Re: [Phys-l] workable versus unworkable energy

[John Denker <jsd@av8n.com>]

On 01/11/2007 12:48 PM, Rick Tarara wrote:
> How you talk about energy and work seems to me to depend on how 
> microscopically you want to analyze the situation.  For example, if I have a 
> block that increases in temperature I could choose to look at the fact that 
> the average, translational kinetic energy per molecule has increased. 


Why say it that way?

I could understand if people wanted to speak in shorthand,
by leaving out certain details ... but why insert details
that (a) add complexity and (b) aren't correct?

First of all, why say "translational"?  In the case of /gas/
molecules, translational is meant to contrast with rotational
and vibrational.  In an ordinary solid block, the thermal
energy is mostly all vibrational.  I'm pretty sure translational
is the wrong word.

Also, why say kinetic?  What does that bring to the table?
In ordinary solids, half of the thermal energy is kinetic,
but why focus attention on that half?  Why not just say
"energy" rather than "kinetic energy"?  It is less detailed,
more convenient, and more correct.