This experiment uses a coil of wire with a solid iron core inside the coil. When the switch is closed and AC current flows through the coil, the continuously changing magnetic field create eddy currents inside of metal rings place over the iron core. The rings will jump different heights depending on their thickness. Sparks can be created with a copper coil, while a light bulb attached to a coil will shine. Resistive heating can be demonstrated by holding the full rings down and feeling them heat up.
Set up time
Physics and Science Concepts
Lenz law, Electromagnetic Induction, Eddy Currents
Set up the apparatus so that the silver pole sticks above the platform a few inches. Place a full ring around the tube and turn the apparatus on. This will make the ring jump into the air. Turn off the machine then, place the split ring around the pole, turn on the machine and this will not do anything. Resistive heating can be demonstrated by holding the full rings down and feeling them heat up. Next, turn off the machine, place the copper coil around the pole and press down on the copper rod sticking off the coil to create sparks. Also, place the light bulb circuit ring against the flat top part of the pole and watch it light up.
Do not place apparatus directly under a light. Do not stand above machine when the rings jump. Do not hold the full ring down too long, you may get burned.