Explore the principles of impulse and the relationship between elastic and inelastic collisions with our Happy and Sad Balls (pack of 10 pairs). Despite their identical appearance, these balls exhibit dramatically different behaviors: the Happy Ball bounces, while the Sad Ball does not. Sold as a pair, these balls provide a vivid demonstration of material properties and collision dynamics.
 
The Happy Ball is made from standard neoprene, characterized by low hysteresis, low surface friction, and weak intermolecular forces, allowing it to bounce back when dropped. In contrast, the Sad Ball is made from Norsorex, which has high hysteresis, high surface friction, and stronger intermolecular forces, causing it to absorb energy and remain motionless upon impact.
 
Instructions included.