why is boiling a bulk phenomenon and why is evaporation a surface phenomenon?
while boiling a liquid ,say water or milk heating is to be done from the bottom of the vessel to bring the temperature of the entire liquid to its boiling point - so it is a bulk process.
During evaporation, the liquid evaporates from the top surface with out heating- say, evaporation of water from the surface of a lake or vesssel. Thus surface phenomena.