Changing its temperature can change matter from one form to another form. If you freeze water, which is in a liquid state, it changes into a solid state (ice). If you boil the liquid, you see the liquid escaping in the form of bubbles and changing into a gaseous state. These states of matter are only the physical properties. There is no change in its chemical composition. Ice and water vapor continue to be water in different forms or states. Sometimes a liquid can be sitting there and its molecules will become a gas. That is called Evaporation. You might be wondering how that can happen when the temperature is low. It turns out that all liquids can evaporate at room temperature and pressure. Evaporation takes place when there are atoms or molecules escaping from the liquid and turning into a vapor. Water is a good example for evaporation and melting. Water is transferred from the surface to the atmosphere through evaporation; the process by which water changes from a liquid to a gas. Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state.