2.6 Physical Change

Define physical change.

Give examples of physical changes.

The melted ice cube may be refrozen, so melting is a reversible physical change

Physical changes that involve a change of state are all reversible.

Other changes of state include vaporization (liquid to gas), freezing (liquid to solid), and condensation (gas to liquid).

When a piece of wood is ground into sawdust, that change is irreversible since the sawdust could not be reconstituted

into the same piece of wood that it was before.

Cutting the grass or pulverizing a rock would be other irreversible changes

A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not.

In a reversible physical change, the original form of the matter can be restored.

In an irreversible physical change, the original form cannot be restored.

Melting ice and grinding wood into sawdust are examples of physical changes.