“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), pp. 186–199. doi:10.32699/spektra.v11i1.8900.