics learning aims so that students can understand scientific products (concepts, laws, principles, theories) based on scientific processes, so physics learning must actively involve students to interact in the learning process, physically or mentally and not just doing activities hand-on but also mind-on. the statement above is in line with the opinion [5], the most appropriate initial step to study physics is to understand the concept first. these concepts are arranged systematically, so that mastery of concepts is needed in each material. mastery of concepts is a basic ability that must be possessed by students to be able to understand concepts in accordance with the understanding of scientists [6]. this is reinforced by [7] which states that the purpose of learning is that students have good conceptual abilities so that students can develop the knowledge that students have previously had. bspn [8] also states that mastery of good and correct concepts can improve students' intellectual abilities in solving problems related to natural phenomena. based on the results of research conducted by researchers at sma negeri 3 bireuen, teachers in the learning process still use conventional methods and are teacher-centered. also besides, the demands of the institution and curriculum that requires the completeness of several some materials taught, so that the results take precedence over the learning process itself. the teacher tends to explain the material, give examples of questions and give practice questions that must be done by students, so students have accidentally been given an understanding that physics is a subject that deals only with numbers and calculations mathematically without explaining related concepts with material first. as a result of the learning process carried out, students become passive and assume physics is a very frightening subject with a variety of formulas and numbers, so students do not understand the concepts of physics material they learn. also besides, students are not able to connect between the material learned with a variety of knowledge and use in everyday life. one of the materials students must master is momentum and impulses. momentum and impulses are quantities related to the velocity and mass of an object, referring to the quantity of motion of an object and the mass of an object. the definition of momentum and impulse itself is interpreted as a quantity obtained from the multiplication between the magnitude of the velocity vector and the scalar mass of an object. n. safarati, et al. / indonesian review of physics 3(1), 2020, 19-22 20 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 based on these problems, rbl is a learning model that helps students to learn effectively to find meaningful physics concepts. trinasih [9] states that research-based learning provides opportunities for students to develop contextual concepts that emphasize the real situation with the stages that must be passed by discovering new things from the process of conducting research. the rbl learning model trains students to think critically and carry out research activities (conducting traces, hypotheses, collecting data, processing data and drawing conclusions). ii. theory concept understanding understanding concepts is a very important aspect and must be applied in learning because with the understanding of student concepts, the ability of students to understand learning material becomes faster and more developed. according to [10], understanding is how someone distinguishes, suspects, expands, concludes, gives examples, rewrites, and estimates. rusman [11] states that understanding is the process of individuals who receive and understand information obtained from learning obtained through attention. according to soedjadi [12], concepts are abstract ideas that can be used to classify or clarify a group of objects. students who master the concepts can identify and treat new questions that are more varied. also besides, if the child understands a concept, then students can generalize an object in various other situations that are not used in learning situations [13]. gusniawati [14] states that understanding concepts is an ability to find abstract ideas to classify objects that are usually expressed in terms and then poured into examples and not examples so that someone can understand a concept clearly. based on the opinion above, it can be concluded that understanding the concept is the process by which students discover, master and understand information obtained through thinking and acting in understanding each concept of an object. research-based learning (rbl) the research-based learning model (rbl) is one of the new learning models that allow students to learn to build knowledge from research steps such as having to search for information, formulate hypotheses, collect data, analyze, make conclusions and prepare reports [15]. research-based learning (rbl) is learning that builds student understanding, learning by developing prior knowledge, learning which is a process of social interaction and meaningful learning achieved through real experience. the learning process with this model requires students to be able to find, explore to face the problems faced, then test the truth of that knowledge [16]. the stages of the research-based learning (rbl) model according to [17] can be seen in table 1. table 1. sintax of the research-based learning model no phase activity 1 formulating a general question provide a formula in the form of a topic or a problem in the form of a question 2 overview of researchliterature examining reference material from various literatures 3 defining the question define question or formulate a hypothesis 4 planning research activities, clarifying methods/ methodologies explain, research methods /methodology 5 undertaking investigation, analyzing data investigate by taking data through observation to school and to analyze 6 interpretation and consideration of results analysis of the data obtained is interpreted and considered through group discussion. 7 report and presentation of results write it in report and presenting iii. methodology this research uses quantitative research with a descriptive approach. quantitative research methods are research methods that are based on the philosophy of positivism, used to examine a population or specific sample, collecting data using research instruments, analyzing quantitative/statistical data to test established hypotheses. descriptive research is research conducted to determine the value of independent variables, either one or more variables (independent) without making comparisons or connecting with other variables [18]. so quantitative research with descriptive approach is research obtained from the results of population and sample analysis with the statistical method that you want to use. with the steps of formulating questions in the form of questions, studying literature, formulating hypotheses, conducting research methodologies, observing, analyzing and making reports. according to [18], the population as a generalization area consisting of objects/subjects that have qualitative and certain characteristics determined by researchers to be studied and then drawn conclusions. the population in this study were all students of class xi ipa of bireuen public high school 3. samples are part of that population [18]. the sample in this study were students of class xi ipa2 consisting of 30 students. the research instrument used was a physics concept understanding test instrument in the form of a multiplechoice test consisting of 10 multiple-choice questions. the reason for using multiple choice tests is because they are objective tests, and facilitate assessment. material momentum and impulses to be tested that include the concept of momentum, impulse, conservation of momentum, and system momentum. the percentage category of students' understanding level can be seen in table 2. n. safarati, et al. / indonesian review of physics 3(1), 2020, 19-22 21 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 2. percentage of shiva's understanding level [19] no percentage category 1 %30 low 2 %6030  x medium 3 61-100% high criteria for understanding students' concepts can be seen in table 3. table 3. student answer criteria [19] no question answer category 1 multiple choice right understand the concept 2 multiple choice right to guess 3 multiple choice right don't understand the concept iv. results and discussion the results of data analysis that have been carried out at sman 3 bireuen, on the material of momentum and impulse using research-based learning (rbl) learning models can be seen in figure 1. figure 1. percentage of students' understanding of concepts based on the results of data analysis shows that the understanding of students' concepts in the material of momentum and impulses using research-based learning (rbl) is in the medium category. from 30 students, the percentage of students understanding the concept category was 53.3%, the percentage of students guessing the category was 20% and the percentage of students in the category, not understanding was 26.7%. understanding the concept of sub-matter in the matter of momentum and impulse can be seen in figure 2. figure 2. percentage of students' understanding of the concept of peru material based on the results of data analysis on students' understanding of the concept of sub-material, it can be seen that the submission of conservation of momentum is the most widely understood concept by students, with a percentage of 60%, while for understanding the concept the least amount is contained in impulse material with a percentage of 10% with a total of 10 multiple choice questions. the most guessed category is found in the momentum submitter with a percentage of 30% while the least guessed category is found in the momentum submitter with a percentage of 16.7%. the category of not understanding the concept is mostly found in impulse submersion with a percentage of 66.7% while the category of not understanding the concept is the least in the submission of conservation of momentum with a percentage of 10%. v. conclusion the conclusion of this study is based on the analysis of research data, namely the understanding of students' concepts becomes more visible when researchers use the rbl learning model. this can be seen from the percentage of the results of data analysis which shows that of the 30 students in class xi2, the percentage of students understanding the concept category was 53.3%, the percentage of students guessing the category was 20% and the percentage of students in the category, not understanding was 26.7%. this shows students will better understand the concept of momentum and impulse by using research-based learning (rbl) learning models. reference n. safarati, et al. / indonesian review of physics 3(1), 2020, 19-22 22 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 [1] s. sagala, konsep dan makna pembelajaran: untuk membantu memecahkan problematika belajar dan mengajar. bandung: alfabeta, 2003. [2] h. gardner, the disciplined mind: what all students should understand. new york: simon & schuster, 1999. [3] f. alatas, “hubungan pemahaman konsep dengan keterampilan berpikir kritis melalui model pembelajaran treffinger pada mata kuliah fisika dasar,” edusains uin syarif hidayatullah, vol. 6, no. 1, pp. 88– 96, 2014. [4] l. deviyanti, “pengembangan panduan praktikum fisika berbasis research based learning untuk mengoptimalkan domain kognitif dan psikomotorik siswa di sma negeri 5 purworejo.” program studi pendidikan fisika fkip universitas muhammadiyah purworejo, 2016. [5] p. r. sasmita, “penerapan metode inkuiri terbimbing menggunakan media kit fisika: upaya meningkatkan aktivitas dan hasil belajar fisika siswa,” j. ilm. pendidik. fis. al-biruni, vol. 6, no. 1, pp. 95–102, 2017. [6] y. t. b. widodo, cara cerdas mengerjakan soal fisika mekanika untuk sma/ma: brilliant solution. yogyakarta: andi offset, 2007. [7] s. rahmawati, s. kusairi, and s. sutopo, “analisis penguasaan konsep siswa yang belajar materi momentum dan impuls berbasis scientific approach disertai formative assessment berbantuan web,” j. pembelajaran sains, vol. 3, no. 1, pp. 1–6, 2019. [8] bsnp, “permendiknas ri no. 22 tahun 2006 tentang standar isi untuk satuan pendidikan dasar dan menengah.” jakarta, 2016. [9] a. b. trisnasih, k. c. suryandari, and suhartono, “peningkatan keterampilan proses dan hasil belajar ipa melalui model research based learning siswa kelas v sd,” kalam cendekia, vol. 4, no. 4, pp. 1–7, 2016. [10] l. w. anderson and d. r. krathwohl, a taxonomy for learning teaching and assessing: a revision of bloom’s taxonomy of educational objetives. new york: longman, 2001. [11] rusman, model-model pembelajaran. jakarta: pt raja grafindo persada, 2010. [12] r. soedjadi, “kiat pendidikan matematika di indonesia.” direktorat jenderal pendidikan tinggi, departemen pendidikan nasional, jakarta, 2000. [13] s. nasution, berbagai pendekatan dalam proses belajar dan mengajar. jakarta: bumi aksara, 2005. [14] m. gusniwati, “pengaruh kecerdasan emosional dan minat belajar terhadap penguasaan konsep matematika siswa dalam sman di kecamatan kebun jeruk,” j. form., vol. 5, no. 1, pp. 26–41, 2015. [15] m. salimi, t. s. susiani, and r. hidayah, “research based leaning sebagai alternatif model pembelajaran di lembaga pendidikan tenaga kependidikan,” j. pendidik. sekol. dasar, vol. 3, no. 1, pp. 1–9, 2017. [16] s. m. wardoyo, pembelajaran berbasis riset. jakarta: akademia, 2013. [17] p. tremp, “research-based teaching and learning: a leru project.” university of zurich, munich, 2010. [18] sugiyono, metode penelitian pendidikan pendekatan kuantitatif, kualitatif dan r&d. bandung: alfabeta, 2013. [19] w. p. sari, e. suyanto, and w. suana, “analisis pemahaman konsep vektor pada siswa sekolah menengah atas,” j. ilm. pendidik. fis. al-biruni, vol. 6, no. 2, pp. 159–168, 2017. microsoft word 16_5-agustus-siregar-3.doc indonesian review of physics, volume 2, number 1, 2019 5 an experiment design for determining the volume of traditional eucalyptus oil with variations in fluid flow speed nur hamida siregar 1, moh. toifur2, and yudhiakto pramudya3 1physics education, darussalam university ambon, 2,3physics education, ahmad dahlan university 1jl. waehakila puncak wara, ambon-97128, 2,3jl. pramuka no.42, pandeyan, umbulharjo, yogyakarta-55161 nurhamidasiregar12@gmail.com abstract – this study aimed to determine the volume of traditional eucalyptus oil from distillation with variations in fluid flow velocity. the method of distillation was distillation with water (water distillation). the material was eucalyptus leaves. to determine the volume of eucalyptus oil produced by distillation, the distillation device was set at the height of the condenser to the source of flow fluid, which was at an altitude of 15 cm, 25 cm, 35 cm, 45 cm, and 55 cm. variation in the height of the condenser would affect the fluid flow rate. the faster the fluid flow rate, the greater the convection coefficient so that it increased the heat transfer rate. this results in greater volume (capacity) of oil produced. from these experimental results, most volumes of eucalyptus oil obtained from the distillation was obtained at 55 cm of the height of condenser with 3.6 ml of oil volume. keywords: eucalyptus oil, water distillation, volume, altitude, condenser. i. introduction traditional medicine has increasingly gained attention in recent years, both medical and industrial circles. it was because of the potential as alternative medicine and a promising prospect for the household product industry, especially the pharmaceutical industry. the main benefit of this oil is to accelerate blood circulation by widening the pores of the skin so that the body becomes warmer and will not interfere with skin respiration due to the nature of volatile eucalyptus oil. because of its wide using, the quality and method of producing eucalyptus oil sold in the market need attention. in order to fulfill these demands, research is needed. to find out the quality of eucalyptus oil, testing the level of purity was conducted. testing the level of purity can be conducted in 2 ways, namely: visual tests and laboratory test methods. there are several factors that influence the production of eucalyptus oil: leaf filling, eucalyptus oil tree varieties, leaf storage, leaf age and distillation technique [1]. to obtain the production (volume) of maximum eucalyptus oil was conducted in one way, by varying the fluid flow rate in the distillation technique. ii. theory a. eucalyptus oil eucalyptus oil plant (melaleuca leucadendra) is one of the plants producing essential oils. these plant leaves contain essential oils about 0.5-1.5% depending on the effectiveness of distillation and the oil content contained in distilled material [2]. eucalyptus leaves can be seen in figure 1. figure 1. eucalyptus leaves essential oils produced from the leaves are useful as raw material for rubbing oil which has many functions, such as analgesics or pain relievers, disinfectants or germ killers, expectorants or sputum and anti-spasmodic decay or abdominal pain relief [3]. siregar et al. an experiment design for determining the volume of traditional eucalyptus oil… indonesian review of physics, volume 2, number 1, 2019 6 b. water distillation in this distillation method, the material to be distilled is directly related to boiling water. the material to be distilled may float on water or be submerged entirely, depending on the specific gravity and quantity of the material to be processed. water can be boiled directly with fire. this water distillation is like a directly boiled plant material [4]. c. condensation condensation is a process of releasing heat from a system that causes steam (vapor) to turn into liquid (liquid). the condensed liquid from the vapor is called condensate. the tool used to condense vapor into a liquid is called a condenser. the working principle of the condenser is that the substance is heated, then the hot steam will rise and then run cold water through the hose so that the steam does not escape into the air but returns to condense and fall down again [5]. d. basic principles of flow in pipes fluid or liquid is a form of a substance that does not have a fixed form, but can flow and take shape according to the container it occupies. 1. flow debit equation mathematically the flow debit can be written: (1) with is the flow rate (m 3/s), is the crosssectional area of the pipe (m2) and is the average velocity in the channel (m/s). 2. continuity equation the equation which states the relationship between cross-sectional area and fluid velocity is called a continuity equation, and is mathematically written as follows: (2) with is a cross-sectional area of 1 (m 2), is the rate of fluid flow when through cross section 1 (m/s), is the cross-sectional area of 2 (m 2) and is the rate of fluid flow when passing through cross section 2 (m/s). continuity equations can also be written: (3) 3. bernoulli equation bernoulli provides a mathematical formulation that states the relationship between the pressure in a fluid, fluid flow and the difference in cross-sectional height is constant (constant). this mathematical formulation is called the bernoulli equation which is written as follows: (4) equation (4) can also be written as follows: (5) with and are the fluid pressure in cross sections 1 and 2 (n/m2), is the density of fluid (kg/m3), and are the velocity of fluid flow in sections 1 and 2 (m/s), is the gravitational force (m/s2), and are the height of cross-sections 1 and 2 (m) [6]. e. relationship between height of reservoir and velocity of fluid flow to find fluid flow velocity at a certain height with pipe diameter (d) and condenser diameter (d), use equation (5) with assumptions , and , so that equation (5) becomes: (6) from equation (2) for a steady flow it is not compressed, it is known that the conservation requirements of mass , with . then obtained equation (7): (7) by subsidizing equation (7) to equation (7), to obtain equation (8): (8) from equation (8), it can be concluded that the greater the fluid height of the condenser, the greater the fluid flow rate in the condenser. the faster or large fluid flow rate will affect the magnitude of the convection coefficient so that it increases the heat transfer rate. this results in a greater capacity of oil produced or produced [7]. f. convection heat transfer convection heat transfer occurs due to temperature differences. the heat transfer rate or convection heat in the fluid is proportional to the cross-sectional area a of an object that is in contact with the fluid and the temperature difference between the fluid and the object stated in equation (9). (9) vaq ×= q a v 2211 vava = 1a 2a 2v 21 qq = tetapghvp =++ rr 2 2 1 2 2 221 2 11 2 1 2 1 ghvpghvp rrrr ++=++ 1p 2p r 1v 2v g 1h 2h 021 == pp hh =1 02 =h 2 2 2 1 2 vghv =+ 21 qq = vaq ×= 2 2 1 vd d v ÷ ø ö ç è æ = 42 1 2 ÷ ø ö ç è æ = d d gh v tia t q d= d d siregar et al. an experiment design for determining the volume of traditional eucalyptus oil… indonesian review of physics, volume 2, number 1, 2019 7 with is the convection coefficient. to determine the value of the convection coefficient ( ) can be obtained by decreasing equation (9) to obtain equation (10). (10) by is the convection heat transfer rate (w), is the convection coefficient (w/m2k), is the mass of the distilled material (kg), is the heat of the type of water vapor (j/kgk), is the initial steam temperature (k), is the steam temperature end (k), is the time of initial steam discharge (s), is the time of final steam discharge (s), is the heat transfer surface area (m2), is the surface temperature (k), and is the temperature of fluid (k). iii. research methods / experiments a. tools and materials 1. 1 set distillaionstall 2. electrothermal 3. storage container 4. measuring cup 5. adhesive as a glass cover 6. pipe (hose) 7. thermocouples 8. ruler 9. water 10. stopwatch 11. separating funnel 12. digital balance. b. research design figure 1. design experiment c. experimental procedure figure 2. experimental procedure iv. research results and discussion based on the results of research carried out for 5 variations of fluid flow velocity based on the height of the condenser in the set distillaionstall, data such as below are obtained: table 1. data analysis no. the height of the condenser, h (m) flow rate of fluid, v2 (m/s) volume of eucalyptus oil (ml) 1 0,15 1,79 2,0 2 0,25 2,31 2,4 3 0,35 2,74 2,7 4 0,45 3,10 3,1 5 0,55 3,43 3,6 from table 1 a linear curve was obtained as shown in figure 2 below: figure 3. relationship of fluid flow velocity with volume refined eucalyptus oil figure 3 is a graph of the relationship between fluid flow velocity and the volume of refined eucalyptus i i ( ) ( ) ( )fp tta tt tt mc i = 12 12 q i m c 1t 2t 1t 2t a pt ft siregar et al. an experiment design for determining the volume of traditional eucalyptus oil… indonesian review of physics, volume 2, number 1, 2019 8 oil. from the linear regression data fitting in the figure, was obtained (11) where is the fluid flow velocity (m/s), and is the volume of eucalyptus oil (ml). based on the results of the graph in figure 2 obtained a fairly high value of 0.973 close to number 1 which showed the relationship of fluid flow velocity with the volume of eucalyptus oil was really accurate with the accuracy of 97.3%. from data in table 1 and figure 3, it can be seen in accordance with equation (8) and the theory which explains that the condenser height affected the velocity of the fluid flow rate. the higher the condenser, the faster the fluid flow rate. the greater the fluid flow rate, the greater the convection coefficient which resulted in greater convection heat transfer rates. thus, the condensation process also required a shorter time to convert the vapor particles into water particles. because the time needed in a process was shorter, the volume of oil produced was even greater in the same timeframe for refining each sample of eucalyptus oil. v. conclusion from the experiments that have been done, it can be concluded that the variation in the height of the condenser influenced the fluid flow velocity. the faster the fluid flow rate, the greater the heat transfer coefficient so that it increased the heat transfer rate. this resulted in greater volume (capacity) of oil produced. this is evidenced by the highest volume of eucalyptus oil produced by distillation at the height of the 55 cm condenser with an oil volume of 3.6 ml. acknowledgment the researcher is grateful to my friend, kamaluddin who has helped me during the research process, and other friends who cannot be mentioned one by one. reference [1] p. armita, effect of varieties and density of eucalyptus leaves in kettles on eucalyptus oil production and quality. thesis, department of forest products faculty of forestry, bogor agricultural institute, bogor, 2011. [2] t.l. lutony dan y. rahmawati, essential oils, penebar swadaya, 1999. [3] f.l. astuti dan i.m. aphari, extraction of eucalyptus leaves (melaleuca leucadendra l) using ethanol solvent by maceration extraction method. a research report, faculty of engineering chemical, engineering department sultan ageng tirtayasa university, banten, 2013. [4] h. sastrohamidjojo, chemistry of essential oils, gadjah mada university press, 2004. [5] f. ardi, phenomenon of condensation on textile ducting made from polyester. thesis, faculty of engineering, department of mechanical engineering, university of indonesia, depok, 2012. [6] d.c. giancoli, principles and application of the seventh edition of volume i, pt gelora aksara praatama, 2014. [7] s. haryadi, effect of cooling water flow direction on the condenser on the condensation results of the waste plastic pyrolysis process. thesis, faculty of engineering, department of mechanical engineering, universitas negeri malang, malang, 2015. 234,0944,0 += xy x y 2r indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 1-5 doi: 10.12928/irip.v3i1.1836 http://journal2.uad.ac.id/index.php/irip 1 effect of the magnetic force on ferrite pendulum oscillation parameters: parametric analysis on ferrite pendulum rusli adi1*, moh toifur1, ishafit1 and rosly jaafar2 1master program of physics education, universitas ahmad dahlan jl. pramuka no. 42, yogyakarta, daerah istimewa yogyakarta, indonesia 2department of physics education, universiti pendidikan sultan idris tanjong malim, perak, malaysia *email: rusliadyfisika@gmail.com article info abstract article history received feb 27, 2020 revised jun 19, 2020 accepted jun 22, 2020 the magnitude of the damping force of the mathematical pendulum swinging on a medium is usually proportional to the speed of the pendulum. in this research, the pendulum oscillation parameters oscillating on an air medium under the influence of a magnetic field of 1.8 g will be investigated. in the initial stage, the effect of the magnetic force on the damping coefficient of ferrite pendulum oscillations with an initial deviation of 15 degrees observed. furthermore, the study continued with varying the angle of deviation from 5 degrees to 25 degrees. the results of the data fitting amplitude (xi) at various swing times (ti) are using to analyze the effect of the angle of deviation on the maximum amplitude. the results showed that for the deviation angle of 15o the coefficient of damping of the medium affected by the magnetic force was 0,0022 greater than the coefficient of air damping 0,00006. it affects the amplitude, which decreases faster than the pendulum amplitude without the influence of magnetic force. variation in the angle of deviation also affects the amplitude of the pendulum. in the deviation angle below 10, the pendulum motion is more influenced by the magnetic force, whereas in the deviation above 10, the pendulum motion is more dominated by gravity. this is an open access article under the cc–by-sa license. keywords: damping coefficient ferrite pendulum magnetic force swing pendulum to cite this article: r. adi, m. toifur, ishafit, and r. jaafar, “effect of the magnetic force on ferrite pendulum oscillation parameters: parametric analysis on ferrite pendulum,” indones. rev. phys., vol. 3, no. 1, pp. 1–5, 2020. i. introduction there are two types of vibrations, namely harmonized vibration and damped vibration. damped oscillations consist of various kinds, namely dumped, overdamped, and underdamped. the type of dropped occurs if there is attenuation, over dumped occurs if the attenuation is maximum so that objects cannot vibrate anymore, underdamped vibrations arise under the influence of force. swing pendulum vibrations with weights made of ferrite material [1] under the influence of permanent magnetic fields [2], [3], [4] are examples of underdamped vibrations. this type of swing is seen as a rather specific swing because the pendulum vibration is limited by the influence of the coercive force, which is a combination of magnetic attraction and magnetic repulsion forces. the spectacle occurs when the pendulum polarity is opposite to the permanent magnet polarity, and the repulsion occurs when the pendulum polarity is the same as the permanent magnet. the pull and push forces and the force of gravity produce a swing that is only slightly damp. it can be observed from the amplitude of the oscillation that changes only slightly so that the swing pattern is still like a harmonic vibration [5]. this condition runs in a few moments. when the gravitational run is no longer able to compensate the attractive and repulsive magnetic forces, the magnetic force is more dominant so that the swing is no longer harmonious. the amplitude of the oscillation decreases dramatically and finally stops. therefore, in this study, the solution of differential equations with dumping force derived from the interaction between the ferromagnetic pendulum and the permanent magnet. by varying the angle of displacement of the oscillator then it can be seen its effect on the maximum deviation after there is a dumping magnetic force. r. adi et al. / indonesian review of physics 3(1), 2020, 1-5 2 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 ii. theoretical damped oscillation vibration is a back and forth repetitive movement that repeats through the equilibrium point [6], [7]. the harmonic vibration equation is given [8] in the eq. (1): 0 2 2  kx dt xd m (1) theoretically on harmonious vibrations, the pendulum will oscillate with a fixed amplitude. but in reality, the object will stop oscillating after a particular time due to air attenuation [9] and other things such as magnetic fields. the equation for damped swing where the damping force is proportional to the swing speed [10] is 0 2 2  kx dt dx b dt xd m (2) where x displacement, m pendulum mass, b damping coefficient, and k string constants. for swing under the influence of the magnetic force, there is a damped force that works period so that it will affect the oscillation frequency and maximum deviation [11]. for a driving force, f cos t the [12] eq. (3) can be written as tfkx dt dx b dt xd m cos 2 2  (3) the magnitude of the interaction force between the ferromagnetic pendulum (a) and the permanent magnet (b) at distance r is expressed by eq. (4), [13], [14], [15].          0 4 3 ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ. . . 5 . . 4 a b ab a b a b b a a b m m f r m m m r m m r m r r m r m r        (4) where ma and mb is the pendulum magnetic moment of a and b, and ˆ am ˆ bm the unit magnetic moment ma and mb, r the distance from a to b, and r̂ the position vector a from b. the magnitude interaction force between a and b is dependent on the interval [16] and the orientation of the magnetic moment of the two magnets. ferrite rod pendulum swing figure 1 shows the ferrite rod an as a pendulum swinging under the influence of a permanent magnet b. at the beginning of pendulum, a deviated at an angle . when the pendulum is released, the gravitational force causes the pendulum to swing near the magnetic pole b, for example, the north pole (u). at the same time, the ferrite pendulum is magnetized by the magnetic field b so that the magnetic dipole moments a near the north pole b become the south pole (s). in this condition, the driving force comes from 2 sources, namely the gravitational force and the magnetic interaction force. assume that the gravity force is greater than the magnetic force. furthermore, when a is near the centre of mass of the permanent magnet b, the status of pendulum a leaves the north pole of magnet b and goes to the south pole of magnet b. in this case, the pendulum is affected by both permanent magnetic poles b. towards the north pole of stable magnet b, the pendulum is pulling, and this pull is inhibiting motion. once it is released from the magnetic north pole, the pendulum is induced by the magnetic south pole so that its polarity reverses to become the north pole due to the pull of the magnetic north pole on the south pole of the pendulum deviation to be reduced. the same pendulum motion occurs in the opposite direction so that the pendulum deviation decreases over time and finally stopped. it should be noted that when the pendulum is near the magnet, the swing becomes less regular, which is slightly away from the line. it is because of the magnetic repulsion force on the pendulum when the polarity of the pendulum is the same as the magnetic polarity. by viewing the magnetic force by magnet b as a damped force, the solution eq. (3) is stated by [17]: u s u s permanent magnet ferrite bar s u  a b figure 1. the pendulum system under the influence of magnetic forces.                t a taetx t cos 4 sin 22222 0 2 (5) r. adi et al. / indonesian review of physics 3(1), 2020, 1-5 3 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 for frequency of damped force  that equals to natural rate 0 then            t a taetx t cos 2 sin (6) where a is oscillation amplitude. the quantities  and  in the sin term differ from those in the cos term, except under certain conditions. iii. method tools and materials the material used in this study consisted of ferrite rods with a mass of 0.0258 kg, a diameter of 0.955 cm, length of 3 cm, a thread of 1 m, rectangular neodymium magnets with a size of 2 cm' 5 cm' 0.2 mm of 2 pieces. this magnet has an 8 mt measured at a distance of 1 cm from it one pole. the tools needed include a protractor to measure the angle of deviation, a 50 cm support rod, a video to record the movement of the pendulum, tracker software to obtain pendulum position data at any time. data collection the ferrite pendulum is hanging on a 38 cm long string then placed on a 40.5 cm high statif. neodymium magnets as permanent magnets 0.5 cm thick are mounted on the base so that the distance from the end of the ferrite pendulum to the permanent magnet is 2 cm. furthermore, the ferrite pendulum is deviated at an angle of 5 degrees and then released. the oscillation of the pendulum is recorded with the video until the pendulum stops swinging. this experiment was carried out in a confined space so that the disturbance from the environment can be minimized. data analysis from the pendulum swing video tracking the pendulum data set of the position of a pendulum at any time (ti, yi) is obtained. the data is then fitted according to the eq. (7):       tetaex dt cossin (7) where x is pendulum deviation, a, , , and d are fitting constants. from this data, fitting also obtained rmse and r2 values. a right r2 is more than 0.95. that the value of r2 is still far from 0.95 so that the fitting parameters are corrected with solver parameters software. iv. results and discussion damping coefficient of the magnetic field figure 2 shows an example of the appearance of the ferrite pendulum tracking results for an angle of 15 degrees without the influence of a magnetic field. data sampling was performed at every 0.02s. we are tracking data in the form of time as x and position as y. from this tracking data, then an x(t) curve is drawn. the same thing is done for the swing with the influence of the magnetic field. the x(t) curve together shown in figure 2. figure 2. display of the tracking process on ferrite pendulum swing to get it to a position at any time. figure 3 shows the curved pendulum ferrite pendulum tracking results for swing without the damping, with air attenuation and with the damping from permanent magnets. from figure 3, it appears that in general, the longer the oscillation, the deviation is decreasing. for oscillations without damping, the amplitude of the pendulum does not change for oscillations with air attenuation the variance of the amplitude decreases. table 1 shows the oscillation parameters of the ferrite pendulum fittings. from table 1 it appears that the deviations in the three types of vibrations were initially the same, namely 17.75 cm. but after swinging, the pendulum influenced by magnetic force tends to be (a + e) smaller than the pendulum with air attenuation or without damping that is a. in contrast, the damping coefficient  of the three types are different. from the value of , it appears that the swing with attenuation from the magnetic force has  = 0,022 higher than the swing without the magnetic force that is  = 0.00006. it shows the role of the magnetic force on the ferrite pendulum swing, especially when leaving the equilibrium position, the pull force between the ferrite pendulum and the magnet can inhibit the pendulum's motion so that the deviation becomes reduced. however, the pendulum still swings at the same frequency on all swing types that is 4.61 rad/s. r. adi et al. / indonesian review of physics 3(1), 2020, 1-5 4 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 3. swing of the ferrite pendulum at an angle of deviation of 15 degrees (a) without damping, (b) with air attenuation, c) with magnetic field attenuation. table 1. fitting constants in various swing conditions type of oscillation equation of pendulum position fitting constants undamping (theoretically)    taey sin a = 17.75 cm  = 4.61 rad/s  = 0 ° air damping     taey t sin a = 17.75 cm  = 4.61 rad/s  = 0.00006 ° magnetic force damping       tetaey t cossin a = 17.75 cm e = 0.13 cm  = 6.61 rad/s  = 0.02200 ° effect of angle of deviation on the amplitude figure 4. the amplitude of ferrite pendulum at various deviation angles. from figure 4, the damping magnitude for air and magnet are displayed at various angles of pendulum deviation. at an angle of 5 degrees to 10 degrees, the pendulum amplitude curve for magnetic attenuation coincides with the pendulum amplitude with air attenuation. at small angles, the gravitational force that moves the pendulum toward the horizontal is almost not present so that the magnetic force dominates the pendulum driving force. assume that the pendulum moves from the right to the left. when the position pendulum at slightly the right of the magnet, the pendulum pulled to the left by the magnet. once it passes through the equilibrium, the magnetic induction process occurs so that the polarity of ferrite pendulum reversed. as a result, the pendulum is pulled back from the left position to the equilibrium point. this movement only occurs a few times, and after that, the pendulum will stay in the place closest to the magnet. for deviation angles above 10 degrees, the amplitude of the ferrite pendulum with a magnetic field damper is smaller than the amplitude of the r. adi et al. / indonesian review of physics 3(1), 2020, 1-5 5 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 ferrite pendulum with an air damper. at an angle of deviation above 10 degrees, the gravitational force can play a more significant role in moving the pendulum. in contrast, the magnetic force is still small because the magnetic distance to the pendulum is further away. when the pendulum released to the equilibrium point, the pendulum moves quickly because of the influence of the gravitational force, and this driving force increased when the pendulum approaches the magnet because the arising the magnetic force. after the pendulum passes the equilibrium point, the polarity changes due to magnetic induction, and this inhibits the pendulum's motion. as a result, the amplitude is reduced. the same mechanism occurs in the swing in the opposite direction until the pendulum stops. thus at an angle of more than 10 degrees, the presence of a magnetic field can reduce the amplitude of the pendulum swing compared to if there is no magnetic field. v. conclusion the ferrite pendulum that swings under the influence of the magnetic force has a characteristic in its swing profile. the damping coefficient is higher than the air damping coefficient, so the amplitude decreases so that the pendulum stops faster. the air attenuation coefficient is 0.00006, while the magnetic damping coefficient is 0.0022. at an angle deviation, less than 10 degrees the force motion in the pendulum more dominated by the magnetic force whereas in the deviation above 10 degrees the force of gravity more dominates the force of movement. but the swing is inhibited by the magnetic force so that the amplitude decreases. reference [1] g. 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[17] l. p. pook, understanding pendulum. springer, 2011. p-issn 2621-3761 e-issn 2621-2889 irip irip (indonesian review of physics) is a journal of physics and physics education research. it is compiled with a commitment to enhance quality of the research. indonesian review of physics (irip) aims to provide a forum for researchers, lecturers, teacher and student on the topics related to physics and physics education. the journal was first published in 2018 and regularly published twice per year in june and december. editor in chief fatin aliah phang scopus id: 57192376607 universiti teknologi malaysia johor bahru, malaysia managing editor dwi sulisworo scopus id:55317003800 universitas ahmad dahlan yogyakarta, indonesia advisory international editorial boards akihiko tomita scopus id: 7201880070 wakayama university japan hassan k. juwhari scopus id: 6503859673 university of jordan jordan rungchatchadaporn vehachart scopus id: 6992533300 thaksin university thailand butch o saulon nueva 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improving learning outcomes for senior high school achmad aswal, hunaidah hunaidah, erniwati erniwati determination of fill factor and efficiency in solar cell type (99 × 69) mm2 with arduino uno r3 based drive assisted by logger pro 3.14.1 hamzah hamzah, moh. toifur, ishafit ishafit development of the conception of mechanical energy conservation with interactive lecture demonstration method using simple experiments for grade 7 students willi anindita wijanarka, julius zai, winda noor santi, laifa rahmawati, mohd rustam bin mohd rameli characterization of activated charcoal oil palm (elaeis guineensiss jacq) shell waste using sem and ftir: effect of activation temperature rasyid syidiq, la ode yusran, muhammad anas, suritno fayanto published by universitas ahmad dahlan irip vol.2 no.2 pp. 28-74 yogyakarta, december 2019 p-issn 2621-3761 e-issn 2621-2889 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/811 http://journal2.uad.ac.id/index.php/irip/article/view/811 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/818 p-issn 2621-3761 e-issn 2621-2889 table of contents regular papers: development student worksheet in the topic of regular circular motion with blended learning based edmodo as learning motivations for student susilawati susilawati1, ishafit ishafit1, eni setyawati1 1program studi magister pendidikan fisika, universitas ahmad dahlan 28 the effect of electrode gap on the nucleation activity of cacl2.6h2o by using sharp end copper electrode risky afandi putri1, ahmad swandi1, annisa rahman1, radhiah anggraeni1, inge magdalena sutjahja2, daniel kurnia2 1graduate study program of physics teaching, faculty of mathematics and natural sciences, institut teknologi bandung 2physics dept., faculty of mathematics and natural sciences, institut teknologi bandung 34 development of lesson plan (lp) with software lectora inspire assisted problem-based learning in improving learning outcomes for senior high school achmad aswal1, hunaidah hunaidah1, erniwati erniwati1 1department of physics education, university of halu oleo 40 determination of fill factor and efficiency in solar cell type (99 × 69) mm2 with arduino uno r3 based drive assisted by logger pro 3.14.1 hamzah hamzah1, moh. toifur1, ishafit ishafit1 1 program studi magister pendidikan fisika, universitas ahmad dahlan 53 development of the conception of mechanical energy conservation with interactive lecture demonstration method using simple experiments for grade 7 students willi anindita wijanarka1, julius zai1, winda noor santi1, laifa rahmawati2, mohd rustam bin mohd rameli3 1program studi magister pendidikan fisika, universitas ahmad dahlan 2program studi pendidikan fisika, universitas ahmad dahlan 3fakulty of education, universiti teknologi malaysia 60 characterization of activated charcoal oil palm (elaeis guineensiss jacq) 67 shell waste using sem and ftir: effect of activation temperature rasyid syidiq1, la ode yusran2, muhammad anas1, suritno fayanto3 1department of physics education, university of halu oleo 2department of master in physics, institut teknologi sepuluh november 3program studi magister pendidikan fisika, universitas ahmad dahlan http://journal2.uad.ac.id/index.php/irip/article/view/909 http://journal2.uad.ac.id/index.php/irip/article/view/909 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/910 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/818 http://journal2.uad.ac.id/index.php/irip/article/view/811 http://journal2.uad.ac.id/index.php/irip/article/view/811 http://journal2.uad.ac.id/index.php/irip/article/view/811 microsoft word halaman dalam irip-vol2-no1.docx p-issn 2621-3761 e-issn 2621-2889 irip irip (indonesian review of physics) is a journal of physics and physics education research. it is compiled with a commitment to enhance quality of the research. indonesian review of physics (irip) aims to provide a forum for researchers, lecturers, teacher and student on the topics related to physics and physics education. the journal was first published in 2018 and regularly published twice per year in june and december. editor in chief fatin aliah phang scopus id: 57192376607 universiti teknologi malaysia johor bahru, malaysia managing editor dwi sulisworo scopus id:55317003800 universitas ahmad dahlan yogyakarta, indonesia advisory international editorial boards akihiko tomita scopus id: 7201880070 wakayama university japan hassan k. juwhari scopus id: 6503859673 university of jordan jordan rungchatchadaporn vehachart scopus id: 6992533300 thaksin university thailand butch o saulon nueva caceres university philippines muhammad abdul hadi bunyamin scopus id: 57195100817 universiti teknologi malaysia malaysia budhy kurniawan scopus id: 6602596727 universitas indonesia indonesia moh toifur scopus id: 570242327000 universitas ahmad dahlan indonesia arlene monslave saint anthony university philippines yudhiakto pramudya scopus id : 57192652457 universitas ahmad dahlan indonesia noorali t jiwaji open university of tanzania tanzania, united republic of tanzania editorial asistant muarif islamiah universitas ahmad dahlan indonesia sari sri sukmawati universitas ahmad dahlan indonesia endra putra raharja universitas ahmad dahlan indonesia publisher address: department of magister physics education, universitas ahmad dahlan (uad) kampus 2 universitas ahmad dahlan jalan pramuka no. 42, pandeyan, umbulharjo, yogyakarta 55161 telp. +62 274 563515, ext. 4902; fax. +62 274 564604 email: irip@mpfis.uad.ac.id p-issn 2621-3761 e-issn 2621-2889 irip (indonesian review of physics) vol. 2 no.1, june 2019 regular papers: variation of mixed banana peel substrate and cow dung in biogas pressure as a learning source for renewable energy sources puspitawati puspitawati, riswanto riswanto, nyoto suseno an experiment design for determining the volume of traditional eucalyptus oil with variations in fluid flow speed nur hamida siregar, moh. toifur, yudhiakto pramudya an analysis of graduate students’ conceptual understanding in heat and temperature (h&t) using three-tier diagnostic test moh. irma sukarelawan, jumadi jumadi, nurulhuda abdul rahman investigating the effects of activation temperature on the crystal structure of activated charcoal from palm bunches (arengga pinnata merr.) vivi hastuti rufa mongkito, muhammad anas, wisda puspita bahar flipped classroom as a millenial teaching model irnin agustina dwi astuti, yoga budi bhakti, ria asep sumarni, dwi sulisworo, moh. toifur published by universitas ahmad dahlan irip vol.2 no.1 pp. 1-27 yogyakarta, juni 2019 p-issn 2621-3761 e-issn 2621-2889 p-issn 2621-3761 e-issn 2621-2889 table of contents regular papers: variation of mixed banana peel substrate and cow dung in biogas pressure as a learning source for renewable energy sources puspitawati puspitawati1, riswanto riswanto2, nyoto suseno3 1,2,3muhammadiyah university of metro, indonesia 1 an experiment design for determining the volume of traditional eucalyptus oil with variations in fluid flow speed nur hamida siregar1, moh. toifur2, yudhiakto pramudya3 1darussalam university ambon, indonesia 2,3universitas ahmad dahlan, indonesia 5 an analysis of graduate students’ conceptual understanding in heat and temperature (h&t) using three-tier diagnostic test moh. irma sukarelawan1, jumadi jumadi2, nurulhuda abdul rahman3 1universitas ahmad dahlan, indonesia 2yogyakarta state university, indonesia 3universiti pendidikan sultan idris, malaysia 9 investigating the effects of activation temperature on the crystal structure of activated charcoal from palm bunches (arengga pinnata merr.) vivi hastuti rufa mongkito1, muhammad anas2, wisda puspita bahar3 1,2,3universitas halu oleo, indonesia 15 flipped classroom as a millenial teaching model irnin agustina dwi astuti1, yoga budi bhakti2, ria asep sumarni3, dwi sulisworo4, moh. toifur5 1,2,3universitas indraprasta pgri, indonesia 4,5universitas ahmad dahlan, indonesia 22 indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 6-10 doi: 10.12928/irip.v3i1.1838 http://journal2.uad.ac.id/index.php/irip 6 measuring the apparent magnitude of planet mars on august 1st and october 2nd, 2018 at the falak observatory at muhammadiyah university of north sumatera muhammad hidayat*, arwin juli rakhmadi, and abu yazid raisal observatorium ilmu falak, universitas muhammadiyah sumatera utara jl. kapten muchtar basri no.3, medan, sumatera utara, indonesia *email: dayatc4@gmail.com article info abstract article history received feb 27, 2020 revised jun 6, 2020 accepted june 22, 2020 the bright stars that were seen by the eyes are the received quantity of the energy flux sent from the celestial body. the energy flux is inversely proportional to the distant quadrant which means that the light of the stars that are visible to our eyes cannot be compared to the actual brightness or even weaker than the others and the visible star lights the apparent magnitude. the purpose of this study is to measure the apparent magnitude of mars. this research methodology is quantitative, by taking number of images/videos of mars and then the data is processed by using iris software. the results of the analysis is using iris software that shows the value of the apparent magnitude of mars on august 1st, 2018 is (-1.56 ± 0.33) and october 2nd 2018 is (-1.84 ± 0.08). this was taken by selecting the best image result in clear night sky. keywords: apparent magnitude image processing iris mars to cite this article: m. hidayat, a. j. rakhmadi, and abu yazid raisal, “measuring the apparent magnitude of planet mars on august 1st and october 2nd, 2018 at the falak observatory at muhammadiyah university of north sumatera,” indones. rev. phys., vol. 3, no. 1, pp. 6–10, 2020. i. introduction studying and understanding the deepest parts of the sun and other stars is a physical situation that seems beyond the reach of traditional scientific research methods. however, this information can be reviewed in the form of observational data [1]. physics consists of various branches of science. an interesting branch of science to study is astrophysics. the aim of astrophysics is to find out the physical nature of objects in the universe. [2]. the solar system is the sun and all the objects that are bound by gravity which include planets with their satellites, asteroids, and comets. all circulating around the sun. there are eight planets in the solar system which are mercury, venus, earth, mars, jupiter, saturn, uranus and neptune. in addition there are also five dwarf planets namely ceres, pluto, haumea, makemake and eris [3]. planet term origin was from the greek word planetai/planetes which means wanderer. the planets form elliptical trajectories while rotating which causes alternation of day and night. mars is a planet that has an orbit between earth and jupiter, which has an average distance from the sun of 227.94 × 106 kilometers and an average diameter of 6,794 kilometers. planet mars also has a 677 day of sidereal period [4]. the ability to determine the star’s/planet’s brightness that is visible from different place can be very useful to describe the world to look more 'real'. for this reason, the astronomers measure the brightness of stars and other objects (including planets, asteroids, spaceships, etc) that are visible in the sky. magnitude scale is basically the way of astronomers to measure their brightness [5]. there are three parameters that can be used to develop formulas for clear estimation and also the absolute magnitude of a star which are radius, distance, and temperature [6]. the magnitude of the celestial object as we see it on earth is called the apparent magnitude. the magnitude of the planet mars can be measured by telescope and camera. digital images obtained from this research were analyzed using iris software. this software contains a sophisticated system to measure the size and position of asteroids, comets or estimate the magnitude of celestial bodies. ii. theory magnitude the light of a star in the sky is expressed in a unit namely magnitude. the magnitude system was used by astronomers to measure the brightness of an object relative to a standard object. pogson determined that a difference of 5 magnitudes meant a difference of brightness of 100 times. the objects with brightness i1 and i2 and magnitude scale m1 and m2 are related through the pogson equation (1): m. hidayat, et al. / indonesian review of physics 3(1), 2020, 6-10 7 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 1 1 2 2 1.5 log i m m i          (1) where: m1 = absolute magnitude 1 star m2 = absolute magnitude of 2 stars i1 = star luminosity 1 i2 = star luminosity 2 equation (1) proves that the star's magnitude is proportional to the brightness logarithm. this is a consequence of the logarithmic eye response as stated by weber-fechner's law. the object's magnitude was measured in a range of electromagnetic wavelengths spectrum. for example, visual magnitude measures the objects brightness in visual area. in essence, the measurement of object illumination (i) is an area measurement under the curve of a black body in a range of wavelengths. magnitude measurement in photometric observation is done by taking a series of object images whose magnitude is to be measured and the image of objects whose magnitude is well known (standard object). after the image reduction process is carried out to clean up the noise coming from the instrument, the light intensity measured from the image of a standard object is then compared to the catalog so that it can obtain atmospheric relations, and the influence of the instrument. by knowing these relations, the correction process can be done to measure the magnitude of the object. the magnitude that we measure as seen on earth is called apparent magnitude, while the magnitude measured from the all-same distance is called the absolute magnitude. in this case, the agreed distance is 10 parsec. the relation between apparent magnitude and absolute magnitude is called the distance modulus equation (2). 5 5 logm m d   (2) where: d = star distance (in pc) m = apparent magnitude m = absolute magnitude (m m) = distance modulus. mars mars is the fourth planet from the sun, and the seventh largest planet in solar system. mars has ecliptical orbit that has impacts on the temperature difference in the perihelion and its aphelion. the tilt of the martian axis is around 25.19 degrees. mars has an orbital eccentricity of about 0.09 among the seven other planets in the solar system. the difference of the temperature is around 30°c. this bring a great influence on mars climate. the temperature is around 218 k. the surface temperatures range from 140 k in winter and more than 300 k in summer [7]. table 1. surface temperature surface temperature min max average kelvin 186 k 268 k 227 k celsius −87 °c −5 °c −46 °c 12”f / 8 ritchey-chretien gso telescope this study was using a 12”f/8 ritchey-chretien gso telescope, meade lx850 mounting, and canon 600d camera. the following is a figure 1 and complete specifications of the telescope and mounting used. figure 1. telescope and mounting the telescope and mounting specifications listed in table 2 and table 3. table 2. telescope specification name description model number 12rct telescope series gso ritcheychretiens telescope optical design ritchey-chretien telescope aperture 12" telescope focal ratio f/8 telescope focal length (mm) 2432 optical coatings 99% reflectivity image circle 30 mm, 60 mm with corrector back focus 288 mm telescope eyepiece(s) included no, sold separately finder included? no, sold separately focuser style crayford/crayford style focuser size 3" focuser speed dual speed telescope mount type no mount ota only telescope ota diameter (in.) 14 telescope ota length (in.) 37.8 telescope ota weight (lb.) 44 telescope warranty period two years software iris iris is oriented towards the processing and analysis of scientific images / photographic images. iris software became known in the technology era mid 1980s, when ccd cameras began to be used by amateur practitioners. this software was created in assembly language which has the ability to process images up to 128 x 128 m. hidayat, et al. / indonesian review of physics 3(1), 2020, 6-10 8 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 megapixels or more. in this study, iris software version 5.59 was produced by christian buil in 2000 [3]. cybersky software cybersky is a planetarium program used to learn astronomy and explore the sky in the past, present, and future. cybersky could display adjusted map to the state of the sky as seen from where we are now or in other locations on earth. this program makes it easy to identify objects in the sky. tabel 3. mounting specification name description mount type german equatorial hand controller autostar® ii object database 145,000 objects pointing precision (highprecision mode) 1 arc-minute (+/-) periodic error correction both axes permanent periodic error correction (ppec) starlock™ yes typical guiding performance with starlock < 1 arc-second slow motion controls electronic slew speeds ra and dec 1x, 2x, 8x, 16x, 64x sidereal and 0.25°/sec, 0.5°/sec, 1°/sec, and 3°/sec (max) tracking rates sidereal, lunar, or customselected from 2000 incremental rates control panel 12v dc in, 12v dc out, power, focuser, reticle, handbox port, 1 computer connection port (rs232), 1 starlock port, 1 aux guide port total instrument capacity 90 lbs. tripod lx850 giant field tripod power 12v dc, 5 amp meade universal power supply gps receiver yes time chip yes smart mount™ yes smart drive™ yes anti-vibration pads included stellarium software 0.18.3 stellarium is a software that gives users the freedom to create a virtual planetarium and provides astronomical calculations on astronomical calculation windows [8]. its small capacity and relatively low computer resources make this software crowded by astronomy and sky lovers. more graphics and scenes that seem realistic make the software in it’s circle jealous. based on experience, using various star simulation software, stellarium may depend on the first order for the graphics needed and does not require high computer resources. stellarium has a gpl license or general public license where we can, share and distribute it free of charge from its maker or more cool stellarium is opensource software. iii. method the method used in this study is quantitative, by taking videos of mars using telescope and then analyzed with iris software. the data of this research is apparent magnitude, the observations results at the falak science observatory of the university of muhammadiyah north sumatra which have been analyzed by iris software. iv. results and discussion data collection mars observations were made at the falak science observatory at the university of muhammadiyah, north sumatra on august 1st , 2018 at 10: 43pm (a) and october 2nd, 2018 at 10: 01pm (b). the data obtained in the form of video was processed into the following picture are the processing steps with using iris 5.59 open iris by double-click the iris icon, select file, settings and select a location / folder to place the processed iris image. for image processing from a previously recorded video, open file, select avi conversion. press the select button and find the video file to be processed. make sure the file format is avi. select then click open. in the "exported image type", select black and white. in the "pancho band output file name" fill in the image code in the form of letters. click convert than continue yes. in the treshold section, select auto than select the analysis menu to determine the magnitude value. after the apparent magnitude determined by iris software, the standard deviation can be calculated to show how much the deviation of the data to the apparent value of the apparent magnitude of mars. following are the observations and figure 2 and figure 3 of planet mars. figure 2. planet mars (a) m. hidayat, et al. / indonesian review of physics 3(1), 2020, 6-10 9 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 3. planet mars (b) determine the apparent magnitude of planet mars the first step is to determine the radius of the circle aperture photometry with a radius ratio of 60: 80: 100 for figure 4 and radius 40: 60: 80 for figure 5 using three digital rings at once with different radius. figure 4. planet mars ratio 60: 80: 100 (a) figure 5. planet mars ratio 40: 60:80 (b) the deepest / smallest ring gives a star the intensity value which must be in accordance with the size of the object to be analyzed, while the outer ring for the intensity of the sky. the ring located in the middle (the second ring) acts as a boundary to ensure that there are no signals from objects that will "pollute" the estimated sky signal or vice versa. the apparent magnitude can be calculated by placing the circle of the aperture photometry radius right on the object. in finding apparent magnitudes planets must first look for constant magnitudes (vega stars). as in the following table 4. in table 4, the average value of mars magnitude is 1.56. these results were obtained from an average of 5 data used to sample a total of 588 frames. as well as for figure 3 contained in the following table 5. tabel 4. magnitude value on figure 2 no time magnitude 1 22:43:01 -1.8 2 22:43:03 -1.7 3 22:43:05 -1.8 4 22:43:07 -1.0 5 22:43:09 -1.5 average -1.56 table 5. magnitude value on figure 3 no time magnitude 1 22:01:01 -1.9 2 22:01:04 -1.9 3 22:01:08 -1.8 4 22:01:12 -1.7 5 22:01:16 -1.9 average -1,84 in table 5, the average value of magnitude of mars is -1.84. these results were obtained from an average of 5 data used to sample a total of 244 frames. correction factor from the results of data analysis using iris software, cybersky and stellarium are used as a comparison. it appears that the magnitude of the magnitude obtained from the iris, cybersky and stellarium software is not much different, namely -1.52 for figure 2 and -1.52 for figure 3. the difference may be caused by observer errors when taking image using camera, lack of focus on the telescope when observing, and telescope instruments used. this might also be caused by a cloud covering the time of data collection, or when taking data there is a human error factor that is shaking when shooting. after the apparent magnitude and apparent magnitude average are known, the standard deviation obtained from the apparent magnitude of mars planet figure 2 is (-1.56 ± 0.33) and the measurement error is:  1.52 1.56 100% 2.63% 1.52 r        the standard deviation obtained for the apparent magnitude of mars in figure 3 is equal to (-1.84 ± 0.08). and the measurement error is:  1.52 1.84 100% 21.0% 1.52 r        v. conclusions apparent magnitude average results of data analysis using iris software on mars at august 1st, 2018 figure 2 is (-1.56 ± 0.33) with a measurement error of -2.63% and on mars at october 2nd, 2018 figure 3 is (-1.84 ± 0.08) with a measurement error of -21.0%. apparent magnitude results obtained in accordance with the reference used, based on cybersky and stellarium software is -1.52. m. hidayat, et al. / indonesian review of physics 3(1), 2020, 6-10 10 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 when preparing this study the authors hope to the reader and all related parties that the apparent measurement of magnitude assisted by iris software is developed for the planet mars at different times, as well as observations on other celestial bodies not only planets but stars. acknowledgment thank you to oif umsu helped to guide the continuity of this experimental research and thank you to all friends who helped us in conducting this experiment. reference [1] p. fierros, a, “the effective temperature and the absolute magnitude of the stars,” j. high energy physics, gravit. cosmol., vol. 2, pp. 66–74, 2016. [2] tanzilla r. ishafit and pramudya. y., “measurement eccentricity the moon’s orbit with image analysis technique by using tracker software,” indones. rev. phys., vol. 1, no. 1, p. 19, 2018. [3] hariyadi p, astronomi dasar. medan: cv prima utama, 2016. [4] elizabeth a. m, kamus sains. pustaka pelajar, 2012. [5] constantine t, absolute and apparent magnitudes. 2005. [6] chandra d.a, “apparent and absolute magnitudes of stars: a simple formula,” world sci. news an int. sci. j., pp. 120–133, 2018. [7] hariyadi r, ensiklopedia astronomi jilid 2: planet. jakarta: erlangga, 2008. [8] rudi h.s. putraga h., stellarium & google earth. medan: umsu press, 2018. cover-vol2-no1 2019volume 2 number 1 p-issn: 2621-3761 e-issn: 2621-2889 published by variation of mixed banana peel substrate and cow dung in biogas pressure as a learning source for renewable energy sources puspitawati puspitawati, riswanto riswanto, nyoto suseno an experiment design for determining the volume of traditional eucalyptus oil with variations in fluid flow speed nur hamida siregar, moh. toifur, yudhiakto pramudya an analysis of graduate students’ conceptual understanding in heat and temperature (h&t) using three-tier diagnostic test moh. irma sukarelawan, jumadi jumadi, nurulhuda abdul rahman investigating the effects of activation temperature on the crystal structure of activated charcoal from palm bunches (arengga pinnata merr.) vivi hastuti rufa mongkito, muhammad anas, wisda puspita bahar flipped classroom as a millenial teaching model irnin agustina dwi astuti, yoga budi bhakti, ria asep sumarni, dwi sulisworo, moh. toifur 2621-3761 p-issn e-issn 2621-2889 publisher address: universitas ahmad dahlan (uad) kampus 2 universitas ahmad dahlan jalan pramuka no. 42, pandeyan, umbulharjo, yogyakarta 55161 telp. +62 274 563515, ext. 4902; fax. +62 274 564604 email: irip@mpfis.uad.ac.id indonesian review of physics, volume 1, number 1, 2018 11 the penetration of mobile technology and its implementation on learning in indonesian high school dwi sulisworo1 and muqoyyanah2 1universitas ahamad dahlan, indonesia jl. pramuka no. 42, umbulharjo, yogykarta email: dwi.sulisworo@uad.ac.id 2universiti pendidikan sultan idris, malaysia tanjong malim, perak darul ridzuan 35900 email: anna.physics87@gmail.com the use of a smartphone as a mobile learning tool in schools is controversial. on the one hand, the teacher prohibits it because it would interfere with the learning process in the classroom; and on the other hand, the teacher saw a lot of potentials can be used from mobile technology. the goal of this study is to describe how the development of secondary schools in indonesia can facilitate students through the use of mobile learning with the hope that it can be taken at the school level policies to strengthen the existing learning system so that students can achieve optimal learning competencies. this research used descriptive qualitative evaluations to make observations on the application of mobile learning in several secondary schools in several regions in indonesia during 2015. the results of this study indicate that some of the schools that have implemented mobile learning have a tendency that mobile learning was not planned and structured as a school program; so that the advantages of mobile technology has not been effectively used. twoimportant things to solve this condition are the availability of government policy and improving teachersliteracy in managing mobile learning application. keywords: mobile learning, education, teaching and learning, learning strategy, wireless technology i. introduction following [1] in his research, shows that indonesians citizen on that year is ready to utilize mobile technology both socially and technologically. however, on the other side, following [2] in his research, shows that school has a paradox where students have already had a good ict literacy, but has not been facilitated by the school for the learning process itself. it can be called that the usage of the smartphone as the mobile learning device in school is controversial. on the one side, school prohibits it as it will interrupt the learning process in the class; and on the other hand, the teacher saw that lots of potentials could be used from mobile technology [3,4]. the good news, in recent years there is a significance changing in the thought of the teacher in utilizing ict in the learning process especially in mobile learning. this phenomenon is part of the implication where wireless and mobile technology developed rapidly for the past few years [5, 6]. the technology becomes more inexpensive and has the higher capability and smaller size. it makes the educator or teacher realize that digital technology provides the opportunity for a different learning process; including the relationship between teacher and student, teacher and teacher, student and student, and also the student with the subject or the competence [7]. this research aims to describe how the development of the secondary school in facilitating the student through the use of mobile learning. the result is hoped that school can take a policy to strengthen the learning system so that the student can achieve their learning competence optimally. ii. literary study the mobile technology penetration in indonesia the use of ict on several activities of the learning process in indonesia is seen on a survey written by [8] concerned with the global digital statistic for the past two years (2014, 2015). although generally, penetration in indonesia is up to 28% in 2015, there was a significant improvement from 2014 which is only 15%. there are many development opportunities, in some sectors this improvement could happen. the time used to access the internet in 2015 is 5.1 hours through laptop devices, and 3.2 hours through mobile devices. it shows the shift towards the mobile devices wherein 2014 the access time through laptop mailto:dwi.sulisworo@uad.ac.id1 volume 1, number 1, 2018 sulisworo & muqoyyanah the penetration of mobile technology and its implementation... 12 devices was 5.5 hours and through mobile devices was 2.5 hours. there is increased access through mobile devices for about 0.7 hours which is 28%. the increase which is relatively high in the shift of laptop devices to mobile devices; although there is a decrease in the global rank from the 3rd rank of 25 countries in 2014 becomes the 7th rank of 31countries in 2015. whereas in the side of mobile share on the web traffic in 2015, indonesia contributes 50% to the 4th rank of 31 where the global average is 33%. the increase of the use of mobile devices can be seen as opportunities for the learning process in the school, where the activities done by the student with the mobile devices can help them to achieve their competence optimally. the definition of mobile learning mobile learning (m-learning) is part of the electronic learning or e-learning that give broader opportunities in mobility and more capabilities for student’s learning. therefore, m-learning can be defined differently from elearning concerned with student’s mobility as the learner [3,9]. the learning can be applied wherever the student is benefited from the existence of mobile technology [4,10]. the perspective of mobile learning can be categorized into four categories, those are technocentric, focusing on e-learning, formal education devices, and student-centered learning [11,12,13]. nowadays, the emphasize of technology in school is used to make sure the implementation of active learning with new opportunities and encourage a better learning performance [7,9,10]. iii. method of research this research is descriptive qualitative evaluation research by having an observation on the implementation of mobile learning in some secondary schools in some regions of indonesia in 2015. the total of schools observed for the implementation of mobile learning is 10 secondary school in the 1st grade or 2nd grade on subject physics. the aspects observed in this research is: kinds of mobile application used in the learning process at school, the reasons of using the mobile learning, the variable observed in the implementation of mobile learning, result and problems found in the implementation of mobile learning, kinds of multimedia used in the learning process, and the learning strategy used. iv. research and discussion kinds of mobile application in this research, the application used are moodle, edmodo, path, facebook and self-developed application. moodle is a learning management system with a complete feature. this app can be used either in a laptop, tablet or smartphone. many choices of features can be seen from two sides, that is the high flexibility of teacher and student interaction with the various method but also make a teacher with the limited literacy of the moodle find it challenging to use. the features can be used for journal, chats, and forums, graded quizzes, lessons, book, wikis, lightbox galleries, voicethread, add gadgets, and rss feeds using html, use the project format, and collaborate in realtime. edmodo is a learning management system that inserts parents as the supervisor to watch the student's learning activities. this app can be used both in laptop and other smart devices with social network-based. the features are not as much as in moodle, but for a particular subject, the features are quite sufficient. the features provided in edmodo are polling, gradebook, quiz, file and links, library, assignment, award badge, parent code. this app matches students at the particular level which still need the encouragement of the parents, but in secondary school and above this parent code feature tend to be barely used. the path is a social network that can be used to share a picture and message. in the beginning, this app is not recommended for learning or education, but individually as an application to reach a broader social network in disseminating information. the high use of this app among teenagers, support the possibility of the user in the learning process. this app has limited features to be used in the learning process. grading the learning activities cannot be done automatically with the system, but with this app, the users are comfortable and convenient in communicating in the form of text (messaging). facebook is an application which relatively similar to the path. it is just facebook also has a page features that path do not has. this app is the most used app in social media. the page features in facebook allow the user to share specific themes. facebook app also can be used for chatting and sharing a document which is more flexible. the self-developed application is an application made by the teacher to be adjusted with some specific learning strategies. seen from the modules, generally, this learning management system is also based on the modules that moodle has. the advantage of this app is it customized by the teacher, but it will be difficult for the teacher with insufficient programming background knowledge. reasons for use there are several reasons stated from the research background conducted by teachers in the implementation of mobile learning in the school. first, the need for flexibility for the time of the learning process. it usually happens in the vocational school where the students are doing their field practice; they cannot follow the learning process in the school. in volume 1, number 1, 2018 sulisworo & muqoyyanah the penetration of mobile technology and its implementation... 