Define evaporation. How does it differ from boiling ? How does evaporation cause cooling ?
Evaporation is change of a liquid into vapours at any temperature below its boiling point.
Evaporation is a surface phenomenon; it takes place at all temperatures. Boiling is a bulk phenomenon.
It takes place at fixed temperature. When a liquid evaporates, it draws the latent heat
of vaporization from anything which it touches or is in contact with. Thus causes cooling.