Amazing! A slow-moving ball bearing collides with a magnet–ball bearing system, knocking away the last ball in the series, obeying the conservation of momentum. One problem—the knocked-away ball appears to shoot at nearly three times the original speed! When a series of magnets and ball bearings are aligned, a simple magnetic linear accelerator is created. Have the laws of physics been broken? On the contrary, this unique demonstration actually shows the fundamentals of the conservation of energy and momentum principles as well as the properties of magnetism. Similar to the energy stored in a stretched spring, or gravitational potential energy, magnetic fields also store energy and give the ball bearing its unbelievable boost. Use this accelerator to launch a ball bearing to study projectile motion. Background information and complete instructions are provided.
Concepts: Potential vs. kinetic energy, magnetic potential energy, conservation of energy and momentum, projectile motion. Time Required: 15 minutes Materials Provided: Angled metal track, neodymium magnets, steel ball bearings, wooden support feet.