13 returns, they need to follow the class online. some vocational schools use this reason. it can be said that mobile learning activities can be used as the replacement of activity in the class as the student is somewhere outside the school. the competence to be achieved through mobile learning is also only part of the competence of subject in one semester. secondly, it gives opportunities to the student to relearn the subject more freely. at the school like this, there is a tendency that mobile learning is used in line with the learning at school. it can be called as blended learning. multiple subject and exercises are provided online. the student can relearn the learning subject themselves. a bit different compared to the first reason, in the second reason, mobile learning activities is more likely as a facilitator of the learning process. from both of the reasons, it can be stated that mobile learning is used only to solve the limitations of the learning process in the class. mobile learning has not been used as structured and planned activities in the school. the teachers individually initiate to use mobile learning. several factors cause it such as there is still no national policy that encourages the school to implement the online learning process. there are several possibilities of the government to do not provide the policy such as consideration of the school infrastructure availability and also the rate of teaching literacy in performing mobile learning. if soon the government still not provide the policy concerned with the implementation of online learning, then the opportunities and the advantages of mobile devices will not encourage the national education development. mobile activities done by the student is only in the use of social media. it is as shown in data on global digital statistic[8]. the observed variable generally, in the implementation of mobile learning in the school observed, the dependent variable seen is the subject understanding level. it is surveyed by giving some exercises related to the subject. the exercises are prepared by observing the taxonomy bloom which match the expected level of understanding, test difficulty, different exercises. of all the school observed shows that mobile learning can improve the subject understanding significantly indeed, the result of the test cannot just only be used for justification. it is because the research that is implemented by the teachers is quasi-experimental research. it is mean that there are several variables which possibly give an effect and not observed. the possibilities of other variables that also can be seen on the coefficient of determination value (or r2) which is around 0.60 in every school. several factors such as some students follow the additional lesson outside the school, and the duration of time allocated to every student to access the provided subject outside the school online. even so, it still can be said that mobile learning provides opportunities on the improvement of subject understanding. learning strategy in general, the learning strategy used in blended learning by using mobile devices is individual learning. it means that the success of learning is determined by the intensity of student interaction with the subject and exercises which are provided online. it can be seen in the learning stage prepared by the teacher in the lesson plan although some mobile learning application provides several features, there is a tendency that the main features used are the provision of the learning subject, discussion (synchronous/ asynchronous), exercises and the exam test concerned with the subject. the learning environment is incapable of fostering the self-directed student learning. the student still conducts online learning as the duty from teacher to a particular lesson. it still can be said that the efficiency and the effectiveness of learning by using the advantages of mobile technology, then there should be a policy that should protect this way of learning. v. conclusion nationally, indonesia undergoes the improvement of mobile technology penetration in various aspects. this condition is still not optimally used to improve student competence in the school lesson. in some schools that implemented mobile learning, there is a tendency that it is still not structured and planned as the school program. this condition makes the advantages that mobile technology used in mobile learning is still ineffective. two significant things to improve this condition is the availability of government policy and the improvement of teaching literacy in operating mobile learning application. references [1] sulisworo, d. (2012). the social readiness to implement mobile learning in indonesia. international conference on culture, communication and multimedia technology (pp. 387-391). yogyakarta: uad. [2] sulisworo, d. (2013). the paradox on it literacy and science's learning achievement in secondary schools. international journal of evaluation and research in education, 2(4), 149-152. [3] tal, h. m., & gross, m. (2014). teaching sustainability via smartphone-enhanced experiential learning in a botanical garden. international journal of interactive mobile technology, 8(1), 10-15. [4] mohammad, h., fayyoumi, a., & alshathry, o. (2015). do we have to prohibit the use of mobile phones in volume 1, number 1, 2018 sulisworo & muqoyyanah the penetration of mobile technology and its implementation... 14 classrooms? international journal of interactive mobile technology, 9(2), 54-57. [5] alqahtani, m., & mohammad, h. (2015). mobile applications’ impact on student performance and satisfaction. tojet: the turkish online journal of educational technology, 14(4), 102-112. [6] sulisworo, d. (2014). conceptual model identification of personal learning environment. innovation and development in teaching and learning (pp. 37-41). perak, malaysia: umm. [7] babiker, m. e. (2015). for effective use of multimedia in education, teachers must develop their own educational multimedia applications. tojet: the turkish online journal of educational technology, 14(4), 62-68. [8] kemp, s. (2015). digital, social & mobile worldwide in 2015. from we are social: http://wearesocial.net [9] thinley, p., reye, j., & geva, s. (2014). tablets (ipad) for mlearning in the context of social constructivism to institute an effective learning environment. international journal of interactive mobile technology, 8(1), 16-20. [10] ebrahim, h. s., ezzadeen, k., & a.k, a. (2015). acquiring knowledge through mobile applications. international journal of interactive mobile technology, 9(3), 71-74. [11] chen, c.-h., chen, s.-h., hwang, g.-j., & yang, t.-c. (2010). factors influencing teachers’ adoption of a ubiquitous technology application in supporting teacher performance. international journal of mobile learning and organisation, 4(1), 39-54. [12] crampton, a., ragusa, a. t., & cavanagh, h. (2012). crossdiscipline investigation of the relationship between academic performance and online resource access by distance education students. research in learning technology, 20, 1-13. [13] kukulska-hulme, a. (2007). mobile usability in educational contexts: what have we learnt? international review of research in open and distance learning, 8(2), 1-12. dwi sulisworo1 and muqoyyanah2 irip p-issn 2621-3761 e-issn 2621-2889 irip (indonesian review of physics) is a journal of physics and physics education research. it is compiled with a commitment to enhance quality of the research. indonesian review of physics (irip) aims to provide a forum for researchers, lecturers, teacher and student on the topics related to physics and physics education. the journal was first published in 2018 and regularly published twice per year in june and december. editor in chief managing editor fatin aliah phang scopus id: 57192376607 universiti teknologi malaysia johor bahru, malaysia email: p-fatin@utm.my dwi sulisworo scopus id:55317003800 universitas ahmad dahlan yogyakarta, indonesia email: dwi.sulisworo@uad.ac.id advisory international editorial boards akihiko tomita scopus id: 7201880070 wakayama university japan atomita@center.wakayama-u.ac.jp hassan k. juwhari scopus id: 6503859673 university of jordan jordan juwhari@ju.edu.jo rizky merian muspa universitas ahmad dahlan indonesia efi kurniasari universitas ahmad dahlan indonesia moh irma sukarelawan universitas ahmad dahlan indonesia publisher address: universitas ahmad dahlan (uad) kampus 2 universitas ahmad dahlan jalan pramuka no. 42, pandeyan, umbulharjo, yogyakarta 55161 telp. +62 274 563515, ext. 4902; fax. +62 274 564604 email: irip@mpfis.uad.ac.id muhammad abdul hadi bunyamin scopus id: 57195100817 universiti teknologi malaysia malaysia mabhadi@utm.my yudhiakto pramudya scopus id : 57192652457 universitas ahmad dahlan indonesia yudhiakto.pramudya@pfis.uad.ac.id noorali t jiwaji scopus id: 57190731624 open university of tanzania, united republic of tanzania noorali.jiwaj@out.ac.tz budhy kurniawan scopus id: 6602596727 universitas indonesia indonesia bkuru07@gmail.com moh toifur scopus id: 570242327000 universitas ahmad dahlan indonesia mtoifur1807@gmail.com johny setiawan scopus id: 8680503300 unimatrix verlagberlin, germany setiawan@uni-matrix.de editorial asistant journal manager rungchatchadaporn vehachart scopus id: 6992533300 thaksin university thailand vahachart@hotmail.com p-issn 2621-3761 e-issn 2621-2889 irip regular papers: effect of the magnetic force on ferrite pendulum oscillation parameters: parametric analysis on ferrite pendulum rusli adi, moh toifur, ishafit ishafit, rosly jaafar measuring the apparent magnitude of planet mars on august 1st and october 2nd, 2018 at the falak observatory at muhammadiyah university of north sumatera muhammad hidayat, arwin juli rakhmadi, abu yazid raisal development of interactive physics e-module using the sets (science, environment, technology, society) approach to improve science literacy dimension of content and process dimensions in fluid dynamics material eka syafutri, widodo widodo, yudhiakto pramudya analysis of students' understanding of concepts on momentum and impulse material using research-based learning (rbl) models nanda safarati, rahma rahma effect of deposition voltage on layer thickness, microstructure, cu/ni sheet resistivity of deposition results by magnetic field electroplating assisted technique willi anindita wijanarka, moh toifur implementation cooperative learning type stad assisted edmodo in improving students' critical thinking skills muhamad epi rusdin, widodo widodo, guntur maruto published by universitas ahmad dahlan irip vol.3 no.1 pp. 1-34 yogyakarta, june 2020 p-issn 2621-3761 e-issn 2621-2889 (indonesian review of physics) vol. 3 no. 1, june 2020 p-issn 2621-3761 e-issn 2621-2889 table of contents regular papers: effect of the magnetic force on ferrite pendulum oscillation parameters: parametric analysis on ferrite pendulum rusli adi1, moh toifur1, ishafit ishafit1, rosly jaafar2 1 measuring the apparent magnitude of planet mars on august 1st and october 2nd, 2018 at the falak observatory at muhammadiyah university of north sumatera 6 development of interactive physics e-module using the sets (science, environment, technology, society) approach to improve science literacy dimension of content and process dimensions in fluid dynamics material 11 analysis of students' understanding of concepts on momentum and impulse material using research-based learning (rbl) models 19 effect of deposition voltage on layer thickness, microstructure, cu/ni sheet resistivity of deposition results by magnetic field electroplating assisted technique willi anindita wijanarka1, moh toifur2 23 implementation cooperative learning type stad assisted edmodo in improving students' critical thinking skills muhamad epi rusdin1, widodo widodo2, guntur maruto3 30 1ikip muhammadiyah maumere, maumere, indonesia 1universitas ahmad dahlan, yogyakarta, indonesia 2universiti pendidikan sultan idris, kuala lumpur, malaysia muhammad hidayat, arwin juli rakhmadi, abu yazid raisal universitas muhammadiyah sumatera utara, sumatra utara, indonesia eka syafutri, widodo widodo, yudhiakto pramudya universitas ahmad dahlan, yogyakarta, indonesia nanda safarati, rahma rahma universitas almuslim, aceh, indonesia 1smp muhammadiyah 1 mlati, yogyakarta, indonesia 2universitas ahmad dahlan, yogyakarta, indonesia 2universitas ahmad dahlan, yogyakarta, indonesia 3universitas gajah mada, yogyakarta, indonesia indonesian review of physics, volume 1, number 1, 2018 7 the effect of the microsoft excel based interactive learning media on the physics problem solving irnin agustina dwi astuti1 and yoga budi bhakti2 1,2 indraprasta pgri, indonesia jl. raya tengah no.80, gedong, pasar rebo, jakarta timur email: irnin.agustina@gmail.com the physics problem solving is needed students to overcome the phenomenon of physics. the development of technology in physics learning is able to explain the concept of abstract physics . this study aims to know effect of use interactive learning media based microsoft excel on the physics problem solving. the subject on this media is heat and temperature. the research method used is pretest-postest controlled group design. the analysis technique is used t-test with spss 16.0 with a margin of error of 5%. the results of this study showed that the mean scores of post-test treatment class students significantly better than the average score post-test control class indicated by the average score of students' post-test treatment class at 80.26 and scores the average post-test control class at 68.00 and with spss analyze sig value is 0.000. while the average score gain results-physics students learn physics class treatment significantly better than the average score gain results physics students learn physics-control class indicated by the average score of physics problem solving gain of 0.77 and the treatment class the average score gain control class student physics problem solving of 0.63. keywords: physics problem solving, interactive learning media, microsoft excel, physics learning. i. introduction physics learning is the combination of learning activities in the form of abstract theories to be connected in a real life. learning activities will be very fun and have meaning if the teacher is right in choose the method, model or media. mistakes in choosing a method or media in the learning of physics will have an impact on less interesting learning process so that the students' learning motivation is low, which will have a low impact on student learning outcomes. inadequate student learning outcomes are caused by low problem-solving abilities. problem solving is a basic activity for humans because in human life will definitely deal with the problem. science can also be interpreted as a way of thinking in solving a problem [1]. however, in-class learning tends to emphasize mastery of concepts and override students' physics problem solving abilities [2]. students experience difficulties when faced with complex problems. students are able to solve simple quantitative problems but lack the ability to solve more complex problems [3]. in fact, one of the goals of physics learning is to create human beings who can solve complex problems by applying their knowledge and understanding to everyday situations [4]. learning media could support learners’ problemsolving and critical-thinking abilities. the use of learning media in a form of e-learning could improve learning into becoming more efficient with support from the learning motivation possessed by learners and it has a sufficiently significant impact on the e-learning [5]. learning with technological media exerts a sufficiently significant influence with learners getting a stimulation effect from the use of the media in the learning process [6]. the aims of physics learning is to develop problemsolving abilities by applying concepts to the calculation appropriately. to improve the ability of physics problem solving, it needs to develop interactive learning media that can explain the concept and also the calculation. the learning media to be developed is microsoft excel. it can be used as a media delivery concept like a powerpoint slide. the advantage of this media is the students can understand concepts as well as mathematical calculations together. volume 1, number 1, 2018 astuti & bhakti the effect of the microsoft excel based interactive learning media... 8 from the result of the development of learning media based microsoft excel by astuti [7], shows that the media worth tested to students with the average feasibility 3.4. media has not been tested to students, it is necessary to conduct large-scale trials to determine the effectiveness of learning media on the learning of physics at school. ii. literature review learning media information and communication technology (ict) in learning makes learners feel more sure and more directly involved in the learning activity and, in addition, ict-based learning activity should also be supported with teacher ability in using ict in daily learning practice [8]. learning media is a tool in teaching and learning process, can be printed media, voice media, audio-video media, interactive media, and e-learning. learning media can add the attractiveness of the material, so it can increase the motivation and the proclivity. then it can take the student's attention to focus on following the material presented, so it also expected the learning effectively will be increased [9,10]. microsoft excel microsoft excel is usually used to analyze values in school activities. this program is often used by accountants to write or record expenses and income in the company or an institution or small agencies. microsoft excel program is very useful in chemistry teaching due to its extensive ability in processing and presenting data [7, 11]. microsoft excel is very important to analyse physics experiment, such as physics simulation, linear regression, vba (visual basic analysis), presentation, and calculate of physics. physics problem solving problem-solving skills in science teaching and learning is an objective of science learning that is expected to be acquired by students so that they can apply scientific knowledge to the real world meaningfully [12,13]. problem-solving involves various metacognitive strategies to enable students to understand how they think and explore the various methods to solve problems in science [13,14]. the ability of problem solving physics able to analyze physical phenomena both real and abstract. students are trained to think of solving physics problems that exist in everyday life. iii. method this research is the quasi-experiment using post test only for control group design. the subjects were students in junior high school in yogyakarta. the number of respondents was 28 students for treatment class and 28 students for the control class. the dependent variables applied in this study was physics problem solving. the independent variable is learning media in which the control group applied powerpoint, while the trearment group applied multimedia based microsoft excel. the physics problem solving instrumen is evaluation questions with multiple choice and essay. the number of multiple choice are 10 questions and the number of essay are 5 questions. test results of this evaluation given before (pre test) and after (posttest) of learning, prior to model use the test is first conducted trials to know the level of validity, reliability, problem difficulty level, and differentiator of test. test the difference in mean treatment class and control class used t-test with spss 16.0 with a margin of error (alpha) of 5%. as for knowing improvement of the physics problem solving of treatment class and control class is calculated by using gain score normalized as shown in table 1. table 1. the category of gain score range category g > 0,7 high 0,3 < g ≤ 0,7 medium g ≤ 0,3 low iv. result and discussion based on the results of this research, obtained the results of pre-test, post-test and gain of treatment class and control class as in table 2. table 2. the results of pre-test, post-test and gain nilai treatment class control class pre test post test gain pre test post test gain maximum 70 86 0,77 64 76 0,63 minimum 50 72 42 60 average 61,36 80,26 54,50 68 deviation standard 4,9 3,5 5,4 4,4 based on table 2, the average value is shown physics problem solving before and after the process learning has improved from results pre-test and post-test of treatment volume 1, number 1, 2018 astuti & bhakti the effect of the microsoft excel based interactive learning media... 9 class or control class. increased yield student learning after science-physics learning because of the different treatments inside the learning process (learning media) is in the treatment class used a learning media based microsoft excel while in the control class use powerpoint. improved of physics problem solving in treatment class and control class can seen from acquisition of gain and value categorization of gain in table 2. the students average value of gain in treatment class is 0,77 (high category of 77%) while the average gain of student learning outcomes in class control that is equal to 0,63 (medium category by 63 %). to know the difference in average results the students learn of treatment class with the students of control class using t test, which first used the test data normality or test of data homogeneity, can be viewed in table 3. table 3. the result of t-test analysis with spss 16.00 levene's test for equality of variances t-test for equality of means f sig. t df sig. (2tailed) mean difference std. error difference 95% confidence interval of the difference lower upper physics problem solving equal variances assumed 3.235 .078 11.561 54 .000 12.286 1.063 10.155 14.416 equal variances not assumed 11.561 51.546 .000 12.286 1.063 10.153 14.419 from table 3 above it can be seen that the physics problem solving between the control group and treatment group were significantly different at the level of error of 5% or 95% level of confidence, with sig 0.000 (< 0.05). hence, it can be said that in the physics problem solving, the students who follow the learning media based microsoft excel reached the higher score than students who follow learning media with powerpoint. based on the data analysis seen that by using learning media based microsoft excel can provide differences in physics problem solving of science-physics students compared with using the learning media with powerpoint. in this research, physics learning by microsoft excel shown the students very fun and can improve learning motivation. learning media based ` given to students in the form of learning media whose contents are material, physics animation, physics experimental video, physics phenomena analysis, practice questions and evaluation, media is one of the alternatives or learning methods that can make students active. in science education, interaction between objects and students are necessary. if it is not possible, the teacher should be able to make a modification, it could be a model of real objector visualization through other media [15]. basic skills of science is an education that not only prioritize the achievement of goals, but the learning process that is directed at the development of students' potential as a whole [16]. learning media based microsoft excel can improve students' learning skill in learning. proven students are able to process data using microsoft excel itself [17]. in the physics learning of microsoft excel is used to analyze the physical phenomena using microsoft excel spreadsheet [18]. it can be interest by the students to improve their skill problem solving. the students can open this media everytime and everywhere. so, the students can study independently. problem solving in general and physics problem solving, in particular, encapsulate several intriguing aspects [19]. the identification and exploration of these aspects can offer a multipronged tool to address the issues pertaining to difficulties faced by many students for problem solving. physics teachers often have the sense that “problem solving is where you learn to actually do physics”, where students should learn the process and sense making that exemplifies good physical thinking [3, 20]. science teachers recognize that students should be prepared to get information related to technology issues of interest to the general public [21]. teachers are able to make the media as interesting as possible so that students are motivated in learning. so with the media can change the cognitive abilities of students in science learning. multimedia learning occurs when students build mental representations from words and pictures that are presented to them. science learning by media is that students can learn more deeply from well-designed multimedia messages consisting of words and pictures than from more traditional modes of communication involving words alone [22,23] learning by using learning media based on microsoft excel this can be used as new learning alternative for volume 1, number 1, 2018 astuti & bhakti the effect of the microsoft excel based interactive learning media... 10 teachers, because this learning proven can improve problem solving ability especially physics subject. this can be seen from the results of student physics problem solving, where the experimental class obtains the average of indigo better than the control class. v. conclusion based on the analysis, the results of research and discussion can be concluded that the use of learning media based on microsoft excel can improve the results of problem solving physics in students. this is in accordance with a normalized gain test that shows an increase in students who were taught using microsoft excel based learning media is 0,77. references [1] syukri m, soewarno s, halim l, mohtar l e, the impact of engineering design process in teaching and learning to enhance students’ science problem-solving skills, jurnal pendidikan ipa indonesia, vol. 7, no. 1, 2018, pp. 66-75. [2] hoellwarth, c., moelter, m. j., & knight, r. d, a direct comparison of conceptual learning and problem solving ability in traditional and studio style classrooms, american journal of physics, vol 73, no. 5, 2005, pp. 459-462. [3] tuminaro, j., & redish, e. f, student use of mathematics in the context of physics problem solving: a cognitive model u, of maryland preprint, 2005. [4] walsh, l. n., howard, r. g., & bowe, b, phenomenographic study of students’ problem solving approaches in physics, physical review special topics-physics education research, vol. 3, no. 2, 2007, pp. 020108. [5] matsuo. k, barolli. l, xhafa f, koyama a & durresi a, new function for stimulating learners' motivation in a web-based elearning system. journal of distance education technologies, 2008, pp. 34-49. [6] sakat.a a, mohd zin. m z, muhamad. r, ahmad. a, ahmad. n a., & kamo. m a, educational technology media method in teaching and learning progress. american journal of applied science, 2012, pp. 874-888. [7] astuti, iad & bhakti, yb. interactive learning multimedia based microsoft excel on the temperature and heat. unnes science education journal, vol. 7, no. 1, 2018, pp. 1-6. [8] dagiane. v, ignatova. n & kubilinskiene. s, ict-based learning personalization affordance in the context of implementation of constructionist learning activities, informatics in education an international journal, vol. 14, no. 1, 2015, pp. 53-67. [9] sukarno & sutarman d, the development of light reflection props as a physics learning media in vocational high school number 6 tanjung jabung timur, international journal of innovation and scientific research, vol. 12, no. 2, 2014, pp. 346355. [10] gonzález,m á, martín m e, llamas c, martínez ó, vegas j, and hernández c 2017 teaching and learning physics with smartphones. in blended learning: concepts, methodologies, tools, and applications (pp. 866-885). igi global. [11] bharathy j b, importance of computer assisted teaching & learning methods for chemistry, science, vol. 3, no.4 , 2015, pp. 11-16. [12] syukri m, soewarno s, halim l, mohtar l e, the impact of engineering design process in teaching and learning to enhance students’ science problem-solving skills, jurnal pendidikan ipa indonesia, vol. 7, no. 1, 2018, pp. 66-75. [13] lee m k, & erdogan i, the effect of science–technology–society teaching on students’ attitudes toward science and certain aspects of creativity. international journal of science education, vol. 29, no. 2, 2007, pp. 1315-1327. [14] halim a, yusrizal y, susanna s, & tarmizi, t, an analysis of students’ skill in applying the problem solving strategy to the physics problem settlement in facing aec as global competition. jurnal pendidikan ipa indonesia, vol. 5, no. 1, 2016, pp. 1-5. [15] rahman mja, ismail. m a & nasir. m, development and evaluation of the effectiveness of computer-assisted physics instruction. international education studies, vol. 7, no. 13, 2014, pp. 14. [16] bhakti, yb & astuti, iad. the influence process of science skill and motivation learning with creativity learn. journal of education and learning, vol. 12, no. 1, 2018, pp. 30-35. [17] bruce. w c & meehan. a m, microsoft excel™ as a tool for teaching basic statistics. teaching of psychology, vol. 28, no. 4, pp. 295-298. [18] brown. a m, a step-by-step guide to non-linear regression analysis of experimental data using a microsoft excel spreadsheet, computer methods and programs in biomedicine, vol. 65, no. 3, pp. 191-200. [19] hegde b & meera b n, how do they solve it? an insight into the learner’s approach to the mechanism of physics problem solving, physical review special topics physics education research, vol. 8, no. 1, 2012, pp. 01010. [20] yang, ya-ting carolyn, building virtual cities, inspiring intelligent citizens: digital games for developing students’ problem solving and learning motivation, computers & education, vol. 59, no. 2, 2012, pp. 365-377. [21] firdaus t, setiawan w, & hamidah, i, the kinematic learning model using video and interfaces analysis, in journal of physics: conference series, vol. 895, no. 1, 2017, pp. 012108. iop publishing. [22] chandler p d, middle years students’ experience with new media, australian journal of education, vol. 57, no. 3, 2013, pp. 256269. [23] mayer r e, the promise of multimedia learning: using the same instructional design methods across different media, learning and instruction, vol. 13, no. 2, 2003, pp. 125-139. irnin agustina dwi astuti1 and yoga budi bhakti2 jl. raya tengah no.80, gedong, pasar rebo, jakarta timur keywords: physics problem solving, interactive learning media, microsoft excel, physics learning. references indonesian review of physics, volume 1, number 1, 2018 15 architecture of atwood machine props with sensor-based passive infrared delia achadina putri1 and dandan luhur saraswati2 1,2pendidikan fisika universitas indraprasta pgri, indonesia jl. raya tengah no.80 kel. gedong, kec. pasar rebo, jakarta timur email: deliachadina@gmail.com the aim of this research is to develop atwood machine propswith sensor-based pir (passive infrared) to determine the acceleration value of earth gravity. this type of research is an experiment conducted in the physics laboratory of universitas indraprasta pgri. atwood machine was developed by using pir (passive infrared) sensors to detect the movement of the objects used. based on the trialof the result of the data analysis experiment tool, the acceleration of gravity was obtained (9.87 ± 0.08) m/s2. whereas the value of acceleration of gravity in the literature is 9,80665 m/s2. the obtained results shows that the acceleration of gravity obtained in this research is not much different from the acceleration value of gravity found in the literature so that atwood machine tool that is developed by using pir sensor is recommended to be one alternative tool in determining the acceleration of earth gravity. key words: acceleration of gravity, atwood machine, pir (passive infrared) sensors i. introduction physics is not merely a theory lesson where its benefits cannot be perceived by society. physics is one of the natural sciences which became the basis of a wide range of technologies in the world [1]. physics study about natural phenomena or subject in the scope of space and time, so that the implementation of physics can be used to study how this natural phenomenon occurs [2]. in physics various motion of objects started from the motion of marbles, motion of planet rotation, motion of rocket, or even the motion of an apple falling from the tree are studied in the branch of physics called mechanics. in general mechanics is divided in two subjects, called the dynamics and kinematics. dynamics study about motion of objects and its causes and kinematics study about motion of objects only without necessarily know the causes [3]. the atwood machine is a tool that can be used to analyze the mechanisms used to measure acceleration. typically, a teacher demonstrating the study of gravity only to prove the existence of gravity acceleration, for example by removing an object from a certain height, but students have never directly done the experiment to find out how to determine the acceleration value of gravity that they have been reading through books. the object will fall with an acceleration caused by the gravitational forces of the earth or earth’s gravity. this earth’s gravity causes an object falling from a certain height with an acceleration known as the acceleration of earth’s gravity. the acceleration of earth’s gravity is influenced by the distance of an object from the earth’s center and the density of earth’s composition in that coordinate [4].the acceleration of earth’s gravity symbolized by ' g ' indicates the average acceleration produced by gravitational field on the earth surface with unit m/s2 [5].with the advance of science, technology and also latest innovation, it provide an opportunity for researchers to create atwood machine props. nowadays, atwood’s machine is used with purposes to demonstrate uniformly accelerated motion with smaller acceleration than the gravitational acceleration g[6]. the atwood’s machine is a device where two masses hang from the ends of string passing over a pulley that can freely rotate on its horizontal axis [7]. the atwood machine is an experimental tool used to observe uninform mechanics’ law of motion. this tool began to be developed around the eighteenth century to measure the acceleration of gravity. the props used to describe the relationship between stress, potential energy and kinetic energy using two ballast (different mass) which are m1 (m+m) and m2 (m) connected by a string on a pulley. objects with larger mass (m1) is higher in position than the lighter mass (m2). thus, an object with mass m2 will move down because of the effect of gravitational acceleration and pull m1 because of the connected rope in the pulley. mailto:deliachadina@gmail.com volume 1, number 1, 2018 putri & saraswati architecture of atwood machine props with sensor-based passive infrared 16 simply put, this tool is composed of a rope connected to a pulley, which at the end of the rope is hooked with mass of loadsm1 and m2. if the mass of the object m1 and m2are equal (m1 = m2), then both will be silent. however, if the mass of the object m2 is greater than the mass of the object m1, then the mass m1 will be pulled by the mass. in this research, the pir sensor used is hc-sr501 type. needs of hc-sr501 sensor input according to its datasheet is 4.5-20v dc with maximum current 50ua. the ability to detect the sensor from 3-7 meters with delay between 5-200 seconds. the angle range is 140 ° [8]. ii. literature review today, it is common that many experimental physics programs include atwood machines and variable masses to introduce more complex concepts in physics. to study the mass dynamics that make up the atwood variable machine, the lab usually uses intelligent pulleys [9]. in thisatwood machine contain elements of translational motion that is uninform linear motion(glb) and accelerated linear motion (glbb). according to marthen kanginan, uninform linear motionis a rectilinear motion of an object, where in this motion its velocity fixed or no acceleration, so the distance traveled is speed times time [10]. while the accelerated linear motion is rectilinear motion of an object, where the velocity is changing [11]. not only the uninform linear motion or accelerated linear motion but the working principles of the pulley is also appl. a pulley is a wheel with a rope around and used to ease the work of people [12]. the acceleration of earth's gravity is the acceleration experienced by objects that fall freely from a certain height toward the earth's surface. based on the literature, the earth's gravity acceleration value is equal to 9,80665 m/s2[13]. the direction of gravitational acceleration is toward the center of the earth or perpendicular to the surface of the ground. the magnitude of gravitational acceleration in several different places may not be exactly equal to 9.80665 m/s2. this is due to the difference in mass density and distance of a place from the center of the earth[14]. the sensor is the equipment used to change a physical quantity to electricity quantity so it can be analyzed with specific electrical network[15].passive infrared sensor is a low cost, low power and reliable sensor [16]. pirbased system saves power consumption and memory space [17]. ir filter contained in the pir sensor is capable of filtering the wavelength of passive infrared light between 8 to 14 micrometers. this infrared ray is then captured by the pyro-electric sensor which is the core of the pir sensor. the pyro-electric sensor consists of gallium nitride, cesium nitrate and litium tantalite which produces an electric current [8].however, unlike most of others infrared where they consist of led and fototransistor, pir does not emit anything as ir leds. in accordance with the name ‘passive’, this sensor only responds energy from the passive infrared beams which are owned by any objects detected by it[18]. pir sensor has two sensing elements connected to the inputwith the order as shown in the following figure [19]. figure 1. pir sensor wave range direction iii. research methods/experiment 1. tools and materials: atwood machine consist of: a. the pole with a pullet at the top b. a hanging rope with a negligible mass c. two load of m1 (just above the sensor hole of timer 1) and m2 (located on the stopper) cylindrical with a sharp point underside d. stopper to hold m2 e. sensor 1 (at point a) used to turn on stopwatch 1. sensor 2 (at point b) with double function that are turn off stopwatch 1 and simultaneously turn on stopwatch 2. sensor 3 (at point c) turnoff stopwatch 2. f. the stopwatch box, which contains stopwatch 1 to record time from point a to point b. stopwatch 2 to record time from point b to point c. volume 1, number 1, 2018 putri & saraswati architecture of atwood machine props with sensor-based passive infrared 17 2. tool design: figure 2. atwood tool design 3. step tes tool : a. prepare the atwood machine device in a flat ground. b. set m1 right above the timer sensor 1 and located in thecenterhole of the sensor and one load again on stopper (m2). c. turn on all stopwatch and reset to zero (0) d. the size of the components required for the calculation of the atwood machine is as follows: table i. table of component amount quantity units (kg)z mass of the load 0,07 mass of the pulley 0,4 e. press the stopper so mass m2 and m1 apart from the andmoving down pass the hole sensor timer 1 to turn on the stopwatch 1, then pass hole sensor timer 2 with double function that is turning off stopwatch 1 and simultaneously turn on the stopwatch 2, and the last pass through the sensor hole 3 to turn off the stopwatch 2. f. observe and record how much time is shown on stopwatch 1 (time from point a to b (tab)) and stopwatch 2 (time from point b to c (tbc)). g. calculate the acceleration value of gravity by using the formula: 𝑔 = (2�̅�+�̅�+𝑚𝑝̅̅̅̅̅).�̅� �̅� (1) iv. research results and discussion in this research we get experiment data that is: table ii. experiment data no load mass [m] (kg) mass of ballast [m] (kg) time a-b [tab] (s) time b-c [tbc] (s) acceleration [a] (m/s2) 1 0,070 0,010 2,75 1,34 0165530 2 0,072 0,011 2,70 1,24 0,180998 3 0,070 0,011 2,50 1,30 0,182820 4 0,069 0,012 2,45 1,35 0,176045 5 0,071 0,010 2,68 1,26 0,179207 after the data were analyzed and the acceleration value of earth gravity was calculated by using the equation (1), so the earth gravity acceleration value in this study was (9,87 ± 0,08) m/s2. these results are better than research conducted by syahrul, et al, who get the acceleration value of earth gravity that is 9,619 m/s2[20]. the value obtained in this study is not much different from the literature that underlie this research which is 9,80665 m/s2. v. conclusion 1. a simple atwood machine can be used to measure the magnitude of earth’s gravitional acceleration 2. the acceleration value of gravity obtained in this research is equal to (9,87 ± 0,08) m/s2. the value obtained in this study is not much different from the literature that underlie this research which is 9,80665 m/s2. acknowledgement researchers say thanks to oki mustava and dr. dwi sulisworo, m.t who has been a reviewers of the journal that has researchers create and thanks to the indonesian review of physics that can publish our journal as well as the physics laboratory of the universitasindraprasta pgri which has become our research place. literature [1] firman nugraha, et al, eksperimen pesawat atwood berbasis pengolahan aplikasi tracker untuk mengamati fenomena gerak lurus beraturan dan gerak lurus berubah beraturan pada pembelajaran fisika sma (atwood aircraft experiments based on tracker application processing to observe the phenomenon of regular straight motion and regularly changed straight motion on high school physics learning), prosiding seminar nasional fisika snf 2017, vol. 6, 2017, p-issn: 2339-0654 [2] hendrik tri wicaksoni, eko setyadi kurniawan and h. arif maftukhin, pengembangan alat peraga resonator sebagai alternatif 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[14] disah nur afifah, dewi yulianawati, nina agustina, ratu dewi sri lestari and muhamad gina nugraha, metode sederhana menentukan percepatan gravitasi bumi menggunakan aplikasi tracker pada gerak parabola sebagai media dalam pembelajaran fisika sma (simple method to determine earth gravity acceleration using tracker application on parabolic motion as a media in high school physics learning), prosiding seminar nasional inovasi dan pembelajaran sains, bandung, juni 2015, isbn: 978-196558-0. [15] zuly budiarso and eddy nurraharjo, sistem monitoring tingkat ketinggian air bendungan berbasis mikrokontroler (microcontroller based dam water level monitoring system), jurnal dinamika informatika, vol 3, no. 1, 2011 [16] pema chodon, et al, passive infrard (pir) sensor based security system, international journal of electrical, electronic and computer system, vol. 14, issue. 2 , 2013 [17] shafiqul abidin and manu ahuja, infra red radiation detection using paassive infrared sensor, international journal of computer applications, vol. 152, no. 5, 2016 [18] jati lestari and grace gata, webcam monitoring ruangan menggunakan sensor gerak pir (passive infra red) (webcam monitoring room using pir (passive infra red) motion sensor), bit, vol. 8, no. 2, 2011, issn: 1893-9166 [19] berri parima dan rozeff pramana, perancangan sistem keamanan rumah menggunakan sensor passive infra red berbasis mikrokontroler (home security system design using microcontroller based passive red sensor), teknik elektro, 2013 [20] syahrul, jhon adler and andriana., pengukur percepatan gravitasi menggunakan gerak harmonik sederhana metode bandul (measuring gravity acceleration using simple harmonic motion of the pendulum method), jurnal teknik komputer unikom, vol. 2, no. 2, 2013, https://repository.unikom.ac.id/30330/1/2.syahrulpengukur-percepatan-gravitasi.pdf diakses pada tanggal 28 mei 2018 https://repository.unikom.ac.id/30330/1/2.syahrul-pengukur-percepatan-gravitasi.pdf https://repository.unikom.ac.id/30330/1/2.syahrul-pengukur-percepatan-gravitasi.pdf delia achadina putri1 and dandan luhur saraswati2 key words: acceleration of gravity, atwood machine, pir (passive infrared) sensors acknowledgement researchers say thanks to oki mustava and dr. dwi sulisworo, m.t who has been a reviewers of the journal that has researchers create and thanks to the indonesian review of physics that can publish our journal as well as the physics laboratory of the u... literature indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 35-39 doi: 10.12928/irip.v3i2.2074 http://journal2.uad.ac.id/index.php/irip 35 the effect of the installation angle of the sky quality meter on the night sky brightness and the beginning of the fajr prayer time abu yazid raisal*, muhammad hidayat, leo hermawan and arwin juli rakhmadi observatorium ilmu falak, universitas muhammadiyah sumatera utara jl. denai no.217, kec. medan denai, medan, sumatera utara, indonesia *email: abuyazidraisal@gmail.com article info abstract article history received apr 18, 2020 accepted nov 26, 2020 published dec 31, 2020 measuring the brightness of the night sky and determining the start of fajr prayer times can be done using sqm. observations were made at oif umsu with coordinates 3o 34' 55.06" n and 98o 43' 17.09" e. the sky brightness was measured using three sqms mounted facing the zenith, eastern horizon, and western horizon. the night sky brightness values for sqm directed to the zenith, eastern horizon, and western horizon are 18.23 mpsas, 15.82 mpsas, and 15.47 mpsas. the beginning of fajr prayer time produced by sqm is after the beginning of fajr prayer time obtained using the accurate times concerning the sun's altitude 18o below the horizon. the difference obtained by sqm directed to the zenith, eastern horizon, and western horizon is 29.5 minutes, 36.7 minutes, and 39.5 minutes. in other words, the beginning of fajr prayer time used in indonesia is earlier than it should be. keywords: fajr prayer time light pollution night sky brightness sky quality meter to cite this article: a. y. raisal, m. hidayat, l. hermawan, and a. j. rakhmadi, “the effect of the installation angle of the sky quality meter on the night sky brightness and the beginning of the fajr prayer time,” indones. rev. phys., vol. 3, no. 2, pp. 35–39, 2020. i. introduction observing the stars during the night is an exciting task to be done. that can only happen if the sky is free of light pollution. globally, light emission has become a concern because it progressively decreases the possibility of seeing stars and reduces the number of light-sensitive species [1], [2]. however, the public often ignores these problems even though the adverse effects of light pollution are known. in contrast to other pollution, light pollution does not mean light that gets the impact of pollution, but light itself is a pollutant for the night sky's dark conditions [3]. the larger the human population, the more light is needed to illuminate human activities at night. light pollution is a condition where, due to accidental illumination caused by improper lighting design, species are exposed to light at the wrong location, time, and intensity [4]. light pollution has a significant effect on the night sky brightness. therefore, it is necessary to measure the night sky brightness to determine the pollution level and become a reference for making policies in outdoor lighting systems [5]. the night sky brightness can be measured using the sky quality meter (sqm). sqm is a system used for calculating night sky illumination. with a size that is easy to hold, this tool makes it possible for the general public to measure the night sky's quality whenever and wherever [6]. besides, this tool is also the choice of night sky brightness researchers because it is user friendly and has good aftersales service and support [7]. sqm is also used to assess the eclipse period and the beginning of the fajr prayer time [8], [9]. sqm has a field of view around 20o with an uncertainty of the order of 10% [10]. with an area of view of 20o, sqm does not record the sky as a whole. in general, the sun rises from the eastern horizon. the eastern horizon is bright earlier than the zenith and the western horizon. this study entitled the analysis of the influence of the sky quality meter's angle on the night sky's brightness and the beginning of the fajr prayer time. this study aims to determine whether there are differences in the value of the night sky brightness in the sky toward the east horizon, zenith, and west horizon. besides, this study also aims to look for the effect of different sqm angles on the beginning of fajr prayer time. ii. theory sqm is divided into two types, namely sqm without a lens and sqm using a lens. sqm that uses a lens (l) has a smaller view than without a lens around 20o, as shown in figure 1. with a smaller field of view, the data reading will be more consistent when the nearest light source appears [11]. sqm measures the night sky brightness in magnitude per square arcsec or mathematically written mag/arcsec2 (mpsas). a. y. raisal, et al. / indonesian review of physics 3 (2), 2020, 35-39 36 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 1. different types of sqm (https://www.unihedron.com) sqm is usually used to find out light pollution in an area. light pollution is caused by the improper and excessive use of artificial light. light pollution is a significant problem throughout the world, especially in urban areas. it causes an increase in the sky's light and prevents us from observing the dark starry sky [12]. besides being used to measure the level of light pollution, sqm is also used to determine the beginning of the fajr prayer time. the beginning of fajr prayer time is defined at the dawn of sadiq seen on the eastern horizon. the dawn sadiq is a white light visible on the east horizon and spread horizontally that appears before sunrise [9]. dawn sadiq in astronomy is understood to be the astronomical dawn when the sun is 18o below the horizon, as seen in figure 2. however, there are differences in the sun's altitude in some countries, as shown in table 1. figure 2. overview of dusk and dawn (https://www.weather.gov) when the sqm value decreases gradually, it is defined as the emergence of the dawn of sadiq. to determine when the sqm value decreases gradually, one can use several methods, one of which is the moving average method [13]. table 1. the sun's altitude in determining the dawn sadiq in several countries [14] no convention sun's altitude 1 shiah ithna ashari (jaafari) -16o 2 islamic society of north america (isna) -15o 3 muslim world league (mwl) -18o 4 umm al-qura makkah -18.5o 5 egyptian general authority of survey -19.5o 6 university of islamic science, karachi -18o 7 malaysia -20o iii. method observations were made at the falak observatory of the university of muhammadiyah north sumatra (oif umsu) with coordinates 3o34'55.06" n and 98o43'17.09" e. oif umsu is located on the 7th floor of umsu postgraduate school, with a height of about 35 meters. the sky brightness was measured using three sqm mounted facing the east horizon, zenith, and west horizon. sqm, which measures the west horizon's direction, uses sqm-lu and sqm, which measures the zenith's direction and the east horizon uses sqm-lu-dl. sqm is set to collect the sky brightness value every 2 seconds. measurements are taken throughout the night from sunset to sunrise. sqm data used is during the new moon phase. hence, the moonlight does not affect the night sky brightness. the moon phase is one of the variables affecting the visibility of the night sky [15]. besides, solar activity also affects the night sky brightness [16]. determination of the beginning of fajr prayer time using the moving average method. the moving average method is a method that is often used in technical analysis that shows the average value during a specified period. sqm retrieves data every 2 seconds then each difference value is sought by subtracting the second data from the first data. furthermore, the difference in data is processed with a moving average. the interval used is 30 data. it was taken because of the need for prayer time with a resolution of 1 minute. then the fajr prayer time obtained by sqm is compared to the prayer time obtained by accurate times. this application can indicate the start of dawn based on the desired sun's altitude. in this study, the sun's altitude was chosen to be 18o below the horizon as a comparison. iv. results and discussion three sqms are placed respectively towards the zenith, the western horizon, and the eastern horizon, as seen in figure 3. each sqm is inserted into the holding so that it can retrieve data even when it is raining. data is collected from august 2018 to june 2019. during the new moon phase, the time taken is so that the moonlight does not affect the night sky brightness value. furthermore, sqm directed to the zenith will be written as sqm1, sqm referred to the eastern horizon is written a. y. raisal, et al. / indonesian review of physics 3 (2), 2020, 35-39 37 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 as sqm2, and sqm referred to the western horizon is written as sqm3. (a) (b) figure 3. (a) sqm directed to zenith and east horizon. (b) sqm directed to west horizon. sqm output data consists of universal time, local time, time, voltage temperature, sky brightness value, and data units. furthermore, local time and sky brightness values will be used. the sqm data used is limited from midnight until sqm shows zero value. it is done to reduce the influence of light used by the community around the observation site. figure 4 is a graph of the night sky brightness against local time on june 5, 2019. the night sky brightness values of sqm1, sqm2, and sqm3 are shown by red, blue, and green lines. the night sky brightness value is relatively constant at night; then, it will decrease when the sun rises. figure 4 shows that the sky brightness value of sqm1 has a higher value than sqm2 and sqm3. figure 4. night sky brightness against local time on june 5, 2019 during data collection, the effects of light, cloud, and air pollution are inevitable. it affects the value of the night sky brightness, which is read by sqm. therefore the darkest value that can be obtained by sqm is taken during data collection. table 2 shows the maximum night sky brightness values obtained by the three sqms from august 2018 to june 2019. the maximum sky brightness value from sqm obtained varies. the maximum night sky brightness values obtained by sqm 1, sqm2, and sqm3 range from 17.43-18.89 mpsas, 15.57-16.01 mpsas, 15.02-15.71 mpsas. the average the night sky brightness value for sqm1, sqm2, and sqm3 are 18.23 ± 0.49 mpsas, 15.82 ± 0.15 mpsas, and 15.47 ± 0.23 mpsas, respectively. table 2. the maximum night sky brightness values date sqm1 (mpsas) sqm2 (mpsas) sqm3 (mpsas) 13/8/18 18.71 15.76 15.68 11/9/18 18.89 15.73 15.60 11/10/18 17.59 15.57 15.39 9/11/18 17.43 15.59 15.11 9/12/18 18.00 15.81 15.68 8/1/19 18.57 15.98 15.71 7/2/19 18.37 15.90 15.61 8/3/19 18.39 15.95 15.51 11/4/19 18.22 15.93 15.42 6/5/19 18.67 16.01 15.42 5/6/19 17.71 15.82 15.02 average 18.23 15.82 15.47 the night sky brightness at the observation location based on the light pollution map info has a 19.02 mpsas, as shown in figure 5. compared with the maximum night sky brightness value obtained from sqm1, sqm2, and sqm3, there is a difference of 0.79 mpsas, 3.2 mpsas, and 3.55 mpsas. figure 5. night sky brightness values at the observation location (https://www.lightpollutionmap.info) sqm lu and sqm lu-dl use lenses and have a field of view of 20o. hence, the sqm directed to the west horizon and east horizon at a certain distance will immediately read the effect of the light produced by trespass light around the observation location. in the west of the observation site, several hotels are higher than the observation location. the value obtained by sqm directed to the western horizon has the lowest sky brightness value than the others. figure 6 shows a graph of the night sky brightness before sunrise on june 5, 2019. at the time before sunrise, the value of the brightness of the sky will decrease gradually. it is because the sun's rays start to illuminate the earth's atmosphere even though the sun is still under the horizon. from figure 6, it can be seen that sqm1 has gradually decreased faster than the other two. when the sky's brightness decreases gradually, this is considered the beginning of the fajr prayer. nevertheless, it is complicated to determine when the sky's brightness value drops gradually by looking at figure 6. a. y. raisal, et al. / indonesian review of physics 3 (2), 2020, 35-39 38 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 6. the brightness of the sky before sunrise on june 5, 2019. figure 7 shows a graph of the moving average value against sqm1 time on june 5, 2019. the sky brightness values obtained are not always the same. the moving average value indicates positive, zero, and negative values. this condition occurs due to light, cloud, and air pollution. the moving average value gradually decreases, or the negative value obtained is getting bigger at a specific time. it is due to the sky brightness value, which drops gradually. the time at which the moving average shows zero before the data afterward indicates a negative value is determined as the beginning of the fajr prayer time. figure 7. graph of the moving average value against the local time in sqm1 on june 5, 2019 table 3 shows the beginning of the fajr prayer time based on sqm and accurate times. the beginning of fajr prayer time at the sun's altitude 18o below the horizon is written as t18. it can be seen that the beginning of fajr prayer time based on sqm is after the beginning of fajr prayer time using accurate times. table 4 shows the differences between the beginning of fajr prayer time of sqm and t18. the difference obtained varies from 19 minutes to 48 minutes. sqm1 has a smaller difference than sqm2 and sqm3. the average difference between the initial dawn time obtained by sqm1, sqm2, and sqm3 were (29.5 ± 8.9) minutes, (36.7 ± 6.3) minutes, and (39.5 ± 5.4) minutes, respectively. there are several high-rise buildings in the west of the observation site, while in the east, there are residential areas, so light pollution in the west and east is higher than the zenith direction. besides, the sky on the eastern and western horizon is often covered with clouds. therefore, the change in the sky brightness value is after the zenith. table 3. the beginning of fajr prayer times based on sqm and accurate times date sqm1 sqm2 sqm3 t18 13/8/18 05.30 05.38 05.42 05.11 11/9/18 05.47 05.53 05.51 05.08 11/10/18 05.46 05.49 05.48 05.01 9/11/18 05.38 05.36 05.40 04.58 9/12/18 05.32 05.43 05.42 05.05 8/1/19 05.42 05.53 05.53 05.19 7/2/19 05.48 05.57 06.03 05.28 8/3/19 05.48 05.57 06.03 05.25 11/4/19 05.35 05.45 05.47 05.11 6/5/19 05.36 05.41 05.49 05.02 5/6/19 05.30 05.39 05.43 04.59 table 4. the differences between the beginning of fajr prayer time of sqm and t18. date sqm1 (minutes) sqm2 (minutes) sqm3 (minutes) 13/8/18 19 27 31 11/9/18 39 45 43 11/10/18 45 48 47 9/11/18 40 38 42 9/12/18 27 38 37 8/1/19 23 34 34 7/2/19 20 29 35 8/3/19 23 32 38 11/4/19 24 34 36 6/5/19 34 39 47 5/6/19 31 40 44 average 29.5 36.7 39.5 from table 4, it can be concluded that the beginning of fajr prayer time obtained by sqm is longer than t18. when compared with the beginning of fajr prayer time concerning the height of the sun 20o below the horizon, the difference obtained will be more significant than that shown in table 4. at the same time, the beginning of fajr prayer time, often used in indonesia, uses a reference of 20o. it indicates that the fajr prayer time used in indonesia is earlier than it should be. v. conclusion the night sky brightness values for sqm1, sqm2, and sqm3 are (18.23 ± 0.49) mpsas, (15.47 ± 0.23) mpsas, and (15.82 ± 0.15) mpsas, respectively. with a field of view of 20°, sqm directed to the west horizon, and the eastern horizon at a certain distance will immediately read the effect of light produced by trespass light around the observation site. so the night sky brightness value obtained by sqm2 and smq3 is smaller than sqm1. the night sky brightness value of sqm3 is the lowest compared to the others. due to the west of the a. y. raisal, et al. / indonesian review of physics 3 (2), 2020, 35-39 39 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 observation site, several hotels are higher than the observation location. the beginning of dawn produced by sqm is after the beginning of dawn obtained using the accurate times with a height of 18° below the horizon. the difference obtained by sqm directed to the zenith, eastern horizon, and western horizon is 29.5 minutes, 36.7 minutes, and 39.5 minutes. in other words, the beginning of fajr prayer time used in indonesia is earlier than it should be. references [1] r. rajkhowa, “light pollution and impact of light pollution,” int. j. sci. res., vol. 3, no. 10, pp. 861–867, 2014. 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[16] i. plauchu-frayn et al., “night sky brightness at san pedro martir observatory,” publ. astron. soc. pacific, vol. 129, no. 973, pp. 1–13, 2017. indonesian review of physics, volume 2, number 2, 2019 28 development student worksheet in the topic of regular circular motion with blended learning based edmodo as learning motivations for student susilawati*, eni setyawati, and ishafit program studi magister pendidikan fisika, universitas ahmad dahlan street parmuka no.42 yogyakarta indonesia email: *susiilawatii2009@gmail.com abstract the research aims to develop learners ' worksheets on the subject of circular motion with the edmodo based blended learning as student motivation in learning physics. in the process of field testing, the study involved students of class x in vocational high school as research subjects. the model used is the addie development model, which includes five stages: analysis, design, development, implementation, and evaluation. to know the feasibility of media done validation. this validation is in the form of a poll with predefined criteria and indicators. from the development of student worksheet conducted an expert test of materials, media experts and users with a percentage of 79.68%, 77.27% and 83.62%, respectively then the student worksheet with blended learning utilize edmodo as the motivation to learn learners in the categorized worthy as a learning media. keywords: edmodo, blended learning, motivation, education i. introduction the development of science and technology increasingly encourages efforts to improve the quality of education by utilizing technological outcomes in learning. improving the quality of education in the learning process is not detached from the role of educators or teachers. student worksheets or learners' worksheets printed teaching materials in the form of sheets of paper containing material, summaries and instructional assignments to be performed by learners [1]. they create a friendly and attractive student worksheet, and there should be an innovation developed [2]. the educators must possess and develop the quality of ict use capabilities and utilize it as a learning tool to create meaningful learning experiences, improve motivation and achievements. the utilization of diverse internet and simulation technologies can help students reconstruct knowledge, and more accessible students observe events with remote instruments and establish communication with educators all over the world [3]. to realize these skills or skills need to conduct learning that implements a blended learning-based learning model. the blended learning method is the development of a conventional and face-to-face elearning model [4]. the blended learning method is a learning model that combines a variety of conveyance methods, educational models, learning styles, and a wide range of technology-based media. the blended learning model has several advantages, including the effectiveness of learning, learning, cost efficiency, and adaptation of learning style that is owned by the learners. blended learning models help students learn independently. edmodo is a social networking website that is similar to facebook that is used for the learning process to facilitate the learning process for educators, students and parents [5]. edmodo can be used as a platform learning communication to support learners ' learning the level of individuals, groups and levels of all classes, both inside and outside the classroom, which can be used throughout the formal and informal learning arrangements, enabling learners to collaborate, communicate, submit tasks with upload and download files. teachers can share notes with susilawati et al. development student worksheet in the topic of regular circular motion with blended learning based … indonesian review of physics, volume 2, number 2, 2019 29 students, connect to useful websites, upload and download, provide reference learning resources for students, create an online quiz, news notifications and event agenda [6]. the subject of circular motion is physics-level learning material of smk grade x. the subject selection of circular motion is irregular due to the irregular circular motion material having a concept that is difficult for learners to understand. many media can be used by teachers in the learning of physics so that learners are easier to understand and master the concept of the material learned. as one of the efforts to motivate learners in the learning of physics, the development and implementation of a physics learning model, especially on the subject of circular motion is irregular using media edmodo. based on the description researchers interested in researching "the development student spreadsheets on in the topic of circular motion with blended learning in edmodo as motivation for learning learners." ii. theory learners ' worksheets are sheets containing tasks that learners must work with to master the required competencies [7]. in the learning of physics, especially in circular motion material, it is necessary to use methods in the learning process to support the development of students ' worksheets. the method used is blended learning that refers to the strategy of combining face to face learning and computer learning, both online and offline conducted through e-learning [8]. edmodo is an application that resembles facebook, but with a high educational value, it appeals to teachers and students [9]. edmodo is a social media platform often depicted like facebook for schools and can function more following the needs of teachers and learners [10]. motivation plays a significant role in student academic work and achievements. in this reflected in the tasks undertaken by the students and in overcoming the obstacles, they face in the learning process [11]. high low motivation at the level of education affects students' success [12]. regular circular motion is the motion of an object on a circular trajectory that has a linear velocity (v) fixed [13]. it also has a centripetal acceleration (leading to the centre of the circle) with the magnitude given by: r v a 2  (1) with r is the radius of the circle (m), can be written centripetal force as: r v mf 2  (2) with f, is a centripetal force (n), v is a linear speed (m/s), m is a mass of objects (kg). physics at the motion of the corners ( ), r s  (3) period (t) the time required by an item to move one round called a period,  2 t (4) with t is a period (second),  is the angular velocity (rad/s), 2 is an angular displacement for one round. 1. linear speed and pace (v) t r v 2  (5) relationship linear velocity (v) and angular velocity ( ) 2. linear speed and pace (v) figure 1. linear velocity in circular motion [13] in figure 1 linear velocity in a circular motion with v is speed (m/s), r is the radius (m),  is the angular velocity (rad/s) is obtained, rv  (6) iii. methodology the types of research used are research and development, which is a method of research used to produce specific products and test the effectiveness of the product [14]. the development model in the study uses addie's model of development, which is analysis, design, development, implementation, and evaluation (evaluation) [15]. the development procedures in this study are as follows. susilawati et al. development student worksheet in the topic of regular circular motion with blended learning based … indonesian review of physics, volume 2, number 2, 2019 30 a. stage analysis stage analysis is an early stage in the process of developing learning media. this stage is used by researchers to conduct a study of concepts or theories, and the student worksheet will be developed. b. planning phase of research at this stage, researchers devised the form of student worksheet on gmb material with mediaassisted edmodo to produce a valid student worksheet. c. stage of design development at this stage the researcher developed an initial product of edmdo assisted by edmodo media, developed student worksheet seen in figure 2 containing: student worksheet summary, learning steps, core competencies and essential competencies, learning objectives, material consisting of regular circular motion material and additional material from edmodo media, practice questions with answer keys, and bibliography. figure 2. student worksheet design d. stage of implementation the assessment in the lkpd tested by the experts covering four aspects of content, conformity of presentation with a learning approach, linguistic, and technical requirements e. stage of evaluation the evaluation stage is the final stage of research. the achievement of research objectives measured from data obtained through a poll. the research conducted at vocational high school, subjects in the study were material experts, media experts, as media validators, and students of vocational high school were students of x-class as users. the types of data collected on this research are quantitative data obtained through a poll as a research instrument. %100 n f p (7) the measures used to provide quality criteria to developed products obtained from experts are: (1) change the statement to score using the likers scale [16]. (2) calculating the values of all components with formulas according to is the number of frequencies, f is the frequency of the respondent who gave the answer and p is the percentage of respondents. tabel 1. value interval for media feasibility level [14] interval (p) eligibility criteria 80% 100% very good 66% 79% good 56% 65% less good 0 % 55% not good iv. results and discussion from the results of the analysis, testing of the program aims to determine media feasibility as a medium of physical learning in gmb material is reviewed from the aspects of content, presentation, language, and technical requirements. overall based on the assessment of the validators of the expert media experts and students as users. at the validation stage, as seen in the test bar diagram of the material expert tests in figure 3. on the bar diagram, the results of the expert percentage of feasibility material 79.68%. on the bar chart, the test results of the media expert in figure 4 of the 77.27% feasibility percentage. figure 3. bar chart of material expert test results susilawati et al. development student worksheet in the topic of regular circular motion with blended learning based … indonesian review of physics, volume 2, number 2, 2019 31 figure 4. bar chart of media expert test results the results of revisions and validations by experts a then tested. the results of the product trials in this study were the responses of the participants in the media edmodo. students ' responses or responses can be known by the way learners are asked to use lkpd with edmodo, and then learners fill their responses to the polls provided. based on the results of the student's overall assessment, the average score of all 83.62% questions with the majority of student responses expressed strongly concur (ss) of edmodo-based learning media as a participant motivation in the physics learning process presented in figure 5. figure 5. student response chart in figure 5, obtaining student response data related to the learning model using social media it used a usability poll known as use questionnaire [17]. the scale used is the likert scale from 1 to 4; where 1 (very disagrees) (sts), 2 disagrees (ts), 3 is concurring (st), and 4 is very concurring (ss). the aspect measured by this poll includes the (usefulness), (ease of use), (ease of learning), and (satisfaction). the development of blended learning is a studentoriented form of learning because in this method students play a very dominant role in the learning process, it can be seen in figure 5, the student response results in the learning process assisted by students worksheet with blended learning by edmodo expressed very agreed (ss) and agreed (st). the results of utami's research, et al, on the influence of edmodo-based blended learning and learning motivation on the learning outcomes of biology and biology students' retention in human blood circulation in grade vii middle school said that the edmodo-based learning process students became interested, because of the interaction between the teacher and students in communication and collaborating on various content in the form of text, images, links, videos, and audio [18]. according to krishnamurthy, edmodo is an advantage and solution for researchers and teachers who are often disrupted by their learning activities because of a sudden agenda or schedule [19]. next is the display of student worksheets using edmodo, as shown in figure 6. edmodo is an online platform to support teachers in learning activities and to improve creativity to involve students in collaborative learning and cognitive distribution. edmodo presents opportunities for students to interact with fellow students and teachers in an academic environment. what is more, the use of edmodo can educate students on how to behave online and be useful for organizing their learning activities with a safe system. edmodo implements an environment with a characteristic of learning and teaching that can produce student excitement, students become more independent, without forgetting the standards of measuring student success. edmodo is a safe learning platform for teachers, students and schools based on social media (figure 6). edmodo gives a regulated and secure way for classrooms to connect and collaborate, share content and access work, grades, and school notifications. edmodo's purpose is to assist educators to harness the power of social media to tailor a class for each student. edmodo can help educators build virtual classrooms based on real-life lessons at school, where there are susilawati et al. development student worksheet in the topic of regular circular motion with blended learning based … indonesian review of physics, volume 2, number 2, 2019 32 assignments, quizzes, and classes at the end of each lesson [20]. figure 6. edmodo display constraints in this study, researcher.s have not been able to connect parents into the virtual media edmodo because not all parents have a smartphone, and difficulties for students on signal internet that is unstable and package quota to access edmodo. as yunita's research results, about the effectiveness of edmodo-assisted problem based learning to improve physics learning achievement in temperature and heat of class x light vehicle engineering at tunas bangsa wanareja vocational school, stated that the deficiencies in learning problem based learning are disruptions to slower internet connections, and there is no choice for sending messages to fellow students, communication with students takes place in groups on edmodo [21]. v. conclusion the students ' worksheets have been developed on the subject of circular motion with the edmodo-based blended learning as the motivations of students based on the overall rate of the score at the entire question of 83.62% with students ' responses are worthy of learning media. the feasibility rate is 79.68% of material experts, and 77.27% of media experts. with the value of the score, this medium is categorized as viable and can motivate learners as a learning medium and can be used by learners in the physics learning process. acknowledgement the author would like thanks to head department of master in the physics education university of ahmad dahlan for support and assisted so the research can be completed. references [1] a. prastowo, pengembangan bahan ajar. jakarta: kencana, 2014. [2] ishafit and n. fitriastuti, “pengembangan lembar kerja siswa (lks) berbasis guided inquiry berbantuan media virtual phet pada materi momentum dan tumbukan untuk meningkatkan penguasaan konsep fisika siswa kelas xi,” in prosiding seminar nasional quantum, 2016. [3] m. m. lombardi, “authentic learning for the 21st century: an overview,” eli pap. 1, 2007. [4] j. . rooney, “blended learning opportunities to enhance educational programming and meetings,” assoc. manage., vol. 55, no. 5, pp. 26–32, 2003. [5] f. gruber, “edmodo: microblogging for education,” http://www.somewhatfrank.com/2008/03/edmodomicroblo.html, 2008. . [6] s. c. kong and y. song, “the impact of a principlebased pedagogical design on inquiry-based learning in a seamless learning environment in hong kong,” educ. technol. soc., vol. 17, no. 2, pp. 127–141, 2014. [7] sulastri, “pembelajaran muatan lokal pendidikan lingkungan hidup dengan model pembelajaran group investigation untuk sma/ma,” j. pendidik. sains, vol. 2, no. 1, pp. 12–17, 2014. [8] m. driscoll, “blended learning: let’s get beyond the hype,” 2002. [9] b. basori, “pemanfaatan social learning network ”edmodo” dalam membantu perkuliahan teori bodi susilawati et al. development student worksheet in the topic of regular circular motion with blended learning based … indonesian review of physics, volume 2, number 2, 2019 33 otomotif di prodi ptm jptk fkip uns,” j. ilm. pendidik. tek. dan kejuru., vol. 6, no. 2, pp. 99–105, 2013. [10] g. suriadhi, i. d. k. tastra, and i. w. suwatra, “pengembangan e-learning berbasis edmodo pada mata pelajaran ipa kelas viii di smpn 2 singaraja,” j. edutech univ. pendidik. ganesha, vol. 2, no. 1, pp. 1–10, 2014. [11] c. peklaj and m. puklek levpušček, “students’ motivation and academic success in relation to the quality of individual and collaborative work during a course in educational psychology,” in 31st annual atee conference, 2006, pp. 146–161. [12] h. douglas brown, teaching by principles an integrative approach to language pedagogy. new york: white plains, 2001. [13] p. a. tipler, “fisika untuk sains dan teknik jilid i.” penerbit erlangga, jakarta., 2001. [14] sugiyono, metode penelitian kuantitatif, kualitatif dan r&d. bandung: alfabeta, 2015. [15] mulyanta and m. leong, tutorial pembangunan multimedia interaktif media pembelajaran. yogyakarta: universitas atma jaya yogyakarta, 2009. [16] a. sujiono, pengantar statistik pendidikan. jakarta: graha grafindo persada, 2011. [17] a. m. lund, “measuring usability with the use questionnaire,” usability interface, vol. 8, no. 2, pp. 3– 6, 2001. [18] u. a. daulay, syarifuddin, and b. manurung, “pengaruh blended learning berbasis edmodo dan motivasi belajar terhadap hasil belajar ipa biologi dan retensi siswa pada sistem peredaran darah manusia di kelas viii smp negeri 5 medan,” j. pendidik. biol., vol. 6, no. 1, pp. 260–266, 2016. [19] n. b. krishnamuty, “pengaruh metode penugasan melalui kelas virtual edmodo terhadap hasil belajar siswa pada konsep jaringan tumbuhan,” uin syarif hidayatullah, 2015. [20] y. ariani, y. helsa, s. ahmad, and r. prahmana, “edmodo social learning network for elementary school mathematics learning,” j. phys. conf. ser., vol. 943, no. 1, p. 012056, dec. 2017. [21] l. yunita, “efektifitas problem based learning berbantuan edmodo untuk meningkatkan prestasi belajar fisika studi pada suhu dan kalor kelas x teknik kendaraan ringan smk tunas bangsa wanareja,” in prosiding seminar nasional xi “rekayasa teknologi industri dan informasi 2016 sekolah tinggi teknologi nasional yogyakarta,” 2016, pp. 159–165. indonesian review of physics, volume 1, number 1, 2018 1 the influence of blended learning model based on problems of physical learning achievements by students of class x science in sma 6 denpasar academic year 2017/2018 ni putu nadia nikki utami1, i wayan santyasa2, iwan suswandi3 1,2,3universitas pendidikan ganesha, indonesia udayana street no.11 singaraja bali 81116 email: npnadianikkiu@gmail.com1 learning achievement is the result achieved by someone after doing the learning process. one of the factors that influence learning achievement is the use of the learning model. this study aims to know the differences in achievement of students learning to use problem-based blended learning models and traditional blended learning. this study uses a quasi-experimental method of "non-equivalent pretest-posttest control group design." the study population is all class x ipa with a total of 6 classes or 210 people. the sample consists of 3 classes or 107 people. student learning achievement data were analyzed by descriptive analysis and anova one-way (α = 0.05). the results of this study reveal that there are differences in student achievement due to the learning model. higher learning achievement was achieved by problem-based blended learning models (f = 264.307; α<0.05). the lsd test results showed that the learning achievement of students in the mblbm group was higher than mbl, the learning achievement of the mblbm group was higher than that of mpk, and the learning achievement of the mblbm group was higher than that of mpk. keywords: problem-based blended learning model, a blended learning model, the conventional learning model, learning achievement i. introduction education has a critical role in realizing quality human resources. in this case, education will function to develop the mindset of human resources to be able to contribute to determining the direction of development of a country. quality education is the mandate of law number 20 of 2003 concerning the national education system (sisdiknas) article 50 section 2 which reads, "the government determines national policies and national education standards to ensure the quality of national education." through this law, it is also stated that national education functions to develop the capacity and form dignified national character and civilization in order to educate the lives of the nation, aiming to develop the potential of students to become faithful and fearful people of god, noble, healthy , knowledgeable, capable, creative, independent, and a democratic and responsible citizen. guided by the national education system, the government has made various strategic efforts to realize the goals of national education in order to create quality education, one of which is the 2013 curriculum development. according to setyorini[1], 2013 curriculum is a curriculum that prioritizes understanding, skills, character education, active in discussions and presentations, and has a high level of courtesy. 