FIRST TERM
SUBJECT: BASIC TECHNOLOGY
CLASS: JSS 2
REFERENCE MATERIALS
- MELROSE, Basic Science and Technology, Book 2�
- NERDC, Basic Technology for JSS, Book 2
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WEEK FOUR
TOPIC: USES OF MATERIALS II
CONTENT
- Uses of Ceramic�
- Uses of Glass
- Uses of Rubber
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CERAMIC
All solid objects made from clay, mud or cement are called ceramics. Ceramics are concerned with clay and clay products, glass and glass products, cements and plasters.�
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USES OF CERAMICS
- Ceramics can withstand very high temperature; they are used in making furnaces.
- Ceramics can carry heavy loads. Thus bricks and cement blocks are used to build houses. The walls carrying the roof of the building.
- Ceramics do not corrode and they are resistant to chemical attack. It can be used to store chemicals and water.
- They can be easily moulded and decorated, so can be used for sculpture.
- They are good insulator of electricity, so can be used as insulation of high-tension voltages. The insulators between the lines are also ceramic.
- They last longer e.g. Benin head.
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EVALUATION
- Explain why ceramics are used in making furnaces
- Name three common ceramics and state their properties.
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USES OF GLASS
- Glass is used for making bottles.
- It is used for making tumblers and mugs.
- It is used for making flower vases.
- It is used for making bulbs.
- Glass is also used to make eyeglasses, magnifying glasses and binoculars.
- It is also used in mirrors, windscreens of vehicles, television screens and computer screens.
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RUBBER
Raw rubber (Latex) is normally too tough and too hard. It is softened by adding certain chemicals and mixed through until it is in a state in which it can be formed.
There are two types of rubber: natural rubber and synthetic rubber.
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NATURAL RUBBERS
Are produced from the latex of rubber trees. Natural rubber deteriorates with age and when it is exposed to sunlight. The process of improving the properties of rubber is called VULCANIZING. This is done by adding sulphur to it together with carbon particles and heating it. Vulcanized rubber is much harder and much heat resistant than ordinary rubber.
SYNTHETIC RUBBER
These are manufactured from chemicals.They are forms of plastics. Examples include butyl rubber and neoprene. They have better quality than natural rubbers.� They are resistant to sunlight and temperature changes. They do not age, like natural rubbers and they are resistant to chemicals. Rubber products include: hoses, pipes, belts, tyres, tubes, footwear, rainwear and mounting.
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USES OF RUBBER
- It can be used as an elastic material e.g. for making catapult.
- Rubber is water proof, so it is used in making sandals and gloves.
- Rubber has insulating property i.e. it is an insulator. Thus it is used in covering electrical wires that supply electricity to the iron or kettle.
- Rubber can be used as shock absorber, thus it is used in making bumper of cars, tyres and tubes of cars.
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EVALUATION
- Differentiate between natural rubber and synthetic rubber.
- List five examples of rubber products.
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READING ASSIGNMENT
Read about GEOMETRIC CONSTRUCTION-LINES
- MELROSE, Basic Science and Technology, Book 2 page 67-69
- NERDC Basic Technology for JSS book 2 page28-32.
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WEEKEND ASSIGNMENT
- All solid objects made from clay, mud or cement are called ____(a) plastics (b) rubber (c) semiconductors (d) ceramics
- The art of using clay to make various objects is called ____ (a) plastics (b) rubber (c) semiconductors (d) pottery
- Which of the following is not a rubber product? (a) tyres(b) pipes (c) foot wear (d) sculpture�
- One of the differences between plastic and rubber is that RUBBER is more _____ (a) cheaper (b) available (c) elastic (d) tougher
- Properties of rubber can be improved through the process called (a)extrusion (b)vulcanization (c) injection moulding (d)compression moulding.�
THEORY
- State three properties of rubber�
- List three good qualities of ceramics.
