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

Code Number:
5K20.23
Demo Title:
Lenz's Law - Zig's Tube
Condition:
Excellent
Principle:
Eddy Currents, Magnetic Induction
Area of Study:
Electricity & Magnetism
Equipment:
Neodymium magnets, aluminum plates on moveable stand, aluminum "V" channel.
Procedure:

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.

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

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.