2013 curriculum in the application of science learning especially physics at all levels of education emphasizes the scientific approach which consists of observing, asking, trying, associating, and communicating. the implementation of the 2013 curriculum to science learning, especially physics at all levels of education emphasizing the scientific approach consisting of observing, asking, trying, associating, and communicating. this strategy can prove that the 2013 curriculum following the nature of physics is to obtain the truth must be empirically through the scientific method [2]. this model is expected to have a positive influence on students' physics learning achievements and the realization of quality education in indonesia. concerning the realization of the efforts that have been made by the government, the quality of physics learning obtained by students in schools has a high qualification which has implications for the optimal learning achievement possessed by students. the reality is that all efforts made by the government have not provided results that are in line with expectations. in a study on the analysis of students' physics learning outcomes at arjasa state high school showed that physics learning outcomes were still low. research conducted by [3], on the analysis of high school physics learning volume 1, number 1, 2018 utami et al. the influence of blended learning model based on problems of.... 2 outcomes showed that physics learning outcomes were still very low with an average score of 56,183. similarly, the research conducted [4] shows that the physics learning achievement of students at smp negeri 2 sawan was still very low, especially in active electrical materials. based on these facts, it was indicated that students' physics learning achievement is still very low. one of the causes of low student achievement comes from external students. [1] which revealed that low student learning outcomes were due to the use of conventional learning models and still emphasized memorization, not discovery. similar results were expressed by [5] improper use of methods caused the low learning outcomes. learning methods applied in schools direct students to memorize and hoard various information and not develop students' thinking skills. based on this opinion, it can be understood that the low achievement of students' physics learning is caused by external factors, namely the use of conventional learning models that are not following the nature of physics learning. the development in the information and communication technology sector (ict) is a product of the times that offer new things to the world of education as a means to support the learning process. one is a learning model that can be used to conduct learning activities outside of school by utilizing information and communication technology without eliminating face-to-face learning activities in schools and encouraging students to develop their thinking skills which will have implications for improving student learning achievement is a problem-based blended learning model. the problem-based blended learning model is a learning model that uses authentic problems as a learning stimulus by combining online and faceto-face learning approaches in class. the research conducted by [6] revealed that blended learning models could improve student learning achievement compared to conventional learning models. the results showed that the application of blended learning that integrates faceto-face learning and e-learning is one factor in improving student learning achievement. between students who study in the experimental group with blended learning models obtain better academic achievement scores and students in the control group who learn to use traditional learning models [7]. blended learning models combine traditional and online-based learning models that allow students to be more flexible in managing learning time. other studies on the application of the problem-based learning model in learning carried out by [9] revealed that the problem-based learning model is a useful learning model in improving student academic achievement including knowledge retention, conceptual understanding, and student attitudes.[9] states that the problem-based learning method can improve learning motivation critically: diligent in doing assignments, resilient in difficulties, interest in problems, happy to work independently, doing assignments regularly, and happy to find and solve problems. state that learning with blended-problem based learning has an impact on student learning activities. in another study conducted by [3] provides student learning outcomes that are learning through blended based learning problems better than students who learn through direct learning based on blended and for students who have the high and low motivation, blended problem-based learning has a positive impact on student learning achievement. another study conducted by [10] revealed that problembased blended learning models are effective in improving student learning outcomes. besides, the application of problem-based blended learning models can increase student motivation in learning. ii. method of research this research was conducted in sma negeri 6 denpasar of the second semester in the academic year 2017/2018. the instrument trial was conducted in class xi ipa in sman 8 denpasar. the population of this research is all the class x ipa consisting of 6 classes with a total of 210 people. the sample that has been used in the study uses three classes selected by two stages of random assignment technique. the three classes in this study are class x ipa 5 as the first experimental class, class x ipa 6 as the second experimental class, and class x ipa 1 as the control class. the number of samples in this study was 107 students which included 36 students in the first experimental class, 36 students in the second experimental class, and 35 students in the control class. this study uses quantitative research methods included in the experimental research. the type of research that will be carried out is quasiexperimental or quasi-experimental research. the research design used in this study was nonequivalent pretest-posttest control group design. the research design is shown in figure 1. volume 1, number 1, 2018 utami et al. the influence of blended learning model based on problems of.... 3 (source: santyasa, 2018) figure 1.research design where: o1: preliminary observations of students' learning achievements with blended learning models based on problems o3: preliminary observations of students' learning achievements with blended learning models o5: preliminary observations of students' learning achievements with conventional models o2: the final observation of students' learning achievement with a blended learning model is problem-based o4: final observation of students' learning achievement with blended learning models o6: final observation of student learning achievement with conventional learning models x1: treatment with blended learning models is problem-based x2: treatment with blended learning models x3: treatment with direct (conventional) learning models the instrument used in this study is a physics learning achievement test to measure students' understanding of simple material momentum, impulses, and harmonic vibrations. the test form was constructed in the form of an expanded multiple choice test consisting of 25 items based on bloom's taxonomy as a result of the revisions of anderson and krathwohl. each item has a score of 0 to 4. all items in the instrument are valid and have cronbach's alfa reliability value of 0.887. data collected from this study were simple physics learning achievement data for momentum and impulse material and harmonic vibration in the form of pretest and posttest. this study used two analytical techniques, namely descriptive analysis, and covariance analysis. descriptive analysis techniques were used to describe percentages, mean values, and standard intersections. the data analysis technique used to test the hypothesis in this study was a one-way covariate analysis (anacova) technique with the covariate variables being the initial physics learning achievement. candiasa (2010) stated several assumptions that must be considered in conducting covariate analysis, namely: (1) data normal distribution, (2) variants in homogeneous groups, and (3) the presence of a linear relationship between the independent variables and the dependent variable. the following statistical hypothesis is formulated: ho:𝜇1 = 𝜇2 = 𝜇3: there is no difference in students' physics learning achievement between students who learn using problem-based blended learning models, blended learning models, and conventional learning models. h1:𝜇1 ≠ 𝜇2 ≠ 𝜇3: there are differences in students' physics learning achievement between students who learn using problem-based blended learning models, blended learning models, and conventional learning models. iii. research results and discussion the data obtained in this study are the initial learning achievement (pretest) and also student learning achievement (posttest). the data collected through the data retrieval process is then analyzed using a statistical approach. dissemination of learning achievement data for each group is presented in table 1 and table 2, the difference between pretest and posttest mean scores of students in each group is shown in figure 2. table 1. data on physics student average pretest learning achievement for experimental groups and control groups class learning model m x ipa 1 mpk 31,26 x ipa 5 mbl 31,36 x ipa 6 mblbm 31,50 table 2. data on physics student average posttest achievement for experiment groups and control groups class learning model m x ipa 1 mpk 67,40 x ipa 5 mbl 76,47 x ipa 6 mblbm 81,25 figure 2. disputes between students' pretest and posttest scores hypothesis testing hypothesis testing uses covariate analysis (anakova) one path with the help of a 0 20 40 60 80 100 mblbm mbl mpk pretest posttest o1 x1 o2 o3 x2 o4 o5 x3 o6 volume 1, number 1, 2018 utami et al. the influence of blended learning model based on problems of.... 4 computer program spss-pc 23.0 forwindows. calculation results are shown in table 3. table 3. results of one-way anakova calculation source type iii sum of squares df mean square f sig. correc -ted model 3815,912 3 1271, 971 200,09 8 0,00 1 intercept 393,857 1 393,857 61,959 0,00 1 pretest 311,380 1 311,380 48,984 0,00 1 model 3360,250 2 1680,12 5 264,30 7 0,00 1 error 657,742 10 3 6,357 total 608147,00 0 10 7 correc -ted total 4470,654 10 6 based on the summary of the results of anakova one path in table 3 it was decided: first, the effect of the initial physics learning achievement on the dependent variable in this study is the achievement of students' physics learning, the statistical value f = 48,984 with the significance number 0,001. the significant number is smaller than 0.05. these results indicate that there is a significant effect (p <0.05) between covariates on students' physics learning achievement. in other words, relevant covariance analysis is used in this study. second, the effect of the independent variable on the dependent variable is the student physics learning achievement obtained by the statistical value f = 264.307 with a significant number of 0.001. the number of significant obtained is less than 0.05, so the decision is to reject ho and to accept h1. empirically it is proven that there are differences in students' physics learning achievement between students who learn using problem-based blended learning models, blended learning models, and conventional learning models. in this study, further testing is needed to find out the significance of the difference between the mean one and the other mean if there is a significant difference. follow-up covariance analysis in this study tested the significance of differences in the average score of the physics learning achievement test between groups using least significant difference (lsd). follow-up test results are presented in table 4. table 4. the significance of differences score of average intergroup learning achievement. (i) model (j) model 𝝁(𝐈) − 𝝁(𝐉) sd sig. mblm mbl 4,622 0,595 0,001 mblm mpk 13,577 0,600 0,001 mbl mblm -4,622 0,595 0,001 mbl mpk 8,955 0,599 0,001 mpk mblm -13,577 0,599 0,001 mpk mbl -8,955 0,600 0,001 based on table 4, the difference in average scores of students' physics learning achievement between the mblm learning group and mbl ∆μ = μ (i) -μ (j) = 4.622 with a standard deviation of 0.595 and significance of 0.000. the difference in average scores of physics learning achievement students between the mblm and mpk learning groups is ∆μ = μ (i) -μ (j) = 13,577 with a standard deviation of 0,600 and a significance of 0,000. the differences in the mean scores of students' physics learning achievement between mbl and mpk learning groups is ∆μ = μ (i) -μ (j) = 8,955 with a standard deviation of 0,599 and a significance of 0,000. the significance value obtained from each difference is smaller than 0.005, while the value of ∆μ obtained from each difference is higher than the lsd value of 1.805. there is a significant difference in the average score of physics learning achievement between groups who study with mblm and mbl, mblm and mpk, as well as mbl and mpk. physics learning achievement achieved by students who study with problembased blended learning models is higher than students who learn to use blended learning models or conventional learning models. this phenomenon shows that the learning achievement of students who take lessons with problem-based blended learning models is relatively better compared to students who take lessons with blended learning models or conventional learning models. this study obtained results that problem-based blended learning models were able to improve student learning achievement compared to blended learning models and conventional learning models. this result is consistent with research conducted [3] which shows that the application of problembased learning models based on blended learning (pbl-bl) has a good impact on students' physics learning outcomes compared to the direct instruction model based on blended learning (dibl). also, the results of this study are supported by research conducted by [10] which states that problem-based blended learning models are effectively used in improving student learning outcomes compared to conventional learning volume 1, number 1, 2018 utami et al. the influence of blended learning model based on problems of.... 5 models. the use of problems in the learning process has been proven to have a positive impact on student learning achievement [1,5,8]. in addition, the application of problem-based learning models has a positive impact on knowledge retention, conceptual development, student attitudes [8] and is able to improve learning motivation with diligent criteria in the system, tenacious in difficulties, interest in problems, doing tasks regularly, and happy to find and solve problems [9]. the results of this study also found that blended learning models were able to improve student learning achievement compared to conventional learning models. this result is in line with the research conducted by [7] which found that students in the blended learning model group obtained better learning achievement compared to students in the traditional learning model group. another study conducted by [11] revealed that the application of blended learning models has a positive impact on student learning outcomes in the form of improving learning outcomes. besides, the use of blended learning based schoology models results in reduced theoretical class hours in class so that it can be filled with practical work to enhance students' understanding further. learning with blended learning models also has a positive impact on student involvement in the learning process [12]. problem-based blended learning models and blended learning models allow the learning process to be more professional to handle learning needs in the most effective, efficient, and high-appeal way. the learning process is not the only face to face in class but increases learning time by utilizing cyberspace. less active direct learning (conventional) is due to monotonous learning and students are placed as passive learners, which means students get knowledge from the material presented by the teacher during classroom learning. students accept the subject matter from the teacher and know the concept without understanding the concept correctly. this results in learning that is less meaningful in class and students assume that all material given by the teacher is memorizing. the conventional learning model considers students as individuals who do not have prior knowledge before learning, and the teacher must transfer that knowledge to students regardless of what concepts students already have. the teacher considers what is taught to be able to be accepted by students as a whole does not depend on the initial concepts that exist in students so that misconceptions often occur in students. this strategy has an impact on the learning achievement that is not maximized by students. the findings of this study have the following implications: first, the average physics learning achievement of students who learn to use mblbm is different from students who study with mbl or mpk. thus, the use of learning models in the learning process has a different effect on students' physics learning achievement. the average learning achievement of students who learn to use mblbm is higher than students who study with mbl or mpk. the relatively high physics learning achievement of students learning to use mblbm is evident from the strength of problem-based face-toface learning and online learning in helping the construction process of knowledge in students' cognitive structures to be more meaningful. iv. conclusion based on the results of testing the hypotheses and the results and discussion described, this study concluded that there were differences in students' physics learning achievement between students who learned using problem-based blended learning models, blended learning models, and conventional x-class science learning models at denpasar 6 public high school. (f = 264.307, with a significance of 0.001) the group of students who learned to use problem-based blended learning models showed that physics learning achievement was relatively higher compared to groups of students who learned using blended learning models even though conventional learning models. references [1] asiah, i. n., sudarti, & lesmono, a. d. (2016). pengaruh model problem based learning (pbl) dengan teknik mind mapping terhadap hasil belajar fisika siswa di sma negeri arjasa kelas x. jurnal pendidikan fisika. 4(4): 327-330. terdapat pada hppts://jurnal.unej.ac.id/. [2] soetardjo & soejitno, p. o. (1998). proses belajar mengajar dengan metode pendekatan keterampilan proses. surabaya: sic. [3] herlina, f., supriyati, y., & astra, i m. (2015). pengaruh model pembelajaran berbasis blended learning dan motivasi belajar terhadap hasil belajar fisika siswa sma. prosiding seminar nasional fisika (e-journal). 4: 61-66. terdapat pada http://snf-unj.ac.id/. [4] supratiwi, n. l. g. f. (2015). penerapan model blended learning untuk meningkatkan motivasi dan prestasi belajar ipa siswa kelas viii b smpn 2 sawan semester ii tahun ajaran 2014/2015. skripsi [5] maulidiyahwarti, g., sumarmi, & amirudin a. (2016). pengaruh model problem based learning berbasis outdoor study terhadap hasil belajar siswa kelas xi iis sma. jurnal pendidikan: teori, penelitian, dan pengembangan. http://snf-unj.ac.id/ volume 1, number 1, 2018 utami et al. the influence of blended learning model based on problems of.... 6 1(2): 94-100. terdapat pada https://journal.um.ac.id. [6] irawan, v. t., sutadji, e. & widiyanti. (2017). blended learning based on schoology: effort of improve learning outcome and practicum chance in vocational high school. cogent education. 4(1): 1-10. doi: 10.1080/2331186x.2017.1282031. [7] ceylan, v. k. & kesici, a. e. (2017). effect of blended learning to academic achievement. journals of human science. 14(1): 308-320. doi: 10.14687/jhs.v14i1.4141. [8] merrit, j., lee, m. y., rilero, p., & kinach, b. m. 2017 [9] nurtanto, m. (2016). peningkatan motivasi dan prestasi belajar dengan metode problem based learning pada pembelajaran gambar teknik melalui pembelajaran terbimbing. journal of mechanical engineering education. 1(2): 201-216. terdapat pada https://jurnal.untirta.ac.id/. [10] aeni, n., prihatin, t., & utanto, y. (2017). pengembangan model blended learning berbasis masalah pada mata pelajaran sistem komputer. innovative journal of curriculum and educational technology(ijcet). 6(2): 84-97. terdapat pada https://journal.unnes.ac.id/ [11] rizkiyah, a. (2015). penerapan blended learning untuk meningkatkan hasil belajar siswa pada mata pelajaran ilmu bagunan kelas x tgb smk negeri 7 surabaya. jurnal kajian pendidikan teknik bangunan. 1(1): 40-49. terdapat pada http://jurnalmahasiswa.unesa.ac.id/. [12] saritepeci, m & cakir, h. (2015). the effect of blended learning environments on student’s academic achievement and student engagement: a study on social studies course. education and science. 40(177): 2013-216. doi: 10.15390/eb.2015.2592. https://jurnal.untirta.ac.id/ https://journal.unnes.ac.id/ indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 40-46 doi: 10.12928/irip.v3i2.2236 http://journal2.uad.ac.id/index.php/irip 40 literature study of understanding the physical concepts of straight motion materials using the gasing method erwin prasetyo1*, budi jatmiko2, and adi jufriansah3 1,3department of physics education, ikip muhammadiyah maumere jl. jendral sudirman, sikka, nusa tenggara timur, indonesia 2department of physics education, universitas negeri surabaya jl. lidah wetan, lakarsantri, surabaya, jawa timur, indonesia *email: wintyo212@gmail.com article info abstract article history received may 31, 2020 accepted dec 01, 2020 published dec 31, 2020 not all physics concepts must be understood and mastered by deriving formulas through differential or integral techniques. mechanics, for example, can be understood with simple logic without formulas, variables, and numbers. the fun method, or known as the gasing method, is a science learning method that has been offered by yohanes surya since 1996. this method offers fun learning activities for students. this research is a literature review of several books and research articles related to learning physics science using top methods. it turns out that with the spinning method, the concepts of velocity and acceleration in straight motion material can be understood easily and can solve some physics problems about straight motion without complicated physics formulas. all these physics problems are solved by simple logic and expressed in words. keywords: gasing method mechanics concepts fun learning to cite this article: e. prasetyo, b. jatmiko, and a. jufriansah, “literature study of understanding the physical concepts of straight motion materials using the gasing method,” indones. rev. phys., vol. 3, no. 2, pp. 40–46, 2020. i. introduction one of the demands of learning in the 21st century is how students can improve their ability to think at a higher level, namely critical and creative [1,2], which is bloom's revised anderson taxonomy enters cognitive levels: c4 (analyzing), c5 (evaluating) and c6 (creating) [3-6]. on the other hand, learning must simultaneously encourage students. the teacher must convey the material taught correctly and efficiently understood to understand the concept quickly and is very engrossed and fun solving daily life problems. many students consider physics as a scary subject [7]. physics is regarded as a complicated subject to study [8-9] because physics is always associated with memorizing numbers and formulas. not all material in physics must be understood by deriving and memorizing formulas. however, some materials can be understood using simple logic. another thing students do not like about physics is teaching methods that are less fun and teacher competencies that are not by their educational background. for example, straight motion material should not be studied by memorizing velocity, distance, and time formulas in regular straight motion material and initial velocity formulas. final velocity, time, and acceleration in straight-motion material change irregularly. with the gasing method, understanding the material of straightline motion and irregular straight-line motion changes in everyday life does not have to derive and memorize formulas [10-11]. however, it can use simple logic without complicated mathematics [12-13]. based on research conducted by schools assisted by the yohannes surya team at surya institut, that interest and skills of high-level thinking on the understanding of physical science concepts using a top method (gampang, asyik, and menyenangkan) [14]. the results of this study indicate that: 1) there is a significant difference in conceptual understanding between groups of students who use conventional learning methods and groups of students who use top learning; 2) there is a significant difference in conceptual understanding between groups of students who have high interest and groups of students who have low interest, and 3) there is a significant interaction effect between the implementation of the gasing method with high and low-interest rates on high level thinking on conceptual understanding [15-18]. from these results, this research aims to obtain information on understanding the concepts of physical science lessons on the material of motion with fun and fun (gasing). ii. method this study focuses on analyzing the literature of journals and books to find out what will be learned from a theory, findings, and references used as a basis for reviewing and describing ideas from previous literature. researchers provide understanding and explanation so e. prasetyo, et al. / indonesian review of physics 3(2), 2020, 40-46 41 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 that readers can understand correctly. this research uses descriptive analysis, namely the details of structured secondary data obtained based on a philosophical and pedagogical approach. this approach was chosen to get new concepts from the development of existing theories. the selection of data sources is based on four aspects, namely credential evidence, the objectivity of ideas, degree of trust, and value of the contribution. this research's primary source is the idea put forward by prof. yohannes surya in 1966, then managed to break the world record in 2015 with the surya institute. this study's data analysis examines the documentation data using bibliographic annotation analysis by looking at the reference source's identity, simple conclusions, and the formulated problem's contribution. iii. results and discussion the gasing method is one part of the direct learning method. the stages are fun or the syntax of the direct learning method, according to joyce and weil [19], as follows: 1. orientation before teaching new material, the teacher needs to provide a direction and learning framework to understand the subject matter more quickly. the forms of orientation can be: a. preliminary activities to assess relevant student knowledge and understanding, b. discuss or inform the objectives of the lesson, c. explain/direction of the activities carried out, d. explain the material or concepts involved, and the activities carried out during the learning process, and e. inform the learning framework. 2. presentation at this phase, the teacher can discuss the material in the form of concepts and skills. presentation of material can be: a. present the material in small parts to make it easier and shorten the time for students to understand, b. giving examples of concepts, c. the modeling or demonstration of skills employing demonstrations or explanations of work steps on the task, and d. re-explain difficult matters. 3. structured exercise in this phase, the teacher accompanies students to work on practice questions. providing feedback, reinforcing, and assessing student understanding is an essential role for teachers in this phase. guided exercise. in this phase, the teacher provides opportunities for students to practice concepts or skills. 4. the guided exercise is also good to be used by teachers to assess/assess students' ability to do their work. in this phase, the teacher monitors and guides students if needed. 5. independent training in this phase, students carry out training activities independently. students can go through this stage if they have mastered the work task stages of 85-90% at the training guidance stage. the gasing method is oriented towards a deductive approach and emphasizes the mastery of concepts and student behavior changes. the characteristics of the gasing method are direct and skill transformation, goaloriented learning, structured learning materials, structured learning environment, and structured by teachers [7],[20]. gasing learning strategies gasing is an alternative method of learning physics [21-23]. gasing learning strategy teaches how to think like a physicist in solving physics problems with a logical approach and almost no formulas [24]. because this gasing learning strategy uses ordinary logic methods based on the basic concepts of physics and necessary mathematical calculation abilities, including adding, less, divide, and times so that students can work on problems quickly and correctly. so, gasing learning strategies train how to express or solve various physics problems with the logic of words, while formulas can adjust afterward [25-28]. according to the results of research conducted by prof. yohanes surya, to make physics easy, fun, and enjoyable (gasing), some things to note are: 1. avoid complicated math calculators; use more straightforward math. 2. take advantage of the correct understanding of physics concepts and emphasize logic rather than using derivative formulas. 3. use integers and easy numbers such as 1, 2, or 10 when teaching concepts through sample problems. do not use decimals or fractions so that students' concentration is not distorted from physical solving to math solving. 4. promote direct dialogue with students about newly taught physics concepts. ask students to express their opinions to solve problems related to the concept given. 5. expand physics experiments and demonstrations so that each student enjoys physics's fun, and students can feel that physics is entertaining. the implementation of the gasing learning strategy is divided into several stages [29-31], namely: 1. simple dialogue dialogue is a form of two-way communication. in this case, those involved are teachers and students. according to the connectionism learning theory or bond hypothesis put forward by thorndike, learning is the formation or strengthening of the relationship between s (stimulus) and r (response) [32], so that between s and r, a relationship (bond) occurs, which gets tighter if often trained. thanks to the exercise of e. prasetyo, et al. / indonesian review of physics 3(2), 2020, 40-46 42 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 the relationship between s and r must provide "satisfaction." a sense of satisfaction is reinforcement or reinforcement. regarding the relationship between s and r, thorndike discovered various laws. some of them are: a. law of effect the relationship between s and r increases when accompanied by pleasure or satisfaction but becomes weak or disappears when accompanied by displeasure. happiness causes the secretion of hormones in synapses, so the relationship becomes smooth. therefore praising and encouraging students (feeling happy) is better in teaching than punishing or reproaching (feeling displeased). b. law of exercise or law of use and law of disuse the relationship between s and r increases tightly if often practiced or used and decreases if it disappears or is never used. it needs to be held a lot of practice and habituation. c. law of multiple responses in a problematic situation where the right response does not appear immediately, individuals conduct various kinds of experiments that initially did not work. still, in the end, they might give the correct answer. this procedure is called "trial-anderror," trial and error while making mistakes. d. law of assimilation or law of analogy a person can adjust or respond according to new situations, which are slightly different from those that already exist but contain the same elements (identical elements). from the four laws above, it can be concluded that the relationship between s (stimulus) and r (response) is significant and interrelated in the learning process to achieve the expected learning outcomes. 2. imagine or fantasize. imagination or fantasy in the education process is essential for students to have [33,34], but teachers in teaching and learning activities largely ignore this aspect. imagination is essential because, with imagination, the students will give birth to a concept, creativity, innovation, and actual behavior in their lives [35,36]. in other words, imagination is more important than knowledge. 3. we are presenting relevant problem examples. training or training is the right way of teaching to instill certain habits. this method can also obtain a student's mastery, accuracy, opportunity, and skills to strengthen students' mathematical mastery. in this exercise, students only practice using simple mathematical logic, namely addition, subtraction, multiplication, and division. 4. we are presenting material in depth. by giving physical meaning to each physics magnitude, students are expected to know what is experienced by each object in the item. 5. stage five: give a variety of questions. assignments or recitation is a way of presenting learning material in giving specific tasks to carry out learning activities, and are accountable for them. assignments given by the teacher can deepen the learning material and can also check the material that has been learned. the task can stimulate students to learn both individually and in groups actively. according to ambotaang and rafiqah [29], the gasing learning strategy's complete stages can be seen in the table 1. table 1. stages of learning with the gasing method stages of the gasing method teacher's activity simple dialogue the teacher starts learning by having a simple dialogue with students about the material to be discovered. students are expected to give their opinions from this dialogue, resulting in a close relationship between s and r. imagine or fantasize the teacher helps students to imagine events related to the material being studied. present relevant examples of problems to strengthen students' mastery of mathematics, the teacher provides exercises for simple questions that only use mathematical formulas besides subtraction, multiplication, and division. presenting material in depth the teacher gives physical meaning after the student feels able to do all the simple questions earlier. give variety question the teacher returns to give questions but is more varied, and these questions can be in the form of story questions. on the other hand, ambotaang and rafiqah [29] slavin put forward seven steps regarding the learning top. 1. explain the purpose and orientation of the lesson to students. at this phase, the teacher conveys the things learned and student performance. 2. review the planned knowledge and skills. at this phase, the teacher asks questions to explore the knowledge and skills students already have. 3. they are delivering subject matter based on the concept of basic understanding. in this phase, the teacher presents the material, shows information, provides examples, demonstrates concepts, etc. 4. carry out guidance. guidance is done by asking questions to assess students' level of understanding and correcting misconceptions. 5. provide opportunities for students to practice. at this phase, the teacher facilitates students to implement skills and use new knowledge individually and collectively. 6. assess students' performance and provide feedback. the teacher reviews students' things, gives feedback on students' correct responses, and repeats the necessary skills. e. prasetyo, et al. / indonesian review of physics 3(2), 2020, 40-46 43 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 7. it provides independent practice starting from concept questions to story problems. at this phase, the teacher needs to provide independent assignments to students to enrich their understanding of the material that has been studied. discussion of the concept of straight motion understanding the concept of physics in the concept of uniform speed can be taught by introducing it by collecting the characteristics of uniform speed, explaining the concept of speed and acceleration, providing examples of concepts, presenting concepts of various forms and multiple-choice descriptions, and developing an understanding by providing examples of phenomena for solving the problem. based on this description, learning activities are fundamental activities. that is, the learning process experienced by students affects the success of achieving educational goals. a person's view of learning will influence his actions related to learning [37]. the following are the top method for understanding speed, acceleration for uniform speed, and uniform acceleration. some questions and solutions were taken from the physics book participant gasing yohannes surya [38]. 1. the uniform speed a. simple dialogue the teacher starts learning by having a simple dialogue with students about the concept of speed. the speed of an object expresses how far the object moves in one unit of time. for example: 1) an object moves as far as 5 meters in 1 second. it can be said that the object is moving at a speed of 5 meters per second, or it can be written five m/s. 2) bicycles move as far as 10 km in 1 hour, so it can be said that the bicycle is moving at a speed of 10 km per hour, or can be written 10 km/hour. b. imagine or fantasize the teacher helps students to imagine the events that are related to regular straight motion material, for example, given a story problem; problem: an object moves at 3 m/s and travels 18 meters; how much time will it take? settlement: 1) according to the concept of speed, the meaning of 3 m/s is that every 1-second objects travel a distance of 3 meters, or each distance of 3 meters takes 1 second, 6 meters takes 2 seconds, and so on. 2) then the distance of 18 meters takes 6 seconds c. present relevant problem examples the teacher gives exercises in the form of simple problems that only use mathematical formulations in addition, subtraction, multiplication, and division. problem: there are two objects, a and b, facing each other 25 meters apart. the velocity of each object is 3 m/s and 2 m/s. when and where do the two objects meet (measured from a)? settlement: 1) according to speed's concept, object a moves at a speed of 3 m/s, meaning that every 1 second, the object travels a distance of 3 meters. 2) while object b moves at a speed of 2 m/s, meaning that every 1 second, the object travels a distance of 2 meters. 3) logically, every second object a advances 3 meters, and object b advances 2 meters, then every 1 second, both objects add near 5 meters, 2 seconds add near 10 meters, and so on. 4) so for a distance of 25 meters, it takes 5 seconds. 5) so when did objects a and b meet? answer at 5 seconds. 6) to find the measured position measured from object a, still, with logic, object a moves at a speed of 3 m/s, meaning that every 1 second, the object travels a distance of 3 meters, 2 seconds travels a distance of 6 meters, and so on. so for 5 seconds, a distance of 15 meters. 7) so, where do the two objects meet measured from object a? answer at a distance of 15 meters from object a d. presenting material in depth the teacher gives physical meaning after the student feels able to do all the simple questions earlier. the solution to the problem above is not with a complicated physics formula. e. give a variety of questions. the teacher returns to give questions but is more varied, and these questions can be in the form of story questions. problem: it is known that two objects, a and b, chase each other, where object a with a speed of 5 m/s chases object b, which has a speed of 4 m/s. if the two objects were initially separated by 5 m, when and where (from position a) did object a meet object b? settlement: 1) by the concept of speed, object b moves at a speed of 4 m/s, meaning that every 1e. prasetyo, et al. / indonesian review of physics 3(2), 2020, 40-46 44 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 second object b moves forward from a as far as 4 meters. 2) object a moves at a speed of 5m/s, meaning that every 1-second, object a moves toward object b as far as 5 meters. 3) the logic: every 1-second object, object b moves away from object a as far as 4 meters and object a approaches object b 5 meters, then every 1-second object a adds closer to object b 1 meter, 2 seconds adds near 2 meters, and so on. alternatively, every 1 meter takes 1 second, so 5 meters takes 5 seconds. 4) so the time needed for object a to chase object b is 5 seconds. 2. uniform acceleration a. simple dialogue the teacher starts learning by having a simple dialogue with students about the acceleration concept material. 1) acceleration means that the object experiences a regular speed increase every 1 second. 2) for an example of a moving object with an acceleration of 2 m/s2, it means that every object has a different speed of 2 m/s. b. imagine or fantasize the teacher helps students to imagine about the events related to the material of irregularly moving a straight motion, for example, given a story problem; problem: an object is initially stationary, accelerated with an acceleration of 4 m/s2 for 2 seconds. how great is the speed? settlement: according to the acceleration concept, a moving object with an acceleration of 4 m/s2 is equal to 4 (m/s)/s, which means that every 1 second, the object's velocity increases by four m/s, 2 seconds the speed becomes 8m/s, and so on. because the initial speed is 0 m/s, the final speed is eight m/s. c. present relevant problem examples the teacher gives exercises in simple problems that only use mathematical formulations besides, subtraction, multiplication, and division. question: an object initially moves at a speed of 4 m/s, then accelerated with an acceleration of 2 m/s2 for 3 seconds. how great is the final speed? settlement: 1) according to the acceleration concept, moving objects are accelerated with an acceleration of 2 m/s2 equals 2 (m/s)/s, which means that every 1 second, the object's velocity increases by two m/s, 2 seconds the speed becomes four m/s, and so on. then for 3 seconds, the speed becomes six m/s. 2) because the initial speed is four m/s, the final speed is ten m/s. d. presenting material in depth. the teacher gives physical meaning after the student feels able to do all the simple questions earlier. the solution to the problem above is not with a complicated physics formula. e. give a variety of questions. the teacher returns to give questions but is more varied, and these questions can be in the form of story questions. problem: a move with an initial speed of 2 m/s and then accelerated for 4 seconds so that the final speed is four m/s; what are the magnitude of the acceleration and the distance of the object? settlement: 1) from the initial speed of 2 m/s and the final speed of 4m/s means, the object has increased speed by two m/s for 4 seconds or means that every 1 second, the speed increases by 1/2 m/s so that the acceleration of the object can be written as 1/2 (m/s)/s equal to 1/2 m/s2. 2) so the acceleration of the object is: 1/2 m/s2 3) from the initial speed of 2 m/s and the final speed of 4m/s, the average speed of the object is 3m/s, which means that every 1 second, the object takes a distance of 3 meters, 2 seconds takes a distance of 4 meters, and so on. 4) then for 4 seconds, the object traveled a distance of 12 meters. so the object's distance is 12 meters. with the above stages, students are expected to master the concept correctly and be able to solve physics problems without using existing formulas. this is in line with the views of jatiutoro et al. [39] and irawan [24]. the study results concluded that the gasing method could be implemented as a learning method for students; this is according to research by rafiqah, ambotaang in class viii [29]. according to prahmana and suwasti [40], math gasing made a real contribution to students' understanding of the concept of division operations. moreover, the learning method can improve motivation and student learning outcomes, according to research by cahya dinata et al. in class ix a smp muhammadiyah 1 banjarmasin [41]. the gasing method by setting the learning cycle increases the average score of scientific attitudes and problem-solving abilities. besides, students' responses to e. prasetyo, et al. / indonesian review of physics 3(2), 2020, 40-46 45 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 the top method's application with the 7e learning cycle setting are in a positive category [42,43]. similarly, according to jatiutoro et al. 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[43] p. g. wartawan, “metode gasing dengan setting siklus belajar 7e untuk meningkatkan sikap ilmiah dan kemampuan pemecahan masalah,” in proceedings seminar nasional fmipa undiksha v tahun 2015, 2015, pp. 395–403. indonesian review of physics, volume 2, number 1, 2019 9 an analysis of graduate students’ conceptual understanding in heat and temperature (h&t) using three-tier diagnostic test moh. irma sukarelawan1, jumadi2, nurulhuda abdul rahman3, 1program magister pendidikan fisika, universitas ahmad dahlan 2department of physics education, faculty of mathematics and sciences, yogyakarta state university 3department of physics, faculty of science & mathematics, universiti pendidikan sultan idris 1jl. pramuka, no.42, pandeyan, umbulharjo, yogyakarta, indonesia. 2jl. colombo no.1, karang malang, caturtunggal, depok, sleman, daerah istimewa yogyakarta 3tanjung malim, perak, malaysia. email: moh.sukarelawan@mpfis.uad.ac.id abstract – there have been many studies that investigate h&t misconceptions among students in indonesia but the respondents are usually limited to senior high school students. this study aims to analyse the conceptual understanding in h&t concepts of masters of physics education students with a focus on identifying their misconceptions. the study employs the survey research design and data were collected using a three-tier diagnostic test. twelve masters of physics education students who are enrolled in one of the private universities in yogyakarta city took part in the study. they were selected using the convenient sampling technique. data on conceptual understanding involve both quantitative and qualitative data. as such, the data was analysed based on the percentage of student response patterns. results showed that the majority of students (62.5%) have some form of misconceptions about the concepts of h&t and only 22.9% hold the scientifically accepted conceptions. the most common misconception held by the students is that both h&t depend on the material of an object. other descriptions of conceptual understanding are false positive (4.2%), false negative (4.2%), and lack of knowledge (6.2%). interestingly, none of the students made a lucky guess in responding to the test items. we conclude that the pattern in conceptual understanding specifically that of misconceptions are ubiquitous regardless of the level of study. years of learning have failed to address misconceptions among students even at the graduate level. this result has implications on how learning should be designed to actively resolve the issue of misconceptions among students. keywords: heat and temperature, three-tier diagnostic test, conceptual understanding i. introduction one important goal in science learning is so students understand concepts that are scientific and logical [1]. more than half a century prior, research relating to conceptual understanding of the topic of h & t has begun to be looked at. a number of studies have widely reported and listed the misconceptions found. the indonesian government has long been aware of this. therefore, explicitly through permendikbud in 2018 in core competencies physics learning mandates that students be encouraged to have the capacity to understand and implement conceptual understanding [2]. determination of conceptual understanding of heat and temperature is important to do [3]. heat and temperature are one of the most appropriate topics to instill scientific instincts [4]. heat and temperature are the basic subjects in science and the phenomenon we experience everyday but some aspects conflict with the interpretation of students [3]. as we know that students' understanding of h & sukarelawan & rahman an analysis of graduate students’ conceptual understanding in heat and temperature… indonesian review of physics, volume 2, number 1, 2019 10 t is basically cliched and scientific (gunes, 2005 in [3]). many students hold misconceptions in h & t. various h & t misconceptions have been identified. students and even prospective teachers often use the terms temperature and heat alternately and not in the context [5], [6]. temperature is a form of energy and joule units and changes in the state of matter are caused by changes in temperature [3]. there are still many students in indonesia who hold heat and temperature misconceptions. students assume that changes in temperature and form can occur simultaneously [7]. the concept of expansion still often misconceptions [8]. various instruments have been created and utilized by researchers to diagnose misconceptions. like interviews [9], multiple choice [10], multipletier diagnostic such as two-tier tests [11] [13] and three-tier tests [14] [16]. multiple choice tests are the best alternative for diagnosing large numbers of student misconceptions. because it is more effective and efficient and has better validity and reliability than the interview method. various studies of h & t misconceptions have been carried out, such as at the elementary school level [9], [17], junior high school [18], senior high school [19], [20] and higher education [21]. in indonesia, research on h & t misconceptions is more dominant at the level of senior high school. like research conducted by [7], [8], [16], [22] [28]. there have been no reports of misconceptions examined at the level of higher education in indonesia. to date, diagnostic tests developed and used in indonesia are limited to a three-tier model and implemented at the high school level. while the misconception of master level students is still very limited in information. therefore, the purpose of this study is to provide an overview of the conceptual understanding possessed by physics education students at the master level. ii. literature review misconception intuitive understanding or views of students on natural phenomena can be constructed through the learning process carried out through formal education in schools and informally from everyday life experiences [29]. this intuitive view or understanding is generally still simple and tends to not be in accordance with the views of scientists today. there are various kinds of terminology used to describe differences in students' conceptual understanding with scientists. common terminologies used are misconception [30], [31] and alternative conception [32], [33]. apart from the differences, these two terminologies together emphasize the existence of differences in students' intuitive ideas/knowledge of current scientific concepts in explaining natural phenomenon [34], [35]. because its use is common in almost all disciplines, in this study uses the terminology of misconception, to describe intuitive conceptions/knowledge that are not in accordance with scientific views [29]. three-tier diagnostic test to examine a person's misconceptions on a particular topic, various diagnostic methods have been used such as short questionnaries, interviews, multiple-choice diagnostic tests, concept mind and conceptual surveys [32], [36]. in the last decade many practitioners and researchers developed measuring instruments in the form of multiple-choice diagnostic tests [19] and multiple-tier diagnostic tests [29]. for large sample sizes, multiple choice tests are the best alternative in diagnosing misconceptions. another advantage of multiple choice tests is having high validity and reliability, more effective and efficient in the assessment. however, multiple choice tests cannot provide an overview of student thinking behind the response of the answers given [37]. therefore, a number of researchers developed multiple-tier diagnostic test instruments. one type of multiple-tier diagnostic test is the three tier test. the three-tier multiple choice diagnostic test is a refinement of the two-tier version. as the name implies, the three-tier multiple choice test consists of three levels, namely the first tier is the usual multiple choice. the second tier is the reason/rational of the answer at the first tier. the third tier is a statement relating to the level of confidence of students in the answers given [38]. iii. method qualitative descriptive research method has been used to get an overview of h&t misconceptions in masters of physics education students. sample this research has been conducted on masters of physics education students (semester 1 – 3) one of the private universities in yogyakarta. students have been selected using convenience sampling techniques. the respondents involved were 12 students who were still active in the 2018-2019 academic year. respondents consisted of 7 men (58%) and women 5 people (42%). the age of sukarelawan & rahman an analysis of graduate students’ conceptual understanding in heat and temperature… indonesian review of physics, volume 2, number 1, 2019 11 students is between 23 years and 30 years. the average age of respondents is 24.5 years with a standard deviation of 1.9. instrument this study has used a three-tier h&t diagnostic test instrument that was developed by eryilmaz [21]. diagnostic test instruments consist of 4 questions that are focused on the concept of h&t variables dependent on the size and material made of objects. table 1 shows the item description to diagnose h&t misconceptions. table 1. items description of h & t diagnostic test item number items description code 1 the concept of temperature dependence on the size of objects q1 2 the concept of heat dependence on the size of objects q2 3 the concept of temperature dependence on material made of q3 4 the concept of heat dependence on material made of q4 data collection and analysis before data collection is carried out, the diagnostic instrument has been formatted into the google form to facilitate the administration of responses from respondents. respondents have been motivated to participate voluntarily and are convinced that all the responses they give will not directly affect their academic value. each item is analyzed into six categories, namely scientific knowledge (sk), lucky guess (lg), false positive (fp), false negative (fn), lack of knowledge (lk) and misconception (misc) [39]. the categorization of student conceptual understandings for the threetier diagnostic test is shown in table 2. table 2. combination of answer patterns at the three-tier diagnostic test [39] 1st tier 2nd tier 3rd tier category correct correct sure scientific knowledge not sure lucky guess incorrect sure false positives not sure lack of knowledge incorrect correct sure false negatives not sure lack of knowledge incorrect sure misconception not sure lack of knowledge iv. results and discussion data collection has been done using google form as an electronic document. this is done to facilitate the administration of data from respondents. scores for correct answers and misconceptions have been analyzed using ms-excel. table 3 shows a tabulation of student response data. sukarelawan & rahman an analysis of graduate students’ conceptual understanding in heat and temperature… indonesian review of physics, volume 2, number 1, 2019 12 table 3. tabulation of student response data respondents q1 q2 q3 q4 category cba cba cca cba q1 q2 q3 q4 1 cba cba baa baa sk sk misc misc 2 aaa aaa baa baa misc misc misc misc 3 cba cba baa baa sk sk misc misc 4 cac cca baa baa fp fp misc misc 5 cba cba baa baa sk sk misc misc 6 aaa aba bba baa misc fn misc misc 7 cba dcb bab dcb sk lk lk lk 8 cba aaa aaa baa sk misc misc misc 9 aaa aaa baa baa misc misc misc misc 10 cba dba baa aaa sk fn misc misc 11 cba cba baa baa sk sk misc misc 12 baa aaa bba baa misc misc misc misc table 4 shows the distribution of student answers to the concepts of heat and temperature. based on the results of the analysis, the overall answers of students were classified as scientific knowledge at 22.9%, 70.5% held misconceptions, namely 62.5% original misconceptions, 4.2% false positives and 4.2% false negatives. 6.2% of lack of knowledge students and 0% of lucky guess. table 4. distribution of student concepts in 3-tier concepts of heat and temperature category cod e question averag e (%) q1 q2 q3 q4 n % n % n % n % scientific knowledge sk 7 58. 3 4 33. 3 0 0 0 0 22.9 false positive fp 1 8.3 1 8.3 0 0 0 0 4.2 false negative fn 0 0 2 16. 7 0 0 0 0 4.2 misconception mis c 4 33. 3 4 33. 3 1 1 91. 7 1 1 91. 7 62.5 lack of knowledge lk 0 0 1 8.3 1 8.3 0 8.3 6.2 lucky guess lg 0 0 0 0 0 0 1 0 0.0 1 2 100 1 2 100 1 2 100 1 2 100 100 heat and temperature depend on the size of the object. to diagnose the conceptual understanding of h & t for the size of objects, we used the case of two iron desk of different sizes, placed in the same space for a long time. as many as 58.3% of students believe that the temperature does not depend on the size of the object. however, only 33.3% understood that heat also does not depend on the size of objects. 8.3% of students believe that heat and temperature do not depend on the size of objects but they reason that the temperature and heat in this case cannot be discussed. sixteen point seven percent of students know that heat does not depend on the size of objects but at the first tier they answer if the small desk has higher heat or the heat of the two desk cannot be compared. sukarelawan & rahman an analysis of graduate students’ conceptual understanding in heat and temperature… indonesian review of physics, volume 2, number 1, 2019 13 33.3% of students strongly believe that the heat and temperature of objects depend on their size. this shows that most students consider heat and temperature to be extensive quantities [20], [40]. these findings prove that the misconception is not only experienced by students [19] but the master level students still hold the same misconception [21]. the percentage of students who have scientific knowledge in q1 is higher than q2. this indicates that the conceptual understanding of heat as an intensive quantity is more difficult for students to understand than the concept of temperature [21]. heat and temperature depend on material made of to diagnose the heat and temperature misconceptions of the constituent material, the case used is the same sized desk (the first and second desks each made of iron and wood) which are stored in the same space for a long time. based on table 4, no student who understands the concept of h& t does not depend on the material made of. the concept of h& t dependence on the material made of is spread into two types of errors, namely misconception (91.7%) and lack of knowledge (8.3%). students holding a misconception in q3 were 91.7%, 91% believed that the temperature of an iron desk was higher than a wooden desk because they thought there were some substances that felt cooler than others. this is in line with the results of the study [20]. while 9% of students holding this misconception believe that iron table temperatures are higher than wooden tables on the grounds that the temperature depends on the type of material making up the object. in this case also, 8.3% of students were of the view that iron desk temperatures were higher than wooden desk because the temperature was dependent on material objects but they were not sure of the knowledge they had. students holding a misconception in q4 as many as 91.7%, 91% believe that iron desk are hotter than wood desk. these findings are not in line with findings from [5], [19] [21]. while 9% of them believe the opposite, namely wood desk feel hotter than iron desk. the reason behind both of their answers is the same, namely heat depends on the material made of. if you look at the distribution pattern of student responses in q3 and q4, it can be concluded that the conceptual understanding of temperature and heat dependence on objects making up materials has the same level of difficulty. v. conclusion based on the results of the research that has been done, it can be concluded that the students of physics education master program semester 1-3 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[40] s. yeo and m. zadnik, introductory thermal concept evaluation: assessing students’ understanding, phys. teach., vol. 39, 2001, pp. 496–504. keywords: heat and temperature, three-tier diagnostic test, conceptual understanding ... reference [40] s. yeo and m. zadnik, introductory thermal concept evaluation: assessing students’ understanding, phys. teach., vol. 39, 2001, pp. 496–504. indonesian review of physics, volume 2, number 2, 2019 34 the effect of electrode gap on the nucleation of cacl26h2o by using sharp end copper electrode risky afandi putri 1,*, ahmad swandi 1, annisa rahman 1, radhiah anggraeni 1 and daniel kurnia 2, inge magdalena sutjahja 2,** 1 graduate study program of physics teaching, faculty of mathematics and natural sciences 2 physics dept., faculty of mathematics and natural sciences institut teknologi bandung, jl. ganesha 10, bandung 40132, indonesia *) riskyafandi15@gmail.com; **) inge@fi.itb.ac.id abstract the performance of the calcium chloride hexahydrate (cacl26h2o) to store the sensible and latent heats is mainly determined by its nucleation or liquid to solid phase transition. this is due to the barrier that has to be overcome when the material undergoes the nucleation process with a reduction in the entropy value. this material, with melting temperature around 29.8 °c, can be used as the thermal energy storage for building applications in tropical areas such as indonesia, in order to reduce the electrical energy for aircond (ac) machines. in this paper, we report the results of experimental study for the effect of the electrical field to the supercooling degree and time period for liquid to solid phase transition. the variation in the magnitude of electrical field was achieved by variation in the gap of electrode for sharp end electrodes (cathode and anode), for the commonly sold copper electrode. keywords: electrofreezing, copper electrode, supercooling degree, induction time, nucleation time i. introduction phase change material (pcm) is a material that can store and release in the form of sensible and latent heats [1]. the capability of pcm to store the relatively large latent heat around its melting temperature is possible by phase transition (solid to liquid) mechanism [2]–[4]. with this characteristic, pcm can be used to control or regulate the room temperature in the building as one of many criteria of thermal comfort of occupant [2], [5]. for this application in the tropical country such as indonesia, calcium chloride hexahydrate (cacl26h2o) is a suitable material. the melting temperature of this material is about 29.8 °c and melting enthalpy around 180 kj/kg [6]. the use of this material, however, is hindered by a relatively large supercooling degree, in which case material’s temperature drop far below the melting temperature before the phase change occur at freezing temperature. this behavior surely inhibits the performance of material as thermal energy storage (tes) system. one method to reduce the supercooling degree of various pcm [7]–[10] is by application of dc electric field (dc voltage), or the so-called electrofreezing. this is a common active method that is effectively proved for nucleation of various materials, such as water [7], [11], salt hydrate [12], or salt solution [13]. the effectiveness of electric field to reduce the supercoooling degree is depend on the magnitude of the electric field itself [14], the shape of edge electrode [15], and the type of the electrode [8], [14]. copper is a kind of electrode materials that is the most effective for nucleation process of various materials mentioned above, with its effectiveness is measured by freezing probability [8], [14]. ii. theory spontaneously, nucleation happens when the change of gibbs free energy is negative ( 0g ) [7]. nucleation is influenced by volume contribution of gibbs free energy, vg (free energy between a very large particle and solute in solution) and the putri, et al. the effect of electrode gap on the nucleation activity of cacl2.6h2o by using sharp end copper electrode indonesian review of physics, volume 2, number 2, 2019 35 surface contribution of gibbs free energy, sg (energy between surface of particle and the bulk of particle) [7], [16]. gibbs free energy of spherical crisstallite in a solution without supplied static electric field, 0g , is defined as, vgrrggg  32 vs0 3 4 4  (1) where r is radius of the sphere,  is the surface free energy of the crystal fluid interface and vg is the free energy change of the transformation per unit volume,   mf ffm v vt tth g   , (2) where fmh , is molar enthalphy of fusion, vm is the molar volume and (tf – t) is the supercooling degree. for applied static electric field, e, the free energy of spherical nucleus, δge, is expressed by  pegrrg v  32 e 3 4 4  (3) where p is the permanent polarization [7], [16]. based on the eq. 3, gibbs free energy can be influenced by supplying static electric field. static electric field can incresing negative δge, in consequence to the nucleation processes [7], [16]. th ice formation is correspond to the critical nucleus, r*expressed by peg r v   2* (4) that is obtained by maximing eq. (3) [17], [18]. thus, with increasing pe term, r* decreases [19]. electric field is influenced by the voltage, v, and the distance between the electrodes, d, d v e  (4) where v is in volt and d is in meters. based on the equation, the strengh of electric field can be modified by v or by d [10]. in this study, modifying electrode gap is used to increasing the electric field. iii. methodology experiment set up is shown in fig.1(a) the experiment set up is consist of 10 kv power supply, 20 ml of cacl26h2o placed in a 50 ml beaker glass, cold water bath, multichannel data logger with thermocouple for temperature sensor, and pc. (a) (b) figure 1. (a) the experimental set up, and (b) the package of the electrodes-thermocouple inside the sample. in fig.1(b), a thermocouple (channel 2) was placed inside of the cold water bath, while the second thermocouple (channel 4) was placed inside the sample in contact with the glass and the third thermocouple (channel 3) was placed inside the sample in the upper of the electrode gap. a package of the electrode and thermocouple channel 3 is placed in the middle of the sample. a pair of sharp end electrodes were used in this experiment. the electrode gap was varied (2.5 mm, 1.5 mm and 0.5 mm) to examine the effect of electrode gap on the nucleation activity of cacl26h2o. the material of the electrode gap was copper (cu) that has a 0.7 mm in diameter. a 20 ml of cacl26h2o was heated until the temperature of the sample reached approximately 52 °c using a hot water bath. after that, the sample was taken out from the hot water bath then it was placed putri, et al. the effect of electrode gap on the nucleation activity of cacl2.6h2o by using sharp end copper electrode indonesian review of physics, volume 2, number 2, 2019 36 and cooled inside the cold water bath. the temperature of cold water bath was kept in constantly at 7 °c. a continuous 1.5 kv voltage was given when the sample temperature reached up to 25 °c in the cold water bath. new sample of cacl26h2o was used for different variation of the electrode gap, with the electrodes that are cleaned by using a sandpaper. for each variation of the electrode gap, the experiment was repeated for about 3 to 5 times, to ensure the data repetition, using the same sample. iv. results and discussion fig. 2 shows the temperature profile obtained during the cooling of cacl26h2o at the first experiment for each variation of the electrode gap and the zero voltage applied. by cooling, the sample’s temperature decreases rapidly due to release of liquid sensible heat to reach a minimum that defined as the supercooling temperature (ts), before suddenly increase to reach freezing temperature (tf). after that the temperature is nearly constant or slightly decrease due to latent heat release, followed by the released of solid sensible heat with more pronounced temperature change. it is to be noted, that the latent heat release is identic with liquid to solid phase transition, or crystallization process of the sample from its solution. for the following discussion, each graph is analyzed to reveal several important temperature and time characteristic, as illustrated fig. 3, while the results are shown in table 1 (for temperature parameter) and table 2 (for time parameter). 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 0 10 20 30 40 50 60 t ( o c ) t (× 1000s) 0 v/m 600 v/m 1000 v/m 3000 v/m figure 2. temperature profiles obtainined during the cooling of 20 ml of cacl26h2o at the first experiment for each variation electrode gap and the zero voltage applied fig. 3(a) presents the temperature-time curve (t vs t), while fig. 3(b) show the first derivative of temperature-time curve (dt/dt vs t) of experimental data. the temperature and time characteristic consist of: induction time (tind), supercooling temperature (ts) that occur at time of supercooling (ts), freezing temperature (tf), and inflection temperature (ti) that occur at time of inflection (ti). figure 3. determination of profile of typical temperature and time during cooling of 20 ml of cacl26h2o. induction time, tind, is the interval time when the crystal nuclei was occurred, and it is determined during the sample’s temperature stay at a constant value, or deviation from a finite value to dt/dt = 0 in fig. 3(b). supercooling time and temperature, (ts,ts), is the time and temperature when the crystal seed reach a significant size to attract another part of sample’s solution to become crystalline. the freezing temperature, tf, is the maximum temperature of nucleation of latent heat release. the inflection time and temperature, (ti,ti) is the end time and end temperature for the crystal growth or latent heat release. besides that, we defined the supercooling degree (δts) as the difference between tf and ts, and crystallization period (tc) as the difference between ti and ts. table 1. the experimentally result (temperature) of the first eksperimen for each various electrode gap (d) under different electrostatic field (e) v (kv) d (mm) e (v/m) ts (°c) tf (°c) δts (°c) ti (°c) 0 0 8.66 27.45 18.79 19.27 1.5 2.5 600 8.75 27.31 18.56 16.85 1.5 1.5 1000 12.95 27.17 14.22 20.99 1.5 0.5 3000 17.26 27.43 10.17 20.75 table 1 present the results of temperature characteristics of the first experiment for each 40 0 1 2 3 4 5 -0,4 0,0 0,4 0,8 (b) (a) t (o c ) t s t i t f 1 st d er iv at iv e o f t (o c ) t (× 1000s) t t tt t t t ind t s t i putri, et al. the effect of electrode gap on the nucleation activity of cacl2.6h2o by using sharp end copper electrode indonesian review of physics, volume 2, number 2, 2019 37 variation of the electrode gap (d) or under different electrostatic field (e) according to formula (4). the smaller d is equivalent to higher magnitude of e. from this table, ts is strongly affected by the electric field, and have the tendency of increases for higher electric field. meanwhile, tf is relatively constant for various d or e. it is clear that the increment of ts and the relatively constant tf resulted to smaller δts. the variation of ts and δts with e is also shown in fig. 4. 0 500 1000 1500 2000 2500 3000 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20  t s (o c ) t s (o c ) e (v/m) t s t s figure 4. relationship between temperature of supercooling and electric field, and supercooling degree and electric field as shown in fig. 4, ts (black square) and δts (red circle) is almost unchanged for the relatively small e of 600 v/m. with further increase of e, ts increases, while the δts decreases at almost the same magnitude. table 2. the experimentally result (time) of the first eksperiment for each various electrode gap (d) under different electrostatic field (e) v (kv) d (mm) e (v/m) tind (s) ts (s) ti (s) tc (s) 0 0 2100 2650 3440 790 1.5 2.5 600 445 1015 2065 1050 1.5 1.5 1000 95 480 1625 1145 1.5 0.5 3000 0 230 1360 1130 table 2 show the results of time characteristic of the first experiment for each variation of the electrode gap under a different electrostatic field. from this table, tind and ts is significantly reduced with the increase of e, signifying the effectiveness of electric field to the nucleation of the material. nevertheless, compared to zero field, tc is increased, but once the field is applied the tc value is almost unaffected by the the magnitude of e. figure 5. relationship between nucleation time and electric field. 0 500 1000 1500 2000 2500 3000 0,0 0,5 1,0 1,5 2,0 2,5 3,0 0 v/m 600 v/m 1000 v/m 3000 v/m t s = 0.199 + 2.457 e -e/513,5 t s ( × 1 0 0 0 s) e (v/m) figure 6. relationship between the time of supercooling and the electric field. fig. 5 and 6 shows the relationship between the tind vs e and ts vs e. from these figures, the decrease of tind and ts with the increase of e is nearly exponential, � = �� + �� ��/��. ec is the critical electric field of the tind and ts. the value ec for tind is 382.1 v/m. the same parameters for ts 513.5 v/m. we note that although the experiment was repeated for 3 to 5 times for each variation of electrode gap, we could only take the results from the first experiment. this is due to the fact that at the second to the last experiment, the electrodes was changed due to crust that attached to the tip of the electrode, as shown in fig 7. 0 500 1000 1500 2000 2500 3000 0,0 0,5 1,0 1,5 2,0 2,5 3,0 0 v/m 600 v/m 1000 v/m 3000 v/m t ind = -0.020 + 2.122 e -e/382.1 t in d ( × 1 0 0 0 s) e (v/m) putri, et al. the effect of electrode gap on the nucleation activity of cacl2.6h2o by using sharp end copper electrode indonesian review of physics, volume 2, number 2, 2019 38 (a) (b) figure 7. the electrode condition of the 1.5mm variation of the electrode gap (a) before applying a dc voltage (b) after applying a dc voltage. fig. 7(a) shows the electrode condition before applying a dc voltage and fig. 7(b) shows after applying a dc voltage. before applying dc voltage, the electrode was clean and colorless. after applying dc voltage, the electrode gap undergoes white thickening. during the experiment, the bubbles occured at the negative pole of electrode (cathode), which might be due to hydrolysis reactions [20]. in addition, the changed of electrode (erosion) is more pronounced for the positive pole electrode (anode), due to chemical process that occur during the experiment that transforms copper into cu2+ ions [21]. these ions then coalesce with cl ions from the melted cacl2·6h2o to form ion-complex compounds that will immediately change in the water environment, to form greenish or bluish solution. these two mechanisms is intricately related to the nucleation kinetics of electrofreezing of this particular material [20], [22]. v. conclusion in this study, the effect of direct-current electric field on the nucleation of cacl26h2o was carried out experimentally to study the role of the electrode gap to the supercooling temperature, supercooling degree, induction time, supercooling time, and crystallization time. the experiment was carried out by using copper electrode with various electrodes gap of 0.5, 1.5, and 2.5 mm of sharp end electrodes. it was found that the smallest electrode gap of 0.5 mm is most effective to reduce the supercooling degree by increasing the supercooling temperature of material, which might be due to the relatively large magnitude of the resulted electric field. the induction time and supercooling time decreases exponentially with the increase of field. the crystallization time, however, is almost constant or it was unaffected by variation in the electrodes gap or magnitude of electric field, once the field is applied. we discuss two distinct interfacial mechanisms that influence the nucleation kinetics, namely, the electrolytic bubble formation from hydrolysis reactions and electrochemistry through the formation of copper ion complex-based coordination compounds. the experimental results could be improved by repetition experiment to get the average and standard deviation values. for each repetitive experiment, the electrode should be cleaned up from attached crust that occur due to chemical processes. acknowledgment this paper is a result of kerja mandiri (fi-6097) study in magister of physics teaching of physics department, faculty of mathematics and natural sciences, institut teknologi bandung. reference [1] l. g. socaciu, “thermal energy storage with phase change material,” leonardo electron. j. pract. technol., vol. 11, no. 20, pp. 75–98, 2012. 