Observe the materials around you. These materials are either natural materials or man-made materials. Natural materials are found in nature. Man-made materials are made by man.
- An eraser is made of rubber. Rubber and silk are natural materials. Do you know why?
- Plastic and synthetic cloth are man-made materials. Do you know why?
- Petroleum is a natural material. We can use petroleum to make plastic. This shows that we can use natural materials to make man-made materials.