Re: Meauring Volts?

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

On Monday, December 9, 2002, at 12:30  PM, Jim Green wrote:

> Ludwik, should we stop  discussing the "flowability" of "energy"
> and "heat"?  Is that discussion also meaningless?

No. To illustrate what is usually meant by this let me invent
a trivial problem. You have two identical tanks with 10 kg
of water. The tanks are coated with thick layers of Styrofoam.
The constant temperature in the tank A is 90 C and that in
B is 20 C. The heat capacity of containers is negligible in
comparison with that of water.

At time zero a thick silver rod is used to link the containers.
The temperature of A starts going down while that of B starts
going up. The rod is removed when the temperature of A
becomes 65 C and temperature of B becomes 43 C.

1) How much thermal energy (heat) was lost by A?
           Q1=c*m*dT1=1*10000*25=250,000 cal
2) How much thermal energy (heat) was gained by B?
           Q1=c*m*dT2=1*10000*23=230,000 cal
3) What happened to the missing 20, 000 calories
     of heat? Part of it  was probably still in the rod and
     the rest in the surrounding air.
4) Is it correct to say that 230,000 calories of heat
     (thermal energy) was transferred (flowed) from
    A to B? WHY NOT?

If my memory is reliable, problems of that nature were
modeled it terms of caloric, a fictitious substance. The
concept of thermal energy, and of molecular motions,
were introduced much later. What was wrong with this?
Ludwik Kowalski