This study aims to investigate the improvement students’ learning outcomes after the application of the experimental method in heat concept. The research design used was classroom action research with data collection techniques using observation sheets, tests, and student worksheets. The subjects of the study were students of class VII.1 of SMPN 7 Muara Bungo in the academic year 2019/2020 with 31 students. This research was conducted in three cycles, starting from October 28, 2019 to November 26, 2019. The results of this study indicate that the application of the experiment method can improve students’ learning outcomes in heat concept. Improved students’ learning outcomes can be seen from the average value, students' absorption capacity, and mastery learning from cycle I, cycle II, and cycle III. For the average value of students in cycle I, cycle II, and cycle III, are: 80, 85, and 88. For the absorption of students in cycle I, cycle II, and cycle III, are: 80%, 86% and 89%. As for mastery learning in cycle I, cycle II, and cycle III, are: 72%, 89%, and 94%.