5K20.25 - Lenz's Law - Tubes and Magnets

Code Number:
5K20.25
Demo Title:
Lenz's Law - Tubes and Magnets
Condition:
Excellent
Principle:
Eddy Currents, Magnetic Induction
Area of Study:
Electricity & Magnetism
Equipment:
Copper and Aluminum Tubes, Brass, Iron, and Aluminum Slugs, Set of Kitchen Magnets, and Set of Neodymium Magnets.
Procedure:

Set the tube up so there is approximately 3" between the bottom of the tube and the drop pad.  Drop any of the wood, copper, or aluminum slugs down the tube and show that there is no significant damping.  The ceramic magnet will show some damping but will still drop quickly.  Drop the neodymium magnet stack and observe that it takes up to 24 seconds for them to travel down the 1 meter tube and 12 seconds for the 1/2 meter tube.

The neodymium magnets now come in a ring version.  These can be used with a copper rod to show eddy currents, and may be more visible than the tube and magnet version.

If you don't wish to use a tube with the slot cut into it you may use the copper and aluminum tubes that have the magnetic detecting film taped to them.  You will be able to observe where the magnet is in the tube as the film will change color when influenced by the poles of the magnet stack.

 

References:
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