Evaporation is the way that liquids turn into gases. The most common liquid to turn into a gas is water. If you leave liquid water in a saucer for a few hours in a warm room, it will disappear, as the water evaporates, that is it changes from liquid that we can see to water vapour, which is a gas we can't see.

If you put the same saucer in a very cold room it might take weeks for the water to evaporate. This shows that evaporation needs warmth, that is heat. Heat is a form of energy.

The best way to evaporate something is therefore to heat it.

Why does liquid water need heat to evaporate? Because water is made of tiny particles called molecules. In liquid water they are all touching. In a gas they are all separate. When you heat water, the molecules take up the heat and begin to shake about. Eventually they shake about enough to break free of the water and they then float up into the air.