1. Exploring materials

2. Questions to think about…
How are materials different?
What are the different types of materials?
How are materials chosen to make objects?

3. What are the different types of materials?
Materials are used to make many objects around us.
Some common types of materials are wood, metal and plastics.
Can you think of others?
To make objects, materials are chosen based on properties that suit their use.

4. Trees are cut down for wood.
Wood comes from trees.
These objects are made from wood.
Trees are cut down for wood.

5. Objects made from glass can be seen through.
Glass is made from sand.
Glass is used to make objects such as window panes, aquariums, spectacles and glasswares such as bottles.
glass aquarium
Objects made from glass can be seen through.

6. Rubber Rubber is made from the sap of rubber trees.
Rubber is used to make objects such as rubber bands, erasers, tyres, gloves and balloons.
sap of rubber

7. Metals Metals come from the ground.
There are different types of metals.
Iron, aluminium and gold are some examples.
raw metal from the ground
objects made of metals

8. Ceramics Ceramics are made from clay.
There are a few types of ceramics.
Mugs, flower pots, floor tiles, bricks and even man-made teeth are made from ceramics.

9. Fabrics Fabrics can come from animals or plants.
Wool and silk come from animals, while cotton comes from plants.
Fabrics can also be man-made.
Fabrics are used to make objects like curtains, clothes and bedsheets.

10. Plastics Plastics are made from oil obtained from the ground.
Many objects around your home, such as containers and cutlery, are made of plastics.
There are different types of plastics, which can be made to look and feel like wood, metal and glass.

11. Why do we classify materials?
For example, at supermarkets, kitchenware made of the same material is usually placed together.
It is useful to classify objects based on the materials they are made of.
How is this useful?
plastic
containers
ceramic
cups

12. How are materials different?
Each material has its own characteristics or properties.
These include strength, flexibility, transparency, ability to float or sink in water, and being waterproof.

13. Paper is not strong. It tears easily.
Strength
The strength of a material is its ability to be pulled without breaking or tearing.
A material can be strong or weak.
You can try to tear or break an object to test for its strength.
Paper is not strong. It tears easily.
Plastic is strong.
It does not tear easily.

14. Wood is stiff. It is not flexible.
Flexibility
The flexibility of a material is its ability to bend without breaking.
A material can be flexible or stiff.
You can try to stretch or bend an object to test for its flexibility.
Wood is stiff. It is not flexible.
Plastic can bend.
It is flexible.

15. Transparency
The transparency of a material refers to how much light can pass through it.
A material can block light or allow light to pass through it.
You can try to shine light through an object to test whether it allows light to pass though it.

16. Ability to float or sink in water
A material can float or sink in water.
You can try to place an object in water to test whether the object will float or sink.
The wooden chopsticks float on water.
The metal chopsticks sink in water.

17. Waterproof A waterproof material does not absorb water.
You can try to drop water on the surface of an object to test whether it is waterproof.

18. How are materials chosen to make objects?
What materials are the objects shown made of?
Why are these materials suitable for making the objects?
This nail is made of metal. Metal is strong. The metal nails can hold up a heavy bookshelf on the wall.
This desk and door are made of wood. Wood is stiff and strong. The desk and door do not break easily.
This curtain is made of fabric. Fabric is flexible. The curtain can be folded at the side of the window.
This bag is made of plastic. Plastic is flexible and waterproof. Different objects can be placed into it and they will not get wet.
This hose is made of rubber. Rubber is flexible. The rubber hose can bend easily.
This window pane is made of clear glass. Glass allows Joe and Sue to see through it.
Ceramics are used to make the bricks of this wall. Ceramic is very strong. The wall cannot be easily broken.

19. How are materials chosen to make objects?
Sometimes, no one material has all the properties that are required in an object.
We usually see an object that is made of more than one material, like the shoe shown on the right.
fabric
metal
rubber
Why are rubber, metal and fabric used to make this pair of shoes?