NCERT Solutions Class 8 Science Chapter 3

NCERT Solutions for Class 8 Science Chapter 3: Synthetic Fibres and Plastic

Science is an exciting subject, and it plays a vital role in a student’s life as it offers various concepts that can appear in the following classes. Class 8 also holds equal importance for the students as it prepares them for their future career options in Science and Engineering. Hence it is a transition phase for any student who wishes to take Science as a significant subject. 

Class 8 Science Chapter 3 is about synthetic fibres and plastic. First, it introduces the various types of synthetic fibres and their characteristics. Here, students learn about fibre, polymer, natural fibre, silk, and nylon. In addition, they will understand how thermoplastic is formed and its characteristics. Furthermore, students can understand the key difference between biodegradable and non-biodegradable materials. 

Students can benefit from our website and access NCERT solutions for Class 8 Science Chapter 3. Our solutions help the students to get detailed  notes, illustrations, and examples, and it also has previous years’ papers. The students will be able to gain confidence in the Science subject with the help of the solutions. 

Extramarks is a leading online learning platform that provides students with the best study material and solutions. The solution tries to build the skills which are essential for enhanced learning. It helps to build a foundation on all the concepts  prescribed in the NCERT curriculum and CBSE Class 8 Science. 

Our NCERT solution guide covers important subtopics such as uses of synthetic fibres, different types of synthetic fibres, characteristics of plastics, and the effect of plastics on the environment. It also elaborates on the role and contribution of other synthetic fibres such as Rayon, Nylon, Polyester, and acrylic. 

Students can visit the Extramarks website for the current updates and notifications about the NCERT syllabus and its exam-related updates. Further, students can access other class solutions, including NCERT solutions Class 9, NCERT solutions Class 10, and NCERT solutions Class 11. 

Key Topics Covered In NCERT Solutions for Class 8 Science Chapter 3

Class 8 Science Chapter 3 solutions maintain the quality by following the guidelines and syllabus for Class 8. Our NCERT solutions are easy to understand with elaborative illustrations and diagrams so that students rarely face any difficulty in learning the answers. The Science teachers have written NCERT solutions for Class 8 Science Chapter 3 in a very simplistic and easy to understand manner to clarify their concepts and help them excel in their academics.  . 

The sub-topic covered in Extramarks NCERT solutions for Class 8 Science Chapter 3 are given below: 

What are synthetic fibres?
Types of synthetic fibres
Characteristics of synthetic fibres
Plastics
Plastic as a material of choice
Plastics and Environment

What are synthetic fibres?

Synthetic fibre is an artificial fibre which is prepared by using raw materials. The materials predominantly originated from petroleum which is also known as petrochemicals. Besides, there are several processes involved in the preparation of fibre. Some of the standard synthetic fibres are rayon, polyester and nylon. 

The fibres are made up of tiny chemical units known as monomers. They are joined together to form a chain, and these chains are called polymers. Synthetic fibres are also obtained by the chemical processing of the petrochemicals, unlike natural fibres made from animals and plant sources. In our Extramarks NCERT solutions for Class 8 Science Chapter 3, we have elaborated on the processing of the petrochemicals in detail. 

Types of synthetic fibres

The classification of synthetic fibres is based on the chemicals used in their manufacturing. Therefore, every fibre differs in its nature of burning, affordability, availability, water absorption, etc. The different types of synthetic fibres discussed in NCERT solutions for Class 8 Science Chapter 3 are listed below: 

  1. Rayon: It is artificial silk known as viscose-rayon regenerated cellulose. The cellulose is obtained from the natural source of wood pulp. Besides, it is also manufactured fibre made in the laboratory by chemical treatment of wood pulp. It is dyed in various colours, and it can also be woven like silk fibres. Rayon is used to making fabrics, bedsheets, carpets, and car upholstery. 
  2. Acrylic: It is a monomer also known as polyacrylonitrile. Acrylic fibre is similar to wool used to make sweaters, blankets, shawls, etc. Therefore, it is affordable, cheap, and durable compared to natural woollen fibres. In addition, acrylics are light, soft, warm and resistant to chemicals, moths, and sunlight. 
  3. Polyester: It is also a monomer ester and manufactured fibre. Polyester offers a brilliant wrinkle-free quality and remains crisp, and it is easy to wash. Therefore, it is used for dresses, suits, rainwear, etc. In addition, a type of polyester known as PET or Polyethylene terephthalate is trendy for making kitchen products, wires, bottles etc. 
  4. Nylon is different from other fabric types; it is a polymer of adipic acid hexamethylenediamine. Nylon is the first fibre made from coal, water and air. They are light, elastic, strong, durable, and lustrous. This property makes it a good choice for fabrics, and it also dries up quickly. Nylon is used in car seats, belts, ropes, curtains, and toothbrushes. 

