Wednesday, 27 April 2011

Changes in matter.

There are two kinds of changes in matter:

- Physical changes.
- Chemical changes.

Physical changes: The matter is the same before and after the change. There is a change in physical properties ( size, smell or colour).

Chemical changes: a material or substance is changed into another one. The change is not reversible, the material or substance is different after this type of change.

Natural materials Vs. man-made materials.

Natural materials

They are found around us.
We have to take them from the living things or extract them from the ground (Minerals).

Man-made materials

We transform natural materials in many different ways, making them man-made materials. This process changes the properties of materials.