NCERT Solutions For Class 8 Science Chapter 3- Synthetic Fibres And Plastics Solutions Pdf Download
NCERT Solutions For Class 8 Science Chapter 3 Synthetic Fibres And Plastics Solutions deals with Synthetic Fibres, the types of Synthetic Fibres, and the Characteristics of Synthetic Fibres. These Class 8 Science Chapter 3 solutions will help you in scoring good marks as they cover important concepts in different patterns like MCQs and short answer questions, worksheets and more. NCERT Solutions For Class 8th Science Ch 3 solution helps students in many ways. Class 8 Science Chapter 3 Question and Answer are designed by our subject expert team.
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NCERT Solutions Class 8 Science Chapter 3 Overview
Crop Production and Management Class 8 Solutions cover the topics of Acrylic, Artificial Silk, Nylon, Plastic, Polyester, Polymer, Polythene, Rayon, Synthetic Fibres, Terylene, Thermoplastics, and Thermosetting Plastics for a detailed study you can check Class 8 Science Chapter 3 Notes.
Class 8 Science Chapter 3 Question and Answer
Q 1. Explain Why Some Fibres are called Synthetic.
Answer:
Some fibres are made by human beings. That is why these are called synthetic or man-made fibres. Synthetic fibre is a chain of small similar or dissimilar units joined together. Each small unit is actually a chemical substance.
Some examples of Synthetic Fibres
- Rayon
- Nylon
- Polyester and
- Acrylic
Q 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.
Answer:
The answer is (b) it is obtained from wood pulp.
Q 3. 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 __________
Answer:
(a) Synthetic fibres are also called artificial or manmade fibres.
(b) Synthetic fibres are synthesised from raw material called petrochemicals.
(c) Like synthetic fibres, plastic is also a polymer.
Q 4. Give Examples Which indicate that Nylon Fibres are very Strong.
Answer:
Nylon fibre was strong, elastic and light. It was lustrous and easy to wash. So, it became very popular for making clothes.
Following are the examples that indicate nylon fibres are very strong
- We use many articles made from nylon, such as socks, ropes, tents, toothbrushes, car seat belts, sleeping bags, curtains, etc.
- It is also used for making parachutes and ropes for rock climbing.
- A nylon thread is actually stronger than a steel wire.
Q 5. Explain Why Plastic Containers are Favoured for Storing Food.
Answer:
Because plastic is non-reactive and will not react with the ingredients of the food items.
Q 6. Explain the Difference between Thermoplastic and Thermosetting plastics.
Answer:
| Thermosetting plastic | Thermoplastic |
| Cannot be bent, it will break if we attempt to bend thermosetting plastic | 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. |
| bakelite and melamine are some examples of thermosetting plastic. | Polythene and PVC are some examples of thermoplastics |
Q 7. Explain Why the Following are Made of Thermosetting Plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Answer:
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.
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, ballpoint pens, plastic bowls, plastic covering on electrical wires, plastic chairs, and electrical switches.
Answer:
| Can be Recycled | Cannot be recycled |
| Plastic chairs | Cooker handles |
| Plastic bowls | Electrical switches |
| Plastic toys | telephone |
| The plastic covering electrical wires | |
| Carry bags | |
| Ballpoint pens |
Q 9. Rana Wants to Buy Shirts for Summer. Should he Buy Cotton Shirts or Shirts Made From Synthetic Material? Advise Rana, Give your Reason.
Answer:
As we know we sweat more during summer and cotton fabric absorbs more sweat as compared to synthetic material and helps the body to cool down. So we advise Rana should buy a cotton shirt for the summer and not a synthetic shirt.
Q 10. Give Examples to Show that Plastics are Noncorrosive in Nature.
Answer:
The following are examples to show that plastics are non-corrosive in nature:
- Iron material gets rusted when exposed to moisture and air but plastic does not react with water and air.
- Plastic does not react with strong chemicals. Hence, cleansing chemicals that we use at home are stored in plastic bottles, instead of metal containers.
Q 11. Should the Handle and Bristles of a Toothbrush be Made of the Same Material? Explain Your Answer
Answer:
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.
Q 12. ‘Avoid Plastics as Far as Possible. Comment on this Advice.
Answer:
We should avoid plastics as far as possible because plastics are non-biodegradable in nature. The waste created by plastics is not environmentally eco-friendly. Burning plastic, create poisonous gases and dumps in the ground that may take years to decompose. Plastic bags thrown in the garbage dump are swallowed by animals choking their respiratory system and causing fatalities in animals.
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 for making parachutes and stockings |
| (iii) Rayon | (c) Used to make non-stick cookware |
| (iv) Nylon | (d) Fabrics do not wrinkle easily |
Answer:
| 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 |
Q 14. ‘Manufacturing Synthetic Fibres is Actually Helping Conservation of Forests’. Comment.
Answer:
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.
Q 15. Describe an Activity to Show that Thermoplastic is a Poor Conductor of Electricity
Answer:
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, 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.
Class 8 Science Chapter 3 KeyWords Solutions
NCERT Solutions For Class 8 Science Chapter 3 KeyWords Definition
Acrylic: These are synthetic fibres which resemble natural wool. They are durable and affordable.
Artificial Silk: Artificial silk or rayon is a man-made fibre made from wood pulp. It has properties similar to that of silk.
Nylon: Nylon is a fully synthetic fibre. It is prepared from coal, water and air.
Plastic: Plastic is a polymer like synthetic fibre. The arrangement of units in some plastics is linear whereas in others it is cross-linked.
Polyester: Polyester is a synthetic fibre. Fabric made from this fibre does not get wrinkled easily. It remains crisp and is easy to wash.
Polymer: The word “Polymer” comes from two Greek words, poly meaning many and meaning part/unit. So polymer is made of many repeating units.
Polythene: Polythene (Poly + ethene) is an example of thermoplastic. It is used for making commonly used polythene bags.
Rayon: Rayon is also known as artificial silk. It is a man-made fibre made from wood pulp.
Synthetic Fibres: The fibres made by human beings are called synthetic fibres.
Terylene: Terylene is a popular polyester. It can be drawn into very fine fibres that can be woven like any other yarn.
Thermoplastics: Plastics which get deformed easily on heating and can be bent easily are known as thermoplastics.
Thermosetting Plastics: Plastics that when moulded once cannot be softened by heating are called thermosetting plastics.
Class 8 Science Chapter 3 Extra Question
NCERT Solutions For Class 8 Science Chapter 3 Extra Question
Class 8 Science Chapter 3 MCQ
NCERT Solutions For Class 8 Science Chapter 3 MCQ
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