Changes of state are:
Evaporation is sometimes confused with boiling. They both involve liquids turning to gases, but evaporation is different because:
Evaporation cools liquids as a result of this energy loss. Evaporation is increased by higher temperatures, a greater surface area or a draft over this surface area.
A substance must absorb heat energy so that it can melt or boil. The temperature of the substance does not change during melting, boiling or freezing - even though energy is still being transferred.
A heating curve is a graph showing the temperature of a substance plotted against the amount of energy it has absorbed. You may also see a cooling curve, which is obtained when a substance cools down and changes state.
The temperature stays the same when a solid is melting or a liquid is boiling (changing state) during a change of state, even though heat energy is being absorbed.
The temperature also stays the same while a liquid freezes, even though heat energy is still being released to the surroundings.