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[22] i. sutjahja et al., “electrofreezing of the phase-change material cacl2•6h2o and its impact on supercooling and the nucleation time,” hem. ind., vol. 4, no. 00, pp. 34–34, 2019. indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 52-56 doi: 10.12928/irip.v3i2.3049 http://journal2.uad.ac.id/index.php/irip 52 the effectiveness of online learning using quizizz education game media during the covid-19 pandemic in applied physics courses nanda safarati*, rahma department of physics education, almuslim university jln. almuslim, no.37, bireuen-aceh, indonesia *email: nandasafarati@umuslim.ac.id article info abstract article history received nov 04, 2020 accepted dec 20, 2020 published dec 31, 2020 online learning is learning that is applied by all educational institutions today. the use of appropriate media can support student effectiveness in education, especially in applied physics courses. this study aims to see online learning's effectiveness using quizizz educational media during the covid-19 pandemic in applied physics courses. this research uses a descriptive research method. the population in this study were students of the almuslim university physics education study program. the sample selection used a purposive sampling method, namely students who were taking applied physics lectures. the data collection techniques used were tests (quizzes) and questionnaires. this study indicates that quizizz educational game media is one of the most effective online learning media used during the covid-19 pandemic in applied physics courses. keywords: covid-19 pandemic learning media online learning quizizz to cite this article: n. safarati and rahma, "the effectiveness of online learning using quizizz education game media during the covid-19 pandemic in applied physics courses," indones. rev. phys., vol. 3, no. 2, pp. 52–56, 2020. i. introduction education is a deliberate and organized attempt to build an environment and learning process for students to successfully improve their capacity for moral, religious, self-control, personality, intellect, noble character, and abilities essential for themselves and society [1]. the outbreak of covid-19 coronavirus in 215 countries poses challenges for educational institutions, especially universities. the government has outlawed crowding, social distancing, physical distancing, wearing masks, and often washing hands to tackle covid-19. the government has not allowed tertiary institutions to offer face-to-face (conventional) lectures through the ministry of education and culture and ordered them to conduct classes or study online (kemendikbud dikti circular letter no.1 of 2020) [2]. higher education is led to be able to have online learning [3]. therefore, it is necessary to review the application of face-to-face learning that can gather students. learning scenarios must prevent any potential for physical contact between students and teacher-students [3]. the government's decision to dismiss students, move the teaching and learning process at home by implementing the work from home (wfh) policy makes many parties nervous. according to sadikin [2], digital technology can allow students and lecturers to carry out the learning process even though they are in different places. according to ferdiana [4], various learning media carried out by lecturers during the pandemic have increased the use of digital technology that is integrated into the entire student learning experience. recent literature studies state that today's students are proficient in using digital technology, are always active and very participatory on social media in the internet network. however, the covid-19 pandemic era, which changed learning habits from offline forced them to go online, is essential to recognize the difficulties in utilizing the right digital technology. this is because the use of digital media for teaching and learning has long been inconsistent and varies widely between fields of study, level of study, and mode of delivery [5]. the use of various learning media is expected to increase student motivation in meaningful teaching and learning during the pandemic. engaging learning will improve learning outcomes [6]. various learning media that are carried out online utilize various internet network platforms, interaction, and facilities to support student learning services [7]. the use of online media or e-learning-based media is one solution to make students understand lecture material well. the learning process through e-learning prioritizes learning efficiency to get full teaching even though they are not facing to face. besides, e-learning can be accessed anywhere, anytime, according to a given task, scheduled with a predetermined time limit. quizizz is one of the e-learning-based learning media to use. quizizz is a game-based instructional software that brings multiplayer classroom activities and makes work in the classroom engaging and enjoyable. students can perform classroom activities on their mobile devices by using quizizz. quizizz has game features like avatars, themes, memes, and fun songs in the learning process. quizizz also helps learners to compete with each n. safarati, et al. / indonesian review of physics 3(2), 2020, 52-56 53 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 other and to inspire them to learn. in class, students take the quiz simultaneously and can see their rating on the leaderboard automatically. instructors/lecturers can directly track the process and can after the quiz is finished, download reports or rating scores to measure student performance. using this app helps to stimulate interest and enhance student focus [8]. the quizizz application media has several advantages: time efficiency in processing learning outcomes, saving paper usage, exciting and fun, can be used anywhere, anytime, and provides data and statistics about student performance. according to tarmini et al. [9] stated that the media quizizz is one of the most effective e-learning-based evaluation tools used to evaluate quickly and directly provide results to teachers, so they can quickly take action on students. through the quiz application media, lecturers give assignments to students, and learning physics becomes more fun. because in addition to students focusing on answering questions while playing games, students can also see the scoring/ranking achieved. students become more motivated to take courses—lectures in applied physics, previous students considered that applied physics courses were boring and monotonous by themselves through the use of quiz application media, but most considered. ii. theory online learning according to wartanto [10], one of the internet uses in education is distance learning. there are various terms to express distance learning, namely e-learning, virtual learning, virtual classroom, web-based learning, and online learning. online learning is a non-face-to-face learning system but uses a platform that can help the teaching and learning process even though it is far away. online learning aims to provide quality learning services in a massive and open network to reach learning space enthusiasts so that more and broader [11]. some of the fundamental design principles for producing quality online learning [12], a. identify student learning outcomes in the aspects of knowledge, skills, and attitudes. b. ensuring that assessment strategies are aligned with learning outcomes. c. by arranging learning activities and assignments progressively, students can target the knowledge, skills, and attitudes that are built in the learning process. d. ensuring a balance between lecturers who provide material, social interactions, challenges, or cognitive loads. one of the challenges with online learning is the expertise in using technology on educators and students. dabbagh [13] states that the characteristics of students in online or online learning activities are: 1. the enthusiasm for learning 2. literacy of technology 3. ability to communicate interpersonally 4. collaborate 5. skills for independent study online learning is the mode of lectures that can be used as a workaround during the covid-19 pandemic. online learning uses internet networks for usability, communication, stability, and the ability to create multiple forms of learning experiences, according to sadikin and hamidah [2]. the research recognized by [14] demonstrates that the use of the internet and multimedia technologies can change the way content is communicated and can be an alternative to conventional classroom instruction. online learning can bring together students and lecturers to carry out learning interactions with the internet [15]. learning media national education association [16] said that learning media is a means of communication in both print and perspective, including hardware technology and the position of learning media. meanwhile, according to aect (association of education and communication technology) [17], media are all forms used to distribute information. if enabled by supportive media availability, the teaching and learning process can operate successfully and efficiently. provision of dynamic media and instructional methodologies that are beneficial to the maximum growth of pupil ability. according to ekayani [16], there are 7 media classifications, namely: 1. audio-visual motion media (sound film, videotape, film, tv) 2. audio-visual media is silent (audio series film, sound page) 3. semi-motion audio (distant voice writing) 4. moving visual media (silent film) 5. visual media is silent (printed pages, photos, microphone, slide mute) 6. media audio (radio, telephone, audiotape) 7. print media (books, modules, independent teaching materials) quizizz education game the quizizz educational game is an educational game that is still very rarely used. this game can use a laptop or smartphone and can be done anywhere. according to [18], quizizz is a digital and online-based learning media which consists of features of quizzes, surveys, games, and discussions. the quizizz application is described as a web tool for creating interactive quiz games that can be run on a device and can be accessed via a website www.quizizz.com. game quizizz is a game-based instructional program that takes to the classroom multiplayer activities and makes it interactive and enjoyable for classroom practice. students can perform classroom activities on their mobile devices by using quizizz. quizizz has game characteristics, such as avatars, themes, memes, and fun music in the learning process, not any other instructional software. quizizz also helps learners to compete with each n. safarati, et al. / indonesian review of physics 3(2), 2020, 52-56 54 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 other and to inspire them to learn. learners take the quiz in class at the same time to see their score on the leaderboard live. to measure student results, teachers can track the process and download a summary after the quiz is finished. the use of this program helps to stimulate interest and increase learner focus [8]. the quizizz application is one of the e-learning based learning evaluation media. quizizz learning evaluation media also provides data and statistics about student performance, and can even download statistics in an excel spreadsheet. lecturers can easily track the number of student answers. the use of quizizz helps educators conduct evaluations without being limited by places, attractive displays, and set times to guide student concentration. iii. method this study uses descriptive research methods to describe and interpret objects according to [19]. descriptive research was obtained using a combination research approach. creswell [20] states that a combination method is a research approach that combines or connects qualitative and quantitative research approaches. the population in this study were students of the physics education program, almuslim university. the sample selection used a purposive sampling method, namely students who were taking applied physics lectures. there are two data collection techniques used in this study, namely, to obtain data on a quantitative approach, tests (quizzes) through quizizz educational media. meanwhile, to get data on a qualitative approach, researchers used distributing questionnaires via a google form. both data collection techniques are carried out via whatsapp. before the research was carried out, the questionnaire and questions were analyzed for validation and reliability. questionnaire validation and questions were given to 2 experts, namely media experts and physics education material experts at almuslim university. as for all questionnaire questions before being validated, there were 15 questions, and only ten questions were declared valid. likewise, with applied physics questions, the total questions before being validated were 20 questions, and only ten questions of applied physics were declared valid. iv. results and discussion we collect research data via a google form. the questionnaire, which was distributed via whatsapp, showed that the educational game media attracted interest and motivated students to learn. figure 1 shows how the quizizz application looks. figure 1. quiz game educational media screen display the analysis results are shown in figure 2. figure 2. percentage of student motivation towards media quizizz educational game based on the research results in figure 2, it can be seen that quizizz educational media is fascinating and can motivate students in learning to agree and strongly agree, with a percentage of 53.3% of students answering agree and 46.7% of students answering strongly agreeing. there were no students who responded to options other than the two categories. the use of quizizz educational game media can also help students understand the material in the applied physics course that has been given. this can be seen from the percentage results in figure 3. figure 3. percentage of students' understanding of applied physics material based on figure 3, it can be seen that the largest percentage of students' understanding of the material given is in the category of agreeing and strongly agree with the rate of 33.3% and 53.3%. this shows that most students understand what has been conveyed through quizzes given with quizizz educational game media. quizizz educational game media can also provide positive challenges for students because in addition to doing quizzes, students can also play games and at the same time can see the ranking of the scores obtained n. safarati, et al. / indonesian review of physics 3(2), 2020, 52-56 55 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 when answering the questions given. this can be seen from the percentage obtained as in figure 4. figure 4. percentage of a positive influence of educational game media quizizz against students based on figure 4, the student answer category agrees and strongly agrees to the type with a percentage of 66.7% and 33.3%, and no one answers other options. then, the researcher gave several trick questions to see whether the students were consistent with the statements that had been given. moreover, the research results prove that students are consistent with their opinions. this can be seen from the percentage results that have been given can be seen in figures 5 and 6. figure 5. percentage of a positive influence of educational game media quizizz against students figure 6. percentage of a positive influence of educational game media quizizz against students the question given for figure 5 is that i do not like quizizz educational media because it is very dull and wastes my time, got a percentage of 53.3% in the strongly disagree category, 26.7% are in the disagree category and only 20% answered agree. then the question is almost the same in figure 6. namely, i am less interested in quizizz educational game media, being in the strongly disagree category of 40%, the disagree category is 26.7%, the category strongly agrees and agrees by 13.3%, and the disagree category is equal 6.7%. researchers' results by giving tests/quizzes to applied physics courses can be seen in table 1. table 1. student test results through educational game media quizizz on applied physics courses no name score accuracy (%) 1 yw 10790 100 2 ws 10790 100 3 rd 10790 100 4 mn 9610 90 5 na 9590 90 6 kh 9550 90 7 rn 9070 90 8 ma 8700 90 9 rj 8480 90 10 fh 8410 90 11 nd 8050 80 12 jr 7560 80 13 rl 6500 70 14 ft 6460 70 15 rh 980 10 based on table 1, it can be concluded that the test results of students using quizizz are very good. students mostly can answer questions given by researchers, while the questions presented are ten questions. students with the highest rank are three people with a score of 10790 and an accuracy score of 100%. then there were seven students scored with 90% accuracy, two students with 80% accuracy, two students scored with 70% accuracy, and only one student got 10% accuracy. based on the use of quiz educational game media, it is proven that most students are very enthusiastic and motivated and get positive challenges through the quiz educational game media. students can answer the questions given well. so it can be said that the quiz educational game media is one of the most effective learning media used during the covid-19 pandemic in indonesia. v. conclusion this study concludes that the quiz educational game is one of the most effective online learning media during the covid-19 pandemic for applied physics courses. this can be seen from students' enthusiasm towards the use of quiz education, game media, and the level of student success in answering the questions given. also, quizizz educational game media is a creative learning medium in distracting students from gameplay. hopefully, online learning using the quizizz application media can be appropriately implemented by students. references [1] n. safarati and r. rahma, "penerapan model advance organizer menggunakan macromedia flash untuk meningkatkan pemahanan konsep siswa sma negeri 3 bireuen," j. ris. dan kaji. pendidik. fis., vol. 6, no. 2, pp. 76-81, oct. 2019. n. safarati, et al. / indonesian review of physics 3(2), 2020, 52-56 56 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 [2] a. sadikin and a. hamidah, “online learning in the middle of the covid-19 pandemic,” biodik j. ilm. pendidik. biol., vol. 6, no. 2, pp. 109–119, jun. 2020. 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[20] j. w. creswell, research design: qualitative, quantitative, and mixed method approaches. sage publications, 2017 indonesian review of physics, volume 2, number 2, 2019 60 development of the conception of mechanical energy conservation with interactive lecture demonstration method using simple experiments for grade 7 students willi anindita wijanarka1*, julius zai1, winda noor santi1, laifa rahmawati2, and mohd rustam bin mohd rameli3 1 program studi magister pendidikan fisika, universitas ahmad dahlan. 2 program studi pendidikan fisika, universitas ahmad dahlan. 3 fakulty of education, universiti teknologi malaysia 1 jl. pramuka no.42, pandeyan, umbulharjo, yogyakarta, indonesia. 2 jl. ring road selatan, tamanan, banguntapan, bantul yogyakarta, indonesia. 3 johor bahru, johor darul takzim, malaysia email: *willy.anindito@yahoo.com abstract the purpose of this research is to develop a student's conception of mechanical energy conservation with the interactive lecture demonstration method. the participants consisted of 19 students of class 7e smp muhammadiyah 1 mlati in 2018/2019 academic year. the analysis of the student's sheet prediction showed that most students do not understand the conception of mechanical energy conservation. after learning applied, it is known that all students have understood the influence of the height of the object on potential energy, 18 of them have understood the influence of the mass of the object on potential energy. while students' understanding of changes in mechanical energy when objects fall and the influence of mass on kinetic energy has increased slightly. through the wilcoxon signed-rank test, it was concluded that there was an effect of the use of interactive demonstration methods on student learning outcomes in the matter of mechanical energy conservation conceptions. keywords: mechanical energy conservation, interactive lecture demonstration i. introduction mastery of conceptions of physics necessary for students to solve problems of physics with the correct approach. referring to the studies in the field of physical education found that there are differences in approach to problem-solving among students who are proficient with the less adept. a proficient student uses problem-solving strategies based on the relevant concept, while students who are less proficient based on shallow surface concept [1]. their less proficient students were caused from the beginning is not applied learning models that reinforce mastery of conceptions. students with a weak conception will certainly be a problem in learning. in learning activities, the teacher gives exercises that usually a quantitative question to students with hope through the question, students can master the conception well. whereas based on studies conducted proved that the quantitative problem solving does not help students to understand the conceptions in depth [2]–[5]. researchers in the field of physical education also agreed that learning only rely on lecture and traditional learning methods do not successfully repair the misconceptions of the majority of students [6]. one of the conceptions of physics that are often misunderstood by the students is the conception of mechanical energy conservation. many students do not understand that mechanical energy conservation involves changes to a form of mechanical energy into other forms of mechanical energy with the energy that neither increased nor diminished. then a learning method is needed to correct the student's misconception. learning models that considered can encourage student involvement and correct misconceptions in physics are the interactive lecture demonstration (ild) [7]. wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 61 the researchers examined the effect of ild in learning, including for the development of energy conservation concepts for 10th-grade students [6]. through this research, it is known that the use of ild promoted students' understanding of the concept and improved their reasoning skills. the combination of traditional learning with a small portion of ild activity has been shown to produce significant ngain values [8], [9]. the ild activity promotes effectively the conceptual understanding of momentum, the conceptual change achieved from predictions to results after observation and discussion are around 70% -80% [10]. ild can make a difference in students' conceptual understanding as well as their experiences, demonstrating the potential value-add that can be provided by investing in active learning to enhance lectures [11]. the design of experiments in this study is dropping eggs with a variety of sizes and heights to develop students' conception of mechanical energy conservation. research conducted aimed at obtaining information about initial students' mastery of the conceptions of mechanical energy conservation and the effectiveness of the interactive lecture demonstration model to correct student misconceptions about the conception of mechanical energy conservation. the application of the interactive lecture demonstration method in this study began with students expressing their predictions of the state of the egg after being dropped, the prediction is poured in the form of drawing. the use of drawing is meant to attract attention, excite, and facilitate communication that is hard to imagine the students about the conception of mechanical energy conservation. the use of pictures is worth as alternative learning to improving learning outcomes because learning physics with pictures makes the student more eager to follow lessons [12]. ii. theory interactive learning demonstration (ild) method in physics learning physics is a branch of natural sciences so physics can be seen as a process, procedure, and product. as a process, physics is a scientific activity to find new knowledge or perfect existing knowledge. as a procedure, physics is a methodology for knowing something (generally in the form of research) that is commonly called the scientific method. as a product, physics is the result of a process, which is in the form of knowledge being taught or in the form of a knowledge book. physics is born and developed through observation, formulating problems, making hypotheses, conducting experiments to test hypotheses, and drawing conclusions. therefore physics learning should use an inquiry approach that involves students' ability to search and investigate systematically, logically, critically, and analytically to the fullest. this will ultimately make students able to formulate their findings with confidence [13]. one method based on an inquiry approach is an interactive lecture demonstration method. the ild is one of the student-centered constructive learning so that students think actively of their conceptions and enable students to build their understanding about main concept through demonstrations and discussion with colleagues [8]. learning in ild through teacher demonstration about a science experiment that lasted interactive with the students for their predictions from students about how something (the experiment) happened. in the ild, students engage in activities that test the validity of the initial understanding of the conception. this model can be applied in large and small class sizes. ild learning consists of three stages: 1. predict the outcome of the demonstration will be done. the first students predict individually and then explain to other students about the most likely outcomes obtained from the demonstration. 2. experience the demonstration. students conduct experiments in small groups, students conduct a survey or process data to test the truth of their predictions. 3. reflecting on the experimental results. students think about the causes of the experimental results in suitable with or not suitable for their predictions. ild is included in the active learning method in which students build their knowledge independently through observation activities. in this method the learning cycle is used, where students confront their initial belief with the results of observations. when the results of observations conflict with the students' initial beliefs, students will change their beliefs. in this learning method, the teacher acts as a guide for learning, not transferring knowledge. discussion and collaboration among fellow students is an important part of the ild method. the role of experiments in this method is not to confirm the knowledge that has been obtained in the classroom, but rather as a basic conception construct. the interactive demonstration method has advantages, including: 1. it does not require a lot of tools and materials and is easy to implement. wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 62 2. make learning activities more interesting. 3. student can compare theory with reality directly. 4. learning departs from the students' initial ideas. the interactive lecture demonstration method has several weaknesses, including not all objects or physical phenomena than can be demonstrated and demonstrations are difficult to understand if done by a teacher who lacks mastery of the topic. iii. methodology the instrument used to measure students' understanding are pretest, posttest, and student prediction sheet. pretest and posttest contain four questions that measure students' understanding of mechanical energy coservation. in the prediction sheet, students predict the condition of the egg after hitting the floor, as a result, dropped from a certain height, the prediction is expressed in the form of drawing. pretest and prediction sheet worked by students before learning begins while the posttest did after going through the learning process. analysis of prediction sheet performed by first categorizing the level of damage to the eggs in the students drawing. furthermore, to determine the initial understanding of the students about the conception of mechanical energy conservation by comparing the level of damage to the eggs in each experiment. by comparing the level of damage to the eggs in the experiment one and two will be obtained information about the students' initial understanding of the conception of the object's mass effect on its mechanical energy. while comparing the level of damage to the eggs in experiment two, three and four will be obtained information about students' initial understanding of the conception of the effects of height on the object of its mechanical energy. the posttest and pretest values were analyzed to determine the effectiveness of learning through normalized gain or n-gain )(  g which satisfies the equation (1). pretest pretestposttest g    100 (1) with normalized gain (n-gain) criterion that can be seen in table 1 [14]. furthermore, the wilcoxon signed rank test was used to test the hypothesis proposed in the study (ha) = "there is a difference between pretest to posttest learning outcomes, which means there is the effect of the use of methods of interactive lecture demonstrations to 7th grade student learning outcomes in the conception of mechanical energy conservation". if the wilcoxon signed rank test results demonstrate the value of asymp. sig. (2tailed) < 0.05 so ha is received, if asymp. sig. (2tailed) > 0.05, ha rejected. table 1. normalized gain criteria n-gain (< g >) criteria (< g >)  0,7 high 0,3  (< g>) < 0,7 moderate (< g >) < 0,3 low tools and materials tool and materials required are: 1. one small-sized eggs (quail egg) and 3 largesized eggs (broilers egg) 2. measuring tape 3. digital balance 4. one piece a3 size paper, 1 piece 2xa3 paper, and 2 piece 4xa3 paper ild scenario students predict the outcome of the four demonstration experiments that will be conducted by the teacher, the prediction expressed in the form of a drawing of egg condition after hitting the floor. four demonstration experiments are: experiment 1: small egg dropped from a height of 1 meter. experiment 2: large egg dropped from a height of 1 meter. experiment 3: large egg dropped from a height of 2 meters. experiment 4: large egg dropped from a height of 3 meters. students conduct experiments 1 to 4 then record the results for comparison with predictions. note the experiment result consists of egg drawing after hitting the floor, the farthest distance of the traces fallen eggs from the point of impact, and a description of the level of egg damage. the farthest distance and the description of the level of egg damage used by the student to infer the relationship between mass and height of falling eggs with mechanical energy. wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 63 iv. results and discussion students prediction sheet the students' predictions of damage level of eggs for each experiment as follows in table 2 until table 5. table 2. kinds of predictions with the number and percentage of answers for experiment 1 the condition of the egg total answers percentage of responses (%) yolk egg white egg shell intact intact cracking 1 5.26 intact intact ruptured 12 63.16 intact intact severe rupture 1 5.26 intact ruptured ruptured 3 15.79 intact ruptured severe rupture 1 5.26 ruptured intact ruptured 1 5.26 table 3. kinds of predictions with the number and percentage of answers for exper iment 2 the condition of the egg total answers percentage of responses (%) yolk egg white egg shell intact intact cracking 1 5,26 intact intact ruptured 8 42,11 intact intact severe rupture 4 21,05 intact ruptured ruptured 2 10,53 intact ruptured severe rupture 1 5,26 ruptured intact severe rupture 2 10,53 ruptured ruptured ruptured 1 5,26 table 4. kinds of predictions with the number and percentage of answers for experiment 3 the condition of the egg total answers percentage of responses (%) yolk egg white egg shell intact intact ruptured 3 15,79 intact intact severe rupture 6 31,58 intact ruptured ruptured 5 26,32 intact ruptured severe rupture 1 5,26 ruptured intact severe rupture 1 5,26 ruptured ruptured severe rupture 3 15,79 indicators that students understand the conception of the object mass influence on the mechanical energy is if the damage of the egg described in experiment two more severe than experiment one. after a comparison of the level of egg damage between experiments one and two, it is known that 58% of students do not understand the conception of the effect of object mass on mechanical energy. students' misconceptions can be seen in the absence of picture that show an increase in egg damage in experiments one to two. students assume that the mass of objects does not affect the amount of mechanical energy generated. students are not able to associate that egg with larger mass at a certain height has larger mechanical energy in the form of potential energy, which when egg dropped, the potential energy gradually turns into another mechanical energy called kinetic energy which results in more severe damage to the eggshell, yolk, and egg white. table 5. kinds of predictions with the number and percentage of answers for experiment 4 the condition of the egg total answers percentage of responses (%) yolk egg white egg shell intact intact cracking 1 5,26 intact intact ruptured 2 10,53 intact intact severe rupture 4 21,05 intact ruptured ruptured 4 21,05 intact ruptured severe rupture 4 21,05 ruptured ruptured ruptured 1 5,26 ruptured ruptured severe rupture 3 15,79 indicators that students understand the conception of the object heights influence on the mechanical energy is if the damage of the egg described successively increased from experiment two to four. after a comparison between experiments 2, 3, and 4 is known that 63% of students do not understand the conception about the effects of height on mechanical energy. students' misconceptions can be seen in the absence of pictures that show the gradual increase in damage of eggs dropped in experiment 2.3, then 4. students assume the height of the object does not affect the mechanical energy. students are not able to associate that eggs at higher positions have larger mechanical energy in the form of potential energy, which when egg dropped, the potential energy gradually changes into another form of mechanical energy called kinetic energy which causes more severe damage to the eggshell, yolk, and egg whites. wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 64 results of students experiment students draw the shape of the eggs after hitting the floor on a sheet of student experimental results, while teachers take the egg photos, photos are shown in the figure 1. (a) (b) (c) (d) figure 1. photo of egg shape after hitting the floor: (a) experiment 1, (b) experiment 2, (c) experiment 3, and (d) experiment 4 it can be seen in the photo that the level of egg damage gradually increased from experiment one to the four. farthest distance data and description of the level of eggs damage is written on the students worksheet (lkpd) are presented in the following table: table 6. farthest distance of the trail egg outbreaks from the point of impact exp egg type (egg size) mass height the farthest distance of the trail eggs outbreak from the point of impact 1 quail egg (small) 10 g 1 m 23 cm 2 broilers egg (large) 50 g 1 m 25 cm 3 broilers egg (large) 50 g 2 m 127 cm 4 broilers egg (large) 50 g 3 m 224 cm the difference between experiments one and two is the egg mass dropped. the egg mass in experiments 2 is greater than experiments 1. by comparing the farthest distance of the trail egg outbreaks from the point of impact and level of egg damage between experiments one and two, students find that the farthest distance of the trail egg outbreaks from the point of impact and the level of egg damage in experiments 2 exceeded experiment 1. that reinforces by comparing drawing of the shape of the egg after hitting the floor between experiments 1 and 2 on a sheet of student experimental results. then students concluded that the greater the mass of the object causes the greater the mechanical energy generated. tabel 7. damage level of the egg exp the level of damage to the eggs eggshell egg whites egg yolk 1 cracked splattered intact 2 split into two splattered splattered 3 broken into pieces splattered splattered 4 broken into pieces splattered splattered the difference between experiments 2, 3 and 4 is the height of the egg dropped. egg height successively increases from experiment 2 to 4. through comparison of experiments 2, 3, and 4, students know that the farthest distance of the trail eggs outbreaks from the point of impact and the level of egg damage in experiments 3 exceeds experiment 2. students also know that the farthest distance of the trail eggs outbreaks from the point of impact in experiment 4 exceeds experiment 3. that reinforces by comparing drawing of the shape of the egg after hitting the floor between experiments 2, 3, and 4 on a sheet of student experimental results. then students concluded that the greater the height of the object causes the greater the mechanical energy generated. pretest and posttest the pretest and posttest consisted of four questions that measured the mastery of conceptions about the conservation of mechanical energy. the number 1 pretest and posttest questions test students' understanding of the effect of object height on potential energy. question number 2 examines students' understanding of the effect of object mass on their potential energy. question number 3 examines students' understanding of the effect of object mass on their kinetic energy. while question number 4 tests students' understanding of changes in the shape of mechanical energy in the case of mechanical energy conservation on a falling object. the average score of the pretest and posttest was 33.55 and 67.11 respectively. n-gain obtained is in wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 65 the medium category which is equal to 0.50. n-gain calculations are also performed on each number whose results are presented in the table 8. table 8. n-gain table for each number no. pretest average score posttest average score n-gain 1 63,2 100 1,00 2 26 95 0,93 3 32 42,1 0,15 4 13 31,6 0,21 furthermore, the normality test. the test sample amounted to 19 which means that on a group 50 then do the shapiro-wilk normality test. probability studies were selected for 0.05 so that the number of 19 samples obtained wilk table at 0.9010. based on the calculation of the shapiro-wilk normality test, wilk obtained count on the results of pretest and posttest respectively 0.94 and 0.79. wilk calculated from the results of the pretest is greater than the wilk table, so the hypothesis is accepted which means the pretest data is normally distributed. whereas wilk counts from the posttest results smaller than wilk tables, so the hypothesis is rejected which means the posttest results data are not normally distributed. if there are data that are not normally distributed, the t-test cannot be applied, so that an alternative test is carried out, namely the wilcoxon signed-rank test to determine the significance of the use of interactive demonstration methods to improve student learning outcomes. from the results of the wilcoxon signedrank test with a research critical limit of 0.05, the asymp. sig value was obtained. (2-tailed) = 0.0005. because of the value asymp.sig. (2-tailed) is smaller than the critical threshold of research so ha is received. based on these results concluded that there is a difference between pretest to posttest learning outcomes, which means there is the effect of the use of methods of interactive lecture demonstrations to 7th-grade student learning outcomes in the conception of mechanical energy conservation. based on the achievement of n-gain at number one and two, it was concluded that the learning carried out was very effective in increasing the mastery of students' conceptions of the influence of height and mass of objects on their potential energy. all students were able to understand the effect of height on mechanical energy. this can be seen in the answer of the number 1 posttest question which shows that all students have been able to sort objects that have potential energy from the smallest to the largest based on object height. based on the answers of the number 2 of the posttest question, it is known that 18 students have been able to understand the influence of mass on the potential energy. this can be seen in the answers of the number 2 in posttest question which shows that 18 students have been able to sort the objects that have potential energy from the smallest to the largest based on object mass. this is because the students see the demonstration directly and do their experiments, and the experimental results reviewed by students that make learning more meaningful for students. assessment of students to the egg drawing after hitting the floor reinforces the conception of the student because the drawing will be meaningful in learning when analyzed or assessed conceptions, relationships between conceptions, and other matters contained in the drawing [15]. it appears that the n-gain for number 3 and 4 is low but still indicate that student understanding of the effect of object mass on kinetic energy and changes in the form of mechanical energy in falling objects has increased. based on students' answers to the number 4 posttest question, it is known that after learning, the majority of students still unable to understand that objects with a certain mass when falling will experience the changing in mechanical energy from potential energy into other forms of mechanical energy, called kinetic energy. then based on the student's answer of the number 3 posttest, it is known that the majority of students unable to understand that the mass of an object is directly proportional to the kinetic energy so that when hitting another object, the object with a greater mass will suffer more severe damage. this is due to the demonstration and experiments carried out less emphasis on kinetic energy aspects. at the demonstration and experiment, the students observed and carried out their experiments to drop eggs with variations in size (or mass) and height imagined by students as demonstrations and potential energy experiments. the lack of emphasis that when it starts falling occurs the process of changing potential energy into kinetic energy makes students unable to imagine the influence of mass on kinetic energy. it also has an impact that students are unable to understand changes in mechanical energy in the case of energy conservation. v. conclusion after learning is applied, students are tested again through the posttest. after going through the calculation process of the results of the posttest and pretest through the normalized gain, the gain in the moderate category was obtained (< g > = 0.50). all students have understood the influence of the height wijanarka et al. development of the conception of mechanical energy conservation with interactive lecture demonstration... indonesian review of physics, volume 2, number 2, 2019 66 of objects on the potential energy. 18 of them have understood the influence of the mass of objects on the potential energy. students' understanding of the effect of object mass on kinetic energy has increased shown in the number 3 posttest learning gain score of 0.15. students' understanding of changes in the form of mechanical energy in falling objects also increases shown in the number 4 posttest learning gain score of 0.21. based on student's answers on posttest numbers 3 and 4, it is known that the majority of students still unable to understand the effect of mass on kinetic energy and changes in the form of mechanical energy in falling objects. through the wilcoxon signed-rank test, it was concluded that there were differences in the pretest and posttest learning outcomes, which means that there is an influence on the use of interactive lecture demonstration methods on the learning outcomes of 7th-grade students in smp muhammadiyah 1 mlati in 2018/2019 academic year on the conceptions of mechanical energy conservation. reference [1] m. y. abdullah, “strategi efektif pembelajaran fisika: ajarkan konsep,” sriwijaya university, palembang, 2012. [2] d. hestenes and m. wells, “a mechanics baseline test,” phys. teach., vol. 30, no. 3, pp. 159–166, mar. 1992. [3] d. hestenes, m. wells, and g. swackhamer, “force concept inventory,” phys. teach., vol. 30, no. 3, pp. 141– 158, mar. 1992. [4] j. clement, “students’ preconceptions in introductory mechanics,” am. j. phys., vol. 50, no. 1, pp. 66–71, jan. 1982. [5] l. c. mcdermott, “millikan lecture 1990: what we teach and what is learned—closing the gap,” am. j. phys., vol. 59, no. 4, pp. 301–315, apr. 1991. [6] s. rachniyom, k. toedtanya, and s. wuttiprom, “development of the concept of energy conservation using simple experiments for grade 10 students,” j. phys. conf. ser., vol. 901, p. 012124, sep. 2017. [7] d. r. sokoloff and r. k. thornton, “using interactive lecture demonstrations to create an active learning environment,” phys. teach., vol. 35, no. 6, pp. 340–347, sep. 1997. [8] a. mazzolini, s. daniel, and t. edwards, “using interactive lecture demonstrations to improve conceptual understanding of resonance in an electronics course,” australas. j. eng. educ., vol. 18, no. 1, 2012. [9] a. mazzolini, t. edwards, w. rachinger, s. nopparatjamjomras, and o. shepherd, “the use of interactive lecture demonstrations to improve students’ understanding of operational amplifiers in a tertiary introductory electronics course,” latin-american j. phys. educ., vol. 5, no. 1, pp. 147–153, 2011. [10] j. j. velarde, c. alvarado, and a. mijangos, “evaluating an interactive lecture demonstration implementation in a lab setting: an example from a collisions and momentum learning activity,” lat. am. j. phys. educ, vol. 6, no. suppl. i, 2012. [11] h. georgiou and m. d. sharma, “does using active learning in thermodynamics lectures improve students’ conceptual understanding and learning experiences?,” eur. j. phys., vol. 36, no. 1, p. 015020, jan. 2015. [12] m. mukaramah, “influence of the drawing media through computer to learning outcomes in class x sma negeri 1 bimomaru,” sci. j. phys. educ., vol. 4, no. 2, pp. 271– 283, 2015. [13] r. d. suyanti, strategi pembelajaran kimia. yogyakarta: graha ilmu, 2010. [14] r. r. hake and j. . reece, analyzing change/gain scores. indiana: indiana university, 1999. [15] indarwati, “the influence of demonstration image analysis on physics learning and knowledge of the procedure of the early semester of prospective physics teachers,” saintifika j., vol. 13, no. 2, pp. 1–15, 2015. indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 11-18 doi: 10.12928/irip.v3i1.1691 http://journal2.uad.ac.id/index.php/irip 11 development of interactive physics e-module using the sets (science, environment, technology, society) approach to improve science literacy dimension of content and process dimensions in fluid dynamics material eka syafutri *, widodo, and yudhiakto pramudya master program of physics education, universitas ahmad dahlan jl. pramuka no. 42, yogyakarta, daerah istimewa yogyakarta, indonesia *email: ekasyafutri@gmail.com article info abstract article history received feb 8, 2020 revised apr 23, 2020 accepted june 18, 2020 this development research produces interactive physic electronic products using the interactive physics sets approach (science, environment, technology and society) in terms of presenting the components of illustration, language, and the suitability of the material. the validity results of the electronic module carried by experts and teachers develeop the average yield of 96.36% so it is feasible to use. the study design is pretest-posttest control group to see the improvement of literacy dimension process. subject of the study consisted of two groups: the experimental group and the control group. the data collection formed by science literacy of dimension content and process is analyzed using manova with significance level of 5%. the results showed that the electronic module using sets approach significantly influence the improvement of science literacy dimension content and process. keywords: dynamic fluid e-module science literacy sets to cite this article: e. syafutri, widodo, and yudhiakto pramudya, “development of interactive physics e-module using the sets (science, environment, technology, society) approach to improve science literacy dimension of content and process dimensions in dynamic fluid material,” indones. rev. phys., vol. 3, no. 1, pp. 11–18, 2020. i. introduction the development of technology for the 21st-century has brought a great influence on the development of education in indonesia. the rare indonesia conditions nowadays is that the number of human resources can follow the progress of science and technology optimally. to create quality human resources education courses closely related to the role in the delivery of the next generation that can compete internationally for education contribute greatly to prepare cadres of the nation. subiantoro [1] suggested that the need for capital generation of scientific literacy be able to apply their knowledge and contribute to the development of science and technology to improve people's welfare. the relevance of education issues was confirmed by the united nations when declared, between 2005 and 2014 about a decade of education for sustainable development. attitudes toward the new challenges of the post-industrial society is a direct consequence of the development of science and technology, the explosion of knowledge and globalization [2]. on the curriculum in 2013, one of the teacher's job is to maximize the learning process. learning approach science, environment, technology, society (sets) is one of the lessons according to the curriculum of 2013. sets is an integrated approach involving elements of science, technology, and society. this approach aims to help students seeing science, development, environmental influences, technology, and society as a reciprocal [3]. in sets learning approach, students are expected to connect the four elements sets with the material being studied. students practice in a way that varies from observing, discussing, asking, answering, and solving problems. a meaningful science learning process for students can be obtained if students have good literacy skills. miller (1998) in [4] argued that scientific literacy can also be defined as the ability to read and write about science and technology. the definition of scientific literacy is looking at multi-dimensional scientific literacy in this aspect of the measurement, like the content of science, the process of science, and the science application context. thus, students can use scientific knowledge and can apply it to solve everyday problems related to the material studied [5] toharudin, hendrawati, and rustama [6] suggested that the process of science is the ability of students to use scientific knowledge and understanding in answering a question or solve a problem. low ability students' science literacy in particular on the dimensions of the process can be seen in 2015 that indonesia increased particular scores in ability of science. however, the latest results of pisa 2018 published the organization for economic cooperation and development (oecd), indonesia still scored below the average of the standards set in which data pisa showed about 40% of indonesian students reached level two for the ability of science. this again shows the level of indonesia is still below the average for oecd defined science capability that is 78% [7]. computer-based instruction learning to have significant benefits in the learning process. the e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 12 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 utilization of computer can serve as a tool in learning process, while as tutor implies that the computer replaces the role of teachers in teaching, presenting information, testing through questions and give feedback as learning program or involve students in the simulation or game [8]. therefore, the electronic module (e-module) is an option that is currently supporting the development of 21st-century learning since conventional learning (print modules) less interactive and static forms or monotonous. the study of physics needs a media that can support the mastery of the concepts of physics, especially in the dynamic fluid material. under the conditions described above, the development of a media-based interactive learning computer technology supports the science literacy approach sets as an alternative learning media that can be used by teachers and students. some similar research to develop e-learning using the e-module has been done. the research is still confined to media development and effective use of the media only. this research is more emphasis on measuring the dimensions increased scientific literacy approach process sets to develop modules nonprinting. ii. theory rahdiyanta [9] revealed that the module is one form of instructional materials packaged as a whole and systematical are contained within a load a set planned learning experiences and is designed to help learners master the specific learning objectives. the rapid development of technology today has allowed the computer to load and deliver various forms of media in it. in this case, heinich, molenda & russel (1996) in [7] argues that: "... it has the ability to control and integrate a wide variety of media still pictures, graphics, and moving images, as well as printed information. the computer can also record, analyze, and react to student responses that are typed on a keyboard or selected with a mouse ". the development of information media is now beginning to transit from print media gradually turning to digital media. presentation materials are not only limited to the print media itself, but already take advantage of digital media. one form of such a presentation is an ebook. borg and gall [9] stated that electronics module (e-module) is a good development of teaching materials since printed modules is less interactive and has a display static images or monotone while e-modules can be interactively present the material displayed by multimedia such as video, animation, simulation and provide direct questions with feedback. the function of the media in the learning process is important in improving the quality of the learning process that supported by the selection of methods or models of learning appropriate to achieve good learning outcomes in this regard is to increase science literacy dimension of the process. electronic modules development in this study using the sets approach which has 5 stages of learning as a guide to learners in the learning process and is expected to increase the motivation to learn about physics. binadja [3] stated vision sets is a way of looking into the future, lead to an understanding that everything in life contains aspects of science, environment, and society influence each other mutually. sets learning leads to a way of thinking about science, how to investigate, and its interaction with the environment, technology, and society. the purpose of education is to form sets visionary individuals who have a science and technology literacy and has a concern for the community and environment. someone who has a science and technology literacy can solve problems using scientific concepts following the material at each level of education, based on the above description that the purpose sets approach is teachers are required to transfer knowledge to students contextually where the situation and given the concept of learning can be packaged into the form of technology and then the students are required to determine the role of these technologies to the public. scientific literacy is a person's ability to distinguish the facts of science from a variety of information, identify and analyze the use of methods of scientific investigation as well as the ability to organize, analyze, interpret clicking quantitative data and information science [10]. lederman [11] states that the essential nature of the scientific literacy of students roommates influences decisions about personal and societal problems. beyond this, however, educators work to influence students ability to view science through a more holistic lens. scientific literacy becomes fundamental because it can affect students in decision-making when faced with social and personal problems [11]. arohman [2] revealed that a man who has the scientific literacy has to assess the science process skills in making daily decisions when dealing with other people, society and the environment, including social and economic development. in contrast to that presented by hoolbrook competence and rannikmae, pisa 2015 assessment of science literacy outlining figure 1. competence in science literacy refers to the process of science involved when answering a question or solve a problem, such as identifying and interpreting evidence and explain the conclusions. the following scientific literacy competence based on three aspects named content, process, and context that are presented in the table. by following the above presentation, learning by applying the approach sets is a process to build on the four foundations of scientific literacy, such as: (1) the foundation sets, build an understanding of the nature of science and technology, the relationship of science and technology, as well as the social and environmental context of science and technology; (2) the foundation of knowledge, building knowledge and understanding of science and apply this understanding to interpret, e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 13 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 integrate, and develop knowledge; (3) the foundation of skills, build the skills necessary to conduct inquiry of science and technology, communicate ideas and scientific results, cooperate and make decisions; (4) the foundations of attitudes/societal value. figure 1. framework for pisa 2015 assessment of science literacy [7] based on the statement, it can be said that the sets approach is able to compensate for the learning process of students to see the students' science literacy skills improvement in developing instruments that refer to syntax sets approach to science literacy achievement indicators in particular to the dimensions of content and process. this is in line with the dynamic fluid material on its application widely used to support the work of man. electronic module development with dynamic fluid material is expected to improve the scientific literacy of students as prepared based on the competencies that match the dimensions of the scientific literacy and science process approach adapted to the stage sets syntax. the module is based on the concepts of dynamic fluid as well as events in the daily life of students related to the dynamic fluid. this is in line with the process of learning to use the sets approach as a review to see the students' science literacy skills improvement. iii. method this development study producesinteraktive e modul product using adobe flash with addie development module, that has five steps: analysis, design, development, implementation, and evaluation. the research design used pretest-posttest control group design [12]. this study consisted of the experimental group using e-modules and development results in the control group that applies classroom learning to use the textbook and worksheets. before performing the application of the product to see the students' science literacy dimension of the process, some early stage of the analysis phase of the method is students needed to begin learning the used of curriculum. after conducting an analysis followed by a design phase, make the lattice e-module before being developed following the storyline created. the instrument used to look at the process of the scientific literacy dimension of the pretest-posttest shaped description were analyzed using n-gain and observation sheet to see the learning process of the student. the following equation n-gain, [13]: post pre maks pre n-gain s s s s   (1) where: spost = score posttest spre = score pretest smax = maximal ideal score table 1. criteria for the change scores of students before and after the learning, [13] score range information > 0.7 high 0.3 ≤ g ≤ 0.7 moderate < 0.3 low the manova test as a prerequisite test analysis to see the connection between e-modules to increase the science literacy development dimension of the process. iv. results and discussion after conducting three phases of analysis: a preliminary analysis, environmental analysis and the analysis of students' school, then followed the design of instruments to be used by following needs that have been previously analyzed. after analysis, the storyline and flowchart design are done in advance as a reference during the development stage. the development of the e-module flowchart is described in figure 2. e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 14 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 after preparing the storyline, we develop the syllabus and lesson plans that are used as a reference for the manufacturing process of learning and assessment instruments. the development result of the storyline is formed of interactive e-module physics. the product consists of a dynamic fluid material, animation proponents of the theory, simulation, and experiment phet interactive exercises. the results of product development can be shown in the following figure 3 to 6: 1. intro page intro page functioned as the first page that appears when the e-module is executed. users enter a name for the access to the main menu page. intro page can be seen in figure 3. 2. the main menu page on the main menu page will be displayed 6 menus named, basic competencies and indicators, material fluid dynamic simulations phet, regarding figures, glossary and details. you can click the sixth menu to access the next page. the main menu page can be seen in figure 4. 3. weather content maps of the material consist of four chapters, named, fluid ideal, legal bernoulli, bernoulli law enforcement and training menu. sub-chapters in the application of bernoulli's law, named, theorem torricelli, pipes, venturimeter, pitot tubes, style lift aircraft and application of bernoulli's law in everyday life. weather exercises consist of two sessions: exercises 1 and exercises 2. the user will be given the processing time 5-15 minutes to complete one matter. users will switch to the next question, after the user has completed the number of the previous problem. sample page layer can be seen in figure 5 and figure 6. the results of the e-module products validation are carried by 2 validator experts and two teachers of physics. content expert validation results can be seen in the table 2. figure 2. flow diagram interface e-module e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 15 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 3. intro page figure 4. main menu page figure 5. (a) content page bernoulli, (b) content page venturimeter figure 6. (a) instructions page exercises, (b) exercises page table 2. results of the validation of product quality by content expert aspects rating validators average per aspects category 2 lecturer 2 teachers contents 3.71 3.79 3.75 vg presentation 3.56 3.56 3.56 vg languange based bsnp 3.44 3.50 3.47 vg sets 3.67 3.94 3.81 vg average 3.59 3.70 very good average of 4 validators 3.65 the percentage is calculated based on table 2. agreement with the acquisition of 97.82% so that the product can be said to be reliable. in addition to ratings. media experts provide advice and input as an improvement to the product. the tests is conducted by expert lecturers and two physics teachers to assess the electronic module of the aspects of screen design, easy of use, consistency, formatting function keys, usefulness, and graphic aspect. media expert validation results can be seen in table 3. e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 16 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 3. results of the validation of product quality by media experts aspects rating validators average of aspect category 2 lecturer 2 teachers design of screen display 3.33 3.67 3.50 vg ease of use 3.40 3.80 3.60 vg consistency 3.67 3.67 3.67 vg format 3.75 3.75 3.75 vg expediency 4.00 4.00 4.00 vg graphic aspects 3.38 3.63 3.50 vg average 3.59 3.75 very good average 4 validators 3.67 the result of media experts and subject matter experts to draft the first module which has been revised by the input of experts. furthermore. the draft module ii trials conducted on a limited basis (preliminary field testing) to 10 students of class xii to see the response of students and produced the third draft that will be used in field tests (main field testing). limited trial (preliminary field testing) to 10 students of class xii students to see the response to the emodule. limited test results can be seen in table 4. table 4. student response data to the e-module physics assessment criteria score score category presentation materials 23.5 a very good linguistic 9.60 a very good graphic 24.6 a very good components sets 16.9 a very good the table 4 shows the results of qualitative data conversion to quantitative students to look at the feasibility modules in a limited test (preliminary field testing). based on the results of expert validation data and student responses on a limited test indicates that the emodule interactive physics using the sets approach suitable as alternative teaching materials to improve students' science literacy dimension of the process. after conducting a limited test. then the test field (main field testing) aims to look at the effect of emodules to increase students' science literacy skills of the dimensions content and process. pretest-posttest assessment data of students in field trials in the experimental group and the control group are shown in table 5 and 6. table 5. pretest-posttest assessment data capability content dimension of science literacy description experiment group control group pretest posttest pretest posttest content content mean 16 72 12 53 standard deviation 2.89 17.64 6.93 19.64 maximum value 20 95 20 90 minimum value 15 50 0 20 gain 0.67 0.48 category medium medium table 6. pretest-posttest assessment data capability process dimension of science literacy description experiment group control group pretest posttest pretest posttest process process mean 41 69 35 41 standard deviation 7.89 10.13 10.05 15.75 maximum value 41 95 43 76 minimum value 1 18 13 20 gain 0.47 0.10 category medium low based on data from the pretest-posttest at the table. it can be seen that the average value of the dimensions of the process in the experimental group increased by 28 from 41 to 69 while the control group increased by 6 on a pretest-posttest from 35 to 41. a comparison of the value of pretest-posttest between the experimental group and the control group on the dimension of the content and process can be seen in figure 7 and 8. e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 17 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 12 53 16 72 0 20 40 60 80 pretest posttest n u m b e r o f v a lu e control group expr. group figure 7. results pretest-posttest control group and the experimental group dimensions of the content 34 4141 69 0 20 40 60 80 pretest posttest n u m b e r o f va lu e s control group expr . group figure 8. results pretest-posttest control group and the experimental group dimensions of the process figure 7 and 8 shows that the tendency to increase the dimensions of the content and process of scientific literacy in the experimental group or the control group had a difference and increase respectively. both groups experienced an increase after being given a different treatment both conventional learning and using e-module development results. it can be evidenced by the gain on the dimension content of the experimental group to 0.67 in the medium category and control group with a value of 0.48 gain in the medium category. the gain on the dimension process of the experimental group to 0.47 in the medium category and a control group with a value of 0.10 gain in the low category. the next test inferential statistical analysis is to determine the relationship of the dimensions of scientific literacy improvement process with the use of e-module development results. the first step taken was to determine the normality of the data distribution that is normally distributed or not and determine homogeneity of variance. the normality distribution data used the chi-square analysis discretion (n) < 50. results of calculations using microsoft excel 2010 can be seen in table 7. variant homogeneity test was performed using levene test output results statistics using spss version 23 gives the figure of significance such as table 8. table 7. results of data normality test research group variable x2count x2table ( conclusion exp. group content -33.553 7.815 normally distributed data for process -26.224 control group content -28.930 7.815 normally distributed data for process -23.750 table 8. results of homogeneity of variance variable levene statistic sig. variants content 0.008 0.929 homogeneous process 1.312 0.264 homogeneous based on table 8, it can be seen that the process variable has a homogeneous variant. according to triton (2006), when the value of f statistic of pillai's trace. wilks's lambda. hotelling's trace and roys reviews largest root significance smaller than 0.05 [13]. then there is a difference in the ability of science literacy dimension process on students who use the e-module interactive physics of developing the company's results. however, if the significance is greater than 0.05 there is no difference. test results multivariate analysis presented in the table 9. e. syafutri, et al. / indonesian review of physics 3(1), 2020, 11-18 18 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 9. results of multrivariate test effect statistical f sig e-module interactive physics approach sets (science. environment. technology and society) pillai's trace 22.953 0.000 wilk's lambda 22.953 0.000 hotelling's trace 22.953 0.000 roy's largest root 22.953 0.000 according to the table 9, the value of f to the four tests has significantly less than 0.05 then h0 is rejected. there are differences in the ability of science literacy dimension in the process of students using e-physics interactive module development results. further test subjects is to examine the independent variables to each dependent variable. manova analysis results presented in table 10. table 10. effect of inter-subject test results source dependent variable f sig. e-module interactive physics approach using sets content 28.294 0.000 process 24 597 0.000 according to table 10. it shows that the value of f on the dependent variable has more significance than 0.05. this indicates that there is the effect in using ephysics interactive module on the dependent variable of the development of scientific literacy dimension content and process. v. conclusion electronic modules have been produced using the sets approach through expert validation and physics teacher with an average percentage of 96.36% making it feasible and can be used as teaching materials for high school students class xii. science literacy skills measured dimensions of the content and process to see the difference between the experimental group using emodule interactive physics using sets approach and control groups were studied using the textbook class xii sma taman mulia kuburaya. gain value of the dimension experimental group 0.47 in the medium category and gain control group scored 0.10 in the low category. the learning model approach to electronics module sets experience faces some difficulties in implementation because of the relationship with the environment indirectly. on implementation, the students are given examples of the application environment based solely on video and pictures and then the students still have to think back to guessing events. in fact, every student has the process of thinking different and so we need the implementation of a real learning environment. in the reference, a number of examples have been given which are often used by international journals. feel free to make use of them. it is expected that for further research the development of e-modules uses different material in an effort to improve the quality of education, especially student scientific literacy. e-module development can then use the latest application base so that the display and navigation look better and more interactive reference [1] a. w. subiantoro, “pentingnya praktikum dalam pembelajaran ipa,” 2010. [2] m. arohman and d. priyandoko, “kemampuan literasi sains siswa pada pembelajaran ekosistem,” 2016. [3] a. binadja, pedoman praktis pengembangan bahan pembelajaran bervisi dan berpendekatan sets. 2007. [4] p. anna, “stem education: inovasi dalam pembelajaran sains,” in prosiding seminar nasional pendidikan sains, 2016, pp. 23–34. [5] a. r. hardisty et al., “biovel: a virtual laboratory for data analysis and modelling in biodiversity science and ecology,” bmc ecol., vol. 16, no. 1, 2016, doi: 10.1186/s12898-016-0103-y. [6] u. et al. toharudin, membangun literasi sains peserta didik. 2011. [7] oecd, pisa 2015 assessment and analytical framework: science, reading, mathematic and financial literacy,. paris: oecd publishing.s. verdu, multi-user detection, cambridge university press, 2015. [8] rusman, “belajar berbasis komputer, pembelajaran mengembangkan profesionalisme abad 21,” bandung alf., 2013. [9] gall, m. d, gall, j. p, borg, and w. r, educational research, an introduction (seventh ed). boston: allyn and bacon, 2003. [10] l. rizkita, h. suwono, and h. susilo, “analisis kemampuan awal literasi sains siswa sma kota malang,” in prosiding seminar nasional ii, 2016, no. 2, pp. 771–781. [11] n. g. laderman, j. s. laderman, and a. antink, “nature of science and scientific literacy,” int. j. educ. math. sci. technol. int. journla educ. math. sci. technol., vol. 1, no. 3, pp. 138–147, 2013. [12] sugiono, metode penelitian kuantitatif, kualitatif dan r & d, vol. 2. bandung: alfa betta, 2013. [13] r. r hake, “analyzing change/gain scores,” unpubl. url http//www. physics. indiana. edu/~ sdi/analyzingchange-gain. pdf, pp. 1–4, 1985. indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 30-34 doi: 10.12928/irip.v3i1.1766 http://journal2.uad.ac.id/index.php/irip 30 implementation cooperative learning type stad assisted edmodo in improving students' critical thinking skills muhamad epi rusdin1*, widodo2, and guntur maruto3 3department of physics education, universitas gadjah mada article info abstract article history received feb 17, 2020 revised may 16, 2020 accepted june 23, 2020 the stad cooperative learning model can support active, independent and responsible learning for students. the application of this model is expected to improve students' critical thinking skills. the purpose of this study was to determine the improvement of students' critical thinking skills using edmodo-assisted learning models. edmodo was modified to become a teacher tool to expand learning at home. this research is an experimental study using a pretest-posttest control group design involving 39 students of class viii mts at-taqwa beru, sikka, east nusa tenggara. based on the results of the study it was found that the edmodo-assisted stad type cooperative learning model can improve students' critical thinking skills. keywords: cooperative learning critical thinking skill e-learning edmodo lms stad to cite this article: m. e. rusdin, widodo, and g. maruto, “implementation cooperative learning type stad assisted edmodo in improving students’ critical thinking skills,” indones. rev. phys., vol. 3, no. 1, pp. 30–34, 2020. i. introduction learning will be saying to be successful and qualified if the majority of students actively involved, both physically, mentally, and socially [1]. however, in the classroom, teachers have always found the lack of ability of learners in critical thinking so that classes tend to be passive [2]. attitude and tendencies associated with critical thinking can generate by applying cooperative learning model stad. there are two attitudes and trends among the other is respect for the opinions of others and tolerance for uncertainty. so that in the process of teaching and learning activities of teachers not only give attention to the interaction between him and the student but the student interaction with other students [3]. stad as one of the techniques of cooperative learning, which is considered a conventional technique. because, stad cooperative learning model can improve critical thinking skills [4]. critical thinking skills are not innate but come as practiced or implemented through a process of learning by educators as facilitators in the learning. so should the effort of teachers to create and understand the innovations in a learning process. these innovations would be able to grow and improve students' critical thinking skills [5]. the teaching of thinking often becomes an integral part of the teaching routine should be done with just a small extra effort [3]. limitations of student learning time in the classroom is still one obstacle, so it needs a bit of extra effort edmodo to continue the learning at home. edmodo is often called facebook for education. unique social media community designed for teaching [6]. edmodo, including mobile and web-based learning using an application that has provided, in which teachers, students, and parents can interact [7]. learning to use edmodo had a positive response from students [8]. in indonesia, nearly 80% of adolescents aged 10-19 in 11 provinces in indonesia addicted to using social media. most teens are still less wise in using social media, 24% of users admitted to using social media to interact with people who are not recognized, 14% of users accessing pornographic content, and the remainder for online gaming and other interests [9]. now, based learning online can be affordable, coupled with the availability of internet signal that allows a person to access the websites of learning. so that the development of internet-based learning is needed, and the use of mobile technology is very carefully related to the lives of children and parents. hence, its use for educational purposes is a necessity [10]. 