Re: [Phys-l] [off list] entropy +- heat

[Ludwik Kowalski <kowalskil@mail.montclair.edu>]

On Jul 23, 2006, at 7:51 AM, John Denker wrote: (in a private message).

> Hi --
>
> 1) Procedural remark:  Your recent posting to phys-l was so badly 
> formatted as
>  to be incomprehensible.  Passages that were supposed to be quotations 
> were
>  not accurate quotations.  I couldn't tell what you were agreeing with 
> and
>  what you were disagreeing with.  Please try again.  Find a way of 
> formatting
>  things so that quotes look like quotes, and your own words look like 
> your
>  own words.
>
> 2) Physis remark:  I think you were trying to defend the idea of 
> defining
> energy in terms of "MECHANICAL WORK".  If so, some obvious questions 
> arise:
>  -- How do you define "MECHANICAL WORK"?
>  -- How is that different from plain old "work"?
>  -- Exactly what is the definition of energy you are advocating?
>  -- How do you explain the two-potato heat engine, where the amount of
>   energy and the amount of work do not correspond?
>  -- If energy is defined in terms of work, and work is defined in terms
>   of something else, and that is defined in terms of ...., where does
>   the process end?  That is, if each concept is defined in terms of
>   something more fundamental, what is the *most* fundamental concept?
>   How do you anchor the chain of definitions?

John:
I was not advocating anything new; I was only commenting on your 
innovating sequence. Yes, by "work" most authors do mean "mechanical 
work." This is not a difficult concept, once the idea of force and 
displacement are introduced. Sorry for the confusion created by using 
quotation marks for the emphasis.

I added "mechanical" because I remember reading (long time ago) about 
other kinds of work. That is what came to my mind when I saw your 
comment that work is a difficult to define concept. Your Two-potato 
steam engine is great; I would refer to it if I were still teaching. I 
am certainly not against innovations in teaching. But I am not 
convinced that your sequence is appropriate for the first physics 
course. That was the most important part of my comment.

P.S. You asked:

>  If energy is defined in terms of work, and work is
> defined in terms of something else, and that is
> defined in terms of ...., where does the process end?

I do not know how to answer this question.

Ludwik Kowalski
Let the perfect not be the enemy of the good.