To understand the properties of synthetic fibres in  detail, students can register on the Extramarks website and access NCERT solutions for Class 8 Science Chapter 3. 

Characteristics of synthetic fibres

  • Synthetic fibres dry up quickly, are durable, and are less expensive. In addition, it is readily available and easy to maintain. 
  • Synthetic fibres melt on heating and can catch fire which can be disastrous. 
  • The fibres are strong, elastic and light. 

Plastics

Many people use plastic in their everyday life. Plastic is also a polymer like synthetic fibres. Further, there are various forms and uses of plastic. It can be recycled, reused, coloured, melted or made into wires. The plastic can be deformed easily by heating and made easily known as “Thermoplastic”. 

Besides, there are some plastics which, when moulded once, cannot be softened by heating, called “Thermosetting” plastic. Bakelite and melamine are two examples of thermosetting plastic. Whereas bakelite is a poor conductor of heat and electricity, melamine is a versatile material. Students can refer to our NCERT solutions for Class 8 Science Chapter 3, where we have elaborated on the  various properties of plastic.

Plastic as a material of choice

Various food items such as water, milk, pickles, and dry food are primarily stored in plastic containers. They are lightweight, strong, durable, have good strength and easy handling. On the other hand, metals like iron rust over time and when exposed to moisture. Yet, it is different with plastic materials. Plastic can easily be moulded into various shapes and sizes. 

Plastic is a lot cheaper than metals. Further, it is used in many industries such as health care, fire industry, IT industry, and wrapping industry. Plastic has a lot to offer as a material. Therefore, students can register on our Extramarks website or refer to NCERT solutions for Class 8 Science Chapter 3. We have explained the critical role of plastic in different industries in detail. 

Plastics and Environment

Plastic as a material is not environmentally friendly as it accumulates in the environment over the years without disintegrating. When we burn plastics, it releases toxic gases into the atmosphere, which pose a health hazard for humans, animals, and plants; further, the plastic is not biodegradable. It means that plastic cannot be decomposed naturally by the action of bacteria. 

When the plastic bags are not disposed of properly, they can clog the drains and can lead to choking in animals. There are five R principles: Reduce, Recycle, Reuse, Recover, and Refuse to keep our environment safe. It can contribute to cleaning our environment. There are also some eco-friendly ways, such as cloth bags, steel utensils and paper bags. 

Students can access NCERT solutions for Class 8 Science Chapter 3 on our website to understand plastic and its impact on nature. 

NCERT Solutions for Class 8 Science Chapter 3: Exercises &  Solutions

Extramarks NCERT solutions for Class 8 Science Chapter 3 offers students all the solved answers to questions from the textbook chapters. The answers are written in a  descriptive  and detailed manner, which helps in answering the question and clears all the doubts while responding to similar  questions while revising and  in exams.. 

Besides, students can take advantage and start with a trial account by registering on our website. Our NCERT solutions have proven fruitful for many students in primary and secondary classes. The solutions cover all the sub-topics in Chapter 3, synthetic fibres and plastic.  All the essential topics  are  explained in a simple and easy to understand language which helps students score well in the Science exams. 

Students can click on the link below to access the exercise specific questions and their solutions which are covered in Extramarks NCERT solutions for Class 8 Science Chapter 3: 

  • Chapter 3: Exercise 3.1 Solutions: 14 Questions

Our NCERT solutions are also available for other primary and secondary classes on our Extramarks website. Students can click on the links given  below:

  • NCERT Solutions Class 1
  • NCERT Solutions Class 2
  • NCERT Solutions Class 3
  • NCERT Solutions Class 4, 
  • NCERT Solutions Class 5
  • NCERT Solutions Class 6
  • NCERT Solutions Class 7
  • NCERT Solutions Class 8
  • NCERT Solutions Class 9
  • NCERT Solutions Class 10
  • NCERT Solutions Class 11
  • NCERT Solutions Class 12

NCERT Exemplar for Class 8 Science

Science is a subject of curiosity about the nature and behaviour of natural things .  It demands a high level of understanding to grasp the concepts. To increase the knowledge of such concepts, solving different equations is always beneficial. It helps to clear the doubt and develop a strong understanding of the topics. 

