Exploring Scientific Concepts Through the Launch of Experimental Rockets in Physics Education

Abstract

Introduction: Traditional physics instruction frequently relies on lectures, which can disconnect abstract concepts such as Newton's laws, pressure, and reaction forces from observable phenomena, particularly in resource-constrained schools. This study investigates the use of hands-on water rockets constructed from recycled PET bottles as a cost-effective, active STEM learning intervention. Methods: We implemented a four-year (2022–2025) longitudinal, mixed-methods, design-based research approach. We analyzed 108 launches, comparing propulsion methods using compressed air/water and sodium bicarbonate/vinegar. In 2025, a three-session workshop involved 24 students aged 10–14 at a public school in Recife, Brazil. Data sources included flight performance metrics, pre- and post-intervention concept tests (0–3 rubric; Cohen's kappa = .85), and observational/video records (inter-observer agreement = .82). Results: The sodium bicarbonate/vinegar propulsion produced a significantly greater mean flight distance than compressed air/water (112.3 m vs. 68.4 m; t = 6.31, p < .001, d = 1.15), with a maximum distance of 310 m but higher variability. The presence of symmetric fins was strongly associated with stable flight trajectories (87.5% vs. 31.3%; χ² = 14.27, p < .001, V = .42). Concept test scores increased from 5.21 to 9.83 (d = 2.34), and student engagement rose from 33.3% to 91.7% (φ = .62). Discussion: The water rocketry intervention enabled students to directly observe and investigate Newton's laws, pressure–thrust relationships, aerodynamic stability, and chemical propulsion, fostering a shift toward hypothesis-driven inquiry. Nevertheless, the limited sample size, lack of randomization, and absence of a control group indicate the need for further research.