Re: [Phys-l] Faraday's Law Demo

[Ludwik Kowalski <kowalskil@mail.montclair.edu>]

On May 31, 2006, at 1:54 PM, Tom Sandin wrote:

> This is not an ad, just a enthusiastic recommendation from a physics
> teacher who has just received a great piece of demonstration
> equipment for Faraday's law (and Lenz's law). It's called Newton's
> Nightmare and is only $12.95 with free shipping in the US.
>
> Check out the video at http://www.penguinmagic.com/product.php?ID=841.
>
> We have an older version using two parallel copper pipes and a cow
> magnet, but Newton's Nightmare is much better.

I made a slightly different version of this demo. Two copper pipes of 
the same length, one open and one with a slot cut along the length. A 
neodymium magnet goes down, in the first case with constant speed 
(after initial moment) and in another with constant acceleration.  A 
light thread glued to the magnet was used to monitor motion. The white 
thread had ink spots every 5 cm.

Ludwik Kowalski
Let the perfect not be the enemy of the good.