NCERT Exemplars are designed in the same manner to help the students to enhance their knowledge  of the topic. It has various types of questions with varying levels of difficulty such as  multiple-choice questions; fill in the blanks and match the following questions. It also contains objective, concise answer type, short answer type and long answer type questions in Chapter 3, Class 8. With the daily practice of the exemplar, students can expect good results in the examination.In other words, effort has been made to ensure that nothing is left in the process.

Our NCERT solutions for Class 8 Science Chapter 3 offers questions from exemplars covering the topics of synthetic fibres and plastic. Here, students will explore different sub-topics, including characteristics of plastics, thermoplastics, thermosetting plastic, and acrylic fibre. In addition, students will understand the critical difference between biodegradable and non-biodegradable materials. It will ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.

Key Features of NCERT Solutions for Class 8 Science Chapter 3

Extramarks has  an in-house dedicated team of subject experts who prepare accurate, up to date and  authentic solutions of each  topic and each section covered in the chapter. Some Students find it difficult to answer the textbook questions and they should  follow the answers on our Extramarks website to get an overall idea about the chapter to help them achieve excellent scores. 

Some of the prominent characteristics of our NCERT solutions for Class 8 Science Chapter 3 are as follows:

  • The solutions help clarify students’ queries that arise while learning the chapter. 
  • The answers are prepared in an understandable language, making it easy for students to learn complicated definitions. 
  • NCERT solutions for Class 8 Science Chapter 3 strictly adhere to the CBSE syllabus and guidelines  for students to prepare for the exam more rigorously so that they don’t have to look for any help elsewhere. 
  • The subject experts frame each answer in the solution with utmost care to encourage and enable reading abilities among students to study independently and master the topic with ease . 

Q.1 Explain why some fibres are called synthetic.

Ans. Man-made fibres are called synthetic fibres. These fibres are prepared from petrochemicals with the help of various processes. Examples of some synthetic fibres are nylon, rayon, polyester, acrylic, etc.

Q.2 Mark (✓) the correct answer.

Rayon is different from synthetic fibres because

  1. it has a silk-like appearance.
  2. it is obtained from wood pulp.
  3. its fibres can also be woven like those of natural fibres.

Ans. Rayon is different from synthetic fibres because

  1. it has a silk-like appearance.
  2. it is obtained from wood pulp. (✓)
  3. its fibres can also be woven like those of natural fibres.

Q.3 Fill in the blanks with appropriate words.

  1. Synthetic fibres are also called ______ or ______ fibres.
  2. Synthetic fibres are synthesised from raw materials called _________.
  3. Like synthetic fibres, plastic is also a ________.

Ans.

  1. artificial, man-made
  2. petrochemicals
  3. polymer

Q.4 Give examples which indicate that nylon fibres are very strong.

Ans. Nylon fibres are strong, elastic and light. In fact they are stronger than steel wire. They are used in making ropes for rock climbing and parachutes. This usage indicates that nylon fibres are very strong.

Q.5 Explain why plastic containers are favoured for storing food.

Ans. The plastic containers are favoured for storing food because plastic is non-reactive, corrosion resistant, cheap, durable, strong and light in weight.

Q.6 Explain the difference between thermoplastic and thermosetting plastics.

Ans.

Thermoplastics Thermosetting Plastics
Thermoplastics can be softened and reshaped when heated, but harden again when cooled. Thermosetting plastics do not soften on heating. Hence, they can be moulded only once.
Thermoplastics can be bent easily. Thermosetting plastics cannot be bent easily and may break when forced to bend.
Polythene and PVC are some examples of thermoplastics. Bakelite and melamine are some examples of thermosetting plastics.
Thermoplastics are used for manufacturing toys, combs and various types of containers, etc. Thermosetting plastics are used for making electrical switches, handles of various utensils, etc.

