This classic collision ball device is a fascinating demonstration of Newton's third law, which states that for every action, there is an equal and opposite reaction. With the collision ball apparatus one can show that if a moving ball collides elastically with an equal mass ball at rest, the entire kinetic energy and momentum of the first ball will be transferred to the second. If one ball collides with a row of equal mass balls, all the kinetic energy and momentum will be transferred to the last ball. An interesting experiment is to pull back two balls on one side and one on the other and release them simultaneously.