Mayang Dela Kesumah; Haerul Pathoni; Muhammad Haris Effendi Hasibuan
This study was motivated by students’ low conceptual understanding of temperature, heat, and thermal expansion at SMP Negeri 28 Batanghari, where learning achievement remained below 50%. Instruction predominantly used PowerPoint-based media, resulting in passive learning and limited contextual engagement. This study aimed to develop web-based interactive multimedia (GlidesApps) integrated with Cepak Kapung ethnoscience that is valid, practical, and effective in improving seventh-grade students’ conceptual understanding. The study employed a Research and Development (R&D) approach using a development model consisting of five stages: analysis, design, development, implementation, and evaluation. The resulting product, named LokaSains, is a web-based learning application accessible via smartphone, laptop, or computer without installation. It presents learning content on temperature, heat, and thermal expansion integrated with the ethnoscience of Cepak Kapung, a traditional cake from Batanghari Regency. Content expert validation obtained a score of 91.07% (very valid), while media expert validation reached 87.50% (very feasible) after two revisions. Teacher practicality assessment produced 98.33% (very practical), and student responses in small-group and large-group trials reached 94% and 90.35%, respectively (very good). During implementation with 28 seventh-grade students, the mean pretest score increased from 46.07 to 76.79 in the posttest. A paired samples t-test produced t = −13.053 with Sig. (2-tailed) = 0.000 < 0.05, indicating a significant difference in conceptual understanding before and after using the multimedia. The N-Gain score of 0.57 indicated moderate effectiveness in improving learning outcomes. Accordingly, the LokaSains interactive multimedia is considered valid, highly practical, and effective for teaching temperature, heat, and thermal expansion at junior high school level.