> > I hadn't really thought about it, but room temperature (say, 
> > 20C), is a bit closer to 0C than 100C!  :-)
> 
> Yes, but don't forget that the energy required for H2O to change state
> from liquid to gas is far more than the energy required to heat the
> same amount of liquid from 0C to 100C (if I remember correctly - it's
> been quite a while).
> 
I think you're right - its about 4 years since  did A-level chemistry, 
but vaporisation & fusion enthalpies were quite a bit greater than 
specific-thermal-capacities. Of course, if you're freezing, you have to 
deal with the enthalpy of fusion (ie. reverse the effect of melting). I'm 
not sure, but I think this is less than vaporisation (boiling).
Richard