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Re: pound mass and pound force



On 27 Aug 1997 Leigh Palmer praised astroners for not confusing people by
changing things too rapidly.

Astronomy provides my ideal model. Astronomers don't change their
conventions over periods as long as millenia! The result of such
regressive behaviour is that the literature of astronomy is accessible
clear back to the old guys like Hipparchus.

I do not know why I am placing myself on the other side of the barricade
again. But I can not help to notice that you are not practicing what you
preach. Heat as a "form of energy" was in textbooks, and in common use,
before the thermodynamic path-dependence of Q was clearly identified.

If this is true (?) then you should be the first among those who want to
rename Q in thermodynamics (more than no-to-noun and yes-to-verb). Don't
you want Millikan, Zemansky, and all other good old books, be accessible
to readers of many generations?

Certainly not! I wasn't referring to textbooks anyway. They are at best
ephemeral, at worst shot through with error. Describing heat as a form
of energy is certainly a gratuitous error in a textbook. There is no
good reason that piece of misinformation should ever appear in a physics
textbook. Who, pray tell, is valuably informed by such a description? Is
work, too, a "form of energy"? Why could one not describe heating and
working as processes by means of which the energy of a system may be
changed? Rather than introducing ideas that are wrong in the context of
physics, why not introduce correct ideas? What is the virtue in the
statement "heat is a form of energy" which makes it a better thing to
tell a naive physics student than "heating is one means of increasing
the energy of a system." Is the latter factoid less assimilable?

Note that all I have said presumes that a suitable foundation for the
statements has been laid by introducing the concept of energy before
anything at all is said about heat. I suspect that too little attention
is usually paid to this preparation to make possible the understanding
of what heating is for the great majority of students. The definition
Ludwik advocates will merely perpetuate the student's intuition for the
caloric theory by saying "heat is".

I'll finish with the question that a reasonably intelligent student
might ask (and that Benjamin Thompson did ask). "If I rub my hands
together hard and fast, does heat build up in them? Where does that
heat come from?"

Leigh

"Heat is work and work is heat." - Flanders and Swan