Class 8 Science – Chapter 3
Synthetic Fibres and Plastics
Worksheet – FULL Answers (Step-by-Step)

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🟢 Section A: Very Short Answer – Answers

1. What is rayon?
   Rayon is a synthetic fibre made from natural cellulose obtained from wood pulp.
2. Name one synthetic fibre.
   Nylon.
3. Which plastic is used to make non-stick cookware?
   Teflon.
4. Write one disadvantage of plastics.
   Plastics are non-biodegradable and cause environmental pollution.
5. What does PVC stand for?
   Polyvinyl Chloride.

🟡 Section B: Short Answer – Answers

1. Why is rayon called artificial silk?
   Rayon looks like silk and is shiny like silk, but it is cheaper and made artificially.
2. Write any two properties of synthetic fibres.
   (i) They are strong and durable.
   (ii) They dry quickly and are wrinkle-resistant.
3. Differentiate between thermoplastic and thermosetting plastic.
   Thermoplastics can be softened on heating and reshaped, while thermosetting plastics cannot be reshaped once hardened.
4. Why should plastic not be burnt?
   Burning plastic releases toxic gases that cause air pollution and health problems.
5. Give two uses of nylon.
   (i) Making ropes and parachutes.
   (ii) Making fishing nets.

🔵 Section C: Long Answer – Answers

1. Explain the characteristics of synthetic fibres.
   Synthetic fibres are strong, lightweight, durable, wrinkle-free, and resistant to chemicals. They are easy to maintain.
2. Describe different types of plastics with examples.
   Plastics are of two types: thermoplastics (PVC, polythene) and thermosetting plastics (bakelite, melamine).
3. Explain the harmful effects of plastic on the environment.
   Plastics pollute land and water, harm animals, block drains, and release poisonous gases when burnt.
4. What are the 4R principles?
   Reduce, Reuse, Recycle, and Recover help in controlling plastic pollution.

🟣 Section D: Application Based – Answers

1. Why are plastic containers preferred for storing food?
   They are lightweight, strong, waterproof, and do not react with food.
2. Why are synthetic fibres used to make parachutes and ropes?
   They are very strong, flexible, and can bear heavy loads.

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