1department of physics education, ikip muhammadiyah maumere jl. jendral sudirman, sikka, nusa tenggara timur, indonesia 2master program of physics education, universitas ahmad dahlan jl. pramuka no. 42, yogyakarta, daerah istimewa yogyakarta, indonesia bulaksumur, sleman, daerah istimewa yogyakarta, indonesia *email: cepi.rusdin@gmail.com m. e. rusdin,, et al. / indonesian review of physics 3(1), 2020, 30-34 31 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 ii. theory learning is an enduring change in behavior, or the capacity to behave in a certain way, resulting from practice or other forms of experience [11]. learning is a mental/psychological activity that interacts directly actively with the environment that results in changes in knowledge, skills, and attitudes [12]. gagne defines learning as an event that is carefully motivated by the aim that knowledge gained through the learning process can be useful [13]. physics learning is often associated with events or phenomena observed in daily life, explaining events in a simple way [14]. learning physics is a process that ideally focused activities on encouraging students to think critically and develop arguments using evidence, justification, and practical explanation [15]. based theories can conclude that the teaching and learning of physics is a process of interaction of teachers and students in a learning environment where teachers help students to learn about the phenomenon observed in everyday life, which allows students to think critically and argue using evidence. according to gross, stad as one of the techniques of cooperative learning, is considered a proper technique. because stad can improve student motivation to learn by exchanging and sharing information, mutually reinforcing, give feedback, and have a responsibility to do their work in a group. it was stated that stad has five main components, namely presentation classes, team studies, quizzes, individual improvement scores, and team recognition [16]. edmodo is a social network designed for the unique learning community. people have called facebook for education [6]. edmodo is web-based learning developed based on the development of web 2.0 and mobileassisted learning. edmodo includes web-based and mobile learning using applications that have provided, where teachers, students, and parents can interact [7]. edmodo is a social networking and micro-blogging service that is designed specifically for education, which can operate like any other social media such as twitter. by checking the access road to a particular room or a group, teachers and students can exchange notes, links, files, announcements, tasks, and exchange information in a secure environment [17]. with many advantages offered by edmodo; teachers, students, and parents can see why social networking is growing so fast education. the advantages of edmodo are as follows [17]: (a) easy to send files, images, videos, and links; (b) send individual messages to teachers; (c) create groups for individual discussion according to specific classes or topics; (d) a safe environment for new students; (e) messages are designed to be easier to understand and are not limited by the number of characters. furthermore, from the advantages that have offered, edmodo also has its disadvantages. disadvantages of edmodo is as follows [17]: (a) disturbances in internet connection may affect the website run slower; (b) students have limited access to an exit because it is only limited in the class; (c) still in the development version and not wholly perfect. thinking is a well-organized mental process and works a role in the decision-making process to solve problems by analysing and interpreting data in scientific inquiry activities [2]. can obtain a design that critical thinking is the thinking skills must be developed and trained from an early time by students to address and provide solutions to social problems that occur both in the community of the students as well as in comprehensive and reliable [18]. according to ennis, critical thinking is thinking in the form of thought-out revisiting something that has happened to focus on what is believed and done if faced with a problem [19]. according to ennis, critical thinking skills indicators consist of five types, namely: a) elementary clarification; b) basic support; c) inferring; d) advanced clarification; e) create strategies and tactics. iii. method this study uses one group pretest-posttest design shown in table 1. the population of this research is class viii mts at-taqwa beru sikka. the sampling technique used random cluster sampling divides the two classes of experimental class (ec) and control class (cc). the experimental class is in class viii-c, and the control class is in class viii-d. table 1. research design no class pre-test treatment post-test 1 experiment o1 x o2 2 control o3 y o4 in this study, the aspects studied were the students' critical thinking skills. thus, the data collection techniques use of test results of the students' critical thinking skills. the matter would be given before and after a given treatment. indicators on aspects of critical thinking skills include elementary clarification, essential support, inferring, advanced clarification, strategies, and tactics. test questions that have passed validity and reliability will be given to the experimental class and the control class for evaluation. the research instruments were adjusted accordingly with the adopted critical thinking indicators. the following lattice of test instruments for critical thinking skills can be seen in table 2. in this study, the experimental class using cooperative learning model type stad with edmodo assisted to continue the learning at home, so that every student directed to have edmodo accounts. after having an account, each student was given a coding class to join the class created by the researcher. edmodo learning media used to support cooperative learning model type stad as a medium that connects teachers and students and students with students in hopes of facilitating information exchange activities after school hours at the end of class. before learning implemented in the classroom. edmodo's role in this research is to upload the m. e. rusdin,, et al. / indonesian review of physics 3(1), 2020, 30-34 32 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 required learning device. the device consists of a teaching topic, student worksheets, and quizzes. table 2. grating test instruments critical thinking skills no indicator of critical thinking critical thinking sub-indicators distribution of questions 1 provide a simple explanation answering the question "why" and "how" 1, 2, 3, 4, 5 2 build basic skills consider the use of appropriate procedures for a problem 1, 2, 3, 4, 5, 6 3 conclude make conclusions based on facts 1, 2, 3, 4, 5, 6 4 set strategy and tactics use logic strategies 4, 5, 6 analysis of the data used is using a normality test, homogeneity test, independent sample t-test, and test ngain. the normality test used to determine the distribution of the data obtained through critical thinking skills tests normal distribution or not. homogeneity test used to determine the data gained through critical thinking ability tests between the experimental class and control class homogeneous or not. tests using independent t-test conducted to know the effect of the carrying out of a sample different from the experimental and control class. the n-gain test was conducted to find out the value of the increase in students' critical thinking skills. iv. results and discussion this research was conducted method of one group pretest-posttest design that consisted of two classes. experimental class (ec) using cooperative learning model stad assisted edmodo and control class (cc) using cooperative learning model stad without assisted edmodo. this research consists of several stages, namely the planning stage, the pre-test, the treatment using the cooperative learning model type stad modified and without edmodo-assisted learning, and the final stage of post-test administration. edmodo is a tool to maintain learning at home can be seen in figure 1. figure 1. display of edmodo class furthermore, learning tools in conducting this research need to be validated. learning device has been validated with four validators, which consists of two lecture of physics education and physics teacher: 1. validation of design a lesson plan is categorized as very strong at 93%, so it can be said that the design is a perfect lesson plan for use in the learning process. 2. the results of the topic validation categorized as active, with a percentage of 88%, so it can be said that this material is very feasible to be used in the learning process. 3. the results of the validation of test critical thinking skills are categorized as very strong, with a percentage of 79%, so it can be said that this test item eligible for use in research. the hypothesis usually considered as a principal instrument in the study. its principal function is to suggest new experiments and observations. many experiments carried out with intentional hypothesis testing objects. the following is a description of some tests to find a hypothesis. normality test normality testing is done by chi-square test table 3. grating test instruments critical thinking skills no class pre-test post-test 1 experiment minimum 61.32 54 maximum 61.90 85 average 14.16 72.68 observer 32.69 16 x2count 79.45 4.93 x2table 46.76 9.49 2 control minimum 41.47 30 maximum 46.67 72 average 18.25 57.17 observer 7.14 23 x2count 65.91 0.83 x2table 58.77 9.49 the results of the analysis of the experimental class following table 3. the pre-test and post-test experimental class consisted of 16 students in the experimental class. the average pre-test results of students' critical thinking skills in the experimental class was 27.31, with a minimum value of 4 and a maximum value of 48. while the average pre-test results of students' critical thinking skills in the experimental class was 27.31, with a minimum value of 4 and a maximum value of 48. the average post-test results of the students' critical thinking skills in the experimental class is 72.68, with a minimum value of 54 and a maximum value of 85. from table 2, after calculating the experimental class pre-test data of 6.02. if consulted with the chisquare table at the significance level of α = 0.05 obtainable x2table = 9.49. thus we can say that the data pre-test with normal distribution for the experimental class x2count (6.02) < x2table (9.48). as for the data post-test m. e. rusdin,, et al. / indonesian review of physics 3(1), 2020, 30-34 33 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 experimental class after calculation x2count obtain of 4.93 with chi-square table at significance level α = 0.05 was obtained x2table = 9.48. thus it can be said that the experimental class post-test data is normally distributed because x2count (4,93) < x2table (9.48). the analysis results for the control class according to table 2. the pre-test and post-test control class consisted of 23 students. the average pre-test results of students' critical thinking skills in the cc is 26.8, with a minimum of 3 and a maximum value of 46. meanwhile, the average post-test results of the students' critical thinking skills in the cc is 57.17, including a minimum value of 30 and a maximum value of 72. from table 2, after calculating the control class pre-test data, x2count was obtaining of 0.70. if consulted with the chi-square table at the level of significance, α = 0.05 was obtained x2table = 9,49. thus it can be said that the control class pre-test data is normally distributed because x2count (0,70) < x2 table (9.49). as for the data post-test control group after calculation x2vount obtain 0.83, with a chi-square table at the significance level α = 0.05 get of x2table = 9.49. it can be concluded that the data post-test control group with normal distribution because x2count = 0.83 < x2 table (9.48). homogeneity test this test carried out to show two or more groups of sample data come from populations that have homogeneous (equal) variance. data can be said to be homogeneous if the significance value calculation results > significance value (0.05). the results of the analysis of homogeneous test showed that the significance value is 0.06; the result looks like in table 4. table 4. homogeneity test post-test experiment and control class no levene statistic df sig. 1 1.227 37 0.275 based on table 4, it can be seen that the data on the post-test experimental and control classes can be said homogeneity, because of the significant value calculation results > value of significance (p-value) is 0.275 > 0.05. independent sample t-test tests using independent sample t-test was conducted to determine the effect of treatment on different samples of the experimental class and control. table 5 shows that the average post-test of the experimental class is 72.31, while the average post-test of the control class is 57.17. the average results of the two classes showed that the average experimental class was higher than the control class, with a difference of 15.14. while the calculation result obtained tcount of 4.80 prices and the price ttabel 2.03 at α of 0.05 with a degree of freedom of 37, significance value calculation results obtained a significance value of 0.000026 at a significance level of 0.05 because t is more significant than ttable (4.80 > 2.03) and a significant value smaller than the level of significance (0.000026 < 0.05). it can be said there is the influence of the use of cooperative learning model edmodo aided in improving critical thinking skills the student. table 5. result of independent sample t-test no experiment control 1 mean 72.31 57.17 2 observer 16 23 3 df 37 4 t-count 4.80 5 p-value (sig) 0,000026 6 t-table 2.03 n-gain test research using edmodo supported cooperative learning models to show very effective results and the use of cooperative learning model without assisted edmodo showing ineffective results. general description of the improved critical thinking skills of experimental and control class students can be seen in table 6. table 6. percentage of n-gain score no class statistics category 1 experiment mean 61.32 quite effective median 61.90 std. deviation 14.16 minimum 32.69 maximum 79.45 range 46.76 2 control mean 41.47 less effective median 46.67 std. deviation 18.25 minimum 7.14 maximum 65.91 range 58.77 based on the results of the analysis of the n-gain test (table 6) shows that the average value of the percentage of the n-gain score for the experimental class (using edmodo-assisted cooperative learning models) is 61.32% included in the category of quite useful, with ngain score of at least 23% and a maximum of 79%. as for the control group, results show that the average value of the percentage of n-gain score amounted to 41.47% is included in the category of less effective with a minimal and maximal score of 58.33%. this is similar with opinion [20], [21]. harahap [20] said that there was an increase in critical thinking skills when using the cooperative learning model type stad. this can be seen through the results of research conducted. after doing the calculations the results of the students' critical thinking skills were obtained from an increase of 70.93% in the first cycle and 86.04% in the second cycle [19]. kustandi [21] said that learning using edmodo media was more effective in improving critical thinking skills than learning without using edmodo, with effective value in m. e. rusdin,, et al. / indonesian review of physics 3(1), 2020, 30-34 34 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 edmodo classes which was 52% greater than classes without using edmodo which was 24% [20]. v. conclusions based on the results of research conducted by researchers and the discussion presented it can be concluded that the learning process at mts at-taqwa beru sikka uses cooperative learning models with the help of edmodo as a tool to continue learning at home on work material, and simple aircraft can improve critical thinking skills the student. based on the analysis using test n-gain edmodo aided cooperative learning models included in the category is quite effective. two factors led to the use of cooperative learning model aided edmodo included in the category is quite effective: 1. specifications smartphones used by students is not good so that the supporting applications such as pdf, microsoft office word, and other supporting applications cannot be used to support the use of edmodo. 2. the price of the internet quota is still high for the east nusa tenggara region. the price of which is only affordable for capable students, so sometimes some students are late in getting information that teachers have shared on the edmodo application. reference [1] t. l. adi sucipto, a. efendi, h. n. hanif, and c. budiyanto, “the influence of learning management technology to student’s learning outcome,” ijpte int. j. pedagog. teach. educ., vol. 1, no. 1, pp. 11–18, feb. 2017. [2] r. alfian, e. wiyanarti, and m. iqbal, “increasing of critical thinking students through cooperative learning model tps type (think-pair-share) in social studies learning (classroom action research in class viii1/ibnu thufail fitrah insani ii junior high school),” int. j. pedagog. soc. stud., vol. 2, no. 2, pp. 46–52, 2017. [3] p. eggen and d. kauchak, strategi dan model pembelajaran: mengajarkan konten dan keterampilan berpikir, 6th ed. jakarta: indeks, 2012. [4] u. karuniawati, “pengembangan perangkat pembelajaran dasar dan pengukuran listrik dengan model pembelajaran kooperatif stad untuk melatih keterampilan berpikir kritis di smk negeri 5 surabaya,” j. pendidik. tek. elektro, vol. 5, no. 2, pp. 609–615, 2015. [5] s. nurazizah, p. sinaga, and a. jauhari, “profil kemampuan kognitif dan keterampilan berpikir kritis siswa sma pada materi usaha dan energi,” j. penelit. pengemb. pendidik. fis., vol. 3, no. 2, pp. 197–202, 2017. [6] g. carlson and raphael, let’s get social the educator’s guide to edmodo. arlington: international society for technology in education, 2015. [7] h. bicen, “the role of social learning networks in mobile assisted language learning: edmodo as a case study,” j. univers. comput. sci., vol. 21, no. 10, pp. 1297–1306, 2015. [8] d. sulisworo and k. permprayoon, “what is the better social media for mathematics learning? a case study at a rural school in yogyakarta, indonesia,” int. j. emerg. math. educ., vol. 2, no. 1, pp. 39–48, 2018. [9] a. hapsari and a. d. ariana, “hubungan antara kesepian dan kecenderungan kecanduan internet pada remaja,” j. psikol. klin. dan kesehat. ment., vol. 4, no. 3, pp. 164– 171, 2015. [10] a. sahin, n. top, and e. delen, “teachers’ first-year experience with chromebook laptops and their attitudes towards technology integration,” technol. knowledge, learn., vol. 21, no. 3, pp. 361–378, 2016. [11] d. h. schunk, learning theories an educational perspective. boston: allyn & bacon, 2012. [12] w. winkel, psikolog pengajaran. jakarta: gramedia, 1989. [13] r. m. gagné and k. medsker, the conditions of learning: training applications, 5th ed. pennsylvania: harcourt brace college pub, 1996. [14] h. stachowiak, “modelle: konstruktion der wirklichkeit,” j. philpapers, vol. 45, no. 2, pp. 226–226, 1989. [15] d. cross, g. taasoobshirazi, s. hendricks, and d. t. hickey, “argumentation: a strategy for improving achievement and revealing scientific identities,” int. j. sci. educ., vol. 30, no. 6, pp. 837–861, 2008. [16] y. q. yusuf, y. natsir, and l. hanum, “a teacher’s experience in teaching with student teams-achievement division (stad) technique,” int. j. instr., vol. 8, no. 2, pp. 99–112, 2015. [17] c. wankel, educating educators with social media. united kingdom: emerald group publishing limited, 2011. [18] r. s. putra, “penerapan metode diskusi tipe think pair share (tps) untuk meningkatkan keterampilan berpikir kritis siswa dalam pembelajaran ips,” int. j. pedagog. soc. stud., vol. 1, no. 1, pp. 119–131, 2016. [19] r. h. ennis, “critical thinking: a streamlined conception,” teach. philos., vol. 14, no. 1, pp. 5–24, 1991. [20] a. n. harahap and i. harahap, “penerapan model pembelajaran kooperatif tipe stad untuk meningkatkan kemampuan berpikir kritis siswa,” peteka (jurnal penelit. tindakan kelas dan pengemb. pembelajaran), vol. 2, no. 2, pp. 45–51, 2019. [21] c. kustandi, “efektivitas e-learning berbasis edmondo dan schoology terhadap kemampuan berfikir kritis mahasiwa program studi teknologi pendidikan fip unj pada mata kuliah profesi pendidikan,” j. educ., vol. 2, no. 1, pp. 1–9, 2017. indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 47-51 doi: 10.12928/irip.v3i2.2632 http://journal2.uad.ac.id/index.php/irip 47 effect of noise intensity of aviation activities on student learning concentrations remigius robinson, pujianti bejahida donuata, agustinus angelaus ete, muhamad epi rusdin* faculty of mathematics and sciences education, ikip muhammadiyah maumere jl. jendral sudirman, sikka, nusa tenggara timur, indonesia *email: cepi.rusdin@gmail.com article info abstract article history received aug 11, 2020 accepted dec 18, 2020 published dec 31, 2020 this study aims to determine the effect of flight activity noise intensity on student learning concentration. this study involved 48 students (male = 24 and female = 24) who were randomly selected in the islamic elementary school waioti, maumere. the intensity of flight activity noise during classroom learning activities is measured using a sound level meter (slm), and students' concentration levels were measured using a 5-level likert scale learning concentration questionnaire. the effect of flight noise intensity on student learning concentration was determined using linear regression analysis. the results showed that the noise level due to flight activities in the waioti islamic elementary school was 58.92 db, exceeding the set threshold value. the intensity level of students' learning concentration disorders reached 71.43%, including frequent disturbance. the level of flight activity noise significantly affects student learning concentration with the regression model: y = 49.972 + 0.834x with r2 of 0.635. keywords: aviation activities effect of noise intensity learning concentration sound level meter students' concentration to cite this article: r. robinson, p. b. donuata, a. a. ete, and m. e. rusdin, "effect of noise intensity of aviation activities on student learning concentrations," indones. rev. phys., vol. 3, no. 2, pp. 47–51, 2020. i. introduction education becomes the main thing to support the government in realizing the ideals of the nation. interaction between a person and the surrounding environment is the process of starting education. every student needs to focus on the material being studied to absorb the material learned adequately in the learning process. thus students can do something that has never been done before. many factors affect students' success; for example, concentration factors in learning [1]. teaching and learning are the interaction process of teacher and student interaction in a learning environment where the teacher helps students learn about the phenomena observed in daily life [2]. concentration is the focus of attention on a particular object. concentration in learning focuses on the mind's power over what is learned by avoiding things that are not related to something learned. learning concentration has an important role, like concentrating on listening to an educator's explanation, understanding the material provided by educators, and doing the assignments to get the maximum learning results [3]. someone experiencing impaired concentration will have difficulty concentrating on an object so that the person needs time to receive the information provided [4]. changes in children's concentration are often challenging to do; therefore, these changes must be immediately recognized and given reinforcement by the school or family [5]. difficulty concentrating is caused by several things, one of which is noise. based on the decision of the minister of environment number: kep. mnlh 11/1996, that noise can hurt someone who is exposed to noise, such as communication disorders, psychological noise can cause deafness. the environment which is affected by noise is one of them the school environment. the school is where the teaching and learning process is carried out. schools provide a conducive atmosphere so that the expected educational goals can be achieved. however, several schools are located close to sources of noise/noisy centers. this noise causes students and teachers to experience interference in communication while in the school area. communication problems that occur impact reducing students' learning performance, reducing students' level of concentration. based on research. goswami [6] said that educational institutions with high noise would make students unable to concentrate properly during the learning process. students can lose interest in learning; high noise can also affect educators' concentration in explaining learning material. the main factor influencing learning activities is concentration. the higher the instructors and students' concentration, the more meaningful the learning activities are, but if students' concentration decreases, the results are achieved less [7]. the concentration of students at elementary school age becomes more selective, adaptable, and planned. first, children become more reliable at deliberately paying attention to only aspects of the situation relevant to their goals. second, they can adapt flexibly to their concentration on task requirements. third, planning r. robinson, et al. / indonesian review of physics 3(2), 2020, 47-51 48 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 increases sharply at this age, namely by collaborating with more skilled planners. all aspects can help elementary school children achieve good performance if supported by school education [8]. ruth conducted a study analyzing soekarno-hatta international airport's noise levels when an airplane was passing (a case study at pandidi junior high school, west jakarta). the results suggest that the noise that occurs in schools should be reduced by increasing the classroom acoustics because the resulting noise has exceeded the school area's noise threshold value [9]. islamic elementary school in waioti maumere is a school adjacent to the runway at fransiskus xaverius seda airport, which is located ± 500 m. if flight activities are in progress, such as an airplane when landing or take off, the noise level that occurs dramatically affects student learning concentration. based on the above problems, the authors are interested in examining the effect of aviation activity noise intensity on student learning concentration. ii. theory learning concentration concentration focuses the mind on a particular object by putting aside things that are not related to the learning and teaching process [10]. concentration is a centering up of attention in behavior change expressed in mastery, use, and assessment of attitudes and values, knowledge, and necessary skills in various fields of study. theoretically, if students' concentration is low, it will lead to low-quality activities and a severe lack of learning. it is not trying that affects the power of understanding the material. however, concentration is the principal capital for students in receiving teaching material and indicates the learning process's success [11]. the ability to focus attention on the learning process is a definition of learning concentration. to strengthen students' concentration in the learning process, educators must use various exciting learning media by considering study time and other activities that need to be done at recess [12]. learning concentration is influenced by two factors, namely, internal and external factors. internal factors are factors that originate from within an individual and can influence individual learning outcomes. these internal factors include physiological factors, psychological factors (intelligence, motivation, interests, attitudes, talents). external factors are factors that originate from outside the individual and can influence individual learning outcomes. these external factors include the social environment (the social environment of the community, the social environment of the family, and the social environment of the school) and the non-social environment (natural environment and instrumental factors) [13]. noise noise is an unwanted sound that can cause discomfort for the listener and can affect all human activities. noise can be interpreted as an unwanted sound originating from biological activities such as speech and human-made activities such as machines [14]. noise is an undesirable form of sound or sound that is not appropriate to the place and time. the noise that has passed the noise level threshold is proven to affect the student learning concentration [15]. noise is a sound that disturbs people when doing an activity, thus eliminating one's concentration on something that is done [16]. noise measurement tool sound level meter (slm) is a tool for measuring noise. the working principle of the tool is based on vibrations that occur. if some objects or objects vibrate, it will cause a change in air pressure will then be captured by the equipment system, and then the analog needle will show the number of noise levels expressed in db values [17]. noise impact and control noise is a bad influence for someone exposed to the noise, such as hearing loss, impaired communication, and can cause deafness. the effects of noise experienced by students resulted in a decrease in learning concentration, especially in reading or doing assignments [18]. apart from hearing loss, noise can also cause various other physiological, psychological, and communication disorders. psychological disorders can include discomfort, lack of concentration, insomnia, and irritability [19]. diseases associated with chronic noise exposure may be limited to people in certain situations and do not occur universally in all people who are exposed to noise. most individuals exposed to chronic noise, for example, from large airports, seem to be tolerating it [20]. noise control can be done naturally and artificially. naturally, control can be done by installing a barrier, such as using syzygium paniculatum (pucuk merah), spanish cherry (tanjung), and terminalia catappa (ketapang). meanwhile, artificially, control can be done by avoiding door with a hole pattern, installing weather stripping on each window, using dampening paint, and using curtains made from thick woven fabrics such as patterned brocade, velvet, and wool [21]. iii. method this research was conducted with a quantitative approach; this type of research is ex-post facto research. the independent variable is the noise intensity of flight activities, and the dependent variable is the learning concentration of students. this research was conducted at an islamic elementary school located in waioti, alok timur, sikka, and maumere. this study population was 262 students registered in the even semester of the 2019/2020 school year. simultaneously, the target population is students of class iva, ivb, va, and vb, totaling 93 students. sampling in this study was carried out randomly, and the sampling technique used was random sampling. based on r. robinson, et al. / indonesian review of physics 3(2), 2020, 47-51 49 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 the slovin formula, a sample of 48 students (male = 24 and female = 24) was obtained. android-based sound level meter (slm) software on smartphones is used to measure the intensity of flight activity noise during classroom learning activities and to learn concentration questionnaires (30 items) to determine the level of student learning concentration. measurement of learning concentration using a 5-point likert scale. the favorable statement starts from never (score 1) to always (score 5), and the unfavorable statement starts from always (score 1) to never (score 5). the instrument's validity was determined based on the expert and empirical team (48 students). empirical validity is determined based on product-moment correlation. meanwhile, instrument reliability was determined using the cronbach alpha technique. the validity and reliability of the instrument were analyzed with the help of spss 20 software. the results of the analysis showed that the r-count value (0.318 2.093) > r-table (0.284) at the 5% significance level, and the cronbach alpha value of 0.835. so it can be concluded that the learning concentration instrument has adequate validity and reliability linear regression analysis is used to see the effect of flight noise intensity on student learning concentration. the classic assumption test has been done before testing the hypothesis. hypothesis testing uses several analyzes, namely linear regression analysis, f test, and product moment correlation test. iv. results and discussion noise intensity level the measurement of flight noise intensity during landing and take-off was used to obtain the average value of the noise generated at the waioti islamic elementary school, maumere. the noise measurement location is in class iva, ivb, va, and class vb, and measurements are made 12 times. the results of noise measurements using the slm (sound level meter) application are presented in table 1. table 1. noise intensity class noise unit iva 61.41 db ivb 60.72 db va 58.31 db vb 55.25 db based on the data in table 1, the average noise level generated at islamic elementary school waioti, maumere is 58.92 db, which means that the noise level of flight activities at landing and take-off has exceeded the value of 55 db as the threshold value set by the minister of environment. student learning concentration the results of the classical assumption test are summarized in table 2. table 2. classical assumption sig. calculation significance level normality 0.995 0.05 linearity 0.926 0.05 table 2 shows that the data is normally distributed, and there is a linear relationship between flight noise intensity and student learning concentration at the 5% significance level. hypothesis testing was performed using regression analysis and obtained r = 0.635. the study shows a positive influence between the intensity of flight activity noise on student learning concentration disorders. this means that if there is an increase in flight activities' noise intensity, it will be followed by an increase in student learning concentration disorders. the regression coefficient is used to determine the regression equation. the regression line is used to see the relationship between student learning concentration disorders due to flight activities' noise intensity. the summary of the regression coefficients can be seen in table 3. table 3. regression coefficient test results model coefficient sig. constan 49.792 0.000 noise 0.834 0.000 r 0.635 r square 0.403 based on table 3, it can be seen that there is interference with students' initial learning concentration when there is no noise from flying activities. the regression coefficient of flight activity noise intensity is 0.834. this means that if the noise intensity of flight activities increases by 1db. the interference of student learning concentration will increase by 0.834. the r coefficient is positive, which means a positive relationship between the noise intensity of flight activities and students' learning concentration disorders. the higher the noise intensity of flight activities. the problem of student learning concentration will increase. r square's value is 0.403, which means that the effect of the noise intensity of flight activities on student learning concentration is 40.3%. meanwhile, other variables influence 59.7%. summary of simple regression test the effect of flight activity noise intensity on students' learning concentration can be seen in table 4. table 4. f-test results model f sig. regression 31.095 0.000b regression f test results in table 4 obtained a value of 31.059 from the number obtained significance < 0.05. it can be said that the intensity of flight noise to the concentration of learners has a significant correlation. to determine the strength of the influence of flight activity noise intensity on student learning concentration r. robinson, et al. / indonesian review of physics 3(2), 2020, 47-51 50 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 used product-moment correlation analysis. the results of the product-moment correlation test obtained that the rvalue, according to the interpretation guidelines, the correlation coefficient has a substantial degree of closeness to influence. a summary of the results of the product-moment correlation test data processing can be seen in table 5. table 5. product-moment correlation test results r sig. 0.635 0.000 based on the test results obtained a significance value = 0.0002 (significant < 0.05). it can be said that there is an influence between the intensity of flight activity noise on student learning concentration. this finding is in line with research conducted by gilavand and jamshidnezhad. they found a negative impact of noise on student learning outcomes and achievement [21]. refers to table 5, the product-moment correlation test was obtained at 0.635, meaning that the effect of flight activity noise intensity on student learning concentration was in the healthy category. educational institutions with a high noise level will make students unable to concentrate correctly during learning activities [6]. judging from the location and position of the waioti maumere islamic elementary school building, it is rectangular. there are several coconut trees (cocos nucifera) and cherry trees (muntingia calabura) whose leaves are quite thick. the existence of trees is useful for reducing noise. besides, each classroom has a closed window, and a curtain or curtain is installed that can act as a noise damper during learning activities [22]. however, the noise of flight activities is not the primary trigger that can interfere with islamic elementary school students' learning concentration, waioti maumere. based on the calculation of the coefficient of determination, another significant factor, 59.68%, affects student concentration. v. conclusion this study was conducted to determine how much influence the intensity of flight activity noise has on the learning concentration of islamic elementary school students in waioti, maumere. the measured average noise level is 58.92 db. this value has exceeded the threshold value set by the minister of environment decree no.48/mnlh/11/1996. students' learning concentration's distraction level reached 71.43%, which is included in the frequent disturbance level scale. islamic elementary school, waioti, maumere is expected to reduce noise by planting noise-reducing plants such as cherry trees, mango trees, and guava trees. schools must facilitate teachers with loudspeakers as a means of conveying the material being taught. teachers do not get tired quickly because they have to scream a little when they hear planes' sound while teaching in class. besides, the learning media must be designed to attract students' attention and concentration to stay focused on the material being studied and ignore the noise. vi. acknowledgment researchers would like to thank the chancellor of ikip muhammadiyah maumere, dean of the faculty of mathematics and natural sciences, chair of the physics education study program, and supervisor to smooth implementation of research activities. researchers are also grateful to the principal and teachers of waioti maumere islamic elementary school and all parties involved and assisting researchers during the research process, which cannot be said one by one. references [1] f. d. mayasari, “pengaruh konsentrasi belajar dan motivasi belajar terhadap hasil belajar siswa di smk negeri 1 ngabang,” j. pendidik. dan pembelajaran khatulistiwa, vol. 6, no. 6, pp. 1–11, oct. 2017. 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[22] a. gilavand and a. jamshidnezhad, “the effect of noise in educational institutions on learning and academic achievement of elementary students in ahvaz, southwest of iran,” int. j. pediatr, vol. 4, no. 3, pp. 1453– 1463, 2016. microsoft word layout-27-05-2019-nugroho.doc indonesian review of physics, volume 1, number 2, 2018 27 the content analysis of bisphenol a (bpa) on water in plastic glass with varying temperatures and contact times using uv-vis spectrophotometer bayu nugroho1, yudhiakto pramudya2, widodo2 1politeknik ilmu pelayaran balikpapan jalan kesatrian km.08 soekarno hatta, karang joang, balikpapan 76127 bayun4030@gmail.com 2universitas ahmad dahlan jalan pramuka no 42, yogyakarta, daerah istimewa yogyakarta yudhiakto.pramudya@pfis.uad.ac.id abstract this study aims to analyze the content of bisphenol a (bpa) on various temperature and contact times between the plastic bag and water. for analysis of bpa, a sample made with variations of temperature (± 70°c, ± 80°c, ± 90°c) and contact time (5 minutes, 10 minutes, 15 minutes) using nine samples. to determine the concentration of bpa, lambert-beer law was employed. according to the analysis of data, the content of bpa on the temperature variation showed that the higher the temperature of the sample, the higher the content of bisphenol a in the sample. the content of bpa with a variation of contact times stated that with the longer contact time, the higher the content of bpa. keywords :bisphenol a (bpa),uv-vis spectrophotometer,temperatures,contact times i. introduction plastic materials has greatly expanded.there are are packaging materials, food containers and plastic cups. bisphenol a (bpa) is a chemical compound found in polycarbonate plastic (pc) which is a dangerous additive. bpa has the molecular formula of c15h16o2, built by two phenol rings connected by a methyl bridge containing two methyl functional groups. if bpa is subjected to high temperatures, the molecular bond can be easily released. the imperfect polymerization ofplastic material that occurs during production or depolymerization due to intentional heating for sterilization or unintentional purposes during storage can release bpa and its derivatives to food by 4-23 µg/pack, drinks by 7 58 µg/g, and saliva by 90-913 µg/saliva which was collected for one hour after installation of dental sealants [1][2][3].. in 2007, efsa has determined an acceptable daily bpa intake (tolerable daily intake, tdi) of 50 µg/kg/day or ppb/day so that the use of bpa remains declared safe. the effects of bpa for body can cause breast cancer, prostate cancer, kidney disorders, damage to eggs and chromosomes, interfere with the quality of the hormone testosterone, interfere with sperm production, hyperactivity, obesity due to increased fat cell production, insulin resistance, and liver disorders. the plastic cups are often used as a container for drinking coffee or tea in hot conditions for a long time. hence, it is possible that the migration of bpa from plastic material into coffee or tea is occurred. bpa migration to food needs serious attention because of the dangers to health such as causing: brain development disorders, breast cancer, prostate cancer, kidney disorders, reproductive disorders, and decreased sperm quality. due to the danger of bpa migration, number of methods have been developed to analyze bpa content, one of which is the uv-vis spectrophotometer. the method is based on the absorbance of electromagnetic wave radiation by nugroho et al. the content analysis of bisphenol a (bpa) on water in plastic glass with... indonesian review of physics, volume 1, number 2, 2018 28 materials for wavelengths of uv light to visible light. using a uv-vis spectrophotometer it is possible to accurately detect the content of bisphenol a (bpa) in solution.the uv-vis spectrophotometer is a tool for quantitatively and qualitatively low-level analysis of elements based on the peaks produced in a particular element spectrum at 200-400 nm uv wavelength and in visible light regions (visible, 400-750 nm). the spectroscopy method has been employed on aluminium concentration in beverages [4] and limonene concentration in kayu putih oil measurement [5]. the method was also applied succesfully on bpa content analysis on water as function of contact time between hot water and plastic glass [6] the principle of spectrophotometer uv-vis is when a light source or radiation source with a certain wavelength is passed on a substance, then a certain amount of light will be absorbed by the substance. absorption of light by substances is influenced by the energy level of the substance, where each compound has a certain energy level related to the type of possible movement of a molecule such as translational motion, rotational motion, and vibration motion as shown in figure 1. figure 1. possible movements of diatomic molecules. (a) translational motion (b) rotational motion (c) vibration motion [7]. ii. method of research a. tools and materials tools and materials in this research are: computer, shimadzu uv-1800 uv-vis spectrophotometer, laptop, mini lab quest, logger pro software, temperature sensor, ultrasonicator, digital heater, digital balance, pumpkin measure, glass funnel, glassware, mineral water (3 liters), crystal naoh (4 grams), plastic drink glasses (9 pieces), cardboard boxes (size: 31 cm x 13 cm x 14 cm). b. research procedure the uv-vis spectrophotometer is connected to a computer to operate the shimadzu uv-1800 uv-vis spectrophotometer directly using the uv probe software. the 4 grams of naoh crystals is prepared by inserting naoh crystals into a 50 ml beker glass.the naoh crystals were mixed by 20 ml of mineral water.the solution were placed in the ultrasonicator to dissolve naoh crystals. the 1n of naoh solution is made on a temperature of 400oc: the 20 ml naoh solution was put into a 100 ml volumetric flask then added 80 ml of mineral water using a glass funnel until the boundary markings. then, it was put into a 100 ml beaker and heated with a digital heater until a 400oc temperature. the solution temperature was measured using a temperature sensor that was connected to the mini quest lab and laptop and analyzed with logger pro software. the sample solutions are prepared according to table1. table 1. variation in samples here, the condition for each temperature group of samples : a. samples on temperature of ± 70oc: in each sample, put 110 ml of mineral water into a 200 ml beaker and then heated with a digital heater to a temperature of ± 70oc as measured by a temperature sensor. after that ± 70oc of mineral water was put into a plastic cup for 5 minutes, b plastic cups for 10 minutes, and c plastic cups for 15 minutes, after which each sample was put in a cardboard box to maintain the temperature. contact times (minute) temperatures (oc) ± 70 ± 80 ± 90 5 sample a sample d sample g 10 sample b sample e sample h 15 sample c sample f sample i nugroho et al. the content analysis of bisphenol a (bpa) on water in plastic glass with... indonesian review of physics, volume 1, number 2, 2018 29 the water from each sample was taken 90 ml and put into a 100 ml measuring cup and mixed with 10 ml of 1 n of naoh solution with a temperature of 40oc, so that a naoh solution with a concentration of 10% was obtained. b. samples on temperature of ± 80oc: in each sample, put 110 ml of mineral water into a 200 ml beaker and then heated with a digital heater to a temperature of ± 80oc as measured by a temperature sensor. after that the mineral water of ± 80oc was put in a plastic cup d for 5 minutes, plastic cup e for 10 minutes, and a plastic cup f for 15 minutes, after which each sample was put in a cardboard box to maintain the temperature. the water from each sample was taken 90 ml and put into a 100 ml measuring cup and mixed with 10 ml of 1 n of naoh solution with a temperature of 40oc, so that a naoh solution with a concentration of 10% was obtained. c. samples on temperature ± 90oc: in each sample, put 110 ml of mineral water into a 200 ml beaker and then heated with a digital heater to a temperature of ± 90ooc as measured by a temperature sensor. after that ± 90oc of mineral water is put into a plastic g glass for 5 minutes, h plastic cups for 10 minutes, and plastic cups i for 15 minutes, after which each sample is put in a cardboard box to maintain the temperature. the water from each sample was taken 90 ml and put into a 100 ml measuring cup and mixed with 10 ml of 1 n naoh solution with a temperature of 40oc, so that a naoh solution with a concentration of 10% was obtained. c. analysis method the standard bisphenol a (bpa) absorption spectrum using uv-vis spectrophotometer can be seen as shown in figure 2. the figure is presented in the supplementary material. as shown in figure 2, the absorption area of bisphenol a (bpa) compounds is at a wavelength of 200 nm-300 nm with maximum absorbance at a wavelength of ± 214 nm. figure 2. bisphenol a (bpa) absorption spectrum [8]. the lambert-beer law defines the relationship between the sample concentration and the number of sources of radiation (energy) absorbed by the sample as in equation (1) : dca e= (1) with: a = absorbance e = constant absorptivity molar (l.mm-1.cm-1) d = thickness of cuvette (cm) c = concentration of samples (mm.l-1) from the figure 2 and using the tracker, the constant absorptivity molar can be determined using tracker software. iii. results and discussion a. spektrum bisphenol a (bpa) bpa absorption spectrum in each sample was obtained in the form of overlay graphs of temperature and contact time relationships as shown in figure 3. based on the spectrum indicated by the overlay 3 spectrum graph for variations in temperature and contact time, the maximum absorbance is entirely at a wavelength of ± 214 nm.the peak wavelength is confirmed by the standard spectrum of bisphenol a (bpa) as shown in figure 2. nugroho et al. the content analysis of bisphenol a (bpa) on water in plastic glass with... indonesian review of physics, volume 1, number 2, 2018 30 (a) (b) (c) figure 3. sample overlay graph at (a) 5 minutes (b) 10 minutes (c) 15 minutes contact time b. bisphenol a (bpa) content with temperature variations in the analysis of bisphenol a (bpa) content with a temperature variation of ± 70oc to ± 90oc using a uv-vis spectrophotometer, the maximum absorbance values in each sample were obtained as shown in table 2. table 2. maximum absorbance of each sample table 2 shows that the temperature is fluctuating around desired temperature. this is because the measurement changes due to the temperature of the environment. hence, the temperature is calculated on average with the standard deviation. table 2 shows that the results obtained that the higher the temperature given to the sample, the higher the maximum absorbance or can be said also as the content of bpa. this is similar results on the hot food that is packaged by plastic material. the hotter food create more possibility of bpa migration [9]. c. bisphenol a (bpa) content with contact time variations bisphenol a (bpa) analysis with various contact times using a uv-vis spectrophotometer showed results as shown in table 3. contact times (minute) temperatures (oc) 70.22 ± 0.05 79.18 ± 0.07 84.25 ± 0.03 5 sampel a sampel d sampel g 0.104 1.411 1.882 10 sampel b sampel e sampel h 0.744 1.608 2.084 15 sampel c sampel f sampel i 1.124 1.745 2.245 nugroho et al. the content analysis of bisphenol a (bpa) on water in plastic glass with... indonesian review of physics, volume 1, number 2, 2018 31 table 3. maximum absorbance in each sample table 3 states that with increasing contact times the maximum absorbance also increases. this is consistent with other result of bpa concentration on hoot food. the bpa migration can increase when the contact time increases, the contact temperature increases, the more additives in the packaging material, the level of contact and the level of food aggressiveness [10]. to show the comparison between the effect of temperature and contact time to the absorbance, the 3d graphics is shown in figure 4. the x-axis is the temperatures, the y-axis is the contact times, and the z-axis is absorbance. the rate of bpa migration from plastic cups to drinks or liquids is dominated by the influence of temperature. while contact time also affects but relatively small influence. the increase in maximum absorbance at temperature and contact time can be interpreted as an increase in the concentration of bpa. bpa concentrations that are soluble in water can be identified using the lambert-beer law. figure 4. the 3d graph of absorbance dependence on temperature and contact time determination of bpa concentration requires a standard sample from the bpa to determine the value of ɛ or constant molar absorption. due to the difficulty of getting a standard sample from bpa, the alternative is to use the bpa absorption spectrum as shown in figure 2. the line in figure 2 is tracked using the tracker software to determine the molar absorptivity (ɛ) of the bpa as shown in figure 5. from the tracking process, the value of absorbance and concentration can be obtained. those values are plotted in figure 5. the slope is the molar absorptivity (ɛ) of the bpa. figure 5. the relation between absorbance and concentration of bpa. from figure 5 and the cuvette thickness of 1 cm, the value of molar absorptivity ɛ is 14.86 mm.cm-1. hence, the concentration of each sample obtained from the variation of temperature and contact time is shown in table 4. temperatures (oc) contact times (minute) 5 10 15 70.22 ± 0.05 sampel a sampel b sampel c 0.104 0.744 1.124 79.18 ± 0.07 sampel d sampel e sampel f 1.411 1.608 1.745 84.25 ± 0.03 sampel g sampel h sampel i 1.882 2.084 2.245 nugroho et al. the content analysis of bisphenol a (bpa) on water in plastic glass with... indonesian review of physics, volume 1, number 2, 2018 32 . referring to the efsa which has set an acceptable daily bpa intake (tolerable daily intake, tdi) of 50 µg / kg / day or ppb / day so that the use of bpa remains declared safe to be consumed. hence, based on the data that has been obtained from the highest concentration (34.449 µg. kg-1) in sample i, the sample is stated to be still in the safe category for once daily intake. table 4. concentration of bisphenol a (bpa) sample maximum absorbance concentration (mm.l-1) concentration (µg.kg-1) a 0.104 0.007 1.642 b 0.744 0.050 11.46 c 1.124 0.076 17.29 d 1.411 0.095 21.70 e 1.608 0.108 24.72 f 1.745 0.118 26.82 g 1.882 0.127 28.92 h 2.084 0.140 32.02 i 2.245 0.151 34.49 iv. conclusion 1. in the study of the analysis of the content of bisphenol a (bpa) with a temperature variation of ± 70oc, temperature of ± 80oc, and temperature of ± 90oc it is known that with the increasing temperature given to the sample, the higher the bisphenol a content in the sample. 2. in the analysis of bisphenol a (bpa) content with a variation of contact time of 5 minutes, 10 minutes, and 15 minutes it is known that with the increasing contact time given to the sample, the more bisphenol a content contained in the sample is increased. references [1] brotons, j. a., olea-serrano, m. f., villalobos, m., pedraza, v., olea, n. xenoestrogens released from lacquer coatings in food cans, environmental health perspectives, vol. 103, no. 6, 1995, pp 608-612 [2] olea, n., pulgar, r., perez, p., olea-serrano, f., rivas, a., novillo-fertrell, a., pedraza, v., soto, a. m., sonnenschein, c. estrogenicity of resin-based composites and sealants used in dentistry, environmental health perspectives, vol. 104, no. 3, 1996, pp 298-305. [3] biles, j. e., mcneal, t. p., begley, t. h., hollifield, h. c. determinations of bisphenol-a in reusable polycarbonate food-contact plastics and migration to food-simulating liquids, journal of agricultural and food chemistry, vol. 45, 1997, pp 3541-3544. [4] wardani, f. p., toifur, m., pramudya, y. perancangan eksperimen penentuan kadar alumunium pada minuman kemasan kaleng menggunakan spektroskopi uv-vis, prosiding seminar pendidikan fisika, fisika, dan aplikasinya, 2016, pp 179-186. [5] siregar, n. h., pramudya, y., penentuan kadar limonene pada minyak kayu putih hasil penyulingan menggunakan prinsip spektroskopi uv-vis, prosiding seminar nasional quantum, 2016, pp 353-358. [6] nugroho, b., pramudya, y. the analysis content of bisphenol a (bpa) on water in glass beverage plastic with time-varying contacts using uv-vis spectrophotometer, proceedings international seminar on mathematics, science, and computer science education, chemistry and chemistry education section, 2015, pp. 498-502. [7] syarif, r. teknologi pengemasan pangan lanjut, stikom surabaya, 2013. [8] lu, ch., wang, y., li, y., yang, hh., chen, x., wang, xr. bifunctional super paramagnetic surface molecularly imprinted polymer core-shell nanoparticles, journal of materials chemistry, vol. 19, no. 8, 2009, pp 1077-1079. [9] winarno, f.g. kimia pangan dan gizi, gramedia pustaka utama, 1997. [10] nasruddin, m.n. studi dan simulasi permodelan laju difusi aditif asam stearad dan asam palmitat dalam zat padat polimer polivinil klorida, dissertation, universitas sumatera utara, medan, 2010. indonesian review of physics (irip) vol. 3, no 1, june 2020, pp. 23-29 doi: 10.12928/irip.v3i1.1530 http://journal2.uad.ac.id/index.php/irip 23 effect of deposition voltage on layer thickness, microstructure, cu/ni sheet resistivity of deposition results by magnetic field electroplating assisted technique 2master program of physics education, universitas ahmad dahlan article info abstract article history received jan 12, 2020 revised jun 6, 2020 accepted jun 6, 2020 the purpose of this research is to make the cu/ni thin layer as an alternative to basic rtd materials through electroplating methods assisted by magnetic fields. electroplating was carried out with variation in deposition voltage ranging from 1 to 5 v. the results of this study indicate that the deposition voltage applied to the coating affects the thickness, sheet resistivity, and microstructure of the coating. thickness increases with increasing deposition voltage. the diffraction intensity and crystal size tend to increase with increasing deposition voltage. the distance between bragg planes after the coating is almost equal for all samples. the highest sheet resistivity was obtained in the coating sample with a 4-volt deposition voltage. keywords: electroplating magnetic field sheet resistivity to cite this article: w. a. wijanarka and moh toifur, “effect of deposition voltage on layer thickness, microstructure, cu/ni sheet resistivity of deposition results by magnetic field electroplating assisted technique,” indones. rev. phys., vol. 3, no. 1, pp. 23–29, 2020. i. introduction sensor are an important product of environmental monitoring. copper (cu) and nickel (ni) can be alternative materials in making low-temperature sensors instead of expensive platinum. this is because copper can be used to measure temperatures as low as -234.5 0c [1] with a linear response. nickel can also be used as a temperature sensor in the range of -200 0c to 320 0c [2]. nickel can be superimposed on copper by electroplating method to form a thin layer of cu/ni. copper and nickel have almost the same atomic size (0.1278 å for copper and 0.1246 å for a nickel) and both have face centered cubic (fcc) lattice shapes [3]. the cu/ni film formed from the combination of the two materials will have a very strong inter-surface adhesion force [3]. the study that examines the effect of deposition voltage on the resistivity and thickness of the layers formed in the manufacture of cu/cu/ni/ni thin films with a voltage variation of 1.5 to 5.5 v was done [4]. through this research it is known that the greater the deposition voltage the layer thickness and resistivity increase. the effect of voltage on the thickness of the chrome coating on the steel plate with a variety of the voltage of 1.5 to 3.5 v shown that the thickness of the layer is directly proportional to the deposition voltage [5]. however, the data in the study [5] show that in a certain voltage range for deposition times 5, 10, and 15 minutes no increase in layer thickness results even though the voltage is increased. the studies mentioned above have not included the influence of external magnetic fields. electroplating research that includes the influence of external magnetic fields in the manufacture of ni-co thin films proven that the application of an external magnetic field caused an increase in mass transport and the rate of electro deposition of metals [6]. this study also examined the effect of the magnetic field on the regularity of the crystal structure on nickel electro deposition. through this research, it is known that by applying a magnetic field will prevent holes in the layer caused by the reaction of hydrogen evolution so that the layers formed are denser. however, the effect of coating resistivity has not been studied. electroplating research on coating copper plates with nickel which includes the influence of external magnetic fields with variations in deposition current density proved that the application of an external magnetic field makes the nickel layer formed thicker and the sheet resistivity to be higher when compared without the application of an external magnetic field [7]. however, this research has not yet examined the effect on the regularity of crystal structures. this research is expected to study thickness, microstructure, and sheet resistivity of the cu/ni layer produced from electrodeposition prosses with a variation of deposition voltage and 200 gauss magnetic fieldassisted. jl. pramuka no. 42, yogyakarta, daerah istimewa yogyakarta, indonesia *email: willy.anindito@yahoo.com jl. magelang km. 7.5, sleman, yogyakarta, indonesia willi anindita wijanarka1* and moh toifur 1smp muhammadiyah 1 mlati w. a. wijanarka, et al. / indonesian review of physics 3(1), 2020, 23-29 24 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 ii. theory the effect of deposition voltage on the electroplating process the relation between current density (j) and deposition voltage (v) is illustrated by the graph in figure 1 [8]. figure 1. graph of the relationship of current density to deposition voltage there is a range of curves in which the current density is linearly related to deposition voltage called the linear region. there is also a range of curves where the current density is exponentially related to deposition voltage called the exponential region. the relationship between the thickness of the formed layer (δ) to the current density (j) satisfies the equation (1). jtm nf    (1) where: t = coating time m = molar mass of the deposited element or metal n = quantity of electrons transferred ρ = layer mass density f = faraday constant (96485.33212 c/mol) at the low deposition voltage range, the thickness of the formed layer increases linearly with increasing voltage, then when the voltage is increased the layer thickness increases exponentially. ideally, the growth rate of the initial deposit is faster than the rate of deposit formation afterward. in conditions of too low a voltage, the initial deposit formation takes place too slowly, so that the subsequent deposit begins to form before the initial deposit is formed perfectly [9]. this can result in the formation of deposits in the form of rough crystals. meanwhile, when the voltage begins to increase, the rate of initial deposit crystal formation begins to increase so that the possibility of deposits becoming more fine-grained [9]. too high voltage results in concentration polarization, which is the emptying of the solution zone around the cathode of ions, so that growth tends to occur at a higher zone of concentration which results in deposit growth in the form of small groups of crystals, resembling trees [9]. too high a voltage can also result in overheating resulting in a burning deposit with a marked black color. the effect of application of the external magnetic field on the electroplating method. by applying an external magnetic field to the electroplating process, three forces arise in the system that depends on the interaction between the moving ions and the magnetic field, namely the electrokinetic force ( ef ), magnetic damping force ( df ), and the lorentz force ( lf ) that acting on each ion. electrokinetic force satisfies the equation (2). 0 d e e f    (2) where d is the charge density of the diffusion layer, e is a non-electrostatic induction field, and 0 represents the thickness of the diffusion layer. as for the magnetic damping force, it is defined as equation (3). df v b b   (3) where  a solution conductivity, v as a velocity of ion, and b as magnetic field. the lorentz force acting on each ion satisfies equation (4). lf qv b  (4) with q an ionic charge. if the direction of the magnetic field vector is parallel with the ion velocity vector then the lorentz force is zero, whereas for the direction of the magnetic field vector perpendicular to the ion velocity vector the direction of the lorentz force is shown in figure 2. figure 2. diagram showing the direction of the lorentz force (direction away from the reader) due to the influence of the magnetic field on ions moving perpendicular to the magnetic field vector. particles that move under the influence of a constant magnetic field in the direction of the velocity vector that w. a. wijanarka, et al. / indonesian review of physics 3(1), 2020, 23-29 25 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 forms a certain angle to the magnetic field vector have a velocity vector component whose direction is perpendicular to the magnetic field and velocity vector components whose direction is parallel to the direction of the magnetic field. with the lorentz force, the particle velocity component whose direction is perpendicular to the direction of the magnetic field vector makes the particles move in a uniform circular motion. while the particle velocity component whose direction is parallel to the direction of the magnetic field vector is not affected by lorentz's force so it keeps moving straight. the combination of these two kinds of motion causes a helical-shaped particle trajectory with an axis parallel to the magnetic induction vector or magnetic field strength vector ( h ). when an external magnetic field is applied, the magnetohydrodynamics effect occurs which results in the evolution of hydrogen gas. this evolution led to the depletion of the nernst diffusion layer which satisfies equation (5).     1/3 1/32/3 1/31.59d rv d nfcb    (5) where d a nernst diffusion layer, ρ electrolyte density, r the working radius of the electrolyte, d the electrolyte diffusivity, n as a number of electrons are transported during the process, and c the concentration of electroactive ions in solution. this depletion causes a reduced screening effect that increasing in diffusion mass transport ( diffj ) that satisfies equation (6). 0 /)( eldiff ccdj  (6) where d electrolyte diffusivity and cel electroactive ion concentration near the working surface of the electrode (in this case the cathode). application of permanent perpendicular magnetic field (ppmf) in the electroplating process in a solution medium whose concentration is not uniform gives rise to paramagnetic forces ( pf ). while the non-uniform magnetic field in the process creates a field gradient force ( bf ). the paramagnetic force satisfies equation (7). 2 02 m p cb c f     (7) the field gradient force satisfies equation (8). 0 m b cb b f     (8) where m molar susceptibility, b magnetic field strength, c concentration, b magnetic field gradient, c concentration gradient arising due to changes in solution concentration with respect to distance, and 0 as vacuum permeability. iii. method this research was carried out from january to november 2019. making cu/ni samples by electroplating method assisted by external magnetic fields, thickness measurement, and characterization of sheet resistivity for cu and cu/ni produced was carried out at the sentral laboratory of physics education at ahmad dahlan university. the microstructure characterization of xrd from the cu/ni thin layer produced was carried out in the pstbm batan serpong. the object of this study was to observe the effect of deposition voltage on the thickness, sheet resistivity, and microstructure of cu/ni thin films generated by electroplating methods assisted by external magnetic fields. the first step in sample preparation is to create a (10 x 1.3) cm cutting sticker design on the cu plate. parts of the plate that are not attached to the sticker are dissolved using fecl3 solution, then cleaned with aquades. the electroplating process is carried out with variations in voltage (v), the voltage used is 1, 2, 3, 4, and 5 v in the electroplating process with 200 gauss magnetic field. the electroplating time is 60 seconds. the size of ni plate used for coating is (12.6 x 5.3) cm. the resulting sample is first tested for coating thickness by first measuring the mass of the sample before and after coating. layer thickness (  ) is determined by equation (9). w a    (9) where w the difference between the mass of the sample after coating and before the coating (gram), ρ the density of the sample (gram/cm3), and a the surface area of the sample (cm2). second, determine the sheet resistivity ( sr ) using voltage (v) and current (i) data measured through a fourpoint probe through the equation (10). ln 2 s v r i   (10) third, analyze the microstructure by looking at the peak x-ray intensity data generated through the xrd test. crystal size ( sg ) determine by the debye-scherrer equation that shows in equation (11). 0.9 cos sg fwhm    (11) where λ the wavelength of the x-ray used, fwhm the width of the diffraction peak at the position of half the w. a. wijanarka, et al. / indonesian review of physics 3(1), 2020, 23-29 26 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 maximum diffraction intensity, and θ the diffraction angle. fourth, determine the distance between bragg planes ( d ) through equation (12). 2 sin d    (12) iv. results and discussion determination of layer thickness coatings are carried out 5 samples coded waw-01, waw-02, waw-03, waw-04, and waw-05 that indicates the sample is coated with deposition voltage 1, 2, 3, 4 and 5 v, respectively. the mass measurements of the samples were carried out before coating (mcu) and after coating (mcu/ni) whose results are shown in table 1. tabel 1. the mass of the sample before and after coating magnetic field (gauss) deposition voltage (v) mcu (g) mcu/ni (g) 200 1 1,89468 1,89970 2 1,81606 1,83142 3 1,87654 1,90220 4 1,81730 1,86204 5 1,89880 1,96412 then determine the thickness of the formed ni layer ( ) using equation (11). the graph of the relationship between the thickness of the nickel layer formed and the deposition voltage shown in figure 3. figure 3. graph of the relationship between thickness of ni layer formed to deposition voltage at deposition voltage 1, 2, 3, 4, and 5 v successively produced nickel thickness of (7.40 ± 0.07; 22.66 ± 0.07; 37.85 ± 0.07; 65.99 ± 0.07; 96.35 ± 0.07) × 105 cm. through linear regression obtained the curve equation that represent the relationship between thickness and deposition voltage shown in equation (13). 4 4 1.90951 10 1.423631 10b       (13) by looking at the gradient that is positive it can be seen that the thickness of the layer formed is directly proportional to the applied deposition voltage. this is due to the increase in deposition voltage which will increase the number of electrons flowing from the anode to the cathode through the conductor. this causes an increase in the amount of ion anode material formed so that the mass of the anode material superimposed increases which also means the thickness increases. by remember that the greater the voltage indicates the higher current density, this result is suitable that obtained in previous studies that the thickness of the layer increases with increasing current density [10]. microstructure test the microstructure test of the coating was done through xrd testing by firing the cu k-alpha 1 rays which have a wavelength of 1.54060 ǻ on the sample. xray diffraction intensity (i) data was taken in the scattering angle range (2θ) of 0ᴼ to 100ᴼ. after phase identification, ni and cu phases are obtained at the first two peaks shown in figure 4. figure 4. results of the identification of ni and cu phases increasingly sharp of graph diffraction intensity indicates the increasing amount of diffraction counts that the detector receives. this is as a result of the increasingly orderly and lengthy arrangement of the crystal-structure atoms. the graph of diffraction intensity w. a. wijanarka, et al. / indonesian review of physics 3(1), 2020, 23-29 27 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 for the first peak is shown in figure 5, where for the second peak show in figure 6. 0 2000 4000 6000 8000 10000 12000 1 2 3 4 5 d if fr a ct io n i n te n si ty (a rb it ra ry u n it ) deposition voltage (v) figure 5. graph of the relationship between diffraction intensity and deposition voltage for the first diffraction pea 0 2000 4000 6000 8000 10000 1 2 3 4 5 d if fr a ct io n i n te n si ty (a rb it ra ry u n it ) deposition voltage (v) figure 6. graph of the relationship between diffraction intensity and deposition voltage for the second diffraction peak by remembering the results of the layer thickness test and observing the graphs in figures 5 and 6 it is known that the diffraction intensity tends to increase with the increase of thickness and deposition voltage. this is because by increasing the element of ni on the cu substrate will increase the amount of ni crystals formed. by increasing the intensity of nickel diffraction the resistivity of thin film will increase because the higher intensity of diffraction indicates a more orderly arrangement of atoms [11]. in the graph of the relationship between diffraction intensity and deposition voltage for the first diffraction peak, the intensity decrease at 4 v deposition voltage. this is probably due to non-uniformity of the thickness of ni that coated, then the x-ray that is fired is not hitting on the part of the sample that represents the characteristics real sample. then the average crystal size is determined from the crystal size for the first and second ni diffraction peaks. the crystal size for each diffraction peak is determined by equation (11). the relationship of the average ni crystal size to the deposition voltage is shown in the figure 7. it can be seen in the graph in figure 7 that crystal size increase with the increase of deposition voltage and thickness. this is consistent with the results of the previous study that increasing the number of coatings increases the size of the crystal [12]. the increase in crystal size will have an impact on decreasing sheet resistivity [13]. figure 7. graph of relationship between average ni crystal size and deposition voltage. then the distance between the bragg plane (d) is determined at the peak of the first and second ni diffractions, each graph shown in figures 8 and 9. 2,0402 2,0404 2,0406 2,0408 2,0410 2,0412 2,0414 2,0416 d is ta n ce b e tw e e n b ra g g p la n e s (å ) figure 8. graph of relationship between distance between bragg planes for first ni diffraction peak and deposition voltage. figure 9. graph of relationship between distance between bragg planes for second ni diffraction peak and deposition voltage. w. a. wijanarka, et al. / indonesian review of physics 3(1), 2020, 23-29 28 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 the distance between bragg planes satisfies equation (12). through this equation, it appears that the distance between the bragg planes is influenced by the diffraction angle of 2 theta. based on the diffraction peak data obtained by the xrd test, there was no phase shift in all sampel which meant the diffraction angle showed almost the same value for all sampel. this makes the distance between the ni bragg planes obtained is also almost equal for all samples. the distance between these bragg planes also affects the magnitude of sheet resistivity. the smaller the distance between bragg planes will increase the amount of electric current flowing thereby increasing conductivity [14]. by remembering that resistivity is inversely proportional to conductivity, it means that the greater distance between bragg planes will result in greater resistivity. sheet resistivity samples waw-01, waw-02, waw-03, waw04, and waw-05 were successively coated with 1, 2, 3, 4 and 5 v deposition voltage. sheet resistivity test was carried out to all sample before and after coating using a four-point probe. measurement of voltage and a current flowing in the sample is carried out five times at five different points with an input voltage made constant at 6 v. the sheet resistivity used is the average sheet resistivity of the sheet resistivity for each measurement point. the sheet resistivity of each sample before and after the coating is shown in table 2. table 2. sheet resistivity of sample before and after coating deposition voltage (v) before coating: rs ± srs (ω/sq) 10-5 after coating: rs ± srs (ω/sq) 10-5 1 4,4125  0,0001 4,5003  0,0001 2 4,4061  0,0001 4,4831  0,0001 3 4,4083  0,0001 4,5344  0,0001 4 4,4120  0,0001 4,5599  0,0001 5 4,3988  0,0001 4,5266  0,0001 the graph of the relationship between sheet resistivity after coating and deposition voltage is shown in figure 10. it can be seen in table 2 that after the coating is done there is an increase in the sheet resistivity of the sample. this is probably due to the impurity of cu samples by ni whose resistivity is higher. there is a tendency for an increase in diffraction intensity, crystal size, and distance between bragg planes with increasing deposition voltage. the increase in distance between bragg planes has a more dominant in influencing the sheet resistivity value for deposition voltage 2 to 4 v so that the sheet resistivity value tends to increase in the deposition voltage range. while at 1 and 5 v deposition voltage, the diffraction intensity and crystal size factor are more dominant in influencing the resistivity value so that the sheet resistivity value decreases at the deposition voltage. 