Q.7 Explain why the following are made of thermosetting plastics.

  1. Saucepan handles
  2. Electric plugs/switches/plug boards

Ans.

  1. Saucepan handles are made of thermosetting plastics because these plastics do not soften on heating.
  2. Thermosetting plastics are poor conductors of heat and electricity. Therefore, they are used in making electric plugs, switches, plug boards, etc.

Q.8 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, electrical switches.

Ans.

Can be recycled Cannot be recycled
plastic toys telephone instruments
carry bags cooker handles
ball point pens electrical switches
plastic bowls
plastic covering on electrical wires
plastic chairs

Q.9 Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason.

Ans. Rana should buy cotton shirts. This is because cotton is a good absorber of water. Therefore, it absorbs the sweat (mainly water having dissolved salts) and exposes it to the environment. With the help of atmospheric heat, water present in sweat is evaporated. During evaporation water is lost and this water takes away heat with it. Thus, it helps in evaporating the water (sweat), thereby cooling our body.

Q.10 Give examples to show that plastics are noncorrosive in nature.

Ans. Plastics are non-reactive and noncorrosive in nature. They are not corroded even by strong chemicals. That is why various kind of chemicals are stored in plastics bottles.

Q.11 Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.

Ans. Handle and bristle of a tooth brush should not be made of the same material. This is because handle of brush is strong and hard, while bristles are soft and flexible.

Q.12 ‘Avoid plastics as far as possible’. Comment on this advice.

Ans. Plastics are non-biodegradable, i.e. they are not decomposed by micro-organisms. Once introduced into the environment they may take several years to decompose. Plastics when burnt produce poisonous gases. They are dangerous to animals like cows, which swallow these bags from garbage. These bags choke the respiratory system of the animals or form a lining in their stomach and may cause their death. Hence, we should avoid plastics as far as possible.

Q.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 to make non-stick
(iii) Rayon (c) Prepared by using wood pulp
(iv) Nylon (d) Used for making parachutes and stockings

Ans.

A B
(i) Polyester (d) Fabrics do not wrinkle easily
(ii) Teflon (c) Used to make non-stick
(iii) Rayon (a) Prepared by using wood pulp
(iv) Nylon (b) Used for making parachutes and stockings

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q.14 ‘Manufacturing synthetic fibres is actually helping in conservation of forests’. Comment.

Ans. Raw material used for making natural fibres is mainly derived from plants. It requires cutting of lots of trees leading to deforestation. On the other hand raw materials required for synthetic fibres are mainly obtained from petrochemicals. It means for manufacturing of synthetic fibres, cutting of trees is not needed. Hence, it can be said that ‘manufacturing synthetic fibres is actually helping in conservation of forest’.

Q.15 Describe an activity to show that thermoplastic is a poor conductor of electricity.

Ans. We can set two circuits to show that thermoplastic is a poor conductor of electricity. For this we need two bulbs, wires, two batteries, a piece of metal and a pipe made of thermoplastic.

Set up the circuits with metal and plastic pipe separately as shown below.

When you turn the switch on the current flows and the bulb glows in the first circuit (circuit with metal) while, bulb does not glow in the second circuit (circuit with plastic).

This activity confirms that thermoplastic is a poor conductor of electricity.

For viewing question paper please click here

FAQs (Frequently Asked Questions)
1. What are the different types of questions in Class 8 Science Chapter 3?

Students will come across  multiple-choice questions and explanatory answers, fill in the blanks and match the following question in the chapter. They will get to solve different types of questions, which will help them to strengthen their knowledge of synthetic fibre and plastic.

2. How many subtopics are included in Chapter 3 of NCERT solutions for Class 8?

The students will get to learn the following sub-topics in the NCERT solutions for Class 8 Science Chapter 3:

  • What are synthetic fibres?
  • Types of synthetic fibres
  • Characteristics of synthetic fibres
  • Plastics
  • Plastics and environment

3. Why should we study from NCERT solutions for Class 8 Science Chapter 3?

Sometimes, it isn’t easy for students to understand the definitions and concepts in the chapter. Therefore, Extramarks NCERT solutions offer answers for all the topics present in the exercises. In addition, the solutions contain explanations for each step to help understand the concepts without difficulty.