Theme 3: Investigating Materials

Unit 5 Materials


1. Variety of Material
(a) Different object may be made of different materials.

(b) Different materials may have different properties.

2. Choice of Materials

(a) The material chosen to make an object depends on the properties of material. The properties of the material must suit the function of the object

(b) More than one material are usually used to make an object

(c) Natural and Man Made Materials

1. All materials can be divided into two big groups- natural materials and man-made material

2. Natural materials are found in nature. Natural materials include plant and animal parts and minerals.

3. Man- made material are made by man from natural material.

3. Conserving Material

(a) Some natural resources are renewable.

(b) Some natural resources are non-renewable.

4. Reusing, Reducing and Recycling Materials

(a) We need to conserve materials by reusing, reducing and recycling.

(b) Reusing mean using something again.

(c) Reducing mean using less amounts of material than usual.

(d) Recycling means reprocessing unused or waste materials into useful new products

5. Rusting

(a) The surface of a rusted or rusty object is covered with rust. Rust id reddish-brown.

(b) Only object made of iron can rust.

(c) Rusting occurs only if both air and water are present.

6. Preventing Rusting

(a) To prevent rusting, we need to keep object made of iron away from air and water.