Learn more physics!
Does the rate at which you heat a substance matter? Such as heating an element to its evaportation point or boiling point in a few seconds.
Genearlly speaking, heating rates do affect what happens. For example,
if you heat a glass very quickly, thermal stresses between different
parts of it may cause it to crack. If you heat water quickly to above
its boiling point, it may become significantly superheated (staying
liquid even above the boiling point) so that when it does start to boil
it can boil explosively. The general point is that it takes a while for
things to reach internal thermal equilibrium, so if they are heated too
fast the can fall out of equilibrium, so different things happen than
would happen in equilibrium.
(republished on 07/27/06)
Follow-up on this answer.