Re: What Flows?

[palmer@sfu.ca (Leigh Palmer)]

James McLean says:

> More semantics.  Some call it internal energy, some call it heat.  Can
> anyone relate an instance where using the noun 'heat' instead of 'internal
> energy' actually caused confusion among students?

Yes. I see it every time I teach thermodynamics.
It is likely the most common cognitive error made
by my students. Jim shouted it; I'll whisper it:

               heat is not energy

This is not "semantics" as you put it; it is the
conventional terminology. Why don't you speak of
work energy, or for that matter torque energy? No
one would be confused if you said "the automatic
transmission boiled over because it received too
much work energy". One would simply correct your
error and recognize that what you really meant
was that it boiled because its internal energy
became too high when too much work was done on it
(actually work was done at too high a rate,
exceeding the power dissipation capability of the
transmission). Clearly the energy that made the
transmission boil over was not heat energy; it
was not heated!

Internal energy is neither heat nor work. Calling
internal energy "heat" won't make it so.

Leigh