NCERT Solutions Class 8 Science Chapter 3 – Free PDF Download
*According to the latest update on the CBSE Syllabus 2023-24, this chapter has been removed.
NCERT Solutions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics are prepared by subject matter experts, and it includes solutions to all the questions present in the NCERT Class 8 Science textbook. All the NCERT Solutions are framed in a systematic manner, according to the latest CBSE Class 8 Science Syllabus (2023-24). All the NCERT Solutions present in this study material include detailed explanations, more examples, formulas, tips, important questions, Exemplar questions, MCQs and short answer questions.
These NCERT Solutions for Class 8 Science have answers to the questions on Synthetic Fibres and Plastics, their source, their uses, different types of fibres, natural fibres, artificial fibres, uses and qualities of plastics, problems caused by waste produced by plastics, proper usage of fibres and plastics. After studying NCERT Solutions, you will be able to understand the topics covered in the chapter thoroughly. It is noticed that many questions are directly asked in previous years’ Class 8 Science examinations. In order to score good marks in the examination, students should study this material in-depth.
NCERT Solutions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics
Access Answers to NCERT Class 8 Science Chapter 3 Synthetic Fibres and Plastics
Exercise Questions
1. Explain why some fibres are called synthetic.
Soln:
Some fibres are called synthetic fibres because they are man-made fibres prepared using chemicals. These are made of small units that join together to form long chains. Some examples of synthetic fibres are nylon, rayon, acrylic, polyester etc.
2. 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.
Soln:
The answer is (b) it is obtained from wood pulp.
3. Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called __________ or __________ fibres.
(b) Synthetic fibres are synthesised from the raw material called __________.
(c) Like synthetic fibres, plastic is also a __________
Soln:
(a) Synthetic fibres are also called artificial or man-made fibres.
(b) Synthetic fibres are synthesised from a raw material called petrochemicals.
(c) Like synthetic fibres, plastic is also a polymer.
4. Give examples which indicate that nylon fibres are very strong.
Soln:
Following are the examples that indicate nylon fibres are very strong:
- Parachutes and ropes of rock climbing are made of nylon
- Nylon is used in making seat belts, fishing nets and tyre cords.
- Nylon is used in making sports accessories like rackets.
5. Explain why plastic containers are favoured for storing food.
Soln:
Plastic containers are favoured for storing food because plastic is non-reactive and will not react with the ingredients of the food items.
6. Explain the difference between thermoplastic and thermosetting plastics.
Soln:
The difference between thermosetting plastics and thermoplastics are as follows:
| Thermosetting plastics | Thermoplastics |
| It cannot be bent; it will break if we attempt to bend thermosetting plastics | Thermoplastic can be bent easily |
| On heating thermosetting plastics, they cannot be softened. This is the reason it cannot be reshaped once it is moulded. | On heating the thermoplastics, it becomes softened and can be moulded and reshaped easily. |
7. Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Soln:
a) Thermosetting plastics are used to make saucepan handles because they are bad conductors of heat, and also, on heating, these plastics do not get softened.
b) Bakelite is a kind of thermosetting plastic which is a bad conductor of heat and electricity. Because of this property, it is used for making electric plugs, switches, plug boards, etc.
8. Categorise the materials of the following products into ‘can be recycled’ and ‘cannot be recycled’.
Telephone instruments, plastic toys, cooker handles, carry bags, ballpoint pens, plastic bowls, plastic covering on electrical wires, plastic chairs, electrical switches.
Soln:
| Can be Recycled | Cannot be recycled |
| Plastic chairs | Cooker handles |
| Plastic bowls | Electrical switches |
| Plastic toys | Telephone instruments |
| The plastic covering on electrical wires | |
| Carry bags | |
| Ballpoint pens |
9. Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason.
Soln:
Rana should buy a cotton shirt for the summer and not a synthetic shirt. Cotton is a good absorber of water. So it can soak the sweat coming out of the body and expose it to the environment. Thus, it helps in evaporating sweat and helps in cooling the body.
10. Give examples to show that plastics are non-corrosive in nature.
Soln:
Plastics are non-corrosive in nature; they do not react even if they come in contact with strong chemicals. For example, the cleaning chemicals that we use at home are stored in plastic bottles instead of metal containers.
11. Should the handle and bristles of a toothbrush be made of the same material? Explain your answer
Soln:
The handle and bristle of a toothbrush should not be made of the same material, as the handle of the toothbrush should be hard and strong while the bristle should be soft and flexible.
12. ‘Avoid plastics as far as possible’. Comment on this advice.
Soln:
We should avoid plastics as far as possible because plastics are non-biodegradable in nature. Once introduced into the environment, they cause pollution. If burnt, they release poisonous gases, and the plastic bags thrown in the garbage dump are swallowed by animals, choking their respiratory system and causing fatalities in them.
