PET-Bottle Rocketry in Secondary Physics Education: An OBAFOG Project-Based Learning Experience Report

This experience report investigated the implementation of Project-Based Learning (PBL) integrated into secondary Physics, Mathematics, and Chemistry education, contextualized within the Brazilian Rocketry Exhibition (OBAFOG). The pedagogical intervention engaged upper secondary students in an authentic, iterative engineering design cycle (Design–Build–Test–Evaluate–Iterate) focused on the fabrication and ballistic optimization of three successive PET-bottle rocket prototypes propelled by an aqueous acetic acid and sodium bicarbonate reaction. As the primary construction outcome, systematic aerodynamic and structural modifications—shifting the Center of Pressure aft via rigid planar fins, advancing the Center of Mass using ballasted nose fairings, and increasing the fuselage fineness ratio—resolved severe aerodynamic instabilities and increased mean horizontal ballistic range from 18.4±2.1″ m”  (Rocket 1) to 92.3±4.2″ m”  (Rocket 3). In terms of educational evidence, the collaborative diagnostic evaluation of early empirical failures fostered deep conceptual learning: students actively mobilized Newtonian mechanics, compressible fluid dynamics, and chemical stoichiometry to overcome technical bottlenecks, exhibiting heightened scientific reasoning, problem-solving autonomy, and teamwork. This study demonstrates that low-cost model rocketry serves as an effective experimental vehicle for authentic STEM engagement in secondary education.