Demonstrate the force on a conductor in a magnetic field.

• Magnetic North pole marked clearly for reference
• Rolling axle is marked to help students see rotation even from a distance

Three pairs of powerful ceramic magnets in a U shape holder provide a uniform magnetic field, with North marked on the top for clarity. Two brass rails are connected to a DC power supply (available separatly) via 4 mm banana sockets. A brass axle with two plastic discs is free to roll along the rails and complete the circuit between rails.

As the axle placed on the rails near the poles of magnets and power supplied to the rails, the Laplace force acts on the axle, and it rolls along the rails in the direction specified by the right-hand rule.