Özet:

STEM is integrated learning which consists of four aspects namely science, technology, engineering, and mathematics. The 5M inquiry is a learning model that is being promoted in Indonesia to increase the critical thinking skills of students. In this study, the 5M inquiry learning activity was integrated with the STEM aspects in developing students' critical thinking skills in learning packages of simple machine materials. This study aimed to determine the effectiveness of STEM-based inquiry learning packages in simple machine material for improving the critical thinking skills of junior high school students. This type of research used quasi-experimental research with a one-shot case study pretest-posttest design. The research was replicated in four of 2nd grade of Junior High School 1 Pamekasan which conducted to 112 of students. The sampling technique used purposive sampling based on the fact that students were quite familiar with excavators. Data collection was used by tests of students' critical thinking skills and questionnaires of students' responses. The critical thinking skills test was given to students before and after the learning process, students were given the same initial test (pre-test) and final test (post-test). Questionnaires of students' responses were given to students after the learning process with STEM-based inquiry learning. Data analysis used descriptive analysis, normalized gain (N-gain) score, and paired t-test. The results showed that: 1) the increase of critical thinking skills based on the N-gain score is the high category; 2) the result of paired t-test showed that there is a significant difference in students' critical thinking skills before and after learning with STEM-based inquiry learning; 3) the student's response is the positive response with very good criteria to STEM-based inquiry learning. Based on the study, STEM-based inquiry learning packages were effective in improving the critical thinking skills of junior high school students.

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