APPLICATION OF THE PJBL-STEM LEARNING MODEL ON SMOKELESS WASTE COMBUSTION DEVICE ON TEMPERATURE, HEAT, AND EXPANSION TO IMPROVE THE COGNITIVE LEARNING OUTCOMES OF STUDENTS OF CLASS VII SMPN 1 TAPUNG HULU. (2025). SPEKTRA: Jurnal Kajian Pendidikan Sains, 11(1), 186-199. https://doi.org/10.32699/spektra.v11i1.8900