5K20.23 - Lenz's Law - Zig's Tube

Code Number:
Demo Title:
Lenz's Law - Zig's Tube
Eddy Currents, Magnetic Induction
Area of Study:
Electricity & Magnetism
Neodymium magnets, aluminum plates on moveable stand, aluminum "V" channel.

The "V" channel and magnet ball bearing are fixed inside a Plexiglas tube.  Rolling the magnet down the "V" channel no matter what the angle will show considerable damping.  Turning the tube 180 degrees, so the ball does not roll on the channel, will allow the ball bearing to roll without damping.

  • Zigmund Peacock, "A Student-Proof Lenz's Law Demonstrator", PIRA News, Vol. 20, # 1, p. 6, 2007.

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