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

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A. Fill in the Blanks – Answers

1. Nylon is the first synthetic fibre.
2. Rayon is also known as artificial silk.
3. Plastics that can be recycled are called thermoplastics.
4. Bakelite is a thermosetting plastic.
5. Plastics do not decompose easily because they are non-biodegradable.

B. True or False – Answers

1. Rayon is obtained from natural sources. (True)
2. All plastics can be recycled. (False)
3. Plastics are poor conductors of heat. (True)
4. Acrylic fibre is used as a substitute for wool. (True)
5. Plastics are biodegradable materials. (False)

C. Very Short Answer – Answers

1. Nylon is one example of a synthetic fibre.
2. Rayon is called artificial silk.
3. Nylon is used to make ropes, parachutes, and clothes.
4. Bakelite is a thermosetting plastic.
5. Plastics are used to cover electric wires because they are poor conductors of electricity.

D. Short Answer – Answers

1. Synthetic fibres are man-made fibres prepared using chemical substances.
2. Thermoplastics can be softened on heating and reused, whereas thermosetting plastics cannot be reshaped once set.
3. Plastic is useful because it is lightweight, strong, durable, and corrosion-resistant.
4. Two disadvantages of plastics are:
   • They cause environmental pollution
   • They are non-biodegradable

E. Long Answer – Step-by-Step

Plastics have several properties that make them useful in daily life:

• They are light in weight
• They are strong and durable
• They do not rust or corrode
• They are poor conductors of heat and electricity
• They can be moulded into different shapes

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