This exhibit demonstrates the principles by which a motor functions. Closing a switch permits electricity to flow through the coils of wire wound around the motor shaft, called an armature. Holding a magnet around the coil causes the motor to turn. All motors operate for the same basic reason: When electricity flows through a wire and a magnet is nearby, the magnet exerts a force on the wire. Without either the magnet or the electricity, there is no "push" to make the motor turn. Turning the magnet over--reversing its magnetic field--reverses the "push" and causes an opposite rotation.