Newton's cradle and Astro-Blaster: toy hybridization for studying chain collisions

We present a multiple-collision apparatus, based on low-cost and easy-to-find materials, which offers the opportunity to plan and conduct a sequence of experimental activities aimed at studying, in a very simple way, the energy transfer in multiple collisions. Our apparatus is based on the use of everyday objects such as toys, which stimulate students' interest by creating a familiar learning context. Two significant experiments on multiple collisions are described and the analyses of the corresponding experimental results are discussed. The first experiment makes it possible to analyze the kinetic energy transfer along a chain of adjacent balls. The second experiment offers the opportunity to give an analogical conceptual illustration of the bounce of a supernova core after gravitational collapse. Each experiment is pedagogically introduced by asking students to answer an appropriate stimulus questions, which were identified by instructors in a preliminary brainstorm session with students. Last, a theoretical model is given for kinetic energy transfer along a chain of balls and the experimental results are compared with the model predictions.