Natural sciences
The earth and beyond
Properties and uses of materials
Educator section
Memorandum
| TYPE OF MATERIAL | Metal | Ceramic | Glass | Plastic | Fibre |
| EXAMPLE | Iron copper | bricks ornaments | bottles ashtrays | plastic-bowls | cotton polyester |
(There can be many other examples)
Assignment 10:
4 (Individual)
The newspaper and flour are wet with water. Then they are mixed to make a new material, paper maché. Through this process a new mixture / compound is created.
By mixing certain materials we can create new products.
(There can be many other examples)
Assignment 11:
4 (Individual)
| NATURAL MATERIALS | SYNTHETIC MATERIALS |
| cotton, silk, wool linen, etc. | polyester, acrylic, viscose, glass fibre |
(There can be many other examples)
Leaner section
Content
Activity: to distinguish the most important groups of materials [lo 1.2, lo 1.3, lo 3.2]
- Materials can be classified in various ways.
- Let's look at the groups you already know
| Type of Material | Metal: | Ceramics: | Glass | Plastic: | Fibre: |
| Example | ____________ | ____________ | ____________ | ____________ | ____________ |
Mixtures / Compounds
New products are formed when we combine different materials. We can combine water, milk, sugar and coffee powder to make a cup of coffee. We can also combine substances in various ways by mixing them. The appearance and texture of the product usually differs from the original materials. Another example of a mixture is safety glass. A thin plastic layer is sandwiched between two layers of glass.
ASSIGNMENT 10 (INDIVIDUAL)
- To make something by combining substances (materials).
When we combine newspaper, flour and water we get papier-mâché. Make your own dinosaur in the following way.
Requirements:
Water
Flour
Metal wire
Pair of pliers
Newsprint
Paint and brushes
String
Procedure:
- Mix one cup of flour with three cups of water.
- Stir the mixture until it is smooth and creamy.
How to make a wire framework for the dinosaur.
- Bend the wire into the shape of a dinosaur with the pair of pliers.
- Fasten the legs and tail to the body with a piece of string.
- The frame should be able to stand on its own.
Completion:
- Tear the newsprint into long strips.
- Soak the strips in the paste.
- Use the soaked strips to build onto the wire framework.
- Allow the figure to dry.
- Complete the dinosaur by painting it.
Conclusion:
In your own words describe the changes that occurred to the newsprint and the flour.
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Nowadays most clothes are made from a mixture of materials, for example by combining synthetic and natural fibres.
- Natural substances: Wool, cotton, silk, etc.
Cotton is light and comfortable, but it creases easily and is difficult to iron.
- Synthetic substances: are made by humans, for example polyester, acrylic, viscose, glass fibre, etc. One can see these names on the labels of clothes. Have a look at the labels on your clothes.