‘KEEP IT HOT’ Module: Integrating STEM with Mathematics as the Core Focus through Problem-Based Learning and the Engineering Design Process

Secondary school STEM programmes often underemphasise mathematics, positioning it as a supporting tool rather than a central component of problem solving. This paper introduces KEEP IT HOT, an integrated STEM module designed to reposition mathematics as the foundation of STEM learning. The module combines Problem-Based Learning (PBL) with the Engineering Design Process (EDP) to immerse students in an authentic design challenge: creating a heat-retaining food container. The task requires applying geometric concepts of surface-area and volume optimisation while considering constraints such as efficiency, material sustainability, and thermal performance. Conceptually developed by aligning curriculum standards with established STEM education frameworks and sustainability priorities, the module integrates science, technology, and engineering around a mathematics-driven optimisation task. It provides structured guidance for teachers and hands-on inquiry for students, addressing common barriers to STEM implementation (e.g., resource constraints and fragmented subject delivery) while fostering critical 21st-century competencies including critical thinking, creativity, collaboration, and communication. This work contributes to the STEM education literature by offering a replicable, mathematics-centred model of integrated STEM instruction and sets the stage for future classroom implementation and evaluation. Integrating PBL with EDP purposefully situates scientific and mathematical knowledge within technological design, enabling learners to envision solutions, marshal evidence, and solve authentic problems (Wahono, Lin, & Chang, 2020).