Page 151 - Primary Five Science

3. Physical changes

These are changes that do not alter the chemical composition

of the substance. These changes are reversible.

Changing the state of a pure substance between solid, liquid,

and gas phases of matter are all physical changes since the

identity of the matter does not change.

Examples of physical changes

 Melting an ice cube  Boiling water

 Freezing of liquids  Evaporating alcohol

 Sublimation  Shredding paper

 Dissolving of solutes such as

sugar and water

 Condensation

 Crumpling a sheet of alumi-

num foil

 Casting silver in a mold

 Breaking a bottle

Characteristics of Physical

changes

1. The substance does not

change

2. The changes are reversible

3. No heat is given out or absorbed

4. The final product is physically different but remain the same

chemically.