The increase of problem solving skills of students through STEM integrated experiental learning with formative assessment

The ability to solve problems becomes one of the main purposes in learning physics. The aim of this study was to increase Problem Solving Skills (PSS) of students through STEM integrated experiential learning with formative assessment. The mixed method was conducted with embedded experimental design, involved 36 students in Grade XI Natural Science, and used the Problem Solving Skills Test instrument which consisted of 6 item essay questions with alpha Cronbach reliability of 0.766. The quantitative data of pre-test and post-test were analyzed with Wilcoxon signed rank test, N-gain, and d-effect. While the qualitative data of essay test answer and learning video, recordings were analyzed by coding, data reduction, and conclusion. The result showed that there was a significant increase in PSS of students, with N-gain 0.69 (medium category) and d-effect size 5.2 (strong enough category). Students experienced improvement in indicators of useful description, physics approach, specific application of physics and logical progression, respectively, 77%, 51%, 76%, 67%, and 64%. The result of the analysis of the various answer question showed that most students had difficulty in determining variables, symbols, physics units, and tended to use plug and chug approach during pre-test. But in the post-test, students could determine variables, made several representations, and used the right approach and physics formula. Therefore, STEM integrated experiential learning with formative assessment can increase PSS of students and can be used in learning.