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Re: Appropriate for Gen Phys? was: comprehending electric/magnetic interactions



On Thu, 3 Jul 2003, Brian Whatcott wrote:

At 06:09 PM 7/3/2003 -0500, John Clement, you wrote:
/snip/
Incidentally some other misconceptions involve the belief that students
have that magnets pick up metals. Of course they are also given
aluminum and copper to play with. In addition students will tell you
that magnets lose strength because the "magnetic particles" recombine or
they drop out when magnets are dropped.

/snip/

John M. Clement
Houston, TX


It's understood that John is writing in shorthand, and that he expects
us to realise that magnets do indeed pick up *some* metals,
and that *some* magnets do indeed lose strength when dropped.
So his issue is the generalization of observables, and the conceptual models
brought to bear: 'recombining magnetic particles' versus 'randomizing
magnetic domains'. This last arouses no great missionary zeal in me:
but I am not teaching the topic.

Exactly! What experiment demonstrates that the "dropping
the magnetic particles" explanation is wrong? The entire philosopy that
most of us want to promote is "learning from experiment". So there is a
level at which "particle dropping" is as good a hypothesis as any.
In my experience it adds fun and interest to the classroom to
tentatively adopt primitive explanatios - the only proviso is that the
explanations must eventually be tested.





Brian Whatcott Altus OK


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