1. NCERT Solutions - Science , Class 8
1. Crop Production and Management
2. Microorganisms: Friend and Foe
3. Synthetic Fibres and Plastic
4. Materials: Metals and Non-Metals
5. Coal and Petroleum
6. Combustion and Flame
7. Conservation of Plants and Animals
8. Cell — Structure and Functions
9. Reproduction in Animals
10. Reaching the Age of Adolescence
11. Force and Pressure
14. Chemical Effects and Electric Current
15. Some Natural Phenomena
17. Stars and the Solar System
18. Pollution of Air and Water
Q1) Explain why some fibres are called synthetic.
Q2) Mark (✓) the correct answer.
Rayon is different from synthetic fibres because
(a) it has a silk-like appearance.
(b) it is obtained from wood pulp.
(c) its fibres can also be woven like those of natural fibres.
Q3) Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called __________ or __________ fibres.
(b) Synthetic fibres are synthesised from raw material called __________ .
(c) Like synthetic fibres, plastic is also a __________ .
Q4) Give examples which indicate that nylon fibres are very strong.
Q5) Explain why plastic containers are favoured for storing food.
Q6) Explain the difference between thermoplastic and thermosetting plastics.
Q7) Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Q8) Categorise the materials of the following products into ‘can be recycled’
and ‘cannot be recycled’.
Telephone instruments, plastic toys, cooker handles, carry bags, ball point
pens, plastic bowls, plastic covering on electrical wires, plastic chairs,
Q9) Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason.
Q10) Give examples to show that plastics are noncorrosive in nature.
Q11) Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.
Q12) ‘Avoid plastics as far as possible’. Comment on this advice.
Q13) Match the terms of column A correctly with the phrases given in column B.
Q14) ‘Manufacturing synthetic fibres is actually helping conservation of forests’. Comment
Q15) Describe an activity to show that thermoplastic is a poor conductor of electricity.
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NCERT Solutions - Science , Class 8
Crop Production and Management
Microorganisms: Friend and Foe
Synthetic Fibres and Plastic
Materials: Metals and Non-Metals
Coal and Petroleum
Combustion and Flame
Conservation of Plants and Animals
Cell — Structure and Functions
Reproduction in Animals
Reaching the Age of Adolescence
Force and Pressure
Chemical Effects and Electric Current
Some Natural Phenomena
Stars and the Solar System
Pollution of Air and Water
Race To Space
Terms & Policies