4,47e-05 4,48e-05 4,49e-05 4,50e-05 4,51e-05 4,52e-05 4,53e-05 4,54e-05 4,55e-05 4,56e-05 4,57e-05 0 1 2 3 4 5 6 s h e e t r e si st iv it y ( o h m /s q ) deposition voltage (v) figure 10. graph of sheet resistivity relationship to deposition voltage. another factor that causes mismatches between sheet 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[14] s. sugianto et al., “pengaruh temperatur annealing pada sifat listrik film tipis zinc oksida doping aluminium oksida,” j. mipa, vol. 39, no. 2, pp. 115–122, 2016. indonesian review of physics, volume 1, number 1, 2018 19 measurement eccentricity the moon’s orbit with image analysis technique by using tracker software ricka tanzilla1, ishafit2 and yudhiakto pramudya3 1, 2, 3physics education,universitas ahmad dahlan, indonesia jl. prof. dr. soepomo sh, janturan warungboto yogyakarta e-mail: tanzilla.ricka@gmail.com one of the interesting physical phenomenon to be studied isabout eccentricity of the moon's orbit on the movement of the earth and the moon as explained in kepler's law. in order to explain the phenomenon,several research has been done to determine themeasurement accuracy of moondiskdiameter using trackers and to know the result of the eccentricity value in the application of kepler's law. this research can produce eccentricity values accordance with the application of kepler’slaw.the research method used is imageanalysis techniqueassisted with tracker. the result of this research shows that the eccentricityvalue obtained is 0.07 ± 0.01. this is in accordance withkepler's first law which stated that orbits of each planet andsatellite is an ellipse and has an eccentricity value of 0 <e <1. the value of eccentricity obtained has accuracy of 22%,if it compared with the actual value.whereas, if it compared with the value of ephemeris then the value of accuracy is 8%. keywords: kepler’s law, eccentricity, moon, tracker i. introduction physics is the study of nature and symptom of objects in the universe with various physical phenomenon such as; the movement of celestial objects, changing process of moon phases, etc. [1]. physics consists of various branches of science. an interesting branch of science to study is astrophysics. the aim of astrophysics is to find out the physical nature of objects in the universe [2]. physical phenomenon related to the universe can be studied through physics. even those that are far from the reach of the eyes. as the basis of astrophysical science, one thing to know is the movement of the planet. planetary movements can be explained through kepler’s law. kepler’s law was initiated by a classical physics scientist, johannes kepler [3].kepler explains the movement pattern of planets surrounding the sun and other celestial objects. fromkepler’s observations it turns out that it agrees with what copernicus has stated is that planets do not surround the earth but surround the sun [4].kepler’s and copernicus' laws have difference. the difference is, according to kepler the orbit is in the form of an ellipse, while according to copernicus the orbit is in the form of a circle [5].johanneskepler and tyco brahe made more precise measurements so that the results obtained were more accurate. therefore the results of the observations and analysis were concluded in the form of 3 empirical laws regarding the movement of the planet calledkepler’s law [6].what is expressed "empirically" shows that these laws are not based on deep theory, but accurately describe the observed motion of the planet. kepler's first law and kepler's second lawwere first published in 1609 and kepler'sthird law was published in 1618 [7]. kepler’s first law states all planets surround the sun in an elliptical orbits, having the sun as one of the foci.kepler’s second law states a radius vector joining any planet to the sun sweeps out equal areas in equal lengths of time. kepler’s third law, the squares of the sidereal periods (of revolution) of the planets are directly proportional to the cubes of their mean distances from the sun.kepler uses planet to prove his physical law [3]. kepler’s law that will be studied in this study is kepler’s first law. most physics books are still stated that all planets surround the sun in an elliptical orbits, having the sun as one of the foci. whereas, what has happened at this time there are many studies showing that not only planets surround the sun in elliptical orbits. but this also happens with the satellites that surround the planet. for example, the moon surrounds the earth in an elliptical orbit. [3]. there are a lot of methods that show that the moon's orbit is an ellipse. research by e. jay sarton under the title measuring the moon’s orbit by using projector screen projection to measure the moon's diameter so that it indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 20 obtained the results of the moon's orbit eccentricity that is 0.0580 [8]. seeing from the lack of the previous research, this study will design eccentricity measurements of the moon's orbit by using tracker so that it will be easier to process the image produced from the moon. moon image is then calculated the moondisk diameter image in pixel and then converted into the moon angle diameter. this experiment was conducted because it knew the accuracy of the diameter measurement of the moon disk using tracker and knowing the results of eccentricity values in the effort to implementkepler’s law. ii. literature review research on the application of moon diameter for measuring the eccentricity of the moon's orbit has been be inspected by banjamin oostra in an experiment entitled measuring the moon’s orbit using a hand-held camera the method used by taking pictures consistently and measuring the visible diameter in the picture. in this study the measurement of the diameter of the moon's appearance using the iris program. in this study the measurement of the diameter of the moon's appearance using the iris program. after obtaining the diameter value, it appears that the next step is analyzed so that the eccentricity value of the moon's orbit is 0.047. eccentricity of the moon's orbit is obtained from elliptical geometry analysis. the agreed value is that the eccentricity value of the moon's orbit is 0.0549 [9]. although the results are inaccurate, this research is able to indicate a simple method to measure the eccentricity of the moon's orbit [10]. subsequent research was carried out by jorge i. zuluaga et al. [11] entitled thesimplest method to measure the geocentric lunar distance: a case of citizen science. this study describes the results of the moon's geocentric distance measurement which aims to explain simple methods with the results of the prescription. this measurement uses the moon's geocentric distance counting method only with images and measurements of the precision of the moon's visible diameter measurements. measuring the diameter of the moon's appearance using the python matplotlib application. so that the geocentric measurements of the moon distance are obtained by d / re =60.51 [11]. subsequent research was carried out by benjamin oostra [10] with the title introducing the moon’s orbital eccentricity. this research provides a way to introduce the eccentricity of the moon's orbit in the introductory class of astronomy. the method used is to exercise direct observation with students to determine the eccentricity of the moon's orbit. moon images taken when moon is in the position of perigee and apogee by using a 12 megapixel camera phone with 12 times the optical zoom shows variations in size due to different distances. the eccentricity value obtained is 0.043 [12]. the next research was carried out by kevin krisciunas with the title determining the eccentririty of the moon’s orbit without a telescope. this study was able to measure the eccentricity of the moon's orbit with a value of e = 0.039 ± 0.006. this research uses a piece of cardboard with a small hole inside which slides up and down with a ruler that allows measuring eccentricity [13]. subsequent research was carried out by tanzilla et al. [14] with the title measurement of the visible moon diameter on the position of perigee and apogee. this study uses gimp software to help calculate the moon's visible diameter. the percentage comparison value when lunar apogee and perigee is 15.77% [14]. a. kepler's law from the study of observational data on the position of the planets collected by johannes kepler with tycho brahe's formulating three laws of planetary motion which are always associated with their names. the three laws are: 1) planet move around the sun in ellipses, with the sun at one focus 2) the line connection the sun to a planet sweeps equal areas in equal time. 3) the square of the orbital period of a planet is proportional to the cup (3rd power) of the mean distance from the sun the first law states that the orbit of mars and implicitly all other planets is an ellipse with the sun in one focus. an ellipse is a form obtained by slicing a cone with a plane at an angle to its base. this is a symmetrical and well-defined form with two focus and properties. the length of a line or string from one focus to any point in the ellipse and then to the other focus is constant [15]. the second law states that the speed of a planet varies so that the line that connects to the sun sweeps out the same area at the same time. so, when the planet is closest to the sun (perihelion) it moves most rapidly and if it is the furthest distance (aphelion), it moves the slowest. although kepler takes nine years to find and publish its third planetary movement law. this law concerns the relationship between the period of the planet and their distance from the sun. the first is known precisely because of the large number of revolutions that have been observed since ancient times, but the distance is very unknown so there is no basis for determining the period varies with distance [16]. b. moon the moon is one of the natural satellites of the earth [17]. the distance of the moon to earth is only around indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 21 384,400 km [18], so that the moon's radiance to earth only takes about one second less (the speed of light is 300,000 km/ second). the moon is the five largest satellites in the solar system and only on the moon is the only natural satellite that has ever been footed by humans. the diameter of the moon is much smaller than the earth, which is only 3,474 km while the earth is 12,742 km [19]. the moon has a surface that is never illuminated by the sun. this is due to the axial minimum slope of the moon, and has an impact on the crater area and other topography near the kurub. the moon remains protected from the sun directly throughout the year [20]. c. ellipse geometry kepler’s first law states that the planets revolve the sun in the form of elliptical orbits with the sun at one focal point of the ellipse. ellipse geometry will provide an explanation of kepler’s first law shown infigure 1[2]. figure 1. ellipse geometry in polar coordinates subsequently, by remembering cos (π θ) = cos (θ), as a result, , )cos(1 )1( )cos(1()1( )cos( )cos(4444 )cos(4444 2 2 222 222 22222      e ea r erea reeara raeeaara raerearara        (1) or , )cos(1 e p r   (2) with )1( 2eap  (3) this is an ellipse in the polar coordinates,p referred as ellipse parameters. if θ = 00 )1( earp  (4) it is termed as perifocal distance. if θ = 1800thus, )1( eara  (5) this is called as apfocus distance. with: a = one half of the major axis (semimajor axis) r = radius ae = focus distance to ellipse foci the site of points with the distance number to the fixedfocus pointis called as ellipse. in the satellite (moon) movement around the earth, the distance is referred as apogee and perigee. the orbit of celestial body in kepler orbit is not only ellipse, but in general, the orbit has a conic section form like in figure 2which has an eccentricity value. eccentricity is the oval sizeofellipse[21]. the eccentricity values can be described as follows: a. if the orbit has 0 eccentricity (e=0), it called as circularorbit b. if the orbit hasthe eccentricity between 0 and 1 (0<e<1), it called as elliptic orbit c. if the orbit has 1 eccentricity (e=1), it called as parabolic orbit d. if the orbit has the eccentricity greater than 1 (e >1), it called as hyperbola figure 2. conic section[15] iii. research/ experiment method in this research, the data collection was conducted at the 4th campus of universitas ahmad dahlan, ring road selatan street, tamanan, banguntapan, bantul yogyakarta at 7°50”southern latitude and 110°22”east longitude. the subject in this study is the depiction of the moon. the collection of moon image is done by using the prime focus technique. the data that have been taken are processed by image analysis technique in the tracker. research instrument can be seen in figure 3. θ r2a-r 2ae π-θ indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 22 figure 3. research instrument the research instrument (figure 3) was used to capture the full moon depiction.the full moon depictionwhich was obtained is process to get the value of moon disk diameter. moon disk diameteris used to find the eccentricity value of moon orbit. a. determine the moon diameter by using tracker 1) insert the moon depiction on tracker and begin the push by using line profilein the full moon depiction. 2) in everyline profileontrcaker, take the value intable x and then processed in excel in figure 4. 3) the sky arena in the moon depiction has a value lower than the moon disk.there is transition from the low value to high value that occurred in the edge of the moon disk. transition value is used as threshold valueto determine the edge of the moon disk. to make it easier to get the threshold value, then use themoving average. luminosity value in every area pixcel near the moon disk and sky is processed to obtain the difference value between adjacent pixcel. the difference in value is up and down randomly, then smoothed with a moving average. there is a significant change. this value is used as the threshold value for the determination of the edge of moon disk. after getting the transition value, maka dapat ditetukan titik tepi piringan bulan. this point is referred asx1andx2.the x value has pixcel unit. figure 4. finding the x1andx2in moon disk 4) after getting the x1 dan x2value, we can calculate the value of the moon disk diameter which is displayed in each line of profile by counting the difference betweenx1andx2 (δx). to determine the diameter of moon disk, then graphs are made for each line profile and difference valueof x (δx), to get the value of moon disk diameter more accurately, we can use the equation (6) 22 0 ) 2 1 ()( nnn xyyr  , (6)=2 (7) rnis radius value of moon disk in each line profile, ynis theyvalue that obtained in every line profile, whileyois the yvalue in the line profile which is considered as diameter focal point of moon disk.δxnis the difference valueof xon each line profile. hence,the diameter of moon disk is obtained by averaging the rnvalue then multiplied by 2 following the equation of a circle. b. calculating the eccentricity value in order to obtain the value of angular diameter (θ) of depiction, then look for nominal angular resolution of the camera (nar) with equation (8) in rad/pixcel. after the nar value is obtained, multiply it by the diameter of the moon disc (equation 7), so the angular diameter value is obtained. telescopelengthfocal ensionimagewidth ensionsensorweidht nar __ dim__ dim__        (8) θis angular diameter. the angular diameteris affected by the distance of earth and the moon as shown in figure 5.if the distance of moon is closer from earth, thus theangular diameteris bigger. it is called asangular diameterperigee(θp).whereas, if the distance of the moon is further from earth, the angular diameter is smaller, it is called asangular diameterapoge (θa). the relation betweenangular diameterand distance can be described by equation (9). = (9) or= (10) then, the eccentricity value that obtained is = , (11) indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 23 figure 5. the angular diameter of an object(source: [22]) iv. research result and discussion a.determining the value of eccentricity and comparing it with actual value. the eccentricity value is obtained from the maximum value of angular perigee diameter and minimum angular diameter apogee by using equation (9). to determine the angular value of perigee diameter and angular value of apogee diameter can be seen in figure 6. the highest or maximum diameter angular value is the perigee diameter angular value and the lowest or minimum value is the angular value of apogee diameter. figure 6. graphical the relation of angular diameter to time from the results of the image analysis technique after obtaining the eccentricity value experimentally, it can be concluded that the eccentricity value experimentally and the actual value of 22% can be seen in table 1. the relatively larger error due to the actual value obtained from the observation results hundreds of years or even thousands of years is then averaged so that the actual value is obtained. the value of error is quite large due to data collection done up to 10 months because there are several obstacles. the constraints that often occur are weather. the weather greatly affects the quality of shooting the full moon and the full moon is less than once in a span of 27 or 28 days. in addition, the telescope used also has drawbacks. the telescope used is a refractor telescope or a lens telescope that will affect the image of the full moon image received. table 1. relative errors between experiment and actual value eksperimen actual value ralat 0,07052779 0,0549 22% based on the experimental calculations the sexentricity values obtained were 0.07 ± 0.01. the existence of differences in eccentricity values can be seen from nasa calculations over 5000 years of eccentricity values included in the susceptible value of 0.0255 to 0.0775. while averaged over 5000 years the eccentricity value is 0.0549 [23]. figure 7. the moon eccentricity from 2008-2010 [23]. figure 7 shows that eccentricity reaches the maximum when the main axis of the moon's orbit points directly towards or directly away from the sun (0° and 180°). this occurs at an average interval of 205.9 days, which is longer than half a year because of the shift of the main axis to the east. eccentricity reaches a minimum point when the main axis of the moon's orbit is perpendicular to the sun (90° and 270°) [23]. b. determining the value of eccentricity and comparing with ephemeris value ephemeris value is an accurate calculation that can calculate the angular diameter of the moon from year to year so that it can be used as a reference value [24]. in table 10 is the difference of the angular diameter value experimently and emphemeris values so that obtained the average value of error is 0.653%. 1700 1750 1800 1850 1900 1950 2000 2050 a ng ul ar d ia m et er (" ) time indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 24 table 2. the differences of angular diameter values experimentally and emphemeris values date angular diameter value exsperimentally angular diameter value emphemeris deviation 22/04/2016 1759.179128 1764 0.273% 14/11/2016 2026.150021 2009.2 0.844% 10/04/2017 1810.84386 1814.6 0.207% 11/05/2017 1772.639268 1769.3 0.189% 09/06/2017 1770.155642 1763.6 0.372% 10/07/2017 1795.741158 1788.5 0.405% 07/08/2017 1828.457749 1804.4 1.333% 06/09/2017 1869.714657 1859.1 0.571% 05/10/2017 1935.562327 1903.3 1.695% 01/11/2017 2007.655893 1994.8 0.644% from table 8 can be described in the form of diameter angular graphs to the time with experiment values and emphemeris values in figure 8. figure 8. the graph of angular diameter relation to the time with experimental and emphemeris value data. the eccentricity value which obtained from emphemeris measurements is 0.065. so that the eccentricity value is measured by the experimental value and emphemeris value, the errors obtained by 8% can be seen in table 3. table 3. relative error between experiment and ephemeris eksperimen emphemeris ralat 0,07052779 0,06509754 8% v. conclusion based on the results of the research and discussion, it was concluded that the measuring accuracy of the moon disk diameter using the tracker can be viewed from the eccentricity value obtained. the eccentricity value obtained has an error of 22% if compared to the actual value, whereas if the eccentricity value obtained compared to the ephemeris value, the error value is 8%. the eccentricity value obtained was 0.07 ± 0.01. this is in accordance with first kepler’s first law which states that the orbit of each planet and satellite are ellipses and has an eccentricity value of 0 <e <1. vi. acknowledgment thank you to pastron and andromedathey helpedto guide the continuity of this experimental research and thank you to all friends who helped us in conducting this experiment. vii. bibliography [1] subagya, hari, and insihwilujeng. fisika sma/ma kelas x kurikulum 2013 kelompokpeminatan mipa [physics for high school]. jakarta: bumi aksara, 2013. [2] sutantyo, winardi. pengantarastrofisikabintangbintang di alamsemesta [introduction to astrophysics of stars in the space]. bandung: itb, 2010. [3] kunjaya, chatief. suplemenastronomiuntuk sma[supplement of astronomy for high school]. bandung: pt trisulaadisakti, 2014. [4] dutton, john a. astro 801. 2017. https://www.e-ducation.psu.edu/astro801/ content/l2_p4.html (accessed june 7, 2017). [5] osler. j, thomas. an unusual approach to kepler's first law.american association of physics teachers, 2001: 69. [6] roy, a e, and d clarke. astronomyprinciple andpractice. bristol: institute of physics publishing, 2012. [7] morison, ion. introduction to astronomy and cosmolgy. university of manchester, uk: wiley, 2008. [8] sarton, e jay. measuring the moon's orbit.the physics teacher, 1980: 504-508. [9] williams, david. nasa. july 3, 2017. https://nssdc.gsfc.nasa.gov/planetary/factsheet/ moonfact.html (accessed july 15, 2017). [10] oostra, benjamin. measuring the moon's orbit using a hand-held camera.american association of physics teachers, 2014: 317-321. [11] zuluaga, jorge i., juan c. figueroa, and ignacio ferrin. the simplest method the geocentric lunar distance: a case of citizen science.american journal of physics, 2014: 1-16. 1700 1750 1800 1850 1900 1950 2000 2050 an gu la r d ia m et er waktu nilai eksperimen nilai emphemeris indonesian review of physics, volume 1, number 1, 2018 tanzilla et al. measurement eccentricity the moon’s orbit with image analysis… 25 [12] oostra, benjamin. introducing the moon's orbital eccentricity.american association of physics teacher, 2014: 460-462. [13] krisciunas, kevin. determning the eccentricity of the moon's orbit without a telescope.american association of physics teachers, 2010: 834-838. [14] tanzilla, ricka, lukman hakim, and yudhiaktopramudya. pengukur diameter tampakbulanpadaposisi perigee dan apogee [measure of moon apparent diameter at the position of perigee and apogee].seminar quantum 2016. yogyakarta: program studipendidikanfisika, universitas ahmad dahlan, 2016. 271-274. [15] angelo, joseph a. encyclopedia of space and astronomy. new york: library of congress cataloging, 2006. [16] wilson, robert. astronomy throughthe ages. francis: taylor & francis e-library, 2005. [17] kindersley, dorling. jendelaoptik astronomy [optic window of astronomy]. jakarta: pt balaipustaka, 2007. [18] dunford, bill. solar system. july 5, 2016. https://solarsystem.nasa.gov/planets/moon/inde pth (accessed july 21, 2017). [19] yani, ahmad. pengantarkosmografi [introduction of cosmography]. yogyakarta: penerbitombak, 2014. [20] denevi, brett. the moon.physics today, 2017: 39-43. [21] celletti, alessandra. stability and chaos in celestial mechanics. uk: chichester, 2010. [22] seeds, micheal a. the solar system, sixth edition. usa: thomson, 2008. [23] young, alex. eclipse and the moon's orbit. january 12, 2012. https://eclipse .gsfc.nasa.gov/sehelp/moonorbit.html (accessed december 29, 2017). [24] espenak, fred. astropixcel.january 13, 2015. http://astropixels.com/ephemeris/moon/moon2 017.html (accessed december 30, 2017). indonesian review of physics, volume 2, number 2, 2019 53 determination of fill factor and efficiency in solar cell type (99 × 69) mm2 with arduino uno r3 based drive assisted by logger pro 3.14.1 hamzah, moh. toifur*, ishafit program magister pendidikan fisika, universitas ahmad dahlan jl. pramuka, no.42, pandeyan, umbulharjo, yogyakarta, indonesia email: *mtoifur@mpfis.uad.ac.id abstract the purpose of this research is to determine the fill factor and efficiency of solar cell type (99×69) mm2 with arduino uno r3 based automatic drive assisted logger pro 3.14.1. this study aims to determine the value of the fill factor and the efficiency of solar cell type (99×69) mm2 on manual and automatic drives with a microcontroller collaboration using arduino uno r3 as a data acquisition tool. the use of samples in research on fill factors and the efficiency of solar cells with automatic drive rotating the surface of the solar cell follows the motion of the light source from 0 to 90 compared to without the automatic drive from 10 to 70. the test results are then implemented to determine the fill factor and efficiency in variations in light intensity. in this experiment the type of solar cell used polycrystalline type (99×69) mm2 was presented in front of a philips 100 w/220 v light bulb at a distance of 18 cm and the solar cell automatic drive was controlled via an arduino uno r3 microcontroller. current and voltage data acquisition is carried out with the help of dcp-bta currents and vp-bta voltage probes that are connected to the mini labquest transducer and displayed to a computer through software logger pro 3.14.1. furthermore, the solar cell voltage-current data is diffitting using the exponential equation in logger pro software. based on the results of solar cell research type (99×69) mm2 percentage of the fill factor value of 60,2  0,5 and efficiency of 26  0,4 in manual motion. whereas in the automatic drive percentage fill factor 66,3  0,4 and efficiency 26  0,1. percentages in automatic drive can increase the accuracy and precision of current and voltage readings so that the fill factor increases by 10% while efficiency does not change. furthermore, the greatest variation in light intensity is 993.34 w/m2 with a fill factor of 71% and an efficiency of 31%. this fill factor and efficiency have an exponential relationship with light intensity. keywords: fill factor, efficiency, arduino uno r3, logger pro software i. introduction sunlight can be used as a renewable energy source, namely solar cells. solar cells during sunny afternoon or midday can produce an intensity of 1000 w/m2, 25oc [1]–[3]in commercial solar cell modules the efficiency ranges from 10% to 30% depending on the composition of material making up [4]–[8]. the quality of the solar cell is determined by the fill factor (ff), the energy conversion efficiency () and the concentration of sunlight received by the solar panel [9]–[12] fill factor is an energy storage parameter that is the ability of solar cells to store the received solar energy. mathematically ff is the ratio of maximum power (pmax) produced by solar cells to theoretical power (pth). whereas efficiency states the percentage of output of electric energy from solar cells to energy that comes in from the solar radiation. this efficiency is a parameter that describes the energy that can be converted by solar cells. hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 54 from preliminary studies that have been conducted by researchers about the effect of the panel angle on the solar cell energy of (99 x 69) mm2, 5v it is obtained the fill factor for all variations of the solar cell plate tilt angle from 10º up to 90º. the maximum fill factor corresponds to a angle of 30 of 67% with a maximum power of 0.023 watts while the maximum efficiency produced is 0.07%. at this angle the direction of the light comes parallel to the direction of the solar cell area. this value is too small for manufacturer's solar cells, because the ff for normal solar cells ranges from 10% to 30%. from the catalog of solar cell size (99 x 69) mm2 it is obtained information that the solar cell was in 2017 so that within 2 years the ff has not yet decreased from its original value. from the re-examination of the data collection techniques, there is something that needs to be corrected, including the luxmeter used as an instrument for measuring the light intensity originated from a smartphone application. this instrument inaccurate after being matched with the luxmeter from vernier logger pro and the ldr sensor on arduino. in addition, the process of measuring voltage (v) and current (i) data is still too long time so that the sun's position has shifted from its original place. with this condition, the angle of incident ray is not perpendicular to the direction of the surface of the solar cell. therefore in this study the data collection technique was improved in an instrument for measuring the light intensity using arduino r3 ldr. this arduino can be programmed to allow rotating solar cell panels so that the surface of the solar cell always perpendicular to the direction of the incident sunlight. voltage-current data was acquisited automatically using a voltage sensor and current sensor logger pro 3.14.1. ii. theory solar cell the electric power generated by solar cells when getting light is obtained from the ability of the solar cell device to produce voltage when given a load and current through the load at the same time. theoretical power is the power generated when the area of the i-v curve is voc isc [13]: th oc sc p v i (1) where pth theoretical power (watts), voc open circuit voltage (volts) and isc short circuit (amperes). the point on the i-v curve that produces the maximum current and voltage is called the maximum power point, maxmaxmax ivp  (2) where vmax is maximum voltage (volts), and imax is maximum current (ampere). intensity of the light received by the solar cell is defined as the power received from solar or light source (pin) divided by the cross-sectional area of the solar cell (a). a p i inr  (3) or in rp i a (4) where ir the intensity of the incident light (w/m2) when the solar cell is in an open circuit condition or maximum current, whereas in the short circuit condition (open circuit) there is no current that can flow so that the maximum voltage is called the voc voltage. an important characteristic of solar cells is the fill factor stated in the equation: max th f p f p  (5) while the conversion efficiency is the ratio between the output power of the solar cell (pout) to the input power of the light source used (pin). max f th in in f pp p p    (6) in experiments there are often errors in determining ff and . as in figure 1 of the data points (vi, ii), then voc is usually taken from the last vi data while isc is taken from the first data ii. voc should be taken from the point of intersection of the curve with respect to the v-axis, and isc is the point of intersection of the curve with respect to i-axis. as a result, pth becomes smaller than it should be [12]. similarly vmax and imax are obtained from the multiplication between vi and ii data. voc and isc should be obtained carefully if the data (vi, ii) is made a curve with the help of data fitting then the curve is extrapolated until it intersects with the v and i axes. hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 55 figure 1. solar cell characteristic curve arduino arduino is an electronic prototype device based on a microcontroller that is open source. arduino functions as a controller of electronic circuits. arduino has a microcontroller board based on atmega328 with 14 input/output pins, 6 pins can be used as output, 6 analog inputs, usb connections, adapter sockets, icsp header pins and research buttons using coding language in the form of c language [14]–[16]. software logger pro logger pro is a software for data acquisition and analysis [17]. in this experiment logger pro 3.14.1 is used to display data readings by voltage sensors and current sensors. in addition logger pro 3.14.1 is also used to fitting data (vi, ii) to obtain the v-i curve equation. iii. methodology experimental procedure this research was conducted at the central laboratory (sensor and transducer laboratory) of uad physics education. some of the equipment used are: polycrystalline solar cell type (99 × 69) mm2, arduino uno r3, servo motors, computers and usb labquest (current and voltage sensors). a sollar cell drive device is arranged according to figure 2. figure 2. schematic of solar cell experiment kit assisted by arduino uno r3 in figure 2, a solar servo motor is used to drive the solar cell which is connected to the arduino pin. servo motors have 3 red power cables (vcc) connected to an arduino 5 volt source. then the black ground wire (gnd) is connected to the arduino gnd pin. while the orange signal (data) cable is connected to the arduino digital 9 pin as a regulator of the rotating direction of the servo motor. then the ldr (light dependent resistor) is installed as a controller to give the drive command to the servo motor. ldr 1 is connected to the vcc servo motor cable then connected to ardunio a0 pin. whereas the ldr 2 is connected to the gnd pin of the servo motor and pin arduino a2. arduino uno r3 voltage source is taken from laptop power using a serial cable. the tilt angle of the solar cell can be read directly through the protractor that has been mounted on the solar cell. then the arduino program is run to activate all components that are already installed. voltage vp-bta and current dcp-bta sensors were used collecting solar cell voltage-current data. these sensors were connected to labquest mini transducer and the reading values were displayed using the logger pro software.. the current and voltage sensors are connected to the labquest mini transducer where the positive current sensor is connected to the positive solar cell cable and the voltage sensor cable is connected to the pin 2 potentiometer. the negative cable of current sensor and the positive cable of voltage sensor are connected to pin 1 potentiometer. the time for data collection was set on 30 seconds and the sampling rate was 0.05 seconds / sample. furthermore, philips 100w/220v bulb as a light source is installed by connecting to the pln voltage source. the potentiometer was rotated from minimum to maximum to obtain the value of a set of data (vi, ii). ld ld solar cell moto r servo ardui auto maticall y rotation light source hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 56 data analysis method the research was carried out following the scheme in the figure figure 3. scheme of experiment and data analysis voc, isc, vmax and imax values are obtained from the vi curve resulted from data fitting of (vi, ii) according to the natural exponential function, exp cx y a b    (7) with, x = i, y = v and a, b, c are the fitting coefficients of equation (7). the value of isc is obtained from the intersection of the curve with respect to the x-axis and voc is obtained from the intersection of the curve with respect to the y-axis. by entering x = 0 in (7) for isc and y = 0 for voc we get: sci a b  (8) whereas the voc equation        a b c voc ln 1 (9) by multiplying eq. (8) and eq. (9) the theoretical power value is obtained as stated in equation (1). maximum power is obtained from the multiplication of voltage (xi) and current (yi) and then taken from the largest value. the light intensity of the lamp is obtained from eq. (3) with a solar cell module area (99 × 69) mm2. the ff solar cells is obtained from equation (5), which is the ratio of maximum power and theoretical power. the value of ff is expressed in percent. sollar cell efficiency  is obtained from equation (6). iv. results and discussion in figure 4.a the results of the design of a solar cell automatic drive type (99 × 69) mm2 are used using arduino uno r3. whereas in figure 4.b is the use of pro logger software to display vi and ii results. figure 4. the set of experimental tools, a. solar cell b. arduino uno, c. servo motor, d. light sensor e. ldr f. protractor, g. potentiometer, h. battery. manually solar cell performance figure 5 shows the performance of a solar cell type (99 × 69) mm2 without an automatic rotation motor in the form of a voltage-current curve at the various angle of the incident beam from 10 to 70. the angle is varied manually and at the beginning, the surface position of the solar cell in the direction of the incident beam. during data acquisition the position of the solar cell remains at its initial angle, while the position of the light source has shifted from its original position according to the sun's rotation. performance of solar cell with manual driver performance of solar cell with automatic driver with variation of inclined angle of [10:20:90] with variation of inclined angle of [0:10: 90]  i-v curve  p-v curve  fill factor  efficiency be compared  i-v curve  p-v curve  fill factor  efficiency variation of intensity to get  i-v curve,  p-v curve  fill factor  efficiency solar cell type (99 × 69) mm 2 hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 57 figure 5. characteristic of solar cells without a driving motor, (a) current-voltage curve, (b) the maximum power. performance of solar cells with automatic solar cell rotation furthermore, the performance of solar cells as discussed in the sub-sections above is compared with the performance of solar cells if the solar cells are rotated automatically with a motor driven by arduino. with this motor, the surface of solar cell can always follow the light source so that the surface direction of the solar cell is always parallel to the direction of the light source. in this way, to vary the tilt angle of solar cells becomes more flexible. in this study the slope angle is varied from 0 to 90. profile of current-voltage and powercurrent curve as shown in fig. 6. figure 6. characteristic curve of a solar cell with a milling motor, (a) current-voltage, (b) maximum power figure 6 shows the solar cell output power at various currents obtained by calculation. the power is obtained from the light of a data lamp with an intensity of 981.73 w/m2 that is imposed on the surface of the solar cell. by varying the load resistance so as to produce a current from 0 a to 0.01 a then record the voltage v between the two poles of the solar cell. next pmax is determined which corresponds to the peak position of each curve in figure 6 (b). by varying the tilt angle of the solar cell panel the charging factor is obtained which varies slightly between 66% to 72% and the efficiency varies from 25% to 27%. furthermore, the performance as obtained in subsections 1 and 2 included fill factor and efficiency is then compared, and the results are tabulated in the table 1. 0,000 0,001 0,002 0,003 0,004 0,005 0,006 0,007 0,008 0 1 2 3 4 5 voltage (v) c u rr e n t (a ) 10° 30° 50° 70° 0,0000 0,0050 0,0100 0,0150 0,0200 0,0250 0,0000 0,0020 0,0040 0,0060 0,0080 current (a) p o w e r (w ) 10° 30° 50° 70° 0 0,001 0,002 0,003 0,004 0,005 0,006 0,007 0,008 0,009 0 1 2 3 4 5 voltage (v) c u rr e m t (a ) 0 degree 10 degree 20 degree 30 degree 40 degree 50 degree 60 degree 70 degree 80 degree 90 derajat 0,001 0,006 0,011 0,016 0,021 0,026 0,031 0 0,002 0,004 0,006 0,008 0,01 arus (a) d a y a ( w ) 40 derajat 80 derajat 0 derajat 10 derajat 20 derajat 70 derajat 50 derajat 60 derajat 30 derajat 90 derajat (a) (b) (a) (b) hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 58 table 1. a comparison of solar cell performance without and with automatic drive performance parameter with manual driven with automatic driven increasing (%) fill factor 60,2  0,5 66,3  0,4 10 efficiency 26  0,4 26  0,1 0 from table 3 it is clear that the fill factor using automatic drive is larger and more precise than that from manual drive. this can be seen from the value of standard deviation which is smaller than the value of standard deviation in manual drive. for efficiency, both methods display the same value, but the efficiency of solar cell from the automatic drive is more precise than manual drive. thus the use of solar cell drives automatically can increase the accuracy and precision of the fill factor and efficiency. furthermore, after knowing the method to determine the fill factor and the efficiency of solar cells using automatic is better then the solar cells with a manual drive methods, variations in the intensity of the incident light on solar cells are carried out. performance of solar cells at various intensity the intensity of the light was varied from 967 w/m2 to 983 w/m2 and the position of the solar cell is parallel to the direction of the incident light. furthermore, by varying the load resistance the current and voltage are recorded between the poles of the solar cell. current-voltage and power-current curves was displayed in figure 7. figure 7. performance of solar cell on the various intensity. (a) voltage – current curve, (b) power – current curve from figure 8 it appears that the greater the intensity the greater the fill factor and efficiency. this is consistent with the phrase that has conducted research on the fill factor and efficiency of solar cells for variations in intensity from 250 w/m2 to 1000 w/m2 and the greater the intensity of the higher current while the voltage is almost unchanged and the conclusion is the greater the intensity the greater the power the maximum achieved [18], [19]. based on the fig. 9 the greatest of maximum power obtained at an intensity of 983,344 w/m2 is equal to 0.0326 watts. the fill factor (ff) and their efficiency () are listed in table 2. from the table it appears that the lowest fill factor and efficiency valuee is lie at an intensity of 967.51 w/m2 which is 63% and 18% respectively. while the highest fill factor and efficiensy is at an intensity of 983.34 w/m2 that is 71% and 31% respectively. the increasing intensity will increase the maximum power and theoretical power of solar cell so that the fill factor and efficiency also increase. the type of increasing fill factor and efficiency is directly proportional to the exponent of its intensity. 0 0,002 0,004 0,006 0,008 0,01 0 2 4 6 voltage (v) c u rr e n t (a ) i= 981 w/m 2̂" i= 967 w/m 2̂" i= 973 w/m 2̂" i= 983 w/m 2̂" 0,00 0,01 0,02 0,03 0,04 0 0,005 0,01 current (a) p o w e r (w ) i= 983 w/m^2 i= 973 w/m^2 i= 973 w/m^2 i= 981 w/m^2 (a) (b) hamzah et al. determination of fill factor and efficiency in solar cell type (99 × 69) mm2….. indonesian review of physics, volume 2, number 2, 2019 59 table 2. value of fill factor and efficiency at various intensity of incident light intensity (w/m2) voc (v) isc (a) pth (w) pmax (w) ff (%)  (%) 967.51 4.82 0.0061 0.03 0.019 63 18 976.71 4.86 0.0073 0.036 0.023 64 22 981.73 4.94 0.0085 0.042 0.028 67 27 983.34 4.92 0.0093 0.046 0.033 71 31 v. conclusion based on the results of analysis and studies that have been carried out regarding the determination of fill factor and efficiency in solar cell type (99 × 69) mm2 with microcontroller based drive arduino uno r3 assisted with logger pro 3.14.1, we conclude as follow: 1. it has been successfully designed an automatic driver of a solar panel (99 × 69) mm2 with an arduino uno r3 microcontroller using an arduino software coding program and using a logger pro software as data acquisition software. 2. determination of the performance of solar cells using an automatic drive machine can improve the accuracy and precision of current and voltage readings so the fill factor might be increased up to 10% while the efficiency of solar cells does not change. 3. in testing solar cells using variations in light intensity, the increasing intensity can increase the fill factor and efficiency of solar cells. fill factor and efficiency have an exponentially relationship to light intensity. reference [1] r. guliani, “exact analytical analysis of dye-sensitized solar cell: improved method and comparative study,” open renew. energy j., vol. 5, no. 1, pp. 49–60, jul. 2012, doi: 10.2174/1876387101205010049. 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[19] d. bonkoungou, z. koalaga, and d. njomo, “modelling and simulation of photovoltaic module considering singlediode equivalent circuit model in matlab,” int. j. emerg. technol. adv. eng., vol. 3, no. 3, pp. 493–502, 2013. indonesian review of physics, volume 2, number 2, 2019 40 development of lesson plan (lp) with software lectora inspire assisted problem-based learning in improving learning outcomes for senior high school. achmad aswal*, hunaidah, and erniwati department of physics education, university of halu oleo street h.e.a mokodompit, kendari, indonesia 93231 email: *aswalachmad@gmail.com abstract this research-based on technological advances that promote the use of technology in learning, on the lack of valid, practical and effective lesson plans, particularly in problem-based learning models that are in line with the 2013 curriculum, and on the use of lectora inspire software in the creation of lesson plans. this study was conducted to develop problem-based learning model based on lectora inspire software. this type of research is research and development (research and development). the design of this study based on five out of ten phases of borg and gall's research design, namely research and collection of initial information, planning, development of original product formats, initial testing and product improvement. the effectiveness test results were rated very well with an average of 88% and 89.04%. the increase (n-gain) of student learning outcomes is 0.62 which can be categorized as a moderate increase. keywords: lesson plan, problem based learning, lectora inspire, learning outcomes, a learning process i. introduction technological developments are taking place very quickly. so people make technological innovations by their fields of expertise [1]. as a result, effective technology products create in all areas. it has changed the paradigm and principles of work in all areas, from the world of information to learning. in the learning process, with the presence of technology products able to deliver students to meet the capacity of the 21st century [2]. a subject that uses technology to support the learning process is physics. according to [3], one of the core competencies needed by a teacher is to communicate and develop the development of a curriculum for the particular area of development, the implementation of educational activities, the development of creatively taught learning topics, and the use of information technology communication. from these requirements and obligations, teachers must be able to assemble teaching topics or innovative learning media, such as printed teaching topics, models, audio teaching topics, audiovisual teaching topics or interactive teaching topics [4], [5]. lesson plan s need to be developed to improve the quality of education [6]. besides, renewal in the field of education itself must be supported. one possible solution is to analyze a learning method used in a syllabus [7]. it hoped that this analysis could contribute to the achievement of learning objectives and does not exclude that the analysis can be used as the basis for developing a learning strategy. problem-based learning is one of the bridges to creating active learning [8]. this learning begins (1) with researching and solving problems to generate, combine, and generalize knowledge. (2) studentcentered; (3) activities to combine new knowledge and existing knowledge [9]. the implementation of problem-based learning will be better if there is a learning approach that supports it. in this context, the aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 41 intended approach is the scientific approach. when you learn with a scientific approach, you need a teacher who can prioritize aspects of observation, thinking, and discovery, a scientific approach. the scientific approach (scientific approach) to learning involves observing, questioning, thinking, trying, and building networks [10]. the learning process touches on three areas: attitudes, knowledge and skills. improving the quality of learning can be supported through the use of relevant learning tools. so that the use of computers as a learning medium is significant, especially in this challenging time, there are already many learning methods based on information technology. one application that supports the teaching and learning process is lectora inspire software [11]. lectora inspire software is an application program that can be used to create presentations and learning media [12]. lectora inspire software lets you create presentations that include text, spreadsheets, images, lp art, audio, video, flash animations, special effects, 3d effects, and other effects [13]. with the lectora inspire software application program, we can prepare a teaching topic, especially in the field of physics lessons for material moments, impulses, and collisions. although with these benefits, it is still rarely used as a learning medium in schools. for example, some researchers have investigated the use of lectora inspire software as a learning tool. research by [14] shows that the use of ict-based learning media with the lectora inspire software application offers many benefits, including: (a) lectora inspire software learning media, if well designed, is a useful learning tool; that can enhance and improve the quality of learning; (b) support individual learning according to students' abilities and can be used as direct feedback; (c) repeating the material as needed without causing boredom; (d) obstacles to the use of ict-based learning media with the lectora inspire software are human resources. using ict-based learning media with the lectora inspire software can increase the quality of science learning. the use of ict-based learning media with the lectora inspire software application is more interesting for students, and students may become slower in accepting it is, adjust [15]. based on the description presented, the author is interested in developing a lesson product for the upper school with lectora inspira. the goal is to create a lesson plan using the lectora inspire software-based problem learning model, based on valid, practical and effective impulses and impulses used for learning in high schools. ii. theoretical framework development is a process to develop and validate products used in education, such as an instructional topic for teachers, subjects, media, questions and management systems. development research is being conducted to solve problems associated with learning tools that are considered problems because they do not exist or do not exist, but that are or do exist but need to be corrected. miller and borg [16] developed 10 steps in the development of learning products, namely: (a) research and information gathering; (b) planning; (c) developing a preliminary product form, (d) preliminary field tests; (e) main revision of the product; (e) field tests; (f) operational product revision; (g) on-site field testing; (h) revision of the final product; and (i) dissemination and implementation. lesson plan according to the order of the minister of education and culture of the republic of indonesia no. 22 of 2016, the lesson plan (lp) is a plan for personal learning activities for one or more meetings. the lesson plan developed from the syllabus to guide students' learning activities and achieve basic competency (bc). each educator in the lesson is required to create a complete and systematic lesson plan that will make the learning interactive, inspiring, entertaining, challenging, efficient, and motivating for student participation. with sufficient room for initiative, creativity, and independence according to their talents and abilities, interests offered and physical and psychological development of the students. the lesson plan organized according to necessary competencies or subtopics, which held in sessions or more [17]. problem-based learning model problem-based learning, according to the ministry of education and culture, is a learning approach that highlights contextual issues that encourage students to learn. in classes that use problem-based learning, students work in teams to solve real-world problems. according to [18] steps to learn a problem-based learning model aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 42 table 1. steps to learn a problem-based learning model step the behaviour of the teacher step 1 orient the students to the problem the teacher explains the learning objectives and advice or logistics needed. the teacher motivates students to participate in selected real problem-solving activities. step 2 organizing students the teacher helps the students to define and organize learning tasks that relate to problems that oriented in the previous phase. step 3 do individual and group examinations the teacher encourages students to gather appropriate information and conduct experiments in order to achieve the clarity needed to solve the problems. step 4 develop and present the work the teacher helps students share tasks and plan or prepare suitable work as a result of problem-solving in the form of reports, videos, or models step 5 analyze and evaluate the problem-solving process the teacher helps students to reflect on or evaluate the problem-solving process that has been carried out. learning outcomes winkel [19] explains that learning outcomes achieved by students lead to changes in knowledge or understanding, skills and attitudes. according to jihad and haris [20], learning outcomes are skills that children acquire after undergoing learning activities. learning itself is a process of someone trying to achieve a relatively permanent form of behavioural change. for learning activities or lesson activities, the teacher usually sets learning goals. students who successfully learn are the ones who succeed in achieving learning goals or teaching goals. learning outcomes is a statement that shows how to understand the lessons learned by the students and to be shown at the end of learning [21]. in other words, learning outcomes identify what students know and can do at the end of the learning program. learning outcomes describe the overall goals or goals of participating in activities during the learning process [22]. in addition, learning outcomes interpreted as describing a result that includes aspects of the knowledge, understanding and abilities that students have acquired during the learning process. learning outcomes can describe the whole process during the learning process [23]. software lectora inspire the lectora inspire software is a learning media development tool, also called authoring software, developed by trivantis. lectora inspire software is a popular application for creating powerpoint presentations. the lectora inspire software can be used for both online learning (e-learning) and offline (classroom) learning purposes, which can be quickly and easily create. the lectora inspire software can be used to combine flash files, capture videos, combine images and take screenshots. . figure 1. part of lectora inspire software iii. method research type this type of research is a kind of research and development, namely the development of a plan for the implementation of problem-based learning models for learning physics with lectora inspire software on the topic of impulse, momentum and collision for the 2013 a-level curriculum and master's programs. research design this research uses research and development design (research and development). this study developed a research design according to [16] from 10 stages of research design, according to borg and miller, this study used five stages. this research uses research and development design (research and development). this study developed a research design according to [16] out of 10 stages of research design according to borg and gall, five stages used in this study. aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 43 research and information collecting planning develop preliminary form of product preliminary field testing main product revision figure 2. research stages steps developing lp software based on lectora inspire's problem-based learning model on pulse, impulse, and collision. research instrument the research tool consisted of the instrument of the validity of the learning program plan, consisting of the reliability and reliability of the product. the practical tool of the learning program plan consists of an observation sheet for learning and a student activity sheet. the tutorial's effectiveness tool consists of student and teacher questionnaires and completeness indicators. data collection techniques and data analysis techniques 1. the data collection techniques include documentation, observation, questionnaires and analysis of the validity and practicability of the lesson plan using aiken's v-formula for the calculation of the content. 2. the analysis of the effectiveness of the proposed learning implementation is to analyze the results of student and teacher responses based on the ngain-value criteria terms of participation for learning plans according to nieveen [24], the requirements for an educational product are assessed based on three criteria: validity, the effectiveness of the product and practicability of the product. the lesson plan with lectora inspire software can be used if the validity level is considered valid. the level of effectiveness and practicality are both used as lesson plan s used in classroom teaching and learning. iv. results and discussion collect research results and initial information the first phase of developing a lesson plan (lp) involves a needs analysis, literature reviews, and the formulation of a learning topic related to the lectora inspire software. the needs met in this study, namely the lack of use of computer applications to support teaching, are fueling teachers' interest in learning the latest software to help learners learn and implementing information technology (it) -based learning and implementation plans learning experts have validated that. a literature review recognizes the use of lectora inspire software as a lesson plan, particularly in terms of the material of impulses, impulses, and collisions. the formulation of the learning topic serves to identify the indicators of the material's necessary competences and to produce a video that will be used for student activities by the 2013 curriculum. planning result after analyzing the literature, the course of the lesson plan can be determined according to an essential part of the lp. lp according to permendikbud no. 22 of 2016 follows the syllabus of 2013. the preparation of the indicators must be consistent with the ministry of education and culture no. 24 of 2016 figure 3. phase lesson plan development scenario result of development the phase of developing the original form of the lesson plan, which created by the draft design that will be integrated into the lectora inspire software. validate lp, learn implementation plans in lectora inspire software, and preliminary and final test aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 44 questions (pretest and post-test). then make improvements as suggested by the validator. the design of lectora inspire software in the development of lp physics divided into several parts that contain the essence of an lp. starting from the home screen, menu, sub-curriculum, sub-lp and other lesson plan s in the form of student worksheet. figure 4. home screen display figure 5. display menu figure 6. display submenus syllabus figure 7. lesson plan display figure 8. fill sub-menu lesson plan: meeting 1 aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 45 the result of validation lesson plan the results of the validation of the lesson plan shown table 2 table 2. the results of the validation of the development planning of the learning implementation with lectora inspire no observed aspects first meeting ∑s aiken’s validati on second meeting ∑s aiken's validat e v1 v2 v3 v1 v2 v3 general format 1 distribution of the material by time location 4 4 5 10 0,83 4 4 5 10 0,83 2 numbering system 5 5 4 11 0,92 5 5 4 11 0,92 content 1 identity is loading 5 5 5 12 1,00 5 5 5 12 1,00 2 load core potential 5 5 5 12 1,00 5 5 5 12 1,00 3 basic compatibility is loading 5 5 5 12 1,00 5 5 5 12 1,00 4 charge indicator 5 4 5 11 0,92 5 4 5 11 0,92 5 load learning objectives 5 4 5 11 0,92 5 4 5 11 0,92 6 teaching material is being loaded 4 3 5 9 0,75 4 3 5 9 0,75 7 contains learning models / approaches / strategies / methods / techniques 5 5 5 12 1,00 5 5 5 12 1,00 8 learning activities are loaded 5 5 5 12 1,00 5 5 5 12 1,00 9 loading tools/topic/ learning resources 5 5 5 12 1,00 5 5 5 12 1,00 10 reviews are loading 5 3 5 10 0,83 5 3 5 10 0,83 learning activities 1 the first activity is to generate motivation and to draw the attention of the students to participate in the learning process actively. 4 4 4 9 0,75 4 4 4 9 0,75 2 the main activities are interactive, inspiring, entertaining, challenging and motivating to participate actively and provide sufficient space for initiative, creativity and independence according to students' talents, interests and physical and psychological development. 4 4 4 9 0,75 4 4 4 9 0,75 3 the core activities are systematically carried out through a process of exploration, preparation and validation 4 5 3 9 0,75 4 5 3 9 0,75 4 final activities reflect activities to end learning activities, create a summary or conclusion and assessment, and provide feedback and follow-up 5 4 4 10 0,83 5 4 5 11 0,92 learn conformity 1 the accuracy between indicators and basic competence 5 5 5 12 1,00 5 5 4 11 0,92 2 accuracy between indicators and learning goals 5 4 3 9 0,75 5 4 3 9 0,75 3 the correctness of the content/material according to the competency standards of the curriculum 2013 4 4 4 9 0,75 5 4 5 11 0,92 4 learning activities are formulated and use operative words so that they can be easily performed in the classroom during the learning process 5 4 4 10 0,83 5 4 5 11 0,92 5 learning steps after steps problem-based learning model 5 4 4 10 0,83 5 5 4 11 0,92 6 compliance with the learning steps of the scientific learning approach 5 5 5 12 1,00 5 4 5 11 0,92 7 agreement with the material order of each meeting 5 4 4 10 0,83 4 4 5 10 0,83 8 compliance with the time allocation used 4 4 4 9 0,75 5 5 4 11 0,92 9 the pbm model marks the suitability as lp. 5 5 5 12 1,00 4 5 4 10 0,83 language aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 46 no observed aspects first meeting ∑s aiken’s validati on second meeting ∑s aiken's validat e v1 v2 v3 v1 v2 v3 1 grammatical truth 4 5 4 10 0,83 4 5 3 9 0,75 2 the truth of the sentence structure 4 5 4 10 0,83 4 4 4 9 0,75 3 the language used is communicative 4 4 4 9 0,75 4 4 4 9 0,75 results 293 0,87 294 0,88 total 0,87 category very valid note : v1 = validator 1; v2 = validator 2; v3 = validator 3; ∑s = aiken total inspire the result of lesson plan assitet software lectora inspire table 3. the validation results of the lectora inspire software assisted learning plan no observed aspects v1 v2 ∑s aiken validity media quality 1 display 4 4 6 0,75 2 use of buttons 3 5 6 0,75 3 text type and size 5 3 6 0,75 4 colour composition 5 5 8 1,00 5 video / audio quality 4 3 5 0,63 6 ease of speech understanding 4 4 6 0,75 7 quality of interaction 4 3 5 0,63 8 attraction and motivation 5 5 8 1,00 9 cover design attracts users 5 4 7 0,88 the program 1 navigation 4 3 5 0,63 2 button consistency 3 3 4 0,50 3 clarity of the instructions for use 3 4 5 0,63 4 efficient screen usage 4 3 5 0,63 5 text efficiency 5 4 7 0,88 practicability 1 lp-assisted applications are easy to execute 5 3 6 0,75 2 digital lp can be set according to the user requirement 5 5 8 1,00 linguistic 1 the language used corresponds to the correct grammar 4 5 7 0,88 2 the sentences used in the text are easy to understand 4 5 7 0,88 final score 111 0,77 category valid note : v1 = validator 1; v2 = validator 2; ∑s = aiken total indicator validity completion result table 4. the results of the validation of the indicator mastery test no l content validity ∑s aiken validity validation of language and writing ∑s aiken validity v1 v2 v3 v1 v2 v3 1 2 5 3 7 0,47 3 5 4 9 0,75 2 3 5 4 9 0,60 4 5 4 10 0,83 3 4 5 4 10 0,67 4 5 4 10 0,83 4 4 5 5 11 0,73 4 5 5 11 0,92 5 5 5 5 12 0,80 4 5 5 11 0,92 6 2 5 4 8 0,53 3 5 4 9 0,75 7 2 5 4 8 0,53 3 5 4 9 0,75 8 2 5 5 9 0,60 3 5 5 10 0,83 final score 74 0,62 final score 79 0,82 category valid category very valid aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 47 indicator validity completion result table 5. data observations of student activities no observed aspects first meeting second meeting average category average category 1 introduction 0,94 vw 0,97 vw 2 problem orientation 0,94 vw 0,94 vw 3 organize students 0,78 w 0,84 vw 4 senior group examinations 0,78 w 0,88 vw 5 develop and present results 0,88 vw 0,88 vw 6 formulate conclusions 1,00 vw 0,94 vw 7 closing 0,96 vw 0,83 vw score 0,89 vw 0,89 sb final score 0,89 category vw note: w = well ; vw = very well the result os student response table 6. student response result no statement vw v we nw nvw percentage (%) category 5 4 3 2 1 1. learning activities with the lectora inspire softwaresupported problem based learning (pbl) model are fun. 17 10 0 0 0 92,59 vw 2. physics learning activities with the lectora inspire software-supported problem based learning (pbl) model are easy to follow. 16 8 3 0 0 89,63 vw 3. physical learning with the lectora inspire softwaresupported problem based learning (pbl) model helps me better understand the material, both conceptually and mathematically. 16 6 4 1 0 87,40 vw 4. i am interested in learning physics with the lectora inspire problem-based learning model (pbl) 14 12 1 0 0 89,63 vw 5. learning physics with the lectora inspire softwaresupported problem based learning (pbl) model encourages me to learn better than usual. 16 6 5 0 0 88,15 vw 6. with the problem based learning (pbm) model supported by lectora inspire software, i am actively involved in group learning in physics learning 14 9 4 0 0 87,41 vw 7. learning physics with the lectora inspire softwaresupported problem based learning (pbl) model must be used as students need to be more active in absorbing knowledge. 13 11 3 0 0 87,41 vw 8. the physical learning process with the lectora inspire software-supported problem based learning (pbl) model on impulse, momentum and collision material makes it easy for me to remember the material 12 14 1 0 0 88,15 vw 9. learning in small groups in physical learning with the problem based learning (pbm) model supported by lectora inspire software is better because it can discuss with group friends, exchange ideas and thoughts 16 11 0 0 0 91,85 vw 10. i think that after attending physics learning with the problem based learning model (pbl model) supported by lectora inspire software, there are advances in physics learning as there is a lot of learning experience 15 8 4 0 0 88,15 vw average 89,04 vw note : vw = very well; w = well; we= well enough; nwnot well; nvw= not very well aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 48 teacher response data on learning implementation lesson plan table 7. the results of teacher response no item value percentage (%) category 1 the lp (lesson plan ) problem based learning (pbl) model supported by lectora inspire software is easy to implement 4 80 well 2 supported by lectora inspire software, the lp (lesson plan ) problem based learning (pbl) model uses easy-to-understand language 5 100 very well 3 the problem modeled learning lp (lesson plan ) physics model, which is supported by lectora inspire software, can support it-based learning 5 100 well 4 the learning material in the lp problem based learning (pbl) model supported by lectora inspire software will be presented coherently 4 80 well 5 the presented material is material that included in necessary skills 5 100 very well 6 learning indicators correspond to the necessary competencies 5 100 very well 7 the presented material corresponds to the learning indicators 4 80 well 8 the lp component is displayed coherently and clearly 4 80 well 9 the language used in lp (lesson plan ) complies with the indonesian language rules 4 80 well 10 levels that listed in lp (lesson plan ) 5 100 very well 11 the sequence of learning activities according to the steps of the learning model of problem based learning (pbl) 5 100 very well 12 the sequence of learning activities according to the steps of the scientific approach 4 80 well 13 the specified time allocation is useful for performing various activities in lp 4 80 well 14 the lp problem based learning (pbl) model supported by lectora inspire software is easy to implement 5 100 very well 15 the lp problem based learning (pbl) model supported by lectora inspire software is constructive in preparing the learning process scenario. 4 80 very well average 88 very well student learning outcomes table 8. student learning outcomes no name pre test post test increased score category score kategori <g> score 1 atr 34 not complete 78 1 atr 34 2 afb 27 not complete 78 2 afb 27 3 abr 32 not complete 72 3 abr 32 4 aeng 34 not complete 83 4 aeng 34 5 ap 36 not complete 72 5 ap 36 6 aaps 60 not complete 83 6 aaps 60 7 fi 27 not complete 83 7 fi 27 8 ff 32 not complete 78 8 ff 32 9 law 32 not complete 69 9 law 32 10 mda 50 not complete 69 10 mda 50 11 mfd 48 not complete 83 11 mfd 48 12 min 32 not complete 76 12 min 32 13 mi 34 not complete 67 13 mi 34 14 nks 30 not complete 75 14 nks 30 15 nap 48 not complete 83 15 nap 48 16 nf 45 not complete 75 16 nf 45 17 nsfa 32 not complete 83 17 nsfa 32 18 n 38 not complete 81 18 n 38 19 n 48 not complete 79 19 n 48 20 n 48 not complete 67 20 n 48 21 rsr 42 not complete 76 21 rsr 42 22 saj 34 not complete 77 22 saj 34 23 ui 45 not complete 75 23 ui 45 24 wa 50 not complete 83 24 wa 50 aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 49 no name pre test post test increased score category score kategori <g> score 25 woid 36 not complete 83 25 woid 36 26 y 27 not complete 74 26 y 27 27 yzk 45 not complete 76 27 yzk 45 average 38,7 not complete 76,9 complete average 38,7 figure 10. the results of student work on the topic being taught learn implementation data table 9. the results of learning implementation no observed aspects first meeting second meeting score category score category 1 preparations 0,89 vw 0,93 vw 2 problem orientation 0,91 vw 0,91 vw 3 organize students 1,00 vw 1,00 vw 4 senior group examinations 0,93 vw 1,00 vw 5 develop and present results 0,75 w 1,00 vw 6 formulate conclusions 0,83 vw 0,87 vw 7 closing 0,83 vw 0,87 vw score 0,89 vw 0,93 sw total score 0,91 sw note: vw = very well, w=well based on observations from preliminary activities, content activities marked by problembased learning steps, and closing activities, the total value of the first meeting was 0.89, which was very good categorized, and the total value of the second meeting was 0.93 which was very well categorized. when the total meeting calculated, the result is 0.91, which is very well categorized. the lesson plan (lp) is a plan for personal learning activities for one or more meetings. the lesson plan has been developed from the syllabus to guide students' learning activities and achieve basic competency (bc). lp uses lectora inspire software to improve students' learning outcomes in the classroom and to assist teachers with teaching and learning activities in the classroom. the evaluation or critical to the success of this product will be the work of students aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 50 assessed in terms of the validity, effectiveness and practicability of the lectora inspire-supported lesson plan. lp validation with a problem-based learning model supported by lectora inspire software on momentum, impulse, and impact topic at the shs / islamic senior high school level in the product validation phase, the experts are executed in this case to obtain validation results. the result of the validation is expert considerations on the developed learning products. the validation technique used by experts to make corrections to the learning product is then repaired or revised in the lp and then. three types of validation are performed, namely lp validation by education experts, lp validation by media experts (it experts), and validation of the indicator completeness test. based on observations from preliminary activities, content activities marked by pbm's steps, and closing activities, the total value of the first meeting was 0.89, which was very good categorized, and the total value of the second meeting was 0.93 which was very well categorized. when the total meeting calculated, the result is 0.91, which is very well categorized. the lesson plan (lp) is a plan for personal learning activities for one or more meetings. the lesson plan has been developed from the syllabus to guide students' learning activities and achieve basic competency (bc). lp uses lectora inspire software to improve students' learning outcomes in the classroom and to assist teachers with teaching and learning activities in the classroom. the evaluation or critical to the success of this product will be assessed in terms of the validity, effectiveness and practicability of the lectora inspire-supported lesson plan. lp validation with a problem-based learning model supported by lectora inspire software on momentum, impulse, and impact topic at the shs / islamic senior high school level in the product validation phase, the experts are executed in this case to obtain validation results. the result of the validation is expert considerations on the developed learning products. the validation technique used by experts to make corrections to the learning product is then repaired or revised in the lp and then. three types of validation are performed, namely lp validation by education experts, lp validation by media experts (it experts), and validation of the indicator completeness test. lp validation by education experts this lp validation is performed to obtain a valid lp based on several learning education experts. the researchers validated three education experts. based on table 2, aspects of the assessment include the general format of the lesson plan, the content, the learning activities, the learning skills, and the language of the lesson plan (lp). according to the table, validation of the results at the lp of the first meeting has a total value of 0.87 for each sub-aspect evaluation and a total value of 0.88 lp of the second meeting. it allows the validation results to be retrieved at the first meeting in the very valid category and the second meeting in the very valid category. the total score obtained is based on the results of 0.87 in the very valid category, so that several education experts have confirmed that the lp has a degree of validity that can be used in teaching and learning in schools. in addition, there are several expert suggestions in table 5, which then repaired or revised. validation of lp products by media experts the validation of the lp by media experts focuses on the completeness and presentation of the lp in the media supported by lectora inspire software (lis). it to help the teacher present and explain the purpose of learning for the students in the class. during the validation phase of this lp, the validator evaluates the entire lp product in the lectora inspire software. based on table 3, validation evaluations by media experts include the quality of lp media, programs, practicability, and language in sli-supported media. the results of the validation show the number 0.77 so that it falls into the correct category. although validated by both validators in the field of media professionals. however, there are some constructive suggestions from media experts, which can be seen in table 6, which revised before being tested in schools. validity check for completeness of the indicator the indicator completeness test is a tool to find out how students can understand each indicator. the test used is an initial test (pre-test) and a final test (post-test) to obtain information about the students' learning outcomes before and after learning. based on table 4.4, the rating or validation assessed by content, language and script. the result of the validation is 0.62 for content validation, so it is considered valid, and 0.82 for language validation and writing is considered very aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 51 valid. however, there are some suggestions from the validator that listed in table 4.7. it will be revised to refine further the concepts that students receive through learning indicators, particularly in terms of topic momentum, impulses, and collisions. the practicality of lp with the problem-based learning model for momentum, impulse and impact material supported by lectora inspire software at the shs / islamic senior high school level. the practical test of the lesson plan, which examined from a variety of perspectives, namely the observation of the learning implementation and the observation of the students' activities in the teaching and learning process. based on the results of tests conducted on 27 xi ipa 6 students from senior high school 2 kendari, the lectora inspiresupported learning plan can be used in the classroom. it is evident from the observation of the learning implementation and observation of student activities, which divided into seven sections: introduction, content according to problem based learning (pbl) consists of problem orientation, organizing the students, conducting the group inquiry, developing and presenting the results, and formulating conclusions and complete. according to 2 teachers from senior high school 2 kendari, the total score at the first and second meetings was 0.89 or could be considered very good. in addition, there is a final total score of 0.91 for the observation of student activities, or it can be very well categorized. the effectiveness of lp with the problem-based learning model in the field of pulses, impulses and collisions at the shs / ishs level supported by lectora inspire software. in addition, an efficacy test is performed to evaluate the development of a good lp product. the product effectiveness test will provide information on the effectiveness of product development when applied in the field learning process. the efficacy test in this study covers students 'and teachers' answers in the form of student questionnaires and learning outcomes for the learning process. the effectiveness of a product based on students' reactions to the implementation of classroom learning. from the results of the survey of students, consisting of 10 statements selected by 27 students. thus, the results obtained with each point are 92.59%, 89.63%, 87.40%, 89.63%, 88.15%, 87.41%, 87.41%, 88.15%, 91, 85% and 88.15% with an average of 89.04%, which are overall in the very good category. as for the reaction of teachers who perform or implement lp products. based on data from 15 statements, the average score is 88% or can be very well categorized. to assess the success of the learning outcomes an initial test (pre-test) and a final test (post-test) performed and an assessment of the improvement (profit analysis) of the results of each student made. although the subject matter of the study conducted for class xi students who received the material in class x, the first test generally yielded a full student of all students, with an average overall score of 38.7 students. the resulting average is still below the standard completeness score of 75 for physics subjects after learning for two sessions about material impulse, impulses and collisions. the final test is then performed to determine student development after learning. at the end test, students scored a total of 25 students out of 27 students, with an overall score of 76.9. student learning outcomes averaged a gain of 0.62, which can be considered moderate. based on the research findings, lectora inspire is an active program for creating lesson plan s and electronic learning development software (elearning) that is relatively easy to apply or can be applied because it does not require a sophisticated understanding of the programming languages. this software can also create implementation plans for learning in the form of e-lesson plans that can publish on the internet. using lectora inspire makes the theme as attractive as possible, it can display videos and animated images on the subject, and the teacher can create test material in it. the learning process becomes more entertaining and meaningful, improving students' learning performance. in general, students feel motivated to learn after seeing the learning steps structured in the lectora inspire software-supported lesson plan. through appropriate videos on the learning topic, students are more interested in learning than just reading in printed books and articles. the activities carried out to strengthen the understanding of the material impulse, the impulses, and the collisions. v. conclusion based on the description that has been described, the following conclusions can be drawn: (1). the implementation plan of lectora inspire software learning on the subject matter of momentum, impulses and collisions that have developed has gone through several stages of validity testing. a decision obtained that the lesson plan assisted by lectora inspire software that developed was valid to be used. (2) the lectora inspire software rocky aswal et al. development of lesson plan (lp) with software lectora inspire assisted… indonesian review of physics, volume 2, number 2, 2019 52 learning implementation plan on the subject matter of momentum, impulses and collisions has carried out practical tests by observing the implementation of learning and observing the activities of students, which are categorized very well. 