Here's a simple way to observe the relation between kinetic and potential energy. Made of durable metal. It consists of a spring gun from which a ball can be launched horizontally and a block to catch the ball. A freely swinging pendulum moves to a maximum height where a pointer delineates its highest point of ascension. By measuring this height and using conservation of mechanical energy, you can determine the kinetic energy of the pendulum plus projectile. Includes: spring gun fixed on base that fires projectiles at 3 speeds; pendulum and block with mass of 80 grams; scale and pointer to indicate highest point of swing; steel ball; operating instructions.