13. Match the terms of column A correctly with the phrases given in column B
| A | B |
| (i) Polyester | (a) Prepared by using wood pulp |
| (ii) Teflon | (b) Used for making parachutes and stockings |
| (iii) Rayon | (c) Used to make non-stick cookware |
| (iv) Nylon | (d) Fabrics do not wrinkle easily |
Soln:
| A | B |
| (i) Polyester | (d) Fabrics do not wrinkle easily |
| (ii) Teflon | (c) Used to make non-stick cookware |
| (iii) Rayon | (a) Prepared by using wood pulp |
| (iv) Nylon | (b) Used for making parachutes and stockings |
14. ‘Manufacturing of synthetic fibres is actually helping conservation of forests’. Comment.
Soln:
The manufacturing of synthetic fibres is helpful in the conservation of forests because if we use natural fibres, the raw materials for them have to be derived from plants, which requires cutting off lots of trees. This proves to be helpful in the conservation of forests.
15. Describe an activity to show that thermoplastic is a poor conductor of electricity
Soln:
In order to show that thermoplastic is a poor conductor of electricity, we will design a circuit. For that, we need a bulb, some wires, a battery, a piece of metal and a plastic pipe (as shown in the figure below). After setting the experiment, switch on the current, and you will observe that the bulb glows in the former case. In the latter case, the bulb does not glow. Hence, a plastic pipe (which is a thermoplastic) is shown to be a poor conductor of electricity.
| Also Access |
| NCERT Exemplar for Class 8 Science Chapter 3 |
| CBSE Notes for Class 8 Science Chapter 3 |
Class 8 Science NCERT Solutions for Synthetic Fibres and Plastics
The different types of clothes which we wear are made of fabrics. These fabrics are made from different types of fibres. There are two types of fibres – natural fibre and synthetic fibre. Natural fibres are those which are obtained from plants and animal sources. They include cotton, jute, silk, wool, etc. The NCERT Solutions for Class 8 Science Chapter 3 contains all the information about NCERT Solutions for Class 8 Science Chapter 3 Synthetic Fibres and plastics.
Synthetic fibres are those which are man-made and are obtained by the combination of different types of chemical substances and raw materials such as petrochemicals. They include nylon, acrylic, polyester and so on. These fibres are also called artificial or man-made fibres. There are 4 different types of Synthetic fibres.
- Rayon – It is synthesised from wood pulp and is dyed using different colours. It is also called artificial silk as it resembles silk. Rayon is cheaper than silk.
- Nylon – It is the first commercially synthesised fibre. It is synthesised by using coal, water and air. Nylon is very strong, and its fabric resembles silk.
- Polyester – It is one of the most popular man-made fibres, which is widely used for making clothes. Polyesters are generally made of repeating units of a chemical called esters.
- Acrylic – It is a man-made fibre which is known as artificial wool or synthetic wool as it resembles wool. Compared to natural wool, acrylic is much cheaper and can be dyed in various colours.
Plastics are polymers that can be coloured, recycled, reused, moulded and can be drawn into wires or various other shapes. They are mainly used to make bags, brushes, chairs, tables, toys, and countless other items. Polythene is one of the most famous types of plastic, which is used in the manufacturing of carrying bags.
Sub-topics of Class 8 Science NCERT Solutions Chapter 3 Synthetic Fibres and Plastics
- What are synthetic fibres?
- Types of synthetic fibres
- Characteristics of synthetic fibres
- Plastics
- Plastic as a material of choice
- Plastics and environment
Students can utilise the NCERT Solutions for Class 8 Science Chapter 3 for any quick references to comprehend these topics and other complex concepts.
We, at BYJU’S, provide free chapter-wise NCERT Solutions for all the classes in order to help students in their academics. Students can either download the NCERT Solutions for Class 8 Science PDF files or can practise online. By referring to these study materials, students can gain extra knowledge about the topic and perform their best both in their class assignments and final exams.
For more information, visit BYJU’S website or download BYJU’S The Learning App.
Frequently Asked Questions on NCERT Solutions for Class 8 Science Chapter 3
Mention the topics included in Chapter 3 of NCERT Solutions for Class 8 Science.
What are synthetic fibres?
Types of synthetic fibres
Characteristics of synthetic fibres
Plastics
Plastic as a material of choice
Plastics and environment
How can students solve the questions presented in Chapter 3 of NCERT Solutions for Class 8 Science faster?
What are the key features of NCERT Solutions for Class 8 Science Chapter 3?
1. The answers are prepared by highly experienced subject experts.
2. The solutions are accurate without any errors based on the latest CBSE syllabus.
3. Every important topic is explained in simple language to help students score well in the exams.
4. Students get a thorough understanding of the important concepts using the NCERT Solutions from BYJU’S.
Nice, it’s very basic, easy to understand and helpful too. Good work
😀😀
Very nice and awesome 👌