Re: simplier is mor difficult

[LUDWIK KOWALSKI <kowalskil@alpha.montclair.edu>]

Date: Wed, 08 Oct 1997 11:49:06 EDT
From: twayburn@juno.com (Thomas L Wayburn)

                   Now Tom is certainly writing about elecro-magnetism.
> ....  stuff about field lines, which must be the E & M version of 
> caloric (just kidding). 

Why "just kidding"? Forget about B being a relativistic manifestation of 
E and focus on the main issue of this thread. Once again it is a matter 
of pedagogy, not physics. A caloric substance does not exist but we can
pretend it does exist and solve many practical problems. The magnetic
poles do not exist but we can pretend they do exist and understand many
gadgets, such as dc motors and galvanometers. By the way, Herb, when will
the correct answer to your bar magnet problem be posted? Are we allowed to
think in terms of the N and S poles? 

I hope to learn more about the B versus E ideas from messages which follow 
those of David Bowman and James Wheeler. But my initial purpose was to say 
that magnetic poles should be part of our vocabulary. And I wanted to discuss 
the concept of simplicity.

> Avoiding the N-word is not easier than avoiding the Q-word. How can we
> teach electricity to non-science majors without using the old magnetic
> poles idea?  Why should we try? What kind of harm can result from saying
> that "in the first approximation a bar magnet, or a planet, behaves as 
> if ..."?
>
> Yes, I do know that magnetism can be presented without introducing the 
> N-word. ... [Some] would say that physics becomes simplier when the 
> unnecessary concepts are eliminated. But what is simplier for them is not 
> always simplier for me, or for my students. Simplifications often make 
> things more difficult. Try to explain a primitive dc motor without using 
> the N, S and B words.
                                                      Ludwik Kowalski