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[24] n. nieveen, “prototyping to reach product quality,” in design approaches and tools in education and training, dordrecht: springer netherlands, 1999, pp. 125–135. indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 66–73 doi: 10.12928/irip.v3i2.3066 http://journal2.uad.ac.id/index.php/irip 66 tunnelling effect for quadruples potential using matrix propagation method chilwatun nasiroh*, bambang supriadi, and rif’ati dina handayani physics education department, university of jember jl. kalimantan no.37, krajan timur, sumbersari, jember, indonesia *email: chilwatunnasiroh25@gmail.com article info abstract article history received nov 5, 2020 accepted nov 28, 2020 published dec 31, 2020 semiconductor materials can be used as potential barriers to tunnelling effects. in this study, four semiconductor materials are arranged in various ways to form a quadruple potential structure to analyze the value of the transmission coefficient. the analysis was conducted using the analytical and numerical matrix propagation method using matlab2018a. the results confirmed that the inverted arrangement produces the same transmission coefficient value for each energy. so that there are 12 kinds of transmission coefficient values generated from 24 arrangements. the semiconductor material composition with the most considerable transmission coefficient value is adcb and bcda, which have a value of 0.8087. the variation of the arrangement affects the value of the transmission coefficient so that it can be used as a guideline for selecting the arrangement that produces the most optimum value of the transmission coefficient from various possible arrangements. keywords: transmission coefficient tunneling effect semiconductor to cite this article: c. nasiroh, b. supriadi, and r. d. handayani, “tunnelling effect for quadruples potential using matrix propagation method,” indones. rev. phys., vol. 3, no. 2, pp. 66–73, 2020. i. introduction previously, scientists believed that all the natural phenomena could be solved using newtonian mechanics and maxwell electromagnetics. until the end of the 19th century, the belief that classical physics could explain all natural phenomena began to diminish when scientists discovered several new phenomena that could not be explained by classical physics concepts. this phenomenon mainly appears in microscopic physical objects such as elementary and atomic particles [1]. one of the interesting phenomena in quantum mechanics is the tunnelling effect. the tunnelling effect occurs when the particles pass through a barrier with an energy higher than the particles' energy. according to classical mechanics, particles with energy that propagate to the right and encounter a potential, then particles will be reflected the left [1]. nevertheless, quantum mechanics believe that particles can pass through barriers. the ability of particles to penetrate this barrier is due to the wave's nature, which plays a more critical role than the nature of particles [2]. particles have the probability of being able to break through a barrier even though the energy is less than the energy of the barrier. the magnitude of this probability is called the transmission coefficient [2]. the transmission coefficient can be analyzed using several methods, namely the variable separation method in the schrodinger equation, the propagation matrix, and the wkb (wentzel-kramers-brillouin). in this study, the transmission coefficient will be analyzed using the matrix propagation method because it is easy to use in cases with a relatively large number of obstructions. abdulhalim's research on some layered structures' optical properties shows that the analytical expression derived from the matrix propagation method is more comfortable to apply than using direct computation [3]. the use of the matrix propagation method is divided into three main steps: first, calculating the propagation matrix to transmit a particle's wave function with energy moving towards a single potential barrier. second, compute the propagation matrix for the wave function between potential steps. third, calculate the barrier's total propagation by multiplying each propagation of each potential [4]. the transmittance of electrons through potential barriers is a research topic that has caught by many researchers'. martinz and ramos [5] determine the transmission coefficient's value analytically and numerically on the potential triple barrier with two potential wells. research on the potential triple barrier of gan, sic, and gaas materials by supriadi has a maximum transmission coefficient value of 0.819 [6], and prastowo's research [7] on the potential triple barrier of graphene material obtained a resonance phenomenon with the most considerable transmission coefficient value is 1.0000 at an energy of 0.9200 ev. research on the effects of breakthroughs has contributed to developing electronic devices on the nanometer scale with increasingly impressive performance. electronic devices use semiconductor materials as their main components. each semiconductor material has characteristics of the size of the potential barrier or energy gap. the research aims to determine the transmission coefficient's value of semiconductor materials of gaas, gasb, alas, and inp that arranged c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 67 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 with several variations to form a quadruple potential barrier structure. ii. theory waves of particles maxwell's theory of light as a wave and electromagnetic theory flourished well into the late 19th century. however, einstein in 1905 rejected the theory based on the phenomenon of the photoelectric effect. according to einstein, light must be seen as a quantum particle called the photon. the energy of the photon is , and momentum is (1) this momentum characterizes the particle properties of light [8]. in 1924, louis de broglie proposed the hypothesis that particles have waves. a particle with momentum has a wavelength called the de broglie wavelength, (2) the wave package fills a quantity capable of accommodating and representing the particles' and the wave's properties. the wave package is approached by combining two plane waves so that the wave function can be represented as follows: (3) n is the normalization constant [9]. schrodinger's equation erwin schrodinger introduced the equation in 1926 to discuss particle waves' description in the atomic dimension that meets physics's principles and laws [1]. the form of the schrodinger equation is a second-order partial differential equation. solving the schrodinger equation is by applying the variable separation method to get the solution. the schrodinger equation must obey the law of energy conservation since the total energythe kinetic energy and the potential energy of a particle is conserved. besides, the schrodinger equation must comply with de broglie's postulate; the mathematical solution for a particle with momentum must be in the form of a wave function with the same wavelength as . solving the schrodinger equation must provide information about the probability of finding the particle that must exist in space. the wave function must be single and finite; otherwise, a particle's existence would be more than one possibility. the wave function must be continuous; it can be interpreted as a breakdown of the particles not to be accepted. the wave function's derivative concerning the position must also be continuous because it is related to the electron's momentum. the indicator of the nature of a well-behaved wave must have a wave superposition characteristic [10]. (4) tunnelling effect the tunnelling effect is a phenomenon in quantum physics when energetic particles pass through a potential region of a barrier on condition (figure 1). figure 1. single potential barrier model ( ) in region i (x < 0), the particles act as free particles because they are not affected by any forces . the schrodinger equation can be written: or with the equation has a solution: (5) figure 1 represented that the free particle moves from left to right when the particle enters the area, the particle encounters a potential equal to , so the schrodinger equation can be written: or c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 68 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 with since so, it can be written or ; . the equation above has a solution: (6) when the particle manages to break through , the particle returns to a free particle so that the schrodinger equation can be written: or with it appears that the wavenumber of the particle returns to its original state and has a solution: (7) the transmission coefficient can be defined as the probability that a particle can break through a potential barrier. the equation that can be used to obtain the value of the transmission coefficient on the breakthrough effect is: (8) since the region i and iii are the same, that is , so and . with a mathematical solution using the elimination and substitution method, it is obtained: (9) matrix propagation method the matrix propagation method is the spread or transmission of a wave using a matrix. the work with the matrix propagation method is divided into four parts, as ilustrated in the figure 2 [4]. figure 2. matrix propagation method first part: calculate the propagation matrix for transmission and reflection and the wave function representing an energized particle entering a ladder potential. the potential ladder in question is in the position in figure 2. in the area , the particles have a wave number and a wave function (10) (11) applying boundary conditions in the area and , at matrix equation can be written (12) this equation can be reduced to (13) are a two × two matrices describing the wave propagation at the ladder potential , with the value ie (14) second part: calculate the propagation matrix for the propagation of the wave function between two ladder potentials. the propagation in question is between and . in figure 2, the width of this propagation is c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 69 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 . the propagation between the potential ladder with the potential width carries information about the phase so that it is in the form of a matrix i.e. (15) the propagation of the matrix over the area consists of free area propagation and ladder propagation. (16) and with this symmetry, it can be written (17) the fourth part: calculate the total propagation matrix for the total ladder potential by multiplying all the propagations of each potential area i.e. (18) when particles come from the left, then and if no particles are reflected from the right then . (19) semiconductors as potential barriers a semiconductor is a material with electrical conductivity between the insulator and the conductor [11]. there is an empty area between the valence band and the conduction band called the bandgap energy in semiconductor materials. if the electrons in the semiconductor material have a high enough energy, they can jump from the valence band to the conduction band through the energy gap or forbidden band. these electrons leave an empty quantum state in the valence band called holes. the motion of electrons and holes in semiconductor materials is the same as free particles' motion [12]. every semiconductor material has a different energy gap at a specific temperature [13]. in this research, the semiconductor material used is a type of iiiv semiconductor alloy. the semiconductor materials include gaas, gasb, alas, and inp. gaas is a material with great potential for electronic and optoelectronic device applications because of its high electron mobility. gaas is typically used for laser diodes and high-speed transistors. gaas has an energy bandgap structure with a direct transition (direct bandgap) of 1.424 ev with a width of 0.565 nm [14]. gasb is an iii-v semiconductor alloy with a direct bandgap with an energy band gap of 0.721 ev at room temperature [15] with a width of 0.610 nm [16]. antimony-based alloy semiconductors have relatively high carrier mobility properties. with these properties, this material is interesting to be applied in electronic and optoelectronic devices such as lasers, infrared detectors, magnetic sensors, and high-speed switching devices [17]. alas is an iii-v semiconductor alloy that is widely applied to optoelectronic devices such as laser diodes. alas has a reasonably large energy bandgap of about 2.95 ev [16] with a width of 0.566 nm [18]. alas has less induced voltage, allowing high-performance electrons high mobility so that alas can also be applied to hemt (high electron mobility transistor) transistors [19]. inp is an iii-v semiconductor alloy. inp has high electron mobility, so it is widely used for high-powered and high-frequency electronic devices such as pseudomorphic heterojunction bipolar transistors operating at 604 ghz. inp has a lattice constant of 0.587 nm and a direct energy bandgap of 1.29 ev, so it can also be applied to optoelectronic devices such as laser diodes [20]. iii. method the semiconductor materials used as a potential barrier are gallium arsenide (gaas), gallium antimonide (gasb), aluminum arsenide (alas), and indium phosphide (inp), each of which has a potential energy of 0.721 ev, 1.424 ev, 2.95 ev, and 1.29 ev. the quantum particle such as an electron tries to pass through the potential barrier with energies in the range ev. the potential barriers are separated from each other by a gap of 1 nm width. the mathematical method used to determine the transmission coefficient is the matrix propagation method. the matrix propagation method is the spread or transmission of a wave using a matrix. the analytical calculates the free particles' transmission coefficient when experiencing a breakthrough effect using the matrix propagation method. in comparison, numerical is carried c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 70 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 out by applying the matrix propagation method to the matlab2018a software. in the matrix propagation method, the potential area is divided into two parts: the ladder propagation ( ) and the free propagation ( ). is the propagation in the area of potential change. meanwhile, it is propagation in areas with a constant potential. the ladder propagation is divided into step up propagation and step down propagation. propagation at the boundary from to is called step-up propagation ( ). propagation at the boundary from towards is called step-down propagation ( ). the free propagation ( ) is also divided into two as well as figure 3. quadruple potential barrier the solution to the schrodinger equation for the potential change in the quadruple barrier from figure 3 is: (20) (21) (22) (23) (24) (25) (26) (27) (28) the propagation of the quadruple potential barrier consists of four steps up propagations, four free propagations, three propagations in the gap between the step-up potential, and four steps down propagations with the values: (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) so that the propagation of each barrier and each gap can be written: therefore, the calculation of the matrix propagation over the quadruple potential barrier is: (44) the variation of the breakthrough effect results from organizing the arrangement of the semiconductor material as a barrier. the quadruple barrier has a different arrangement or . to simplify the analysis, the semiconductor material alas is denoted a, gaas is denoted b, gasb is denoted c, and inp is denoted d. the arrangements formed are as figure 4. c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 71 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 figure 4. arrangement variations iv. results and discussion the transmission coefficient is analyzed due to variations in the barrier's potential arrangement. the occurrence of the tunnelling effect is highly dependent on the width and height of the barrier. in this study, the barrier's width was reasonably uniform, ranging from 0.565 to 0.610 nm. meanwhile, the height of the barrier used was varied, namely three obstacles with a reasonably uniform height (b, c, and d) and other potential barriers, much higher than the other obstacles (a). these four barriers are the iii-v semiconductor alloy. the barrier selection is based on its application, which is widely applied as electronic and optoelectronic devices. the tunnelling effect happens when a particle breaks through a potential barrier that classical physics cannot occur. electrons are represented by the wave function in each potential region. the wave functions that represent electrons have different shapes in the regions and . in the area, the wave function in the complex exponential form with value is imaginary . however, when the electron is in the potential region , the wave function is exponential, and the value is real . this happens because, in the region , electrons have material properties. according to de broglie's postulate, when the electrons break through the barrier, the particle properties will change to wave properties. electrons moving from the left direction are free particles that are not affected by potential, so they have momentum as considerable as the electrons move towards the first barrier. when an electron encounters a potential region , it will experience a change in momentum is being the order of the barrier potential . electrons that successfully break through the potential barrier will accelerate until their momentum returns to their value . after passing the last barrier, the transmittance or the number of electrons that have successfully penetrated the four barriers indicated by the transmission coefficient's value can be analyzed. the use of the matrix propagation method analytically results in the formulation of the transmission coefficient on the tunnelling effect of the quadruple potential barrier, namely with (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) the use of the matrix propagation method in determining electrons' transmittance is beneficial for many barrier structures because the calculation is sufficient with matrix multiplication and a little mathematical manipulation. the transmission coefficient is the probability of the particle breaking through a potential barrier . the tunnelling effect variation is intended to arrange the semiconductor material to form a quadruple potential barrier with different barriers. the barrier is the potential energy of the area that blocks particles' motion when trying to breakthrough. table 1 showed the transmission coefficient value using matlab2018a. c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 72 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 1. the transmission coefficient of the quadruple potential barrier e (ev) t abcd abdc acbd acdb adbc adcb 0 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1 0.0001 0.0001 0.0000 0.0000 0.0000 0.0000 0.25 0.0000 0.0007 0.0008 0.0008 0.0007 0.0008 0.5 0.2551 0.0607 0.6035 0.7695 0.0618 0.3000 0.506 0.2502 0.0681 0.7100 0.8054 0.0697 0.2837 0.518 0.2284 0.0851 0.8009 0.7082 0.0885 0.2434 0.733 0.1205 0.3232 0.1669 0.1539 0.3613 0.1200 0.75 0.1301 0.3317 0.1760 0.1644 0.3650 0.1303 0.76 0.1368 0.3376 0.1825 0.1718 0.3683 0.1375 1 0.7711 0.5466 0.5058 0.5547 0.5064 0.8087 bacd badc bcad bcda bdac bdca 0 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1 0.0001 0.0001 0.0001 0.0000 0.0001 0.0000 0.25 0.0007 0.0007 0.0007 0.0008 0.0006 0.0008 0.5 0.0980 0.0274 0.0981 0.3000 0.0290 0.7695 0.506 0.1120 0.0299 0.1132 0.2837 0.0321 0.8054 0.518 0.1442 0.0357 0.1496 0.2434 0.0396 0.7082 0.733 0.1831 0.2981 0.2021 0.1200 0.6991 0.1539 0.75 0.1849 0.3208 0.2023 0.1303 0.6904 0.1644 0.76 0.1870 0.3341 0.2035 0.1375 0.6794 0.1718 1 0.4404 0.7329 0.4267 0.8087 0.5026 0.5547 cabd cadb cbad cbda cdab cdba 0 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.25 0.0006 0.0006 0.0007 0.0007 0.0007 0.0007 0.5 0.0264 0.0290 0.0251 0.0618 0.0274 0.0607 0.506 0.0291 0.0321 0.0274 0.0697 0.0299 0.0681 0.518 0.0355 0.0396 0.0326 0.0885 0.0357 0.0851 0.733 0.6592 0.6991 0.3244 0.3613 0.2981 0.3232 0.75 0.6777 0.6904 0.3532 0.3650 0.3208 0.3317 0.76 0.6805 0.6794 0.3697 0.3683 0.3341 0.3376 1 0.5467 0.5026 0.7575 0.5064 0.7329 0.5466 dabc dacb dbac dbca dcab dcba 0 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1 0.0001 0.0001 0.0001 0.0000 0.0001 0.0000 0.25 0.0007 0.0007 0.0006 0.0008 0.0007 0.0003 0.5 0.0251 0.0981 0.0264 0.6035 0.0980 0.2551 0.506 0.0274 0.1132 0.0291 0.7100 0.1120 0.2502 0.518 0.0326 0.1496 0.0355 0.8009 0.1442 0.2284 0.733 0.3244 0.2021 0.6592 0.1669 0.1831 0.1205 0.75 0.3532 0.2023 0.6777 0.1760 0.1849 0.1301 0.76 0.3697 0.2035 0.6805 0.1825 0.1870 0.1368 1 0.7575 0.4267 0.5467 0.5058 0.4404 0.7711 the results show that the inverted arrangement produces the same transmission coefficient value for each energy. there are 12 kinds of transmission coefficient values generated from 24 arrangements. even though the 24 arrays consist of the same four semiconductor materials, it turns out that different arrangements produce different transmission coefficient values, except for the reverse arrangement, which results in the same transmission coefficient value for each energy. it can be observed in table 1 that an arrangement that has identical transmission coefficients are abcd with dcba, cdba with abdc, etc. based on table 1, it can be analyzed that the increase of the electron energy resulting in increased electron transmittance. the simulation results show that the transmission coefficient increases with increasing electron energy until it reaches the maximum value but decreases. this decrease occurs because the transmission coefficient's essential function is hyperbolic trigonometry, which causes the transmission coefficient to be periodic. at some point, the value will reach a maximum, then drop to a minimum, and rise again. according to the figure 5, the composition of semiconductor materials with the most considerable transmission coefficient value is adcb and bcda, valued at 0.8087. this means that 80.87% of the electrons can pass through the potential barrier. the arrangement of adcb and bcda has a reasonably large coefficient value than other arrangements because the three potential barriers whose potential heights are quite symmetrical are close together. this arrangement of the barrier causes a resonance so that the probability of the electron passing is high. however, this probability cannot reach the maximum because the electrons have to return through the potentially high barrier. from the figure 6, the smallest transmission coefficient value generated by the bcad and dacb arrangements is 0.4267. this means that only 42.67% of the electrons can pass through the potential barrier. in this arrangement, the symmetrical potential barrier is separated by one barrier, which has enormous potential. furthermore, the adjacent barrier is not symmetrical enough so that the resonance phenomenon that occurs cannot be maximized. therefore, it can be analyzed that one potential barrier affects another potential barrier. the variation of the arrangement affects the value of the transmission coefficient so that it can be used as a guideline for selecting the arrangement that produces the most optimum value of the transmission coefficient from various possible arrangements. figure 5. adcb arrangement that produces the maximum transmission coefficient value figure 6. bcad arrangement that produces the minimum transmission coefficient value c. nasiroh, et al. / indonesian review of physics 3(2), 2020, 66-73 73 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 v. conclusion the transmission coefficient of the quadruple potential barrier using the matrix propagation method can be formulated as follows. the variation of the tunnelling effect on the quadruple barrier potential is as many as 24 arrays. the research shows that 24 potential arrangements of the quadruple barrier produce 12 variations in the value of the transmission coefficient, with the reverse arrangement resulting in the same transmission coefficient value for each energy. the semiconductor material composition with the enormous transmission coefficient value is adcb and bcda, which have a value of 0.8087. moreover, the smallest transmission coefficient value generated by the bcad and dacb arrangement is a value of 0.4267. this variation of the breakthrough effect occurs because one potential barrier affects another potential barrier. vi. acknowledgment we gratefully acknowledge the research group of department physics education from fkip-university of jember. references [1] r. a. sani, m. kadri, quantum physics. jakarta: bumi aksara, 2016. [2] r. m. eisenberg and r. resnick, quantum physics of atoms, molecules, solids, nuclei and particles. new york: john wiley & sons, 1985. [3] i. abdulhalim, "analytic propagation matrix method for anisotropic magneto-optic layered media," j. opt. a pure appl. opt., vol. 2, no. 6, pp. 557–564, 2000. [4] a. f. j. levi and w. r. frensley, applied quantum mechanics. cambridge: cambridge university press, 2003. [5] s. d. g. martinz and r. v. ramos, "double quantum well triple barrier structures: analytical and numerical results," can. j. phys., vol. 94, no. 11, pp. 1180–1188, 2016. [6] b. supriadi, z. r. ridlo, yushardi, c. i. w. nugroho, j. arsanti, and s. septiana, "tunnelling effect on triple potential barriers gan, sic and gaas," j. phys. conf. ser., vol. 1211, no. 1, 2019. 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[20] a. mikrajuddin, nanomaterial characterization. bandung: cv rezeki putera, 2010. indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.4, no.1, june 2021, pp. 1 7 doi: 10.12928/irip.v4i1.3052 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 1 implementation of learning cycle’s model based on scl (student-centered learning) to improve students’ creative thinking ability in learning evaluation subjects at universitas almuslim fatimah*, m. taufiq department of physics education, faculty of teacher training and education, universitas almuslim, indonesia email: icut.unimus88@gmail.com article info abstract article history received: nov 04, 2020 revised: dec 24, 2020 accepted: feb 17, 2021 the main problems in conducting this research include 1) the ability of the students to analyze the question was less creative in answering; 2) the students learning activities were still low; 3) the students’ interest and response were still low in the instruction. those problems that had an impact on the instruction were not a success as individual and classical. therefore, we need an innovative instruction model in enhancing the learning and teaching process, such as; sclbased learning cycle model. this research was classroom action research (car) which consisted of planning, acting, observing, and reflecting. this research was the students in the fifth semester in the physics education department that consisted of 21 students. based on the research results, it was concluded that the implementation of learning cycle 5e through scl-based had improved students’ creative thinking skills, lecturer’s and students’ activities in the teaching and learning process. this is an open-access article under the cc–by-sa license. keywords: classroom action research creative thinking skill learning cycle student-centered learning to cite this article: fatimah and m. taufiq, “implementation of learning cycle’s model based on scl (student-centered learning) to improve students’ creative thinking ability in learning evaluation subjects at universitas almuslim,” indones. rev. phys., vol. 4, no. 1, pp. 1–7, 2021, doi: 10.12928/irip.v4i1.3052. i. introduction in improving the quality of education, teachers and schools have a significant role in determining the quality of education. increasing the quality of education is generally seen from the success of teachers and schools in producing high-achieving graduates. in this case, the teacher has made many changes in schools' implementation, especially in designing learning based on the revised 2013 curriculum. besides, teachers are active in improving work professionalism through various activities such as increasing teacher competence, certification, mgmp activities, workshops, and other activities to support their professionalism [1], [2]. this is following government regulation number 19 of 2005, which mandates that instructors possess a high degree of competence in the four competencies of an educator, namely pedagogical, personal, professional, and social competencies [1]. however, these various efforts have not fully yielded maximum results. at a lower level in maximizing teacher quality, universities must produce teacher candidates with qualified competencies to become competent and professional teachers in the work environment later [3]. in this case, lecturers are obliged to improve the competence of their students, one of which is through lecturing activities in class. students can obtain the best possible course material in lectures to enhance their quality as competent teacher candidates. many children are challenged with challenges that require higher-order thinking skills (hots) to answer at a higher level of education than at the school level. critical thinking skills, creative thinking skills, communication skills, and collaboration are hots [4]. in this case, many students have not used higher-order thinking skills in solving problems encountered in lectures. this is because students are still accustomed to solving problems given by the lecturer using only low thinking skills. these student habits cause students to be less creative in analyzing http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& http://journal2.uad.ac.id/index.php/irip/article/view/3052 http://journal2.uad.ac.id/index.php/irip http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 1 7 2 fatimah, et al. implementation of learning cycle’s model based on scl …. p-issn: 2621-3761 e-issn: 2621-2889 questions and providing answers to the issues presented by the lecturer. on the other hand, improper class management also causes students to be passive in lectures, resulting in low students’ creative thinking skills. lectures are conducted monotone and are still teacher-centered. students tend to be more passive in learning in class management, resulting in low student interest and learning activities in education. for this reason, it is necessary to apply a classroom management method that can increase student learning activities so that students are more experienced in learning independently through teacher direction and guidance. learning in question is learning that is student-centered learning (scl). according to lee and hannafin, student-centered learning (scl) defines students as the proprietors of their learning [5]. furthermore, kaput explains that centered learning effectively increases student activity in learning. scl effectively creates a learning environment where students feel ownership of their learning [6]. studentcentered learning provides students with more learning opportunities and reconstructs the information dynamically [5]. in this study, researchers tried to apply the 5e learning cycle model based on student-centered learning (scl) to develop more innovative learning. the student-centered learning (scl) 5e learning cycle model can provide opportunities for students to build knowledge independently with teacher guidance and direction through several stages such as engagement, exploration, explanation, elaboration, and evaluation [7], [8]. this activity hopes that it can solve developing education in a better direction to improve the quality of indonesian education in general. ii. theory learning cycle the learning cycle model is a set of phases designed to support students in mastering their skills. the first three aspects of the learning cycle are exploration, introduction, and application of concepts. before the exploration stage, the engagement stage is introduced. at the end of the cycle, the evaluation phase is introduced [9]. in this model, explaining and elaborating are called the stage of concept introduction and concept application. therefore, the 5phase learning cycle is often called the 5e learning cycle for engagement, exploration, explanation, elaboration, and evaluation [7]–[11]. the engagement stage aims to prepare students to take the next step by exploring their actual knowledge and ideas and discovering potential misunderstandings in prior learning. the engagement phase is the initial phase. at this early stage, it allows students to be involved in learning tasks [8]. we can determine students’ understanding of this engagement phase as their initial knowledge [12]. students mentally focus on a problem, situation, or event. the activities of this phase must be linked to the learning activities of the previous and present meetings [11]. this phase can also be used to identify student misconceptions. this engagement phase can be shown in demonstrations, questions, graphics, events, or phenomena [12]. second, students form small groups of 2-4 students during the exploration stage. they can work in small groups without learning directly from the teacher [8], [10]. students are given direct experience through group learning before explaining the subject matter. this can be done by observing, questioning, investigating, testing predictions, hypothesizing, and communicating among group members [12]. students can explore their understanding of the material being studied [11], [13]. this phase is an opportunity for students to test their hypotheses or predictions, discuss them with a group of friends, and make decisions [14]. the next stage is the explanation stage. students must explain a concept with their sentences/thoughts [7], [12]. teachers also asked for clarification on the evidence and explanations of students. besides, at this stage, the teachers and students hear each other explain the concept being studied. with this discussion, the teacher offers a definition and explanation of the concepts discussed by the preceding students [9]. the elaboration phase is the fourth phase of the learning cycle model. in elaboration, students apply the concepts and skills learned in new situations or contexts. this stage can also be carried out through additional investigative activities such as giving practice questions to students [12]. as a result, pupils will learn more effectively by applying what they have learned in new settings. student learning motivation can indeed stimulate increased student learning outcomes if the teacher correctly designs this stage [8], [12], [15]. the last stage is evaluation. at this stage, the teacher is tasked with observing students’ knowledge and skills in applying concepts and changing students’ thinking [8]. at this stage, too, the teacher can give tests to students in the form of homework, quizzes, exams, or assignments [12]. student-centered learning (scl) student-centered learning is one of the references for developing a learning approach in the classroom [14]. in this case, the lecturer is more of a guide and director. students are allowed to study independently through lecturer guidance and guidance. scl places students as active and independent subjects/learners, fully responsible for their learning. this student-centered learning process will make it possible for students, in turn, to gain a profound understanding and improve the quality of their knowledge [16]. students should be encouraged to motivate themselves and work towards the desired competence under the scl learning strategy. this can be done by increasing the time for discussion to be able and brave to express their opinions. the hope is that by implementing the scl learning system, students can participate actively, have critical power, analyze, and solve problems [16]. the role of the teacher is not an instructor but a facilitator. teachers help guide and manage students’ http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 1 7 3 fatimah, et al. implementation of learning cycle’s model based on scl …. p-issn: 2621-3761 e-issn: 2621-2889 activities and direct their learning [14]. students become active participants in the learning project. perry found that when they have high academic controls and take appropriate steps to prevent failures, they are most successful in college completion. this is because students are independently solve learning problems [5]. creative thinking skills learning activities carried out are closely related to a person’s thinking ability. thinking is an activity that uses reason to consider and decide something. one type of thinking ability is thinking creatively, which is problemsolving activities that require someone’s creativity. the ability to think creatively is one of the ability to build ideas based on fluency, flexibility, elaboration, sensitivity, and originality of the concept [17]. guilford’s theory, torrance’s theory, amabile’s theory, and others are some of the ideas that underpin the theory of creative thinking abilities. guilford, in 1967, that creative thinking is linked to divergent thinking, which includes fluency, elaboration, flexibility, and originality [18]. the test proposed by guilford emphasizes the various answers expressed by the research sample relating to one problem posed to the sample. the answers expressed by the research sample were assessed in terms of fluency, elaboration, flexibility, and originality [18], [19]. torrance’s theory of creative thinking ability is better known as the torrance tests of creative thinking (ttct). in theory, torrance relates creativity to moral commitment, self-confidence, the ability to see problems from different perspectives, and abilities to find different solutions [20]. the ttct is a theory of the results of the adoption of guilford’s theory. in his theory, torrance developed four aspects of creative thinking skills similar to guilford’s theory, namely fluency, originality, elaboration, and flexibility [21]. evans in 1991 suggests that creative thinking is a mental activity to make continuous (continuous) connections so that the “right” combination is found or until someone gives up [22]. creativity occurs through the similarities of a concept or analogical thinking. collection of ideas to form new ideas. in other words, creative thinking is a mental activity that requires someone to find a combination of ideas that did not exist before to create a new idea [17]. meanwhile, amabile in 1983 suggests, “creativity can be considered as the quality of products or responses judged to be creative by appropriate observers” [23]. amabile argues that identifying, definition, and problem-solving are essential aspects of creative thinking [24]. a person’s success in creative thinking can be seen from the indicators of creative thinking aspects. according to guilford and torrance, there are four characteristics of creative thinking, namely 1) original thinking ability (originality); 2) the ability to think fluently (fluency); 3) ability to think flexibly (flexibility); and 4) the ability to think in detail (elaboration) [17], [21]. evans in 1991 suggests that creative abilities can be seen from 5 kinds of creative behavior: fluency, flexibility, detail, sensitivity, and authenticity [25]. fluency can be seen from the ability to develop many ideas, answers, problem-solving, or questions. meanwhile, the ability to generate various ideas, answers, or questions, see problems from different points of view, look for many other alternatives, and change the approach can determine a person’s flexibility in thinking. furthermore, detail is the ability to develop an idea, add or detail in detail an object, idea, or situation. the fourth aspect is sensitivity, as seen from a person’s ability to capture and produce problems in response to a situation. finally, authenticity, namely the ability to express one’s own opinion in response to a situation at hand. in previous research, researchers have measured students’ creative thinking abilities with aspects that refer to guilford and torrance's theory [17]. in this study, researchers will examine students’ creative thinking abilities with the number of indicators measured as many as five indicators, namely aspects of fluency, flexibility, elaboration, sensitivity, and authenticity, such as the theory presented by evans in 1991. iii. method this research uses a qualitative approach because the researcher wants to obtain in-depth and natural data about students' steps in solving the questions. according to moleong [26] states that “(1) humans as instruments, (2) data are analysed inductively, (3) descriptive research results, (4) problem boundaries and (5) special criteria for data validity”. qualitative research will produce descriptive data in written or spoken words and the observed behavior of a person. this type of research is classroom action research conducted through research procedures based on john elliot’s principles [27]. in john elliot’s model, each cycle may consist of several actions, namely between 2-5 actions. meanwhile, each action may consist of several steps, which are realized in teaching and learning activities. in practice, in the field, every subject usually cannot be completed in one step. still, it will be resolved in several ways, which is why john elliot developed a different model of car, which is schematically different from other models (see figure 1). this research was conducted at universitas almuslim in the fifth-semester physics education study program students who took the learning evaluation course, namely 21 students. the data collection instruments used in this study were lecture contracts, rps, sap, lkm, test questions, lecturer observation sheets, student observation sheets, and response questionnaires. methods of data collection are done through tests, observation, and questionnaires. the data that has been collected is then analyzed using percentage statistics. for data on students’ creative thinking abilities they were analyzed by looking at their level of completeness in learning. according to trianto and ibnu [28], determine student learning completeness (individually) can be calculated using the equation (1). http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 1 7 4 fatimah, et al. implementation of learning cycle’s model based on scl …. p-issn: 2621-3761 e-issn: 2621-2889 figure 1. classroom action research (car) design by john elliot based on the instructions for implementing the teaching and learning process, a student can be complete to get 65%. at the same time, classical completeness is if the absorption reaches 85%. equation (2) is used to analyze classical completeness [28]. furthermore, the data on the activities of lecturers and students in each assessment component was analyzed using equation (3) [29]. meanwhile, it was analyzed to find out student responses by presenting the answers to the questionnaire given to students using the percentage technique in equation (4) proposed by sudijono [29]. the criteria for assessing the activities of teachers, lecturers and students as well as student responses to the use of the scl-based 5e learning cycle model are: very good for 90% < p ≤ 100%, good for 80% < p ≤ 90%, sufficient for 70% < p ≤ 80%, less for 60% < p ≤ 70%, and very less for 0% < p ≤ 60% [29]. completeness of study = the number of scores obtained total score 𝑥100% (1) absorption = the number of students who completed the total number of students 𝑥100% (2) p = score obtained total score 𝑥100% (3) p = f 𝑁 𝑥100% (4) iv. results and discussion analysis of students’ creative thinking ability based on data analysis, the changes in students’ creative thinking abilities in each cycle can be seen. the change in creative thinking skills shows an increase in lectures with the scl-based learning cycle learning model. the difference in students’ creative thinking abilities in the first and second cycles can be seen in table 1. table 1. increasing creative thinking skills in each cycle no. cycle complete not complete complete percentage 1 i 11 10 52% 2 ii 19 2 90% based on table 1, it can be seen that the implementation of lectures by applying the scl-based learning cycle learning model can improve students’ creative thinking skills. however, there were only 11 students who completed the study in the first cycle, and the remaining ten students did not complete the study. these data show that lectures by applying the scl-based learning cycle model have been able to complete students in lectures individually. still, classically, it has not been successful. in this case, there are still many obstacles to make improvements in the next cycle. in the second cycle, the level of individual learning completeness has increased with the number of students who complete as many as 19 students and only two who do not. classical completeness is the completeness seen from the number of students who have completed learning in a class. a class is classically complete if more than 85% of students complete the study in the class. for example, students’ creative thinking skills in the second cycle showed that 19 completed their studies. in contrast, only two had not finished their creative thinking skills. so, it can be said that the implementation of learning by applying the scl-based learning cycle learning model has been successful both individually and classically. from the analysis of the test results per indicator of creative thinking ability, it was found that classically, students’ creative thinking ability had increased from cycle i to cycle ii. more clearly, the percentage level of student learning completeness per indicator of creative thinking ability can be seen in table 2. table 2 shows that in cycle i individually, students have completed learning in each indicator. still, classically it cannot be considered complete. furthermore, based on cycle ii data, it was found that the level of student learning completeness increased in each indicator of the ability to think creatively. this can be seen from the high percentage of students who complete learning on each indicator of creative thinking abilities. the percentage obtained by the http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 1 7 5 fatimah, et al. implementation of learning cycle’s model based on scl …. p-issn: 2621-3761 e-issn: 2621-2889 indicator is ≥ 85%. thus, students’ creative thinking skills are complete, both individually and classically. table 2. percentage of completeness level of learning per indicator of creative thinking skills no. indicator of creative thinking skills cycle i (%) cycle ii (%) enhancement (%) 1 fluency 57 95 38 2 flexibility 52 90 38 3 elaboration 38 86 48 4 sensitivity 42 86 44 5 originality 42 90 48 analysis of lecturer and student activities in addition to the ability to think creatively, the activities of lecturers and students during lectures by applying the scl-based learning cycle 5e learning model also increased. so that the lecture process runs as expected, which can increase teaching and learning activities. the increase in the activities of lecturers and students in lectures can be seen in table 3. based on the data analysis in table 3, it can be seen that lecturer activity at each meeting from the first cycle to the second cycle has increased. for example, for action i in the first cycle, lecturer lecture activity was only 61%, then increased to 73% at action ii. for the first action in the implementation of the second cycle, lecturer activity reached 86%, then increased to 96% at the second action. so, the increase in lecturer activity from cycle i to cycle ii is 35%. like lecturer activities, student activities during lectures by applying the scl-based learning cycle model have also increased. for the first action in the first cycle, student activity in lectures was only 57%, then increased to 77% at the second action. for the first action in the second cycle, student activity reached 84%, then increased to 96% at the second action. so, the increase in student activity from the first cycle to the second cycle was 39%. student response analysis in addition to increasing the ability to think creatively and the activities of lecturers and students, the application of scl-based learning cycle learning in lectures can provide positive student responses to lectures. this can be seen from the number of students who stated that they were very happy and happy with each of the questions on the student response sheet. student responses to the implementation of lectures by applying the scl-based learning cycle model were analyzed using descriptive statistics. retrieval of student response data to the sclbased learning cycle model using student response questionnaires. the general description of student responses by applying the scl-based learning cycle model is summarised in figure 2. figure 2. diagram of the percentage of student responses to scl-based learning cycle the diagram in figure 2 shows that student responses to lectures with the scl-based learning cycle model obtained a positive response. this can be seen from the number of students who gave positive responses to each of the statements in the student response questionnaire. among other things, 64% of students said they were very happy implementing the scl-based learning cycle model. the rest, 36% of the total number of students who said they were happy with the conducted lectures. thus, it can be ignored that implementing learning using the sclbased learning cycle learning model can increase student interest and motivation to learn. besides that, the learning atmosphere becomes more enjoyable. this research was conducted to determine students’ creative thinking skills, lecturer and student activities, and responses after applying the scl-based learning cycle model in learning evaluation courses. if there are still obstacles during lecture activities, the researcher must improve the next cycle [28]. if lectures using the sclbased learning cycle model can improve student learning outcomes, the learning has been successfully carried out. the increase in students’ creative thinking abilities in lectures proves that using the scl-based learning cycle model is very effective. table 3. percentage of lecturer and student activities in lectures activities cycle i cycle ii enhancement action i action ii action i action ii lecturer 61% 73 % 86 % 96 % 35 % students 57 % 77 % 84 % 96 % 39 % http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.4, no.1, june 2021, pp. 1 7 6 fatimah, et al. implementation of learning cycle’s model based on scl …. p-issn: 2621-3761 e-issn: 2621-2889 learning activities carried out from the first cycle to the second cycle also increased. this can be seen both from lecturer activities and from student activities, namely in table 3. in this case, using scl-based learning methods can improve student learning activities. this is because in lectures with the scl-based learning cycle 5e model, students are more active in the lecture process. in contrast, lecturers’ lecturers’ duties guide and educate, not just teaching material or concepts to students. this is in line with the research results from putra et al. [8], which showed an increase in learning activities in terms of lecturers and students in each cycle compared to the initial conditions when implementing the learning cycle in learning. besides, in student-centered learning (scl), students will be more critical in shaping their knowledge through various learning activities to shape their knowledge [5]. the vital point of student-centered learning is that students become wiser in carrying out learning activities. therefore, every activity or activity carried out by students is used to form knowledge [6]. in this case, knowledge is formed following the 5e learning cycle learning flow. one of the essential stages in the learning cycle is where students are taught to assess the work of themselves and their peers by asking constructive critical questions, namely, through the explain stage [8]. in addition, the theoretical and practical skills that will be learned and implemented are given numerous opportunities [6]. learning using a suitable method can increase the effectiveness of the learning system itself. automatically, learning becomes more meaningful and enjoyable for students. this can be seen from the student’s response to learning using the scl-based learning cycle 5e learning model. student response to scl-based learning cycle 5e is very good. this can be seen in figure 2, which shows the percentage of student responses to the statements in the student response questionnaire. furthermore, a good form of student response can also be seen during the lecture process. this can be seen from the high interest and motivation to learn during the lecture. besides, students also seemed very enthusiastic in expressing their opinions during the presentation and the accountability of group performance. data from the research results of astrodjojo [11] also show the same thing. in their research, about 50% of students stated that they strongly agreed with the learning cycle model’s implementation, 49% answered agreed. only 1% answered “disagreed” with some of the question items in the response questionnaire. v. conclusion based on the analysis and discussion results stated previously, it can be generally concluded: (1) the implementation of the scl-based learning cycle model can improve students’ creative thinking skills. this can be seen from the increase in students’ creative thinking abilities from 52% in the first cycle to 90% in the second cycle. (2) the implementation of the scl-based learning cycle model can increase the activities of lecturers and students in lectures. this can be seen from the increase in the activities of lecturers and students in each cycle. for example, the rise in lecturer and student activities reached 96% at the second meeting of the second cycle, namely an increase of 35% for lecturer activities and 39% for student activities. (3) implementing the scl-based learning cycle model can describe a positive response from students to the ongoing lectures. in this case, 64% of students said they were very happy with their learning. vi. acknowledgment the faculty of teacher training and education at universitas almuslim (fkip umuslim) has involved researchers in this pds grant to produce an article. references [1] n. s. permana, “peningkatan mutu tenaga pendidik dengan kompetensi dan sertifikasi guru [improving the quality of educators with teacher competence and certification],” stud. didakt., vol. 11, no. 01, pp. 1-8., 2017. [2] s. makhmudah, “upaya memperbaiki kualitas guru dengan memaksimalkan terpenuhinya kompetensi kepribadian dan profesionalisme guru [efforts to improve teacher quality by maximizing the fulfillment of personal competence and teacher professionalism],” j. stud. islam, vol. 11, no. 1, pp. 80–103, 2016. 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https://doi.org/10.17509/eh.v8i1.5125 http://journal.um.ac.id/index.php/jptpp/article/view/9180 https://doi.org/10.26737/jpmi.v2i2.219 https://doi.org/10.20527/edumat.v4i1.2289 indonesian review of physics (irip) vol. 3, no 2, december 2020, pp. 57-65 doi: 10.12928/irip.v3i2.3064 http://journal2.uad.ac.id/index.php/irip 57 analysis of improving students' physics conceptual understanding through discovery learning models supported by multi-representation: measurement topic la sahara1, nafarudin2, suritno fayanto3*, babajanova asal tairjanovna4 1department of physics education, halu oleo university jl. h.e.a mokodompit, kendari, southeast sulawesi, indonesia 2physics teacher in public high school 1 kendari, jl. mayjen sutoyo, kendari, southeast sulawesi, indonesia 3physics teacher in private high school tahfidzul qur'an mu'adz bin jabal kendari jl. m. jasin, kendari, southeast sulawesi, indonesia 4department of information technology, tashkent university of information technologies 108 amir temur avenue, tashkent 100200, uzbekistan *email: suritnofayanto@gmail.com article info abstract article history received nov 5, 2020 accepted dec 27, 2020 published dec 31, 2020 this study aimed to analyze students' conceptual understanding by using a multirepresentation assisted discovery learning model in measurement. this research was conducted in public high school 1 kendari. this research is a quasi-experimental study using a one-group pre-post test design. the research method consisted of a conceptual comprehension test using a caliper and a screw micrometer in an essay in the form of a multi-representational test on long measurements. the analysis showed an increase in conceptual understanding between the pre-test and post-test with an average pre-test score of 16.24 (sd = 14) and a post-test of 61.4 (sd = 21). these results indicate an increase in students' understanding of concepts after learning with an average n-gain increase of 0.5 (sd = 0.2) in the medium category. it also obtained the most significant increase in students' understanding of the indicators mentioned parts caliper and micrometer with an n-gain average of 0.6 in the medium category. keywords: conceptual understanding discovery learning multi-representation to cite this article: l. sahara, nafarudin, s. fayanto, and b. a. tairjanovna, "analysis of improving students' physics conceptual understanding through discovery learning models supported by multi-representation: measurement topic," indones. rev. phys., vol. 3, no. 2, pp. 57–65, 2020. i. introduction the role of multi representation in learning is an essential topic in educational research, and representation in physics learning plays an essential role in explaining natural phenomena. students can understand well a topic learned is presented in a form that is easy to learn. in textbooks, the presentation of natural phenomena in physics usually expressed in the form of various representations such as text, diagrams, graphs, and mathematical equations, tables, charts, symbols, and this used to understand and study physics, as well as to convey the ideas and concepts it has [1-4]. besides, representations help improve students' understanding of physics problems, create bridges between mathematics and verbal or text representations, and help students develop ideas that give mathematical symbols meaning [5]. physics is a branch of science that studies matter and energy-related natural phenomena. by the interaction of different physical quantities, natural phenomena are created. physics is a part of natural science with some elements [6,7]. physics often involves modeling real-world physical phenomena using external representations that range from concrete to abstract forms: pictures, diagrams, words, graphs, and equations [3], [8]. given the importance of understanding physics's content by students, teachers, and students' concerns should always be logical mastery and student learning progress in physics. students can see how their knowledge can be conveyed by reflecting on what is used in solving the problem. it will not be difficult for learners who already understand physics's meaning to communicate their understanding in the form of different representations [6]. martaida et al. [9] reported that one of the problems in education, especially in science subjects, was the learning process's weakness. students are less motivated to explore their information, but students ask to recall what the teacher has given them. consequently, students can not solve the problems that occur, especially if the issue is related to the definition of science. the learning system tends to approach mathematics to get stuck after the mathematical process without understanding physics concepts. therefore, we need an l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 58 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 alternative learning model that can enable students to build their knowledge, one of which is the discovery learning model. discovery learning is a model for developing active student learning by finding out and investigating so that the results will last a long time in memory, not easily forgotten by students [10,11]. the advantage of the discovery model of learning is a learning process based on problem-solving [12]. with this model, students can be more intense in solving problems, making it useful for life in the future [13]. besides, discovery learning focuses on solving a problem relevant to current developments required to think about society's problem-solving. therefore, discovery-learning needs to be actualized in real life so that students can respond to more complex life problems. ansori et al. [14], in their study, reported that implementing the discovery learning model can support students to think critically. besides, applying the learning discovery made the children learn to think the analysis and try to solve the problems they face themselves [9], [15]. the combination of multi-perception based knowledge to students can optimize the role of discovery learning models. multi representation is a model that rerepresents the same concept in several different formats. some representation types may be terms, images, diagrams, graphs, simulations of machines, and mathematical equations in physics. multi-representation can help learners understand and construct a concept, solve problems, help solve problems, and help solve problems [16,17]. in developing knowledge of scientific concepts and processes, setyandaru et al. [18] argue that developing science learning in schools requires understanding and connecting verbal, visual, and mathematical representations. in his research, sunyono and meristin [19] argued that multiple representationbased learning could enhance students' conceptual understanding of high school chemistry materials compared to discovery learning. meanwhile, altan and eksi [20] reported using several representations to enhance learners' conceptual understanding of energy concepts, such as tables, data-meaning tables, conceptual change texts, concept maps, and analogies. the solution proposed to solve this problem is to choose models, methods, techniques, or learning approaches with learning paradigms that emphasize students' superiority or behavior in response to different facts and science learning issues (student-centered learning). the exploratory learning model can accommodate all of these things. discovery learning is a model that promotes the active participation of each student by prepared issues presented by the instructor to discover the concepts and values individually or in groups. according to the specified target, the teacher's task in this model is to direct students with a few roles in seeking concepts and principles. to solve this issue solution proposed is to choose models, methods, strategies, or learning approaches of learning paradigms that emphasize students' dominance or action in learning in response to various facts and problems of science learning (student-centered learning). a learning model that assumes that all these items can be accommodating is the learning model for exploration. discovery learning is a model that facilitates each student's active involvement through the teacher's prepared questions to explore the concepts and values individually or in groups. in this model, the teacher's job is to direct students with a few roles to look for concepts and principles according to the goal defined. several researchers have studied the use of multirepresentation based discovery learning models. puspitasari et al. [21] reported that the guided discovery learning model accompanied by multi-representation student worksheets based on problem-solving could improve students' conceptual understanding. meanwhile, ummu et al. [22] argued that applying a multiperception-based discovery learning model could improve students' conceptual understanding by a percentage of 90%. however, based on the results of searches using google scholar, eric, and proquest, it is still rare to explain in detail the use of multi-representation with the discovery learning model, especially on the topic of measurement. in this study, researchers focused on multiperception on measuring instruments in the form of calipers. this selection is due to the lack of literature sources that examine multi-perception on several measuring instruments. therefore, researchers are interested in studying students' conceptual understanding through models of discovery learning supported by multiple representations from what has been mentioned. this study aims to analyze and provide an overview of students' conceptual understanding based on multi-representation with discovery learning models on measurement. ii. theory concept understanding understanding is the keyword in the learning. according to berns and erickson [23], understanding is an absolute prerequisite for high cognitive abilities, application, analysis, synthesis, and evaluation in a learning domain. according to amien [24], a concept is based on relevant experiences that can be generalized to form a concept. physics is a discipline that needs more comprehension than memorization, so the ability to use three principal points of physics, namely concepts, laws or principles, and theories, is the key to success in studying physics. in learning physics, the ability to conceptualize physics is an absolute requirement in achieving the success of learning physics. according to bloom, the taxonomy of teaching objectives in the cognitive realm consists of six levels: remember, understand, apply, analyze, evaluate, and create. competence is characterized by learners' ability to understand concepts, formulas, or facts to interpret and restate them with their own words. for example, tasks that fall under this skill summarize the subject matter, l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 59 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 clarify the fairy tale contents to one's own experience, and include examples of events similar to those mentioned by the instructor. discovery learning discovery learning model of learning based on constructivist learning theories [25]. learning is the active method of creating context, argument, dialogue, and physical experiences from constructivism. an assimilation process takes place and connects the experiences or knowledge that has been acquired [26]. in discovery learning, students are not given the concept in its final form, but students are encouraged to find the concept. students build knowledge based on new information and data-sets they used to investigate learning [27]. participation in finding concepts in learning gives students a more profound impression so that information is stored longer in students' memory. the process of exploring the concepts being taught also gives students the incentive to make more discoveries to improve their learning interest. syntax discovery learning consists of six phases as follows: (a). stimulation, (b).the problem statement, (c). data collection (d). data processing, (e). verification, and (f). generalization. multi-representation according to ainsworth [28], a multi-representation learning environment's conceptual analysis shows three main functions of multi-representation used in learning situations to complement and build conceptual understanding. the first function is to use representations to obtain additional information or support existing and complementary cognitive processes. secondly, the representation can be applied to restrict the interpretation of the possible. recently, multi-representation can be used to encourage students to build a deeper understanding of the concept. sunyono and meristin [19] concluded that multirepresentation involves the importance of restating principles that have been taught in different forms and different acts and expressions, such as delivery by word of mouth, gestures, visuals. therefore, multirepresentation represents the physical processes in various ways; verbal, sketches, diagrams, graphs, and mathematical equations. there are several advantages of using the first representation; representation helps students understand the material as a visual aid to increase perceptual understanding. second, the representation is a physical nature, bridging between verbal representations with mathematical representations. the representation of a physical nature helps facilitate students in moving from words into mathematical equations. iii. method this type of research includes experimental research. the research design was made in the form of a pretest-posttest one group design. the experiment was conducted in public high school 1 kendari class x-mipa on measurement with 36 students. the research instrument consisted of a multi-representation test, as presented in table 1. data collection techniques in the form of a written test and an indicator containing multiple representations, multi-representation based student competency achievement indicators with discovery learning models are presented in table 2. data analysis techniques consisted of descriptive analysis and categorization and the students' understanding of statistical analysis in which there are test n-gain normalization [29]. formula descriptive analysis presented in equation (1). %100 c b a (1) symbol a is the total score obtained, b is the score obtained, and c is the maximum score. iv. results and discussion understanding is a manifestation of a person's perception or viewpoint given a problem. an individual is said to understand whether the issues he faces may derive meaning from messages or clues [30]. understanding representations is meaningful because information on a problem is often represented differently, such as providing visuals information [31-33]. multirepresentation understanding, namely, students' understanding of visual, verbal, mathematical, pictures, and graphics [34]. students are expected to master various representations during learning, such as experimental results, conceptual results, formulas, images. it can be seen in figure 1 that students are more focused on responding to the questions given. figure 1. the results of the student's work l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 60 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 1. the instrument of the student's multi-representation ability caliper mathematical symbol representations the measurement results = su + (sn nst) text representation the measurement results on the calipers are: 1. viewed and read designation numbers on the main scale (the fixed jaw) adjacent or before zero on a nonius scale (on a sliding jaw) as readings main scale 2. view and read the scale on the nonius scale, which is precisely in line with the scale on the fixed jaw and multiplied by the smallest unit value on the caliper used as the nonius scale reading. (of all the scales contained in the nonius scale or on a sliding jaw, there is only one (1) scale that is aligned with the scale on the fixed jaw, scale readings in mm 3. the measurement result is the sum of the main scale and the nonius scale. representation of image symbols micrometer text representation the measurement result on the screw micrometer is: 1. viewed and read designation scale of the highest rates in the major scale (fixed jaw) near the jaw swivel as reading the main scale 2. view and read the scale on the rotary jaw, which is in line with the horizontal line (horizontal) on the fixed jaw and multiplied by nst (smallest unit value) on the micrometer screw, which is used as the nonius scale (sn) reading. of all the scales contained in the rotary scale or on the rotary jaw, there is only one (1) scale that is entirely in line with the horizontal line on the fixed jaw, with the reading scale in mm. the measurement results are the sum of the main scale and the nonius scale. mathematical symbol representations the measurement results = su + (sn x nst) representation of image symbol l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 61 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 table 2. a multi-representation based competency achievement indicator with a discovery learning model no student competency achievement indicators 1 differences measure to calculate and provide an example 2 named parts of the caliper 3 named parts of the micrometer 4 the procedure used and the scale reading caliper 5 the procedure used and read the scale micrometer screw 6 read the measurement of the length of an object using a caliper 7 the reading the results of measurement of the length of an object using a .micrometre applying multi-representation in the discovery learning model makes it easier for students to understand and question more about the questions given. the findings of the study can be seen as follows, based on the review of research data: a. the pre-test and post-test application of the discovery learning model assisted by multiple representations of the measurement topic are shown in table 3. table 3. pre and post-test results in the application of discovery learning model assisted by multi-representation test value min max average sd pre test 2.9 55.7 16.3 13.9 post test 11.4 88.6 61.4 21.0 g 0.07 0.8 0.5 0.2 note: g (n-gain normalization); sd (standard deviation) it appears in table 3 that the use of multirepresentation-assisted discovery learning on the subject of measurement increased the comprehension of the measurement content by students from an average of 16.3 to 61.4. after the application model with an increase in n-gain (normalized gain) of 0.55, which is in the medium category. an increase in n-gain of 0.55 means that students in class xmipa-4 experience an increase in learning outcomes by 55% from the difference between the student's pre-test average score and the ideal or maximum average (or 100) from the test on the topic of measurement. in other words, the difference between the mean of the initial test and the ideal mean of the students class xmipa-4 is 83.7 (from 100 16.3), and 55% of 83.7 is 46.04, or the average value of students after learning increases by 46.04 from the initial test so that the average test eventually to 62.3 (relative value equal to the value of post-test, differ only because of rounding). thus, learning multi-representation assisted discovery models can improve students' understanding of the topic of measurement with an average n-gain of 0.55. suhandi and wibowo [35] argued that multirepresentation is one approach that is quite effective to use to instill an understanding of physics concepts. while, utami et al. [36] reported that multi-representation could improve students' conceptual understanding of physics education in the optical wave course with the ngain value obtained is 0.69, which is in the medium category. therefore, the use of multi-representations with discovery learning models emphasizes qualitative analysis and the quantitative aspects. the emphasis on multi representation with discovery learning significantly assists students in explaining physical phenomena problem-solving. b. total percentage of students (%) based on the ngain category. the distribution of categories for increasing understanding of concepts on the topic of measurement to students' numbers is shown in table 4. table 4. percentage of total students (%) based on ngain category category total student (%) high ( ngain ≥ 0.7 ) 30.6 medium ( 0.3 ≤n-gain < 0.7) 50.0 low ( 0 < n-gain ≤ 0.3 ) 19.4 table 4 shows that the increase in n-gain usually is distributed; it means that more students (50%) have a medium increase or as the gain category, in general, is 0.55, which is in the medium category. however, the number of students who have a high n-gain category is more significant than those in the low gain category. c. description of the distribution of students' pre-test and post-test scores in terms of the aspect of competency achievement indicators on the topic of measurement. the distribution of student understanding for measures of student competency achievement is shown in table 5. the distribution of understanding of each indicator on the measurement subject is illustrated in table 5. in general, based on this data, students had a poor understanding of all indicators before learning. the lowest indicator was using and reading the scale on the initial screw micrometer of 6.9. the extended measurement results using a caliper are also low on the indicator, and the micrometer parts of 10.7 and 11.6 are reported, respectively. however, students calculate and offer marginally better examples than all other aspects of the distinction aspect. students' comprehension improved after the learning process, with the highest average being 70.1 in terms of mentioning the caliper components and 67.4 in terms of saying the screw micrometer components. compared to other aspects, namely 0.63, these two elements also had the most considerable n-gain rise. table 5 shows that the distinguishing aspect of measuring by counting and giving examples has the lowest n-gain increase of 0.48. it also appears that although the invention has been applying aided l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 62 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 instructional model representation, there are still students who do not understand the concept of the last four indicators (even no value 0 both on the pre-test and posttest). table 5. the distribution of students' pre-test and final test scores in terms of n-gain for each indicator of student competency achievement no student competency achievement indicators pre test post test n gain min max average sd min max average sd 1 differences measure to calculate and provide an example 12.5 43.8 26.2 10.2 21.9 93.8 61.8 17.5 0.4 2 named parts of the caliper 0.0 66.7 19.2 25.8 25.0 100 70.1 14.6 0.6 3 named parts of the micrometer 0.0 66.7 11.6 22.3 16.7 100 67.4 20.8 0.6 4 the procedure used and the scale reading caliper 0.0 50 20.8 19 0.0 100 62.5 26.7 0.5 5 the procedure used and read the scale micrometer screw 0.0 50 6.9 15.4 0.0 100 53.5 32.3 0.5 6 read the measurement of the length of an object using a caliper 0.0 69.2 10.7 17.3 0.0 100 60.1 40.3 0.5 7 reading the results of measurement of the length of an object using a micrometer 0.0 84.6 13.2 24.4 0.0 100 59.7 40.2 0.5 teachers need to increase the awareness of students' multi-representation in different ways of presenting the knowledge to grasp an abstract topic that becomes tangible in all analysis areas [37]. one way to apply learning with multiple representations approach as the research results widianingtiyas et al. [38] obtained a multi-representation approach can positively influence students' cognitive abilities, including low-level cognitive and high-level cognitive. understanding is a form of student cognition in the learning process. d. description of the success rate of mastery of the subject matter on the measurement topic table 6 and table 7 shows the number of students based on mastery of the material for measurement subjects, both in the initial and final exams. table 6. the distribution number of students (%) each indicator of conceptual understanding in terms of the success rate of mastery of the material on the initial test (pre-test) no level of success category indicator codes and number of students (%) 1 2 3 4 5 6 7 1 mastering all topics/indicators of subject matter (100%) excellent 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 most of them master the topic/indicators of the subject matter (76 % 99 %) very good 0.0 0.0 0.0 0.0 0.0 0.0 5.6 3 students master 60% 75% of indicators/subject topic materials good 0.0 16.7 5.6 0.0 0.0 2.8 2.8 4 students only master a small portion of the topic/topic indicator of the lesson (1% 59%) lest 100 27.7 19.4 75 22.2 50 33.3 5 students do not master the topic/indicator topic of the lesson (0%) not master 0 55.6 75 25 77.8 47.2 58.3 indicator information: (1) differences measure to calculate and provide an example; (2) named parts of the caliper; (3) named parts of the micrometer; (4) the procedure used and the scale reading caliper; (5) the procedure used and read the scale micrometer screw; (6) read the measurement of the length of an object using a caliper; (7) reading the results of measurement of the length of an object using a micrometer table 7. the distribution number of students (%) each indicator of conceptual understanding in terms of the success rate of mastery of the material on the final test (post-test) no level of success category indicator codes and number of students (%) 1 2 3 4 1 6 7 1 mastering all topics/indicators of subject matter (100%) excellent 0.0 8.3 11.1 5.6 2.8 36.1 36.1 2 most of them master the topic/ indicators of the subject matter (76 % 99 %) very good 19.4 16.7 16.7 25.0 25.0 13.9 13.9 3 students master 60% 75% of indicators / subject topic materials good 30.6 69.4 55.5 36.1 25.0 5.6 2.8 4 students only master a small portion of the topic/topic indicator of the lesson (1% 59%) lest 50.0 5.6 16.7 25.0 27.8 38.8 36.1 5 students do not master the topic/indicator topic of the lesson (0%) not master 0.0 0.0 0.0 8.3 19.4 5.6 11.1 indicator information: (1) differences measure to calculate and provide an example; (2) named parts of the caliper; (3) named parts of the micrometer; (4) the procedure used and the scale reading caliper; (5) the procedure used and read the scale micrometer screw; (6) read the measurement of the length of an object using a caliper; (7) reading the results of measurement of the length of an object using a micrometer l. sahara, et al. / indonesian review of physics 3(2), 2020, 57-65 63 http://journal2.uad.ac.id/index.php/irip p-issn: 2621-3761 e-issn: 2621-2889 it appears that of the 36 students, the level of comprehension of the students is still in the decent/minimum group below (the level of mastery of materials is below 76% for all indicators), based on table 6 and table 7 before learning. besides, the indicator uses a micrometer to read the long measurement results. even more than 50% of students do not master the content/subject matter on four indicators, namely, mentioning parts of the calipers, mentioning parts of the micrometer, procedures for using and reading the micrometer screw scale reading the length measurement using a screw micrometer. more than 50% of the students had a degree of understanding of materials or indicators of more than 60% (good, excellent, and special categories) after learning, except for differentiating indicators calculated by counting and offering. for instance, no students met a particular category. moreover, no more students are not mastering the content for the first three indicators after learning. however, there are still students who are not mastering the material for the last four indicators. it can be observed from this clarification that the implementation of the discovery learning model with multi representations can enhance the comprehension of each indicator in the measuring material by students. as explained, indicators mean n-gain on the subject calculation; all indicators have increased with an average n-gain between 0.48-0.63. e. the relationship between initial knowledge and pretest and post-test on measurement topics the relationship between the original information gained from the basic understanding of physics assessments for class grouping when entering school to understand students on the subject of measurement is presented in table 8. table 8. the relationship between students' initial ability levels with pre-test and post-test on the topic of measurement no initial ability level average ta pre-test posttest n-gain 1 groups of students with low abilities 37.5 13.2 62.8 0.57 2 groups of students with medium abilities 41.4 17.2 58.0 0.52 3 groups of students with high abilities 45.0 17.0 66.5 0.61 average total (n=36) 41.5 16.3 61.4 0.55 standard deviation total 2.8 13.9 21.0 0.21 note: ta (initial ability) the mean comprehension of students on the measurement content tends to be compatible with their initial ability (ta) based on table 8. in contrast, the pretest has almost the same mean between students with modest abilities and elevated abilities. in the post-test performance, it can be shown that high-quality students have a higher increase in n-gain (0.61) compared to the middle and low-quality student classes with an average n-gain of 0.52 and 0.57, respectively. the rise n-gain of the high-capacity and lowcapacity groups of students (0.61 and 0.57 respectively) can be shown from the data in table 8 to be higher than the n-gain of the moderate-capable group (0.52). it implies that implementing the multi representation discovery learning model is appropriate for enhancing the comprehension of the measurement content by highcapacity students and low capacity. these findings indicate that multi representation based learning is effective in increasing the conceptual understanding of students with "low" and "medium" initial abilities [19]. v. conclusion based on the explanation of the study, it indicates that there is an improvement in the conceptual comprehension of students with a mean pre-test score of 16.2 (sd = 14) and post-test 61.4 (sd = 21) via the multirepresentation aided discovery learning model on the subject of measurement between pre-test and post-test. these results indicate that the concept is substantially improved with a boost in the un-normalized gain of 0.5 (sd = 0.2) and the intermediate category. by offering representational learning facilities, student communication can be generated, and students can help solve problems and better understand concepts. moreover, with an average n-gain of 0.63, an improvement in understanding the principle on the subject of measurement, particularly on the indicators explaining the calipers' sections and the screw micrometers obtained. acknowledgment the researcher would like to thank public high school 1 kendari for facilitating the research to be completed properly. furthermore, the authors would like to thank halu oleo university for the financial support provided to finish this research. references [1] w. roth, m. k. mcginn, and g. m. bowen, "how prepared are preservice teachers to teach scientific inquiry?," journal of science teacher education, vol. 9. pp. 25–48, 1998. 