From: Ronald Wong (ronwong@inreach.com)
Date: Thu Mar 13 2003 - 13:24:19 PST
Message-Id: <l03102801ba9694a2ab08@[209.209.19.165]> Date: Thu, 13 Mar 2003 13:24:19 -0800 From: Ronald Wong <ronwong@inreach.com> Subject: re: got bismuth?
Eric mentioned that he was
>...looking for some bismuth to play around with in an
>attempt to demonstrate diamagnetism.
If all one wants to do is demonstrate diamagnetism, the simplest way would
seem to be to use the most common material around - water.
It may not be as dramatic as bismuth - which is far more diamagnetic than
water - but it is something that the students are very familiar with and is
very easy to get a hold of.
A watch glass or petri dish, projection lamp, and one of those overwhelming
powerful magnets that every science class has nowadays is all that you
need.
A nice flat board with a hole near one end into which you can drop the
magnet so that it is flush with the top of the board is the only other
thing that you might want to consider.
You place the magnet in the hole of the board, put the board on a table,
pour some water in the petri dish, place it at the other end of the board
from the magnet, and shine a beam of light on the surface of the water so
that it's reflection can be seen on a distant wall. Then, while holding the
petri dish in place so that the beam light still falls on it, slide the
board underneath the dish until the magnet is underneath it. If you have a
strong enough magnet and haven't placed too much water in the dish (about
1mm is all that is necessary), the class will see a change in the spot of
light on the wall that is consistent with the effect that the magnet is
having on the water.
For those who would prefer to look directly at the surface of the water to
"see" the actual change in the shape of the water's surface, place a thin,
dull, black material between the magnet and the dish (or on the bottom of
the dish) so that you can reduce that amount of reflected light to just
that coming off the surface of the water.
------------------------------------------
With regards to bismuth and shotgun shells, check out:
http://scitoys.com/scitoys/scitoys/magnets/suspension.html
if you already haven't.
You may have to go to a large gun shop/sporting-goods-store that does a lot
of business with the hunting fraternity to find the shells you're looking
for.
Happy hunting.
ron
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