Re: [Phys-l] thermodynamics without entropy ?!??

[Bernard Cleyet <bernardcleyet@redshift.com>]

I wonder, has anyone measured the efficiency of a rubber 
refrigerator?    Would it work at 0 C *,  so one could freeze water? 
(big band little water)

Great demo. if possible.

A rubber formulation w/ typical room temp. properties at 0 C?

bc, first shown the cold rubber band in 1962, and has only a little 
understanding of adiabatic demagnetization.



chuck britton wrote:

> I'd gladly give up 'entropy' as soon as I see how to do the same  
> stuff differently.
>
> Introductory Thermo gets short shrift in most Intro Physics courses  
> and I suspect that the evil head of entropy is a major reason to  
> 'skip' it.
>
> Energy and Entropy are (IMHO) the two most important cross-discipline  
> topics that there are.
>
> How can I explain the cooling of a relaxing rubber band without a  
> handwaving salute to entropy etc.
>
>
>
> On Oct 3, 2007, at 3:44 PM, John Denker wrote:
>
>  
>
> > Has anybody recently looked at the last two chapters of
> >  Arnold Arons _Teaching Introductory Physics_ (1996)?
> >
> > IMHO it has problems.
> >
> > Chapters III-3 and III-4 are a long discussion of thermodynamics ---
> > mentioning heat, sensible heat, latent heat, caloric, friction, and
> > energy --- without ever mentioning entropy.  Ideas such as spontaneity
> > and irreversibility that are intimately connected with entropy are
> > almost-explicitly attributed to energy instead.  Also the student is
> > led by detailed historical arguments (*) to a wrong theory, namely
> > conservation of caloric.  This will have to be unlearned later.
> > Unlearning is never easy.
> >
> >  (*) Tangential remark: this is yet another illustration of why
> >  IMHO it is a bad idea to follow the "historical approach".
> >
> > The discussion of friction in section 4,22 seems like wrong physics
> > and bad pedagogy.  Including unobservable microscopic effects in W
> > largely defeats the purpose of thermodynamics.  (I can explain in
> > more detail if anybody is interested.)
> >
> > Is there something worthwhile I'm missing here?
> >
> >    
>