[time-nuts] Mass vs BTU Function

[Mike S]

At 05:33 PM 1/27/2011, J. Forster wrote...
>If you want the thermal mass to behave close to an isothermal body,
>diffusivity is very important.
>
>For example, a large mass of still water has high heat capacity, but 
>poor
>diffusivity. Much of the heat capacity is useless.

If the equation given ["Thermal Diffusivity" = (Specific Heat) / 
(Thermal Conductivity)] is correct, then lower conductivity is desired 
for greater diffusitivity.

I'm not clear on how low conductivity helps make an isothermal mass - 
intuitively, it seems the opposite is desired, so that any local 
temperature variations are quickly balanced through conduction.