Abstract :
Solar system is an abstract phenomenon that needs to understand by junior high school students. The phenomenon cannot be observed directly in the classroom. In this research, the role-play model is first proposed to provide analogical phenomenon combined by Stellarium as an astrophysical virtual laboratory to give better visualization of Solar System Model. Role-play is a part of psychodrama used as a learning method to help students understand some aspects of science. However, the best strategy on this approach needs to be further investigated. The research attempts to improve students’ understanding on learning solar system. The role-play model is applied before or after using Stellarium virtual observatory as pre and post role-play learning designs, respectively. This research employed quasi-experimental method. The method used in this research is experimental with pretest-posttest design. There are three types of instrument used in this research. There are objective test, rubric, and questionnaire. The quantitative data of this research was collected by objective test (pretest-posttest), while the qualitative data is used to describe students’ performance and students’ responds in role-play. The result shows that there are statistically significant between pre role-play and post role-play. The N-gain of students’ understanding improvement on post role-play was 0.40 and pre role-play was 0.18. The result is confirmed by students’ performance and responds implying that students need learning concept previously so that they can perform role-play effectively.