PHASE CHANGES
Matter can exist in three states, or phases a solid phase, a liquid phase, or a gas phase. A solid is matter with definite shape and
a definite volume. Coal, wood. potatoes, and apricots are solids. Liquid is matter with no definite shape, but with a definite volume, such as coffee or fruit juice. Gas is matter with no definite shape or volume, such as air or oxygen. A phase change is a physical change of matter from one state to another. Freezing is the change from a liquid phase to a solid state Melting is the process in which a solid changes to a liquid. When ice melts, for example, the resulting product is liquid water. This has exactly the same chemical formula, H2O, as the ice had. The phase of the sample has changed but it is still water The same would be true if the liquid water were boiled and changed to steam. Vaporization (vay-pur-ih-ZAY-shun) is the process in water can exist as a solid, a liquid and a gas.