Magnetic field around a solenoid with pivoting probe magnet.

Magnetic field around a solenoid with pivoting probe magnet. A large D.C. current (about 100 Amps), is sent through a simple solenoid coil made of heavy copper wire. The magnetic field produced is explored by a hand-held 'exploring magnet', or with a compass needle on a stand. NOTE: The current is large, so a Timer box is set for 20 seconds to remind one to turn the demo off. Also, double wires are used from the switch to the coil in order to handle the large current.