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Re: Teaching Magnetism



I am not familiar with the instrument but I can guess
why labeling may not be clear. Suppose a C-shaped
electromagnet is used to magnetize a bar magnet
inserted between its poles. It is obvious that the bar
magnet will have N where the S pole of the
electromagnet is. Likewise, the bar magnet will have
S where the N pole of the electromagnet is.

But the instrument maker has a dilemma. Should the
labels identify the poles of the C or should they identify
the poles of the bar magnet. No matter what decision
s/he makes somebody might be disappointed.

Fortunately the dilemma can be resolved by testing the
bar magnet. Then new labels may be made, if desired.
Ludwik Kowalski

On Monday, Jul 7, 2003, at 21:59 US/Eastern, Justin Parke wrote:

In a message dated 7/6/2003 10:39:31 PM Eastern Daylight Time,
britton@NCSSM.EDU writes:

What if the 'Commercially Sold' re-magnetizer is marked BACKWARDS?


Ahhhh I am not crazy after all. It seems the school at which I teach
bought
one of these before I got there. It seemed clear to me...an "N" with
an arrow
pointing down seemed to mean "put the north pole down" but alas it
does not.
Thanks for helping me feel not so alone!

Justin Parke