Supporting Inquiry-Based Learning of Density Using a 3D-Printed Instructional Kit

Teaching density and buoyancy through inquiry-based science learning is often constrained by the lack of instructional materials that enable controlled comparison of mass and volume. This study examined the use of a 3D-printed instructional kit, the Density Discovery Kit (DD-Kit), designed to support inquiry-based learning of density by stabilising experimental conditions and enabling systematic comparison of mass and volume. By reducing extraneous variation in object properties, the kit foregrounds proportional reasoning and evidence-based explanation rather than perceptual or intuitive judgement. The kit comprises a set of cubes and spheres that create contrasting density scenarios, including several cubes and spheres of identical volume but different mass and an additional cube and spheres with a different volume and mass. These configurations were used to elicit predictions and challenge the common misconception that heavier objects necessarily sink. A mixed-methods approach was employed with 68 students, using pre- and post-tests and classroom observations. Results from a Wilcoxon Signed-Rank Test showed a statistically significant improvement in students’ post-test scores (Z = −4.451, p