One of the problems of entering into discussions on points of physics
teaching is knowing when enough is enough and being prepared to
quietly fold up one's tent and slide away into the bush.
It's hard to resist the temptation to write a little more and to show
that you can be as thin-skinned as anyone (everyone) else.
So, staying around for a little while, I'll make some comments on Jim
Green's and John Denker's replies to my post. (BTW, thanks to John
Barrer's supportive reply off-line.)
Jim has problems with Callen's analogy:
He writes " Some of us look to the First Law and ask what then is "q".
You want to say that "q" and"q" are the stream and the rain below --"
Comment: It's Callen's analogy. not mine. And he has the stream as w,
not q; the rain is q.
Jim continues "But these are things that"flow". Some of us have found
that this image is very counter-productive. They end up thinking that
"q" (and maybe "w") are fluid-like and are "added" to the system and
then they are "inside" the system."
Comment: There's always the problem with analogies; they are not a
one-to-one correspondence. The processes involved in changing the
level of the lake do involve the transfer of substance (water). The
instructor would be well advised to probe, with appropriate Socratic
questioning, for signs of any "over-application" of the analogy.
Jim: "Traditionally the students confuse "q" with internal energy".
Comment: Yes, yes,yes. The analogy can be used (read it all) to help
with this confusion.
Jim: But it should be made clear to the students that "q" and "w" are
DONE tothe system - We can discuss just what to call them -- but they
are ACTIONS.
Comment: Yes -I like the word PROCESSES but ACTIONS is even more
direct.
Jim: And for some of us who regard the Second Law with some value, we
note that "q" is _work_ which _may_ be due to a temperature
difference, but need not be.
Comment: The Second Law is very important but, Jim, you lose me (am I
alone?) with your unusual definition of q in this context
Jim: While these brethren [Zemansky, Callen, Arons] made some
valuable contributions, if one wishes to promote the same picture, one
really should go back to Aristotle or before -- to those who started
this mess.
Comment: Don't damn them with faint praise. It's the work of
educators such as them who have made great strides in sorting out what
you refer to as Aristotle's and other's mess but which is really a
model built up with logical thinking and the application of
common-sense. The pity is that this model is unproductive - as Joule,
Carnot, Clausius and others found out.
Jim: for some of us, "for clarity and precision" we think that the
picture should be _correct_ rather than convenient.
Comment: I agree completely
Jim: This seems to be best done by never using the word "heat" .
Comment: This is one solution, somewhat extreme, but certainly worth
considering. I've looked at your web pages a number of times over the
past four years; why don't you polish them a bit more and look for a
publisher - even a privately published monograph would be worth while.
Jim: A postscript: does the list note that, in many of our
discussions, a suggesting is given and then many of the most
loquacious spent a great deal of time defending their then current
views -- their own status-quo.
Comment: Sorry, I'm so loquacious, Jim (although I believe the most
useful and interesting contributors to this list such as, but not
exclusively, Leigh and John and Michael and David and yourself are
quite loquacious).
Jim: It seems as if they we saying something like "Hey these have
been my views since HS or this is the way I have given my lecture for
many years and I am not going to change now."
Comment: I don't agree here. I think most of us are really receptive
to new outlooks and ideas. I've been involved with university
teaching for over 40 years now and, boy, have I have changed many
attitudes, beliefs and approaches. Coming across the electricity text
of Chabey and Sherwood a few years ago was a real eye-opener and
didn't it go down well in class. However, the Net and bouncing
e-mails back and forth isn't really the environment for
road-to-Damascus conversions.
This has got quite long (and loquacious). I'll comment on John
Denker's interesting and useful contribution later.