Re: Question about light and heat

[John Clement <clement@HAL-PC.ORG>]

Right is a moral judgement, and when there is not universal agreement on
what a term means or how it is to be used it is not proper to make such a
judgement.  Since we can not agree to a universal definition of the word
weight, then we will not be able to agree to a definition of the word heat.
 From the point of view of instructing students we need to start where the
students are, and not where we would like them to be.  This may mean using
words we consider imprecise as the noun heat or heat energy.  As the
concepts develop they can be weaned from this usage to more precise terms.
Remember, physics consists of models not absolute God given truth.

Since Halliday and Resnick is an introductory book the particular usage of
the word heat may be appropriate at that point in the development of physics
ideas.

In my class the MOP text uses the term microscopic energy.  However students
get the word microscopic confused with macroscopic and do not seem to able
to make the distinction between them very well.  The word heat does conjure
up images that can be correctly attached to the desired concept.  So heat is
a useful term.  If I fail to use this term, they will not make any
association between observable physical changes and the production of
microscopic energy.  I often bring out the idea that understanding of
physical phenomena means first looking at the big changes, and then later
investigating the small effects.  Many of my students are prepared to
understand that with more physics courses ideas must be refined or even
changed.  If they continue to take physics, they will be ready to use more
exact terminology.

BTW I think this is the way Arons might do it if he were teaching my
students.

John M. Clement
Houston, TX

> > From: Tina Fanetti <FanettT@QUEST.WITCC.CC.IA.US>
> >
> > > > 1) "Heat" is NOT energy even if one erroneously wants to thin
> of "heat" as
> > a substance.  There is no such "thing" as "heat" -- "heat" is done  on a
> > system not pored into it.<<
> >
> > HUH?
> > I am looking in Halliday, Resineck and Walker and it says that
> heat is transferred internal energy.  Is this not saying heat is energy?
> >
> Lots of textbook authors don't get it right!
>
>
> Cheers,
> Joe Heafner - Instructional Astronomy and Physics