Date: Fri, 08 Nov 2002 08:51:11 -0500

Author: Sam Sampere

Subject: Re: mod on eddy current


Here's another variation - do this with a faculty member. Roll the magnet
down each sheet having the faculty member catch the magnet as it rolls across
the table top. Then, set the copper sheet on the table top. Raise the
incline of the plastic sheet pretty steep with the bottom resting on the
copper sheet. Then roll the magnet down the plastic sheet asking the faculty
to catch the marble. The marble just comes to a dead stop. Marble - $7.50,
plastic sheet - $1.50, copper sheet - $don't ask, look on faculty face -

Now I want a 4" diameter NdFeB sphere! And paint it up like Otto the Orange!


Vacek Miglus wrote:

> At 10:35 AM 11/7/2002, you wrote:
> >First, roll the ball down a long piece of flat plastic. It's not very
> >spectacular, you get just what you expect. Then roll it down a long
> >piece of copper. I'm using a piece of 1/8" x 8" x 36" OFHC. The ball
> >very slowly rolls down the new incline. Repeat this several times until
> >the copper is vertical. It's just too cool!
> It is just way cool! I went to the back room and got my 5/8" dia magnet
> and rolled it down an Al channel. Worked great! Works even better as an
> counter-intuitive inertia demo.
> Place the "Ball Bearing" in a short piece of channel or on a small Cu
> plate. Have your victim place their hands under the plate to catch the
> bearing when you jerk the plate out from under the "bearing". Watch their
> face.
> Vacek