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Re: What Flows?



1. At some particular level, it is often the case that more than one
description of a phenomenon or class of phenomena will work equally well.
Isn't it a waste of time to argue over points until we decide what level
students we are talking about and have some realistic idea what their
experience and initial conceptions are? It is entirely possible that for
many students at the introductory level the points we argue are esoterica
with no logically necessary basis in _their_ experience with the phenomena
(including what we show them in class). Hence, the relevance and
significance will not be meaningful at all.

Insisting that our students accept a more complicated explanation for their
experiences than their experiences (including those we provide in class)
'logically demand or support' is a kind of training which is _exactly the
opposite_ of what we wish, namely: accept this more complicated explanation
for which you can see no logical requirement because We say it is True.
So, whether they are non-science majors or they are physics majors, this,
it strikes me, is not something I, and I hope others, would ever want a
part of.

We are not discussing a topic which is within their realm of experience;
we are talking about building an understanding of Nature. She will present
them with many counterintuitive experiences in their intellectually naive
state. It is our purpose to cast some light onto the problems they perceive.
We will certainly not advance them toward the goal of enlightenment by
telling them what is untrue or misleading or useless.

A good example: If hot air rises, why is the atmospheric temperature
gradient usually negative? Shouldn't the equilibrium condition of the
atmosphere be one in which the warm air overlies the cool? Most people
know that "hot air rises" and most people also know "it's cooler in
the mountains". You as a physics teacher have the obligation to point
out to them that this is a paradoxical situation, and as a physics
teacher you ought to be able to take the best student to a higher level
of understanding. You won't help things by gratuitously perpetuating
physical falsehoods. One cannot synthesize from factoids like those I
have mentioned. Moreover misconceptions are no more valuable after the
last exam is written than they were when brought in to be nurtured.

2. Do we have _any_ justification for being so arrogant as to insist that
we are so absolutely in the possession of Truth that we can take the
responsibility of dictating language and "stamping" what we do not like
out? The history of physics certainly does not justify such a position.

I would have said that it does. Hasn't physics advanced our knowledge
of Nature remarkably by doing just what you're objecting to? I thought
we were doing pretty well. We are, if anything, less inclined to think
we know absolute truths than the great unwashed are.

3. Do we have _any_ evidence that the insistence on using particular words
has any significant effect on the thinking of any significant number of our
students concerning the nature of the phenomena? This has been advocated
and practiced many times before, but one could argue that what we
accomplish is turning people off to us and our profession more than
instilling in them any of our 'Truth.'

Now you're beginning to hurt! A significant number? No, certainly not
a large fraction of the general physics students I have in my classes.
I frequently encounter my old students in daily life (I've been teaching
here for 30 years) and they are very enthusiastic and pleased to bring
me up on their activities subsequent to graduating. Of course the only
ones who ever approach me are the ones who liked my course, so my sample
is probably skewed. They mostly all tell me how much they enjoyed my
course back then. Only very rarely does one of them tell me that he was
greatly enlightened by the course. I do think that they learn something
from me, however. No small number of them are* now physics teachers, and
the chances are that if they liked my course then they will perhaps
think favorably about my methods from time to time and act accordingly.

Leigh

*See, I'm a regular guy. I toss off ungrammatical usage with aplomb. It
is enough for me that I notice it when I'm doing it.