Happy and Unhappy Balls

These balls are the real deal: vivid contrast between elastic and inelastic collisions.

These fantastic rubber balls may look the same, but they behave very differently upon impact with a solid surface. The 'Happy' ball stores very little energy in collisions and bounces well. The 'Unhappy' ball stores and transforms most of its kinetic energy and doesn't bounce. These balls are used to conduct experiments in discrepant event science, polymerization, and the coefficients of friction and restitution. This is a great aid for every momentum and collision study, or use the balls to demonstrate key points of kinetic molecular theory in gases. A must-have for chemistry and physics classrooms everywhere!