Dave says:
> When ice sublimes, or water evaporates, a similar process may be taking
> place. Heat is extracted from the water remaining during vaporization so
> that a net cooling of the remaining water takes place. If I recall, wind
> blowing over a wet leaky bag is used for cooling in some locals. Vapor
> sprays can be used in a similar fashion.
No, it's not a similar process. Macro "temperature" is a statistical effect
(an average of molecular energies). The molecules leaving water as it
evaporates are those with highest energy (they escape easiest). This also
accounts for the lowering temperature effect of evaporating fluids. Yes, in
some countries when the weather is (very) hot, people hang damp cloth in the
windows to lower the air temperature.
/Sunil
