Evaporation causes cooling

Evaporation: conversion of a liquid into its vapour either by exposing the liquid to air at the room temperature or by heating it below its boiling point is called ‘evaporation.’ For example: take common salt or sodium chloride in a porcelain dish and place it on water bath. After some time, the water from the porcelain basin has evaporated, leaving behind sodium chloride as residue.

Explanation for the process of evaporation: As the particles of liquid are constantly moving, they collide with each other. They also collide with particles of air when left exposed. In doing so, some of the particles at the surface of the liquid acquire extra energy and overcome the intermolecular forces of attraction that pull them back and keep them with the bulk of the liquid. These highly energetic particles leave the surface and go into vapour.Evaporation causes cooling: when the surface particles take up energy and escape into air as gas. This results in fall of temperature of liquid. The liquid is thus cooled.