<![CDATA[Environmental problems require science learning that connects conceptual understanding, problem-solving skills, and school-based environmental action. This study aimed to develop a science teaching module integrating the School Environmental Care and Culture Movement into Problem Based Learning and to examine its validity, practicality, and effectiveness in improving junior high school students' problem-solving skills and environmental understanding. The study used research and development with the ADDIE model, consisting of analysis, design, development, implementation, and evaluation. The subjects involved five expert validators, two science teachers, and 60 seventh-grade students of SMP Negeri 22 Padang divided into experimental and control classes. Data were collected through validation sheets, practicality questionnaires, and tests of problem-solving skills and environmental understanding. Validity and practicality data were analyzed using percentages, while effectiveness was analyzed using gain score, N-Gain, effect size, and the Mann-Whitney test. The module obtained a validity score of 91.40%, teacher practicality of 93.89%, and student practicality of 94.17%, all in the very good category. The experimental class showed higher improvement in problem-solving skills than the control class, with p < .001, effect size of 0.75, and N-Gain of 0.48. Environmental understanding also improved significantly, with p = .003, effect size of 0.39, and N-Gain of 0.53. Therefore, the developed module is valid, practical, and effective for strengthening GPBLHS-based science learning.]]>
