03 Synthetic Fibres and Plastics
NCERT solutions for Science Synthetic Fibres and Plastics
NCERT Class 8 Science Chapter wise Solutions
- 1 – Crop Production and Management
- 2 – Microorganisms : Friend and Foe
- 3 – Synthetic Fibres and Plastics
- 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
- 12 – Friction
- 13 – Sound
- 14 – Chemical Effects of Electric Current
- 15 – Some Natural Phenomena
- 16 – Light
- 17 – Stars and The Solar System
- 18 – Pollution of Air and Water
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
Class–VIII Science NCERT SOLUTION
Ch-3 Sythetic Fibres and Plastics
1. Explain why some fibres are called synthetic.
Ans. Since man-made fibres are obtained by the synthesis of petrochemicals, they are called synthetic fibres.
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
2. Mark () the correct answers.
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.
Ans. (b) it is obtained from wood pulp.
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
3. Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called ———– or ———— fibres.
(b) Synthetic fibres are synthesized from raw material called ———–.
(c) Like synthetic fibres, plastic is also a —————-.
Ans. Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called artificial or man-made fibres.
(b) Synthetic fibres are synthesized from raw material called polymer.
(c) Like synthetic fibres, plastic is also a petrochemicals.
4. Give examples which indicate that nylon fibres are very strong.
Ans. They are used to make parachutes and ropes for rock climbing.
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
5. Explain why plastic containers are flavored for storing food.
Ans. The main advantage of using plastic for storing food are-
a. Plastic has light weight.
b. Good strength.
c. Easy to handle.
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
6. Explain the difference between thermoplastic and thermosetting plastics.
Ans.
| Thermoplastic | Thermosetting plastics |
| (i) These are the plastics which get deformed easily on heating and can be easily bent.
(ii) These are used for making toys, combs and various types of containers. (iii) Ex- polythene, PVC. | (i) These are the plastics which when molded once cannot be softened by heating.
(ii) Used for making electrical switches and handles of various utensils. (iii) Ex- Bakelite, melamine etc. |
NCERT Solutions for Class 8 Science Synthetic Fibres and Plastics
7. Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plug/ switches /plug boards
Ans. (a) Saucepan handles: Saucepan handles are made from the thermosetting plastics because these are bad conductors of heat and electricity. They do not bend or deform on heating.
(b) Electric