What is evaporation And Why does evaporation cause cooling

What is evaporation? Why does

evaporation cause cooling? 

Answer: The process in which a liquid changes into its vapour state at temperatures below the boiling point is called evaporation. 

Evaporation is an endothermic process i.e. liquid absorbs heat during evaporation. This heat may be provided either by the surroundings or by liquid

itself. When the evaporating liquid takes the required heat from other parts of the liquid, the rest of the liquid cools down. 

On the other hand, if the liquid takes

heat from the surroundings, it causes cooling of the surroundings. 

E.g. on a hot day (sunny day), we perspire. When this sweat evaporates, it absorbs the required heat from our body, and we feel cool.