Re FLOW of energy

[LUDWIK KOWALSKI <kowalskil@alpha.montclair.edu>]

"The internal energy of cube A increases by 500 J and that of cube B 
decreases by 500 J". There is absolutely nothing wrong with this, Jim.
But my question was not answered. I wanted to know:

> Why is it bad physics to say that there is a flow of 500 J of energy,
> from cube A to cube B, during the equilibrating process? 

Actually, let us look at these two formulations more critically. Yours 
seems to be more general, it may be a statement about a block A in 
Sahara desret (when sun is rising) and block B in my home refrigirator.
The blocks are not interacting. It just happens that A gained 500 J of 
energy (flowing from the sun) while B lost the same amount (flowing into 
air of my kitchen). This is not the same as "internal energy flows from
A to B". You may think that I am being picky (the context in which we
describe what happens makes it clear that A and B are interacting) but
I am not. As long as the context is specified your formulation is as good 
as mine, perhaps a little better. 

At the end you wrote that you "have no trouble saying things like BLOCK 
A DID WORK ON BLOCK B". I am still thinking about this alternative. The
law of consrvation of energy is more profound than we often think. Is the 
concept of FLOW an essential part of thermodynamics or not? I do not have
an opinion. The block A in Sahara does not work on the block B in my 
refrigirator, at least not directly. Sorry for being philosophical today.

                                                     Ludwik Kowalski