> That is very interesting to know, Thank you. I have heard many
people tell
> me that they "feel" an intuitive qualitative difference between
water heated
> in a microwave and water heated on a stove. Perhaps their
intuition is not
> off at that. Next time someone tells me that I will tell them
that there is
> a difference. Thanks again,
> William


Well, there is a difference, in a puristic sense. The heating takes
place as a result of two different mechanisms of energy tranfer.
One a stove, a thermodynamic convection process is occuring whereby
heat is tranfered from the coils of the burner, through the metal of
the pan (of heat capacity C), and then into the water (heat capacity
4.184 J/g deg C). In a microwave, electromagnetic radiation that is
resonant with a rotational transition is impinging upon the sample
(water), and causing excited rotations. So the first mechanism can
be treated more thermodynamically, and the second mechanism is
treated quantum mechanically (or statistically mechanically, if you
prefer).

One interesting side note:

Because in a microwave, there is a discrete amount of microwave
photons that are required to affect a certain amount of heating,
normally placing twice the amount of material to heat requires about
twice as much exposure time. In the oven, heating twice as much of
something does not seem require the same condition. The microwave
must produce twice as many quanta of energy (therefore, twice the
time). The oven simply must maintain a specific amount of heat in
the oven to keep the temperature constant. Not quite as much time
is required to do that.

Jesse