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HEAT1=HEAT2 ?



On 8/31/97 Jim Green <JMGreen@sisna.com> asks:

... What are you now going to call the "Q: in the First Law: dU=Q+W.
U is internal energy, no? You don't want to change *that* do you?
What *you* suggest above is to call U "heat"="internal energy". ...
I don't see how using two words for U helps.

It is not "two words for U" (the status quo situation) that I consider
to be the source of confusion. It is ONE word for TWO DIFFERENT concepts,
Q in the first law and q in elementary teaching. I was suggesting that
we tolerate the noun "heat" as a synonym of U. The main point, however,
was that it is bad pedagogy to use the same word (heat) for both U and Q
in the FIRST LAW. Tolarating the noun "heat" as a synonym for U would,
as you are pointing out, lead to this situation. Leigh tries to eliminate
confusion by avoiding the noun "heat".

A suggestion for calling Q "thermal pseudo-energy" (emphasizing its path-
dependence) can be debated, the main point is to stop calling Q "heat".
Why there is so much fuss about a trivial renaming (affecting only an
advanced course)? I would like to return to your suggestion of calling
Q "work". But let us wait for the current two threads on energy to be
exhausted.

There is nothing wrong with forgetting the noun heat, while referring
to q, and using the internal energy instead. But how can this be done
without a coordinated effort of all textbook writers, all authorities
and all librerians? The battle is not worth fighting; we can use our
mental energies more productively on really important issues. Such
issues are often raised on phys-L; "the same name for Q and U" is just
one of them.
Ludwik Kowalski
P.S.
I have to understand better the argument of "no FLOW of energy either".
Perhaps somebody will help me by answering the two questions on that
topic; they were reposted this morning.
Happy new academic year to everybody.