“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”. SPEKTRA: Jurnal Kajian Pendidikan Sains, vol. 11, no. 1, July 2025, pp. 186-99, https://doi.org/10.32699/spektra.v11i1.8900.