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[38] l. widianingtiyas, s. siswoyo, and f. bakri, “pengaruh pendekatan multi representasi dalam pembelajaran fisika terhadap kemampuan kognitif siswa sma,” j. penelit. pengemb. pendidik. fis., vol. 01, no. 1, pp. 31– 38, 2015. indonesian review of physics (irip) p-issn: 2621-3761 | e-issn: 2621-2889 vol.6, no.1, june 2023, pp. 24 44 doi: 10.12928/irip.v6i1.8240 http://journal2.uad.ac.id/index.php/irip email: irip@mpfis.uad.ac.id 24 investigating the density distribution of dark matter in galaxies: monte carlo analysis and model comparison budiman nasution1, ruben cornelius siagian2*, winsyahputra ritonga3, lulut alfaris4, aldi cahya muhammad5, arip nurahman6 1,2,3departemen of physics, faculty of mathematics and natural science, medan state university, indonesia 4department of marine technology, politeknik kelautan dan perikanan pangandaran, indonesia, 5department of electrical and electronics engineering, islamic university of technology, bangladesh 6department of physics education, indonesian institute of education, west java, indonesia. email: rubensiagian775@gmail.com article info abstract article history received: jun 4, 2023 revision: jun 27, 2023 accepted: jun 30, 2023 the understanding of dark matter distribution in galaxies plays a crucial role in unraveling the structure and evolution of galaxies. this research utilizes monte carlo probability analysis to investigate the density distribution of dark matter in galaxies. multiple distribution models, including the beta model, brownstein model, burkert model, einasto model, spherical exponential model, and isothermal model, are employed to estimate the density of galaxy matter at different distances from the galactic center. the analysis involves assessing the goodness of fit, sensitivity analysis of parameters, and chi-square analysis to evaluate the compatibility and accuracy of each model with the observed data. the results highlight the variations in dark matter density with increasing distance from the galactic center, indicating a higher concentration near the center and a lower concentration in the galaxy's outer regions. understanding the distribution of dark matter density provides insights into the gravitational effects, dynamics, and observed structures of galaxies. the monte carlo probability analysis facilitates the estimation of probability distributions and the assessment of model uncertainty, enhancing our understanding of the dark matter distribution in galaxies. the research findings suggest the suitability of certain distribution models, such as the beta and brownstein models, for describing the observed dark matter distribution. however, further research is required to validate and refine these models, considering the complexities and variabilities of dark matter distribution in galactic systems. this is an open-access article under the cc–by-sa license. keywords: monte carlo density distribution model galaxy structure mass distribution of galaxies dark matter phenomenon mathematical model to cite this article: b. nasution, r. c. siagian, w. ritonga, l. alfaris, a. c. muhammad, and a. nurahman, “investigating the density distribution of dark matter in galaxies: monte carlo analysis and model comparison,” indones. rev. phys., vol. 6, no. 1, pp. 24–44, 2023, doi: 10.12928/irip.v6i1.8240. i. introduction dark matter is one of the main components in the cosmos that has not been directly detected yet but has significant gravitational effects [1], [2]. it refers to matter that cannot be seen or detected using traditional observational instruments, such as optical telescopes or particle detectors [3]. the dark matter gets its name because it does not interact with electromagnetic light, so it does not emit, reflect, or absorb light, which makes it dark or invisible [4], [5]. the importance of dark matter lies in its strong gravitational influence on the structure and evolution of the cosmos [6], [7]. although not directly detectable, the gravitational effects of dark matter can be observed through gravitational interactions with visible matter, such as galaxies and gas [8]–[10]. some strong evidence for the existence of dark matter includes observations of galaxy rotations inconsistent with the distribution of visible matter, the formation of cosmic structures on large scales, the swelling of gravitational rings, and its influence on the background cosmic radiation [11]. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.12928/irip.v6i1.8240 http://journal2.uad.ac.id/index.php/irip mailto:rubensiagian775@gmail.com http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/ indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 25 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 previous research in the field of dark matter has included various approaches and methods to search for experimental evidence of its existence [12]. one commonly used method is particle detector experiments, which attempt to detect interactions between dark matter and visible matter. some of these experiments attempt to detect dark matter particles known as wimps (weakly interacting massive particles). however, while plenty of circumstantial evidence supports the existence of dark matter, the true nature of dark matter particles is still the biggest mystery in physics and astronomy [13]. current research continues to attempt to understand the nature and origin of dark matter. some of the research gaps that this study aims to close include: one of the main goals of dark matter research is to identify particles that are dark matter candidates. several theoretical models, such as the wimps (weakly interacting massive particles) have been proposed as potential candidates. however, searching for direct experimental evidence of dark matter particles is ongoing. further research is needed to understand the nature and interaction of dark matter with visible matter. this includes studying the energy and time scales at which dark matter operates and how it interacts through forces other than gravity. dark matter research also focuses on modeling the distribution and evolution of dark matter on a cosmic scale. this involves developing accurate models and computer simulations to describe the formation of cosmic structures, the formation of galaxies, and the evolution of the entire universe. the current research discussed explicitly contributes to identifying a dark matter distribution model that fits the observational data. this study uses the goodness-of-fit analysis method to evaluate the tested dark matter distribution models [14]. through this analysis, the study determines the model best fits the observational data. in addition, this study uses the monte carlo method to analyze the distribution properties of dark matter in the tested models. by performing random simulations with parameter variations, this study produces a dark matter distribution that can be compared with the observational distribution [15]. this monte carlo approach helps to measure the model's fit to the observational data, estimate the uncertainties in the model parameters, and derive the probability distribution for each parameter and the simulated matter [16]. the background of this research is related to understanding the phenomenon of dark matter in physics and astronomy [3]. dark matter is one of the biggest mysteries in physics and astronomy because it cannot be observed directly but can be recognized through the gravitational effects it produces [2]. in physics, laws such as newton's law of gravity and newton's laws of motion are used to study the phenomenon of dark matter [17], [18]. newton's laws of gravity describe gravitational interactions between masses, while newton's laws of motion relate the force acting on an object to changes in its velocity. in the context of dark matter, these laws are used to observe and model the gravitational effects of dark matter on objects in the universe [9]. in addition, albert einstein's general theory of relativity is also very important in understanding the phenomenon of dark matter [13]. the general theory of relativity explains gravity as a property of space and time and provides a more accurate description of gravitational interactions [19], [20]. in the context of dark matter, the theory of general relativity is used to study the mass distribution in the milky way galaxy and explain the gravitational effects produced by dark matter [7], [21], [22]. in addition to physics, mathematics is an important tool in modeling and understanding dark matter phenomena. mathematical concepts such as differential equations, probability theory, harmonic analysis, and statistics are used to develop mathematical models that explain the behavior and distribution of dark matter in the universe [23], [24]. mathematics is also used to analyze observational data and identify patterns or structures that could indicate the presence of dark matter [25]. in dark matter research, physics and mathematics are closely intertwined. physical theories provide the conceptual framework for understanding natural phenomena, while mathematics provides the formal tools for developing models and performing analysis. by combining physics and math, scientists can build a deeper understanding of the nature and existence of dark matter and its impact on the structure and evolution of the universe [20]. in the galactic halo model, several parameters are used to explain the structure of the galactic halo and the mass distribution within it [26]. these parameters, such as rc, rt, rho0, and r200, help to describe the structure and mass distribution in the galactic halo. mathematical models, such as the navarrofrenk-white (nfw) model, explain the galactic halo's structure and mass distribution [27]. the research question addressed explicitly is the extent to which the tested dark matter distribution models fit the observational data. in this context, the high p-value indicates that the tested models do not fit the observational data well. therefore, this study needs to continue the analysis by trying other models or making parameter adjustments to improve the fit of the observational data. this research aims to improve the accuracy of predicting the distribution of dark matter and to describe dark matter phenomena more effectively. by using the goodness-of-fit analysis method and the monte carlo approach, this research contributes to understanding the nature and distribution of dark matter and improving dark matter modeling that fits observational data. this research aims to understand the phenomenon of dark matter in the universe through physics and mathematics concepts [24]. dark matter is one of the biggest mysteries in physics and astronomy because it cannot be observed directly but can be recognized through the gravitational effects it produces [28]. in physics, laws such as newton's law of gravity and newton's laws of motion http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 26 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 are used to study the phenomenon of dark matter [22]. albert einstein's general theory of relativity is also important in understanding dark matter phenomena. in addition to physics, mathematics is an important tool in modeling and understanding dark matter phenomena [29]. mathematical concepts such as differential equations, probability theory, harmonic analysis, and statistics are used to develop mathematical models that explain the behavior and distribution of dark matter in the universe [30]. in dark matter research, physics and mathematics are closely intertwined. physical theories provide the conceptual framework for understanding natural phenomena, while mathematics provides the formal tools for developing models and performing analysis. by combining physics and mathematics, scientists can build a deeper understanding of the nature and existence of dark matter and its impact on the structure and evolution of the universe. the benefits of this research are as follows: this research helps us gain a deeper understanding of the nature and existence of dark matter, which is one of the main components of the universe. this contributes to our knowledge of how the universe formed and evolved. this research leads to the development of mathematical models that can explain the behavior and distribution of dark matter in the universe. these models help scientists predict and interpret dark matter-related phenomena and validate observational and experimental results. in an effort to understand dark matter, this research can lead to discoveries about the nature and characteristics of dark matter. these new findings could change the paradigm and expand our understanding of the universe. research on dark matter can have farreaching impacts on technology and applications. a better understanding of dark matter can help develop new technologies and applications, such as remote sensing technology, astronomy, cosmology, and modeling the structure of the universe. the research limitations of this research are brief: this research uses existing laws of physics, such as newton's law of gravity and newton's law of motion, as well as einstein's general theory of relativity. these constraints allow us to study the gravitational effects of dark matter and the mass distribution in galactic halos. since dark matter cannot be observed directly, the research relies on observations of the gravitational effects of dark matter. this limits the research to analyzing the observational data and identifying patterns or structures that could indicate the presence of dark matter. this research uses mathematical concepts such as differential equations, probability theory, harmonic analysis, and statistics. mathematics is used to develop mathematical models that explain the behavior and distribution of dark matter in the universe. this research uses galaxy halo models, such as the navarro-frenkwhite (nfw) model, to explain the structure and mass distribution in the galaxy halo. this model is based on computer simulations and assumes the presence of dark matter as the main constituent of the galactic halo. the level of resolution in a monte carlo density distribution model can affect galaxies' structure and density distribution. the higher the resolution level, the more detailed and complex the model can reproduce galaxy structures. however, higher resolution levels also require more intensive computations. ii. theory parameters in the milky way halo model the parameters in the milky way halo model, namely rc, rt, rho0, and r200, describe the galactic halo structure. the core radius (rc) is a parameter that represents the distance from the center of a galaxy to the region where there is a significant concentration of halo mass [31]. it determines the size of the core of the galactic halo. in other words, within the core radius, the density of the halo mass is relatively high, indicating a central region of concentrated mass. the tidal radius (rt) is another parameter that indicates the distance from the center of a galaxy to the region where the gravitational influence and tidal forces from other galaxies become significant [32]. it represents the point at which the galactic drag and tidal effects due to the gravitational interactions with neighboring galaxies start to have a noticeable impact on the galaxy. beyond this radius, the influence of neighboring galaxies becomes more pronounced. the mass density (ρ0) is a parameter that characterizes the mass density at the center of the galaxy halo [33]. it provides information about the concentration of mass at the central region of the milky way galaxy. a higher value of rho0 indicates a higher mass density at the galaxy's center, while a lower value suggests a lower mass concentration. the r200 parameter represents the distance from the galaxy's center at which the galactic halo rotates at a speed of 200 km/s [34]. it provides insights into the size of the galactic halo and the effect of rotation at this specific distance. this parameter is often used as a reference point to study the rotation curves of galaxies, which provide valuable information about the distribution of mass within the galaxy and the presence of dark matter. model navarro-frenk-white (nfw) the navarro-frenk-white (nfw) model is a mathematical model used to describe the structure and mass distribution in galactic halos [35]. this model has become an important framework for understanding the milky way galaxy and related cosmic phenomena. the nfw model is based on a few basic assumptions that form the mathematical basis of the model. the first assumption is that the dark matter in a galactic halo is concentrated at the center and spreads outwards with a density that decreases quadratically with distance from the center [36]. this means that the density of dark matter in the center of the galactic halo will be higher than outside the center. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 27 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 in this model, the mass distribution in the galactic halo is described by several parameters. these parameters include rc (core radius), rt (truncation radius), rho0 (central density), and r200 (halo radius). solving the mathematical equations underlying the nfw model makes it possible to determine these values. the parameter rc describes the size of the core radius, which is the distance at which the dark matter density reaches half of the center density (ρ0) [37]. the parameter rt, the truncation radius, indicates the distance limit at which the nfw mass distribution no longer applies [38]. the parameter rho0 is the central density of the mass distribution, which represents the concentration level of dark matter at the center of the galactic halo. while r200 is the halo radius, the distance at which the dark matter density reaches 200 times the critical density of the universe. using the nfw model, researchers can calculate and estimate the values of these parameters based on observational data and mathematical analysis. the nfw model provides a useful framework for understanding the structure and evolution of the milky way galaxy and related cosmic phenomena. the model has been used in various studies to study the mass distribution in galaxies, help identify galaxy structures such as rings and substructures, and provide insights into dark matter and overall galaxy evolution. six models of the galaxy density distribution six galaxy density distribution models describe how the mass density within the milky way galaxy is distributed. each model has its characteristics, differences, and parameters affecting the galaxy's density distribution. these models include: the beta density distribution model assumes that galaxy density can be approximated as a three-dimensional isotropic spherical distribution propagating radially from the galaxy center [39]. the model has parameters rho0 and rc that affect the density at the center and the radial scale of the distribution. the brownstein model is also based on a radially propagating isotropic spherical distribution but has a higher exponent in the denominator, resulting in a faster decrease in galaxy density as the distance from the center increases [40]. the burkert model introduces an additional parameter, the density scale c (cuspiness), which affects the shape of the density distribution at greater distances from the galactic center [36]. the einasto model assumes a density distribution that can be described by an exponential function with an alpha parameter [41]. it shows a sharper drop in density at greater distances from the galactic center compared to the beta or burkert models. this model assumes an exponential function can describe the density distribution outside the galactic center. the isothermal model assumes that the density distribution of galaxies follows an isothermal velocity distribution, also known as velocity proportional to gas temperature [42]. this model has an additional parameter rc, that affects the density at the center and the radial scale of the distribution. velocity vs. distance (r) graph for all six models the velocity vs. distance graphs for the six density distribution models gives an idea of how the velocities of objects in the milky way galaxy change with distance from the galactic center. each density distribution model has a different velocity pattern, and these differences are relevant to the mass distribution in the milky way. for example, the beta and brownstein models show a velocity pattern that increases at small distances, reaches a maximum point and slows down as the distance from the galactic center increases. the burkert and spherical exponential models show an exponential increase in velocity at small distances, reaching a maximum velocity before slowing down. the isothermal and einasto models show a velocity pattern that increases linearly at small distances, peaks at a point, and slows down as the distance from the galaxy center increases. these differences in velocity patterns provide important information about how mass is distributed in the milky way galaxy. by studying the velocity vs. distance graph, we can gain a better insight into the structure and evolution of this galaxy and other related cosmic phenomena. this graph helps us understand how mass distribution in a galaxy affects the speed of objects moving. relationship between velocity and gravitational potential the relationship between speed and gravitational potential refers to the connection between the speed of motion of objects within a galaxy and the gravitational potential generated by the mass distribution [43]. in this context, the speed of sound refers to the maximum wave propagation speed in the medium. at the same time, the dark matter distribution describes the density of dark matter at a certain distance in the galaxy [37]. the speed of sound can be related to the dark matter distribution through the density of matter in the medium. "hotter" or high-energy density distribution models, such as beta, brownstein, and einasto models, tend to have higher propagation speeds at the same radius than "cooler" models, such as isothermal models. therefore, if using the sound speed parameter instead, the "hotter" models will likely give higher sound speed values at the same radius compared to the "cooler" models [44]. however, it should be noted that this relationship is not linear and is highly dependent on the other parameters in the density distribution model. monte carlo density distribution model method another research method used in this study is the monte carlo density distribution model method. this approach is used to analyze the mass distribution in galaxies. this method combines monte carlo techniques with the concept of random density distribution. a random density distribution is given as input, which reflects the way the mass of the galaxy is distributed http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 28 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 across different regions in the galaxy. the monte carlo method generates random masses and coordinates based on the given random density distribution. the galaxy mass distribution is then plotted as a histogram, visualizing the mass distribution at various galaxy coordinates. analysis of these histograms provides information on mass concentration at various coordinates. monte carlo analysis limitations while monte carlo analysis can provide important information on how dark matter models match the observational data, the results should not be used as the sole benchmark [45]. in determining the best-fit model, it is important to use other methods that can provide a holistic view and consistency with the observational data. this is because the monte carlo analysis results only reflect the variation of the parameters included and cannot guarantee the correctness of the model as a whole. it is important to validate dark matter models using observational data consistently. while monte carlo analysis can give an idea of how well the model fits the observational data, consistency with different observational methods and datasets is necessary to strengthen the model's reliability. monte carlo analysis can produce probability distributions for each parameter in the dark matter model. however, it is important to remember that these uncertainties only consider the variations included in the monte carlo simulation. other factors, such as measurement uncertainty and the assumptions underlying the model, also need to be taken into account in evaluating the model's accuracy. monte carlo analysis is based on certain models and assumptions about the nature and behavior of dark matter. the accuracy of the analysis results largely depends on the validity of the models and assumptions used. remember that the dark matter models tested in the monte carlo analysis may have limitations and may not perfectly represent the complexity of the universe. iii. method summary of mathematical dark matter distribution model to calculate the density distribution of galaxies at a given distance r from the galactic center. the beta(r) function calculates the density distribution of galaxies in the beta model, where rho0 and rc are the parameters that determine the shape of the galaxy density distribution [46]. to derive the expression for the density, we can start by using the mass density formula: ( ) ( ) ( ) m r r v r  = (1) where m(r) represents the mass enclosed within a sphere of radius r, and v(r) represents the volume of the sphere of radius r. now, to calculate the mass enclosed within a sphere of radius r, we can use the equation: ( ) ( ) ³ 4 3 r m r r = (2) substituting the given formula for rho(r), we get: ( ) ( ) ( ) ( )3 ³ ²2 3 2 ² m r r m r exp   −=  (3) next, we can calculate the volume of the sphere of radius r as: ( ) 4 ³ 3 r v r  = (4) now, substituting the expressions for m(r) and v(r) in the mass density formula, we get: ( ) ( ) ( ) ( )²³ 2 ² 2 4 ³³ 3 3 r exp m r r r     − =  (5) simplifying the expression, we get: ( ) ( ) ( )² 2 ³ 2 ² m r r exp   = − (6) equation 6 is the given formula. hence, we have derived the expression for the density of a galaxy at a distance r using the given formula. the beta model describes the density distribution of galaxies as follows: ( ) 0 3 2 ² 1 c r r r    =           +  (7) where ( )r represents the density of the galaxy at a distance r, 0  is the central density, rc is the core radius, and β is a measure of the steepness of the density profile. the brownstein(r) function calculates the density distribution of galaxies in the model proposed by brownstein based on the mond-modified theory of relativity. this function returns the density of galaxies at a distance r calculated from the formula: ( ) 2 0 2 1 c r r r   =         +   (8) the burkert (r) function calculates the density distribution of galaxies in the burkert model, which has a "cored" galaxy density profile, meaning that the density of galaxies in the center is not infinite. this function returns the de the formula: http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 29 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 ( ) 0 2 1 1 c c r r rr r   =  + +                                   (9) the einasto(r) function calculates the density distribution of galaxies in the model proposed by einasto, which has a more complex galaxy density profile than previous models. this function returns the density value of a galaxy at a distance r calculated from the formula: ( ) 0 2 1 2 r exp r r     − =  −                          (10) where  and 2 r are the parameters that determine the shape of the galaxy density distribution. the exp sphere(r) function calculates the galaxy density distribution in a spherical exponential distribution model, where ρ0, rs, and rt are the parameters that determine the shape of the galaxy density distribution. this function returns the density of a galaxy at a distance r calculated from the formula: ( ) 0 c r r exp r  =  −       (11) for a distance leq rt, and rho(r) = 0 for the distance r > rt. the isothermal(r) function calculates the density distribution of galaxies in the isothermal model, which has an infinite density p [47]. source: data processing by the author (2023) figure 1. the distribution of the dark matter density of the milky way galaxy connecting each model in the velocity vs. r graph, we need to notice that each model of the distribution of the galactic density gives the relationship between the mass density ( )r at a distance r from the galactic center and the orbital velocity v(r) of matter particles at that distance [48]. therefore, we can use the law of conservation of angular momentum and newton's law of gravity to generate a velocity vs. r graph [49]. in general, the law of conservation of angular momentum states that the angular momentum of a particle moving in a gravitational field is constant. in contrast, newton's law of gravity states that the gravitational force between two particles of masses m1 and m2, at a distance r, is: 1 2 2 g m m f r  = (12) where g is the gravitational constant, in a symmetrical and homogeneous galaxy density distribution model, the orbital velocity v(r) of matter particles at a distance r from the center of the galaxy can be calculated by the following equation [50]: ( ) ( ) v r m r r g=  (13) where g is the gravitational constant, m(r) is the total mass of all the matter in a sphere of radius r, and r is the distance from the center of the galaxy. each galaxy density distribution model can produce a different velocity vs r graph in this context. for example, for the isothermal model, the orbital velocity v(r) of a particle of matter at a distance r can be calculated as: ( ) ( ) 2 2 0 2 2 4 c c v r pi g r r r r m r g r   =    = +              (14) meanwhile, for the burkert model, the orbital velocity v(r) of a material particle at a distance r can be calculated as: ( ) ( )  ( )3 2 2 0 2 2 4 c c m r g r v r g r r r r r   = =  + +       (15) using these equations, we can generate velocity vs. r graphs for each galactic density distribution model described previously. the dimensional parameter (  ) can be calculated from each galaxy density distribution model using the following formula: 1e-11 1e-07 1e-03 0 50 100 150 200 radius (kpc) d e n s it a s d m ( s o lm a s s /p c ^ 3 ) densitas dm beta brownstein burkert einasto exp sphere isothermal densitas dm di bima sakti http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 30 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 ( ) ( ) 2 4 g r r    = (16) where g is the gravitational constant, ( )r is the density of the galaxy at a distance r from the galaxy center, and σ2 is the velocity dispersion at a distance r. if the six models are plotted to the dimension parameter () against the radius (kpc), the results will reflect the galaxy's structure differences. source: data processing by the author (2023) figure 2. the plot of dimensionless parameter (omega) vs. radius (kpc) and omega (km.kpc/s) vs. log density and plot of sound of speeds dark matter effect vs radius (kpc) in milky way galaxy goodness-of-fit analysis the research results show that "goodness-of-fit statistics" is a statistic used to measure the extent to which the tested models fit the observational data used in the analysis [51]. this statistic provides information about the level of fit between the distribution generated by the model and the distribution of the observed data. goodness-of-fit was calculated using the kolmogorov-smirnov test [52]. the values shown are pvalues, representing the probability that the differences between the model and observational data distribution are random. the smaller the p-value, the lower the probability of random differences, indicating a higher level of fit between the model and the observational data. source: data processing by the author (2023) figure 3. r-programming language for fitting the dark matter density distribution model to observational data and using the kolmogorov-smirnov test to display the p-value as a goodness-of-fit measure figure 3 shows a program that illustrates a method that will be used in research that uses the dark matter density distribution model to analyze observational data. the following is an interpretation of the program steps: observational data is represented as an observational_data vector containing a number series. this is the data that is observed or measured in the study. this study used the dark matter density distribution model to model the data. this model is represented by the dark_matter_model function, which accepts the argument x (the point for which the probability is to be calculated) and the relevant parameters. the researcher 0 1 2 3 0 50 100 150 200 radius (kpc) d im e n s io n le s s p a ra m e te r o m e g a beta brownstein burkert einasto exp. sphere isothermal 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -5 -4 -3 -2 -1 log density (solmass/pc 3̂) ( k m /s /k p c ) 0.000 0.005 0.010 0.015 0.020 0.025 0 50 100 150 200 radius (kpc) d e n s it a s d m ( s o lm a s s /p c ^ 3 ) densitas dm beta brownstein burkert einasto exp sphere isothermal densitas dm di bima sakti http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 31 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 should define this function according to the dark matter density distribution model they are using. it returns the probability value at point x based on the model used. to test the fit of the model to the observational data, the program generates a distribution of the data from the model using the dark_matter_model function with relevant arguments, such as x_values representing the points where the probabilities are to be calculated. this distribution will show how the data generated by the model is distributed in the relevant parameter space. the program calculates goodness-of-fit using the kolmogorov-smirnov test to measure how much the model fits the observational data. the kolmogorovsmirnov test compares the distribution of the observational data with the distribution of the data generated by the model. the kolmogorov-smirnov test results are stored in the variable ks_test, containing the test statistic and p-value. the p-value is the probability that the difference between the model and observational data distribution is random. the smaller the p-value, the lower the probability of random differences, indicating a higher fit between the model and the observational data. the p-value is accessed via ks_test$p.value. the p-value is displayed via the print(paste("p-value:", p_value)) command. this program is one method to analyze the fit of a dark matter density distribution model to observational data using the kolmogorov-smirnov test and displaying the p-value as a goodness-of-fit measure. the p-value interpretation will provide information on how well the model fits the observational data. monte carlo analysis method in dark matter distribution analysis application the research method used in this study is monte carlo analysis. the purpose of using monte carlo analysis was to calculate the distribution properties of the material in the six models studied. this method involves using random simulations by entering random values for the parameters in each model. these simulations resulted in different matter distributions for each model. after the material distribution is generated from each model, the next step is to compare the material distribution from each model with the material distribution observed in the empirical data. the purpose of this comparison is to measure the level of fit of each model with the observational data. the model that best fits the observational data will produce a material distribution closest to the observed material distribution. in other words, the model with a distribution of matter that best matches the observational data is considered the best-fit model. parameter sensitivity analysis is the process of understanding how changes in model parameter values can affect the model's outcome or output. in simulation studies of the dark matter density distribution in galaxies, parameter sensitivity analysis can provide insight into sensitive parameters and their impact on model accuracy [53]. here is an effective and well-structured method for conducting a parameter sensitivity analysis in the dark matter mass distribution model. the program shown in figure 4 is an implementation in the r-programming language that represents the monte carlo research method in the analysis of the distribution of matter in the six models studied. source: data processing by the author (2023) figure 4. the r-programming language that describes the monte carlo research method in material distribution analysis http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 32 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 the program starts by loading the ggplot2 library, which is used to visualize the analysis results. next, the program determines the parameter ranges to be used in the analysis. this range includes rho0, r0, and beta, which are parameters in the material distribution model that will be varied in the simulation. the program defines a monte carlo simulation function (monte_carlo_simulation) that will be used to generate a random distribution of matter based on the given parameters. the function also compares the generated matter distribution with the observed matter distribution in the empirical data to calculate the degree of fit between the model and the observational data. next, the program performs a monte carlo analysis by running a series of simulations. in this example, the number of simulations is specified by num_simulations 1000 times. the program randomly generates parameter values rho0, r0, and beta at each simulation iteration within a predetermined range. then, the monte carlo simulation function (monte_carlo_simulation) is called to generate the material distribution and calculate the model's fit to the observational data. the simulation results and the fit level are stored in the results data frame. after completing the monte carlo simulation, the program uses the ggplot2 library to visualize the resulting fit distribution. a histogram with a constraint of 0.1 is used to display the frequency distribution of the fit level. next, the program performs parameter sensitivity analysis using the sobol2002 function from the sensitivity library. identify the parameters in the dark matter mass distribution model that can be varied. in this case, the parameters are rho0, r0, and beta in the beta model. establish the range of values for each parameter that will be varied. ensure that the chosen ranges are relevant to the scale and significant variations in the mass distribution. consider previous studies or the observed physical phenomenon to define meaningful value ranges. run simulations by varying the parameter values within the specified ranges. conduct separate simulations for each parameter variation. for example, run simulations with different rho0, r0, and beta values in the beta model. examine the simulation results for each parameter variation. observe both qualitative and quantitative changes in the dark matter mass distribution. pay attention to the impact of parameter variations on the mass distribution's shape, scale, and statistical properties. perform a parameter sensitivity analysis to determine the sensitive parameters. these are the parameters that have a significant impact on the simulation results. note the most significant changes in the dark matter mass distribution when these parameters are varied. discuss the impact of parameter sensitivity on the accuracy of the model. determine if variations in certain parameters lead to significant differences in the resulting dark matter mass distribution. consider whether sensitive parameters require more precise estimation or measurement. identify any limitations or restrictions of the model based on parameter sensitivity. determine if parameters are so sensitive that higher precision in estimation or measurement is required. consider potential areas for improvement. based on the parameter sensitivity analysis, pinpoint areas that can be optimized or improved in the dark matter mass distribution model. determine if there are any unknown or poorly known parameters that need further investigation. explore potential relationships or interactions between the parameters that require further investigation. use the insights gained from the parameter sensitivity analysis to improve the accuracy and usefulness of the model. implement necessary improvements, such as refining parameter estimation or measurement techniques. thus, the sensitivity analysis represented in figure 4 helps identify the parameters that significantly influence the simulation results. in the above program, sensitivity analysis is performed by considering the gaussian model. the results of the parameter sensitivity analysis are printed to the screen using the print(sensitivity) function. this information provides an understanding of the most sensitive parameters and their impact on model accuracy. iv. results and discussion the generated plot depicts the density distribution of dark matter as a function of distance from the galactic center. in physics, research on dark matter density is highly significant as it provides insights into the structure and evolution of galaxies. in this plot, the x-axis represents the radial distance from the galactic center in kiloparsecs (kpc), while the y-axis represents the dark matter density in mass per volume units. the visible data points on the plot are the results of observations and measurements conducted to estimate the dark matter density at specific distances. the forked lines connecting these data points represent the estimated function of dark matter density based on linear model fitting. a linear model establishes the relationship between distance and dark matter density in this case. from this plot, we can observe that the dark matter density tends to decrease with increasing distance from the galactic center. the physical interpretation of the decrease in dark matter density with distance is as follows: around the galactic center, the dark matter density tends to be higher in regions closer to the center. this indicates that dark matter congregates in the galaxy's central region, creating higher density. however, as the distance from the galactic center increases, the dark matter density tends to decrease. this suggests that dark matter is less concentrated in the galaxy's outer regions. understanding the distribution of dark matter density has significant implications in galactic physics. it aids in comprehending how dark matter contributes to the gravitational effects in galaxies, influencing the dynamics of stars and gas and shaping the observed structures of galaxies. moreover, research on the distribution of dark matter density also assists in unraveling the nature and composition of dark matter http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 33 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 itself, which remains one of the great mysteries in modern physics. the model utilized involved linear fitting to obtain coefficients used in calculating the dark matter density at each radius. in the plot, the x-axis represents the values of the galaxy radius in kiloparsecs (kpc). in contrast, the y-axis represents the standard deviation of smd (surface mass density) in solar mass per square parsec (m☉ pc2) units. through the plot, we can visually understand the relationship between radius and the standard deviation of smd. the formed line patterns can indicate trends or patterns within this relationship. significant fluctuations in the standard deviation values are observed at certain specific radius points. additionally, several data points may act as outliers, exhibiting significantly higher or lower smd standard deviation values compared to other points at similar radii. these outliers provide additional insights into unusual variations in mass distribution around those radii. in the context of physics, the plot provides information about variations in the galactic mass distribution at different radius scales. the observed patterns in the plot may indicate a connection between radius and mass, leading to variations in the standard deviation of smd. this plot can serve as a basis for further research in understanding galaxy dynamics and evolution and factors influencing mass distribution across different radius scales. source: data processing by the author (2023) figure 5. dark matter density distribution and radius smd.standard dev. . source: data processing by the author (2023) figure 6. model distribution density dark matter this plot illustrates the relationship between the radius and standard deviation of smd (surface mass density) in a galaxy. the standard deviation of smd provides information about the variation in mass distribution at each observed radius. we need to refer to the legend at the bottom of the plot to enhance our understanding, which provides information about the colors representing each distribution model used in this analysis. the colors on the plot represent different distribution models. each distribution model has its distinct physical interpretation and is used to depict specific physical phenomena related to the relationship between radius and density. for example, the beta distribution model has a physical interpretation related to the density around a specific radius in the galaxy. the brownstein distribution model offers a different perspective on the physical phenomena occurring at different radius scales. meanwhile, the burkert, einasto, spherical exp, and isothermal distribution models provide insights into -2.434915e-30 1.147355e-29 2.538202e-29 3.929048e-29 5.319895e-29 0.0 0.5 1.0 1.5 2.0 radius (kpc) d e n s it y dark matter density distribution 0.5 1.0 1.5 2.0 5 0 0 0 1 5 0 0 0 2 5 0 0 0 radius smd standard dev. radius (kpc) s m d s ta n d a rd d e v . (m ☉ p c ^ -2 ) -1.620220e-21 7.290992e-21 1.620220e-20 2.511342e-20 3.402463e-20 0.0 0.5 1.0 1.5 2.0 radius d e n s it y distribusi density -1.620220e-21 7.290992e-21 1.620220e-20 2.511342e-20 3.402463e-20 0.0 0.5 1.0 1.5 2.0 radius d e n s it y model distribusi densitas dark matter http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 34 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 the unique mass distribution and galactic structure within different radius contexts. through sensitivity parameter analysis, this research provides a deeper understanding of the limitations and potential improvements of the distribution models used in galactic physics. by considering the sensitive parameters, this study explores their influence on model accuracy and identifies areas that can be enhanced. table 1. the goodness of fit results of the model against observer data model the goodness of fit value beta 6.05e-39 brownstein 6.05e-39 burkert 8.11e-57 einasto 8.11e-57 isothermal 8.11e-57 spherical 8.11e-57 source: data processing by the author (2023) the research focuses on analyzing dark matter distribution models and their goodness of fit. the findings of this study provide valuable insights into model constraints and potential improvements in dark matter distribution modeling. the analysis involved testing multiple distribution models against observed data and utilizing the goodness of fit errors as a metric to evaluate each model's compatibility with the data. moreover, a sensitivity analysis of parameters was performed to identify key parameters and observe their impact on model accuracy. notably, parameters such as rho0, r0, and beta were found to be sensitive and informative regarding the dark matter distribution in the studied system grouping the models based on goodness of fit errors allowed for an understanding of how well each model fits the data. the beta and brownstein models demonstrated exceptionally small goodness of fit errors, indicating a strong agreement with the observed dark matter distribution data. this suggests that these models offer a promising representation of the dark matter distribution in the system and can be considered for use in future modeling efforts. the burkert, einasto, isothermal, and spherical exp models also exhibited very small goodness of fit errors, suggesting a good fit with the observed data. these models, too, are worth considering in the context of dark matter distribution modeling. however, it is important to note that while the small goodness of fit errors indicates the models' relative accuracy, they do not guarantee absolute truth. due to the variability in dark matter distribution and the complexity of galactic systems, further comprehensive modeling and testing are necessary to ensure the validity of the models used. nonetheless, the research provides significant insights into selecting appropriate models for describing the dark matter distribution in the studied system. source: data processing by the author (2023) figure 7. chi-square analysis results the resulting plot is a bar graph that shows the chisquare analysis results for each dark matter distribution model. the x-axis displays the names of the distribution models. in contrast, the y-axis displays the chi-square values, representing the level of agreement between the observed data and the expected data based on each distribution model. in the graph, each bar represents the chi-square value for each distribution model. the higher the bar, the higher the chi-square value, indicating a significant difference between the observed and expected data based on that distribution model. additionally, the color of the bars in the graph is determined by the p-value. on the color scale, blue indicates a high p-value (close to 1), while red indicates a low p-value (close to 0). this provides information about the statistical significance of the fit of the distribution model to the observed data. in this case, all distribution models have high p-values (close to 1), indicating insufficient statistical evidence to reject the distribution model. the research utilized monte carlo analysis to generate probability distributions and assess the fit of density distribution models to observed data. the resulting plot depicts the observed data as red dots, representing observations of radius and rotational velocity. in contrast, the blue dots represent simulated 0 2 4 6 be ta br ow ns te in bu rk er t ei na st o is ot he rm al sp he ric al e xp on en tia l model c h is q u a re 0.9999998 0.9999999 p-value chi-square analysis results http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 35 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 data generated through monte carlo simulations with gaussian noise. the monte carlo simulations added variation to the observed data, producing new parameters for fitting density functions and calculating dark matter density at each radius. by comparing the results of multiple simulations to the observed data, the researchers assessed the level of fit or mismatch between the density distribution models and the observed data. this analysis provided valuable insights into the properties of matter distribution and the uncertainty associated with different models, enhancing our understanding of the dark matter distribution in the studied system. source: data processing by the author (2023) figure 8. monte carlo analysis of density models figure 9. distribution monte carlo analysis in program r plot source: data processing by the author (2023) in the monte carlo analysis, the distribution of material resulting from each model can be compared with the distribution of observational material to measure the level of fit of the model with the observational data [54]. the model that best fits the observational data will produce a distribution of material closest to the distribution of observational material [55]. in addition, monte carlo analysis can be used to measure the uncertainty in the model parameters and the resulting distribution of matter [56]. by performing many random simulations, it is possible to calculate probability distributions for each model parameter and the resulting material distributions, which can provide important information about the uncertainties in the models and the resulting predictions. the monte carlo analysis of the six dark matter models above will depend on the parameters used in the simulation. however, monte carlo analysis generally shows how well a model fits observational data. by doing the simulation many times with different http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 36 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 parameters, the probability distribution for each model can be obtained [57]. in this case, the results of the monte carlo analysis will help determine how well these six models model the distribution of dark matter in the galaxy. models that have a probability distribution that is closer to the observational data are considered to be preferable [58]. in addition, monte carlo analysis can also help identify the parameters most sensitive to the simulation results so that the model's accuracy can be increased by optimizing the values of these parameters [59]. however, keep in mind that monte carlo analysis is only one method for evaluating dark matter models, and the results cannot always be used as a single benchmark in determining the most suitable model [60]. it is always necessary to use other methods and more consistency with observational data to validate and refine dark matter models. the plots presented in this study depict the probability distribution of different models obtained through a rigorous probability analysis using the monte carlo method. these plots specifically explore the distribution of dark matter in galaxies. the x-axis represents the distance (r) from the galaxy's center, reflecting the position within the galaxy being studied. on the other hand, the y-axis represents the density of the galaxy material at specific distances (r). a higher density value indicates a denser concentration of galaxy material at that particular distance. notably, the red line on the plot represents the average value of galaxy matter density derived from extensive monte carlo simulations. this average estimate provides valuable insights into the probability distribution. additionally, the green line represents the median value of galaxy matter density, serving as the median estimate of the probability distribution. the blue area between these two lines represents the 95% confidence interval, offering crucial information regarding the uncertainty associated with estimating galaxy matter density at each distance (r). by comprehensively analyzing these plots, significant findings and inferences can be drawn about the probability distribution and uncertainty of galaxy matter density, contributing to our understanding of the distribution of dark matter in galaxies. this high-quality and effective research study employs monte carlo probability analysis to create a model of the dark matter distribution in galaxies. multiple models, such as the beta model, brownstein model, burkert model, einasto model, spherical exponential model, and isothermal model, are utilized to estimate the density of galaxy matter at a specific distance (r) from the galaxy center. the plot includes the "mean" and "median" lines, representing the average and median values of galaxy matter density obtained through monte carlo simulations with randomly generated parameters. the confidence intervals (depicted in blue) provide a 95% confidence level range of potential galaxy matter densities at each distance (r). by analyzing this plot, we gain insights into the uncertainties in dark matter distribution models and obtain statistical estimations such as the mean and median galaxy matter density the research findings also indicate the parameter sensitivity within the beta model, which measures the influence of parameter value changes on the model's accuracy. three parameters, namely rho0, r0, and beta, are evaluated by varying them by 10% and calculating the squared error between the model output and observational data. the parameter sensitivity for rho0 and r0 is valued at 2.151764e-40, suggesting that a 10% change in these parameters has a negligible impact on the model's accuracy. the parameter sensitivity for beta is 1.778317e-40, indicating a slightly larger but still relatively small influence on the model's accuracy compared to rho0 and r0. source: data processing by the author (2023) figure 10. monte carlo probability analysis in density vs. distance (r) graph in mean and median http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 37 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 these findings imply that the beta model used in this study is not highly sensitive to variations in rho0, r0, and beta parameters, which can be seen as a limitation. further research could explore alternative models or fitting methods that are more sensitive to these parameters, aiming to enhance the accuracy of reproducing observational data. the study's results provide valuable insights into the distribution of dark matter in galaxies and its implications for galactic physics. the plot depicting the density distribution of dark matter as a function of distance from the galactic center reveals a decreasing trend in dark matter density with increasing distance. this suggests that dark matter tends to be more concentrated in the central regions of galaxies and less concentrated in the outer regions. understanding the distribution of dark matter density is crucial for comprehending the gravitational effects, stars and gas dynamics, and galaxies' observed structures. the analysis of the standard deviation of surface mass density (smd) at different radii offers further insights into the variations in mass distribution within galaxies. the plot's observed patterns and outliers indicate specific radius points with significant fluctuations and unusual mass distribution variations. these findings contribute to our understanding of galaxy dynamics, evolution, and the factors influencing mass distribution across different radius scales. the plot illustrating the relationship between the radius and the standard deviation of smd for different distribution models enables us to evaluate their fit to the observed data. the colors representing each distribution model highlight distinct physical interpretations and provide insights into density and mass distribution phenomena at different radius contexts. the goodness of fit analysis and chi-square analysis further assess the compatibility of the models with the observed data, indicating the relative accuracy of each model. the monte carlo analysis conducted in the study enhances our understanding of the uncertainties associated with the density distribution models. the probability distributions obtained through monte carlo simulations offer insights into the properties of matter distribution and the level of fit between the models and the observed data. the research findings highlight the sensitivity of certain parameters within the beta model and suggest potential areas for improvement in modeling the distribution of dark matter. it is important to note that while the goodness of fit errors and chi-square values indicate the relative accuracy of the models, further comprehensive modeling and testing are necessary to validate their absolute truth. the study provides valuable guidance for selecting appropriate models for describing dark matter distribution in galaxies. still, other methods and consistency with observational data are also essential for validating and refining these models. v. conclusion the density distribution of dark matter in galaxies shows a tendency for the density of dark matter to decrease with increasing distance from the galaxy center. the density of dark matter tends to be higher around the galaxy center and decreases with increasing distance from the center. this discovery provides insight into how dark matter contributes to the gravitational effects in galaxies, affects the dynamics of stars and gas, and shapes the structures observed in galaxies. the results of this study identify dark matter distribution models that fit the observed data. models such as the beta model, brownstein model, burkert model, einasto model, spherical exponential model, and isothermal model show good agreement with the observed dark matter distribution data. these models are promising representations in modeling the dark matter distribution in the system under study. sensitive parameters, such as rho0, r0, and beta, play an important role in the accuracy of the dark matter distribution model. however, the results show that the beta model used in this study is relatively sensitive to variations in the parameters rho0, r0, and beta values. this can be considered a limitation of the model. a practical suggestion is to conduct further research to explore alternative models or fitting methods that are more sensitive to these parameters to improve the accuracy of reproducing observational data. conduct more comprehensive modeling and testing to validate and refine the dark matter distribution models used. due to the variability of the dark matter distribution and the complexity of galaxy systems, further research involving other methods and consistency with observational data is needed to ensure the validity of the models used. we are exploring alternative models and fitting methods that are more sensitive to the parameters involved in the dark matter distribution. in this study, the beta model showed limitations in terms of sensitivity to certain parameters. therefore, further research can consider using alternative models to represent the dark matter distribution better. further, analyze the variation of galaxy mass distribution at different radius scales. the observed data show significant fluctuations in the smd standard deviation values at certain radius points and outliers that indicate unusual 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[60] d. abercrombie et al., “dark matter benchmark models for early lhc run-2 searches: report of the atlas/cms dark matter forum,” phys. dark universe, vol. 27, p. 100371, jan. 2020, doi: 10.1016/j.dark.2019.100371. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& https://doi.org/10.3847/1538-4357/abd777 https://doi.org/10.1140/epjc/s10052-020-8272-4 https://doi.org/10.1140/epjc/s10052-020-8272-4 https://doi.org/10.1093/mnras/stab1317 https://doi.org/10.1093/mnras/stad1299 https://doi.org/10.1093/mnras/stab235 http://arxiv.org/abs/2303.12838 https://doi.org/10.1088/0004-637x/759/2/138 https://doi.org/10.1140/epjc/s10052-019-7169-6 https://doi.org/10.1093/mnras/stad625 https://doi.org/10.1140/epjc/s10052-023-11399-w https://doi.org/10.1051/0004-6361:20021513 https://doi.org/10.1046/j.1365-8711.1999.02609.x https://doi.org/10.1046/j.1365-8711.1999.02609.x https://doi.org/10.1103/physrevlett.83.1719 https://www.jstor.org/stable/20488488 https://doi.org/10.1103/physrevd.68.103003 https://doi.org/10.1016/j.jocm.2020.100257 https://doi.org/10.1103/physrevd.107.083504 https://doi.org/10.1093/pan/mpr025 https://doi.org/10.1086/155591 https://doi.org/10.1016/j.scitotenv.2004.08.020 https://doi.org/10.1029/2007wr006720 https://doi.org/10.1890/07-2153.1 https://doi.org/10.1016/j.envsoft.2014.05.026 https://doi.org/10.1016/j.dark.2019.100371 indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 40 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 declarations author contribution : budiman nasution contributed to the conceptualization of the research and the selection of relevant distribution models for analysis. additionally, he played a crucial role in the data collection and processing, ensuring the accuracy and reliability of the observed data. budiman nasution also participated in the interpretation of the results and contributed to the writing and review of the manuscript. ruben cornelius siagian played a leading role in the research, providing guidance throughout the study. he was responsible for designing the monte carlo probability analysis methodology and implementing it to investigate the density distribution of dark matter in galaxies. ruben cornelius siagian conducted the model comparison and performed the goodness of fit, sensitivity analysis of parameters, and chi-square analysis to assess the model's compatibility with the observed data. he was also actively involved in interpreting the results, discussing their implications, and drafting the manuscript. winsyahputra ritonga contributed to the development of the research framework and methodology. he played a key role in the selection and implementation of specific distribution models, such as the beta model, brownstein model, burkert model, einasto model, spherical exponential model, and isothermal model, for estimating the density of galaxy matter at different distances from the galactic center. winsyahputra ritonga also assisted in the analysis of model results, data visualization, and contributed to the interpretation of the findings. lulut alfaris made substantial contributions in the context of data gathering and analysis. he played a role in collating observational data related to the distribution of dark matter in galaxies and ensured the data's proper organization for further analysis. lulut alfaris also participated in the discussion of the results and contributed to the critical revision of the manuscript. aldi cahya muhammad contributed to the research by providing valuable insights and expertise related to the field of electrical and electronics engineering. he played an essential role in assessing the gravitational effects and dynamics of dark matter distribution in galaxies. aldi cahya muhammad was involved in reviewing and editing the manuscript for technical accuracy and clarity. arip nurahman made substantial contributions to the theoretical aspects of the research. being an expert in physics education, he provided valuable perspectives on the significance of understanding the dark matter distribution in galaxies and its implications for teaching and learning. arip nurahman participated in discussions and contributed to the critical revision of the manuscript. funding statement : we would like to acknowledge that this research project, titled "monte carlo analysis and model comparison," was entirely self-funded by the authors listed below. no external funding or financial support from any organization, institution, or government agency was received for this study. conflict of interest : all authors certify that they have no competing interests. additional information : no additional information is available for this paper. http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 41 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 apendix: derivation of the mathematical model of dark matter density distribution galaxy density distribution first, we will find the constant of integration in this equation. we can do this by integrating the galaxy density equation over the radial variable r in the range 0 to  : 2 0 1 ( )r r dr  =  (17) now, we will substitute the given galaxy density equation into the integral: 2 0 1 exp 2 2 m r r dr    =  −               (18) we will change the integration variable to simplify the calculation. suppose , then 2 2 r dr u du   = = , and 2r u= . by making this substitution, we get: 2 0 1 exp( ) (2 ) (2 ) 2 m u u du    =  −          (19) now, we will simplify this equation: 2 0 4 1 exp( ) m u u du   =  − (20) we can solve this integral using the partial integration technique. by using the following integral formula: 1 exp( ) exp( ) exp( ) n n n x x dx x x n x x dx − =  − = −  − −  −   (21) we can apply this formula with $n = 2$. using this technique, we will get: 2 4 1 exp( ) 2 exp( ) m u u u u du  = −  − −   −   (22) now, we will solve the remaining integral by using the exponential integral formula: exp( ) exp( ) exp( ) x x dx x x x =  − = −  − − −  (23) substituting this result into the previous equation, we can simplify it into: 2 exp( ) 2 ( exp( ) exp( )) 4 u u u u u m  = −  − −  −  − − −   (24) we will continue simplifying to get the final result. by noticing that exp( ) exp 2 r u  − = −       , we can simplify this equation into: 2 4 1 (2 ) exp( ) 2 exp( ) m u u u u  = −  − +  −   (25) finally, we will replace the variable $u$ with r again in this equation: 2 2 exp 4 2 2 2 1 2 exp 2 r r r m r       −  − + =  −                            (26) density distribution of beta model dark matter galaxies we start by assuming that the mass distribution of dark matter in galaxies can be described by the beta density model. first, we will use a normalization constant to ensure that the total mass in galaxies is constant: 2 total 0 4 ( )m r r dr   =  (27) to do this integration, we need to change the variables. suppose 2 1 c r u r = +       , so 1 c r r u= − and 1 c r dr du u = − . the equation becomes: 3 total 0 3 / 21 1 4 c u m r du u     − =  (28) now we will calculate the integral. let's solve this step by integrating the above equation: 3 3 / 2 total 0 3 / 21 1 1 4 c m r u du du u       − = −         (29) the first integral is the integral of 3 / 2 u − from 1 to infinity, and the second integral is the integral of 3 / 2 1 u  from 1 to infinity. the first integral can be calculated as follows: http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 42 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 3 / 2 1 3 / 2 1 1 3 / 2 1 u u du     − +  − = − +        (30) in this case, we need 3 / 2 1 1 −  for the integral to converge. therefore, we get: 3 / 2 1 3 / 2 1 1 1 3 / 2 1 1 3 / 2 u u     − + − = − + −       (31) so, the first integral becomes: 3 / 2 3 / 2 11 1 1 1 1 3 / 2 1 1 3 / 2 u du u       − − = = − = −          (32) the second integral can be calculated as follows: 3 / 2 1 3 / 21 1 1 3 / 2 1 3 1 1 / 2 u du u      − +  = = − + = −        (33) finally, substitute the integral result into the equation for total m : 3 total 0 1 1 4 1 3 / 2 3 / 2 1 c m r    = − − −       (34) by knowing total m , we can express 0  in the beta density model equation as follows: 3 total 0 4 3 c m r = , so; (35) 1 total 0 3 3 1 1 4 1 3 / 2 3 / 2 1 c m r     − = − − −       (36) density distribution of dark matter galaxies brownstein model we will use the poisson equation in the spherical coordinate system to describe the mass density distribution: 2 4 ( )g r   = (37) where phi is the gravitational potential and g is the gravitational constant. we will find the solution of this poisson equation by replacing ( )r with the brownstein density model. let's find the form of the solution that satisfies spherical symmetry, namely ( )r . 2 2 2 0 2 2 1 4 (1 ( / ) ) c r r r r g r r       =   = +       (38) to ease the calculation, we will do some substitutions. suppose c r x r = , so that c r xr= . also, let us define 2 0 ( ) ( ) 4 c r r g r     = . with this substitution, the poisson equation becomes: 2 2 2 2 1 1 (1 ) d d x x dx dx x  = +       (39) let's solve this differential equation using the separation of variables method. we assume the solution is in the form ( ) ( ) ( )x x x y x = . by substituting this solution form into the equation, we can separate the variables and get two separate differential equations: 2 2 2 2 2 2 0 2 0 d x dx x x x dx dx d y y dy = + − = − = (40) the solution of the second differential equation is 2 2 1 2 ( ) y y y y c e c e − = + , where 1 c and 2 c are constants. the solution of the first differential equation is a bessel differential equation of zero order, given by: 3 0 4 0 ( ) ( 2 ) ( 2 )x x c j x c y x= + (41) where 0 j and 0 y are zero-order bessel functions, and 3 c and 4 c are constants. we can use the constraints given by the physical state to choose a suitable solution. in this case, we will choose a solution that does not diverge when 3 x , so we can ignore the y(x) component. therefore, the accepted solution is: 3 0 ( ) ( 2 )x x c j x= (42) returning to the original variables, we can write the solution for ( )r as follows: http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 43 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 2 0 0 3 ( ) ( ) 4 ( 2 / ) c c r r g r j r r c r     = = (43) to determine the constant 3 c , we can use boundary conditions or additional requirements given by certain physical states. without more information, it is impossible to determine the exact value for 3 c . finally, by replacing ( )r with ( )r , we get the equation of the brownstein density dark matter galaxy model: 0 2 2 ( ) (1 ( / ) ) c r r r   = + (44) this is the density equation derived by the brownstein model to describe the distribution of dark matter in galaxies. density distribution of burkert model dark matter galaxies given the burkert function density dark matter galaxy model equation: 0 2 ( ) 1 1 c c r r rr r   =  + +                        (45) first, we simplify the equation by multiplying both factors in square brackets: 0 2 (1 ) ( ) 1 c c r r r r r    + = +       (46) using the chain rule, we can calculate the first derivative of the equation: 0 0 2 2 2 2 1 (1 ) 2 ( ) 1 1 c c c c c r r r r rd r dr r r r r      +   = − + +                (47) we calculate the second derivative of the initial equation by applying the chain rule to the first derivative we calculated earlier: 2 2 ( ) ( ) d d d r r dr dr dr  =       (48) calculating the second derivative: 0 0 2 2 2 2 1 (1 ) 2 ( ) 1 1 c c c c c r r r r rd d d r dr dr dr r r r r      +   = − + +                                (49) after calculating the first derivative with respect to each factor in the numerator and denominator, we get the second derivative of the initial equation: 02 22 2 22 2 1 (1 ) 2 0 ( ) 1 1 c c c c c r r r r rd r dr r r r r     +   = − + +                (50) this is the calculation of the burkert function density dark matter galaxy model equation. density distribution of einasto model dark matter galaxies in this model equation, we introduce the following variable changes: 1 2 r x r  =       (51) using this change in variables, the equation can be simplified into a simpler form. we need to calculate the derivative of x with respect to r. with the chain rule, this derivative can be calculated as follows: 1 1 1 2 2 2 1 1 1 1dx r x dr r r r     − − =   =         (52) by replacing the variables in the original equation using x and our newly calculated dx dr , we can obtain the einasto function density model equation for dark matter galaxies: 0 2 1 ( ) exp 2 ln r r r     − =  −                (53) density distribution of exp-sphere model dark matter galaxies we start with the equation for the density of dark matter galaxy: http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&& indonesian review of physics (irip) vol.6, no.1, june 2023, pp. 24 44 44 b. nasution, et al. investigating the density distribution of dark matter … p-issn: 2621-3761 e-issn: 2621-2889 0 ( ) exp c r r r  =  −       (54) to derive this equation, we begin with the basic exponential equation: 2 3 4 exp( ) 1 2! 3! 4! x x x x x= + + + + + (55) assuming r and rc are positive real numbers, we substitute x with c r r −       in the exponential series above: 2 3 4 1 1 exp 1 2! 3! 1 4! c c c c c r r r r r r r r r r − = − + − + −                         (56) we aim to find the constant 0 ( ) that makes the above equation a suitable density model for the dark matter galaxy. for this, we need to normalize the equation. normalization is done by integrating the density over the entire space. since we are modeling a spherically symmetric galaxy, we integrate the density in spherical coordinates. as a reference, in spherical coordinates, the volume element is 2 4dv r dr= . let's calculate the normalization integral: 2 0 ( ) 4 1r r dr    = (57) substituting the given density model equation: 2 0 0 4 exp 1 c r r dr r   −  =        (58) in this integral, we can perform a change of variable with c r u r = , so 1 c du dr r = . the integration limits also change to u = 0 when r = 0 and u =  when r =  . with this substitution, the integral equation becomes: 2 0 0 4 exp( ) ( ) 1 c c u r u r du  −   = (58) we simplify this equation by combining constants: 3 2 0 0 4 exp( ) 1 c r u u du  − = (60) the integral in this equation is the gamma integral. the value of the gamma integral 2 0 exp( )u u du  − is 2! or 2. substituting this value into the previous equation: 3 0 4 2 1 c r  = (61) now, we can solve this equation to find the value of the constant 0 ( ) : 3 0 8 1 c r = (62) 0 3 1 8 c r   = (63) finally, we can write the normalized equation for the density model of the dark matter galaxy: 3 1 ( ) exp 8 c c r r r r   = −       (64) http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526275227&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1526650381&1&&