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CBSE Sample Paper Class 8 Science Synthetic Fibres and Plastics
Synthetic Fibres and Plastics
1.) Answer the short questions
a.) What is synthetic fiber?
b.) Which synthetic fibre resembles wool?
c.) What are thermoplastics?
d.) What are thermosetting plastics?
e.) Why wires are wrapped in plastic?
f.) Which type of plastic is used for making non-stick cookware?
g.) Which plastic coating is used in firemen uniform?
h.) What are biodegradable materials?
i.) What are non-biodegradable materials?
j.) What is 5R principle?
2.) Briefly answer the questions
a.) What is polymer?
b.) What is rayon? Mention its uses.
c.) What is Nylon? Mention its uses.
d.) Write down the characteristics of synthetic fibre.
e.) Why plastic has variety of uses?
f.) Write about the non-reactive property of plastic.
g.) How plastic can harm out environment?
h.) How we can reduce the pollution caused by plastic?
3.) Fill in the blanks
a.) Synthetic fiber is made of small units called _______ .
b.) All of the synthetic fibre is made from a raw material called ________ .
c.) ________ is used to make plastic bags.
d.) Plastic is ______ conductor of electricity.
e.) _______ is used to make non-stick cookware.
f.) Rayon is made with _______ .
g.) _______ fibre is made from coal.
h.) Polycoat is a mixture of ______ and ______ .
(4) Name some daily used products and write the material it is made of and type of material it is.
Name |
Made of | Type of material |
|
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Answer
(1) Answer the short questions (10×1)
(a) What is synthetic fibre?
Answer – The fibers which are artificially made by men is called synthetic fibre.
(b) Which synthetic fibre resembles wool?
Answer – Acrylic fibre resembles wool.
(c) What are thermoplastics?
Answer – Some plastics get deformed when heat is applied to it and they can be bent easily, these type of plastics are called thermoplastic.
(d) What are thermosetting plastics?
Answer – The plastics which after mouldedonce cannot be soften by heating are called thermosetting plastic.
(e) Why wires are wrapped in plastic?
Answer – Plastic is poor conductor of electricity so it is used to wrap wires.
(f) Which type of plastic is used for making non-stick cookware?
Answer – Teflon is used for making non-stick cookware.
(g) Which plastic coating is used in firemen uniform?
Answer – Melamine coating is used in fireman uniform.
(h) What are biodegradable materials?
Answer – Materials which gets decomposed by natural process are called biodegradable materials.
(i) What are non-biodegradable materials?
Answer – Materials which are not decomposed or easily decomposed by natural process are called non-biodegradable materials.
(j) What is 5R principle?
Answer – The 5R principle is reuse, reduce, recycle, recover and refuse.
(2) Briefly answer the questions (8×3)
(a) What is polymer?
Answer – Polymer comes from two Greek words, ‘poly’ means many and ‘mer’ means unit. So polymer means many units.
Synthetic fibre is made with small units joined together. These repeating small units which forms synthetic fibre is called polymer.
(b) What is rayon? Mention its uses.
Answer – Rayon is a synthetic fibre made with wood pulp. It is called “artificial silk” because it has properties similar to silk.
The uses of rayon includes,
(1) For making silk like fibres.
(2) Rayon is mixed with cotton to make bed shits.
(3) Mixing with cotton to make carpets.
(c) What is Nylon? Mention its uses.
Answer – Nylon is the first fully synthetic fibre. It was made without any natural raw material. It is prepared from coal, water and air.It is very strong, light and elastic.
Uses of nylon include,
(1) Making clothes.
(2) Ropes
(3) Tents
(4) Toothbrush
(5) Car seat belt
(6) Parachutes
(7) Curtains
(d) Write down the characteristics of synthetic fibre.
Answer – Characteristics of synthetic fibre are,
- Synthetic fibres dry up quickly.
- Some fibres are water resistant.
- It is light and durable.
- Less expensive and readily available.
- Easy to maintain.
(e) Why plastic has variety of uses?
Answer – Plastic has variety of uses. It is because plastics are easily mouldable into different things. So plastics are article can be different shapes and sizes. Plastic is very light, easy to maintain, water resistant and poor conductor of electricity. So various kinds of article can be made with plastic.
(f) Write about the non-reactive property of plastic.
Answer – Metals such as iron gets rusted when it is exposed to moisture but plastic never gets rusted. This happens because plastic do not react with water and air. They are not corroded easily. So they are non-reactive in nature. Because of this property plastic containers are used to store different kinds of things including chemicals.
(g) How plastic can harm our environment?
Answer – Plastic harms our environment in various ways. It is a non-biodegradable material, so it doesn’t get easily decomposed. So it is not environment friendly. It cause pollution. If plastic materials are burnt to remove them they release poisonous gases which pollute air.
Sometimes plastic are mixed in garbage dump. When animals are eating they eat parts of plastic too. This can cause serious problems for them and even death so.
(h) How we can reduce the pollution caused by plastic?
Answer – We can reduce the plastic pollution by avoid using is as less as possible. We can use jute or cotton made bags. We should separate the biodegradable waste from non-biodegradable waste to prevent animals from eating plastic. We should follow 5R principal, Reduce, Reuse, Recycle, Recover and Refuse.
(3) Fill in the blanks (8×1)
(a) Synthetic fiber is made of small units called polymer .
(b) All of the synthetic fibre is made from a raw material called petrochemicals .
(c) Polythene is used to make plastic bags.
(d) Plastic is bad conductor of electricity.
(e) Teflon is used to make non-stick cookware.
(f) Rayon is made with wood pulp .
(g) Nylon fibre is made from coal.
(h) Polycoat is a mixture of polyester and cotton .
(4) Name some daily used things and write the material it is made of and type of material it is. (8×1)
Name |
Made of | Type of material |
Pen | Plastic |
Non-biodegradable |
Door |
Wood | Biodegradable |
Chair | Plastic |
Non-biodegradable |
Spoon |
Metal | Non-biodegradable |
Bucket | Plastic |
Non-biodegradable |
Pencil |
Wood | Biodegradable |
Bottle | Plastic |
Non-biodegradable |
Book |
Paper |
Biodegradable |