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I like Allen's use of colored vinyl tape on the pole faces of the ring magnets. It gives dandy pole identification and also reduces breakage by cushioning the inevitable shocks .
Allen also mentions trying a horizontal rod with the magnets. We have done something like that but instead of stringing them on a horizontal rod we have suspended them from a rectangular frame support so they swing easily towards or away from their adjacent neighbors. We have a line of about eight magnets about 1 inch apart, and poles oriented so each repels its neighbors. We made the suspensions out of thin brazing rod, real cheap in 36-inch lengths, bent them into a V shape with the bottom of the V curved to match the magnet and the top half inch or so bent out horizontally to rest in grooves cut in the wooden support frame, permitting swinging only towards or away from the adjacent magnets, not sidewards. It acts very much like the "Newton's Cradle" toys with steel balls colliding and recoiling. However the magnet model is completely silent. One can get into interesting conversations about whether or not they are hitting each other, and stimulating profound thoughts about what "touching" means on a molecular level.
Al Read
Science Discovery Center of Oneonta (NY)
-----Original Message-----
From: Informal Science Education Network on behalf of Allan Ayres
Sent: Wed 3/24/2004 5:26 PM
To: [log in to unmask]
Cc:
Subject: Re: ring magnets for simple levitation
ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************
Edmund Scientific's "Scientifics" catalog also has an excellent
assortment of magnets.
http://www.scientificsonline.com/
We've tried any number of types of magnets, coatings, etc., in our
quest for floor-worthiness. For our vertically-oriented floating
magnet exhibit, our best solution has been to tape up ceramic magnets
from Edmund using black vinyl tape. Slap some red vinyl tape on one
pole and they look pretty slick.
Doing the taping is fairly laborious, but the result is quite
surprisingly durable; we've had four floating magnets stacks on the
floor for almost two years with the original magnets! (Two stacks
use 3-7/8" O.D. rings on a 1-3/4" O.D. polycarbonate tube; the other
two use 1-3/4" O.D. rings on a 3/4" O.D. polycarbonate rod.)
We've tried and tried to do a horizontally-oriented "sliding magnet"
setup, but we haven't yet found a way to make it durable enough. For
whatever reason, the magnets are much more likely to 'bind' when
strung on a horizontal tube, so as the visitors push them sideways,
they break in half. sigh. It's a really fun activity, but we've
never been able to make it floor-worthy.
--
~~
Allan Ayres
Exhibit Developer
Lawrence Hall of Science
University of California, Berkeley
Berkeley, CA 94720-5200
[log in to unmask]
510-642-1254
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