Lenz's law kit

The Lenz law apparatus allows students to easily see that "An induced current is always in such a direction as to oppose the motion or change causing it". The apparatus consists of a copper tube, with one side removed, and two identical metal cylinders only one of which is magnetised. Lenz's law is demonstrated by the fact that when the metal cylinders are dropped through the copper tube the magnetised cylinder falls at a much lower rate because of induced eddy currents in the copper tube wall. Students will be intrigued by this highly visual experiment which forms an ideal part of a course on motors and generators.