A physical change is a change in which no new substances are formed. Physical changes affect the form of a chemical substance, but not its chemical composition. Mixtures can be separated into their parts by physical methods, such as spinning in a centrifuge. but can not usually be used to separate compounds into chemical elements or simpler compounds.
Most physical changes are reversible and their mass does not change. Examples: changes of shape, changes of states, passing electricity through a copper wire. Some physical changes are melting, freezing, boiling.