If we keep heating the water which has been formed in this way, its temperature again begins to rise, which is seen in faster and faster movements (now of displacement) of its molecules. The fastest can escape by breaking the surface and turning into gas. This process called evaporation, intensifies as temperature increases, but when it gets to 100 ºC, all the mass of liquid begins suddenly to change into gas forming bubbles in the middle of the liquid water. These bubbles rise and  burst into the atmosphere: we say that the water is boiling. The process is called ebullition. Evaporation and ebullition are two different ways in which a liquid changes state and becomes a gas, a process called vapourization.

Clothes dry because the water they contain evaporates, but it is not necessary for the clothes to have a temperature of 100º C.
In a saucepan on the gas water reaches 100º and starts to boil.

This journey from solid to gas can be made in the opposite direction. In this case it is not only unnecessary to heat the system but it must in contrast lose the same amount of heat that it gained before. The change from a gas to a liquid is called  condensation, and from a liquid to a solid, solidification (in the case of water it is also called freezing).

Finally, on some occasions a solid changes directly into a gas, this is called sublimation, and from a gas to a solid, reverse sublimation.