Re: heat is still a noun

["John S. Denker" <jsd@MONMOUTH.COM>]

At 05:04 PM 5/7/01 -0700, Larry Woolf quoted Craig Bohren as saying:
> Some of my heretical ideas about heat were presented last year at a Gordon
> Conference on the teaching of thermodynamics. I shall send you the relevant
> sections as an attachment. Anyone who wants the full text can write to me,
> but it is not for the faint of heart.

Larry forwarded an attachment to me.  It is only a couple of pages.  I
suspect this is not the "full text".  In any case it didn't cause any great
stress on my heart.

It begins:

> Consider the following piece of nonsense, taken from a  famous textbook of
> physical chemistry. Hydrogen and oxygen are enclosed in a rigid, insulated
> container. They react to form water. The book says that in this process
> heat is absorbed? Where on earth from? From the ether? By anyone's
> definition, this is an adiabatic process, one in which no "heat is
> absorbed or emitted (ugh!)". In fact, on a previous page of this textbook
> an adiabatic process is so defined. But then the author forgets what he
> said previously and presents us with an adiabatic process in which is
> "heat is absorbed" but who knows from where.

I don't know what "famous textbook" is being cited.  I don't know what it
was trying to say.  Maybe it made sense in context, maybe not --- but it
doesn't even matter for present purposes.  My point is that even if the
"famous textbook" is guilty of abusing "heat" (the noun), that does NOT
imply that all uses of "heat"(n) are abusive.  I've seen lots of students
abuse F=ma, but I don't hold it against Newton.

To summarize:  The section of argument quoted above is formally
invalid.  It rests upon an invalid generalization.

==================

In the next section the argument continues:

> Since heating and working appear symmetrically in first law, why is it
> that we don't refer to the amount of work in a body or the work added to
> it or absorbed by it or the work content? We don't, because we recognize
> that working is a process, and work is not a substance, but heat still
> survives as a substance, a thing.

a) It would be a fallacy to speak of the amount of "work" in a body the way
we speak of the amount of energy in a body.  This is such an obvious
fallacy that it is hard to imagine anyone committing it.

b) It is not necessary to write the first law of thermodynamics in such a
way that "heat"(n) and "work" appear symmetrically.  Similarly, it is not
necessary to write it in such a way that "heating" and "working" appear
symmetrically.  Doing so is quite common, but it is not necessary and it is
not wise.

 -- I agree to the highly conditional statement that IF one imposes a
symmetry between work and thermal energy, which is fallacy (b), THEN one
quickly produces fallacy (a) and related fallacies.
 -- HOWEVER it is not necessary to commit fallacy (b), and therefore this
indictment against "heat"(n) must be dismissed.

I emphasize yet again that the main issue here is not something as
superficial as the meaning of a single word;  it has to do with how the
first law is formulated and interpreted.

=================

In the next section the argument continues:

> Consider the following simple demonstration. I rub my hands together
> vigorously, thereby experiencing the feeling of warmth. There are two ways
> of describing this: heat was generated (despite this being an essentially
> adiabatic process ); or, the temperature of my hands increased.

1) This argument is formally invalid on its face.  There is no basis for
the assertion that there are only two ways of describing this
process.  Everything that follows from this false assumption is invalid.

2) Moving from formal logic to physics:  It is clear that non-thermal
energy is being transformed to thermal energy.  Although the process is
adiabatic (using the definition that was intended(*)), the process is
certainly not isentropic.

        (*) Note there is some lack of consensus as to what "adiabatic"
        means.  A lot of people say "adiabatic" in cases where saying
        "isentropic" would be more nitpick-resistant.


This section continues:

> How do I measure the amount of heat generated?

Try this:
  http://www.google.com/search?q=calorimetry

I got 41,000 hits.  There are entire books on the subject.  I even saw
something called the "56th Calorimetry Conference".  Maybe some people
don't know how to measure heat, but there are a heck of a lot of people who
do know how.

> By letting it drip into a can?

Colorful language cannot take the place of a scientific argument.

> So let's get rid of heat as a substance once and for all from thermodynamics

I'm not sure what "substance" means in this context.  There are lots of
important things (nouns) in physics that are not "substances" in the usual
sense.

> and teach our students that heating  is a process in which a system's
> energy increases or decreases by virtue of a temperature difference
> between it and its surroundings.

That conclusion is not at all supported by the arguments given.

=============================================

The rest of the document is devoted to a discussion of "substances" and
"substantives".  It cites a paper
        "published in, of all places, The American Journal of Psychiatry".
among other arguments.

Alas, the whole line of reasoning is very misguided.  Suppose you prove
that "thermal energy" or "heat" is not a "substance" -- so what?  That does
not prove that it is not a "thing" (the sort of thing that is represented
by a noun).

As I have said before, my opinion is supported by my dictionary (Random
House) which gives 21 definitions for the word "thing".  Of these, items 3,
4, 5, 6, 7, 8, 11, 13, 15, 16, 18, 19, 20, and 21 clearly refer to
abstractions and/or
intangible things.

Saying that heat cannot be a "thing" is not merely pedantry -- it's just
plain wrong.