Important Questions Class 7 Science Chapter 3

Important Questions Class 7 Science Chapter 3- Fibre to Fabric

Class 7 Chapter 3 is about everything from Fibre to Fabric. In Class 6, students learned that silk comes from cocoons of the silk moth, and wool is derived from the fleece(hair) of Sheep, goats, and yak. Some fibres are also obtained from plants. Further, Class 7, Chapter 3, students will learn about two types of animal fibres:

• Wool.
• Silk. 

Further processing into finished products like sweaters, shawls, silk sarees, etc., will also be taught in this chapter. You will also learn about animals that yield wool, the rearing and breeding of Sheep and Silkworms, occupational hazards, Sericulture, the life history of the silk moth, and pure and artificial Silk. 

Extramarks provides the most comprehensive and reliable study and practice resources,  such as NCERT solutions, CBSE revision notes, NCERT books, CBSE sample papers, etc., developed carefully by our experienced science faculty to assist students get an in-depth and clear understanding of all the concepts.

A full list of Chapter 3 Class 7 Important Science Questions, CBSE extra questions, and other such study materials will benefit you to get acquainted with examination question patterns and improve up on time management skills. Students are suggested to thoroughly practise these Class 7 Chapter 3 Important Questions for the examination preparation and score well.

To access Class 7 Science Chapter 3 Important Questions and other study materials, register on the Extramarks’ website immediately.

Important Questions Class 7 Science Chapter 3 – With Solutions

Practising questions not only helps surface the gaps in learning, but also strengthens memory and reduces examination anxiety. Understanding this, the expert panel of Extramarks has gathered the questions from various sources like NCERT Textbook, NCERT Exemplar, past years’ examination papers, other sources, etc. Detailed and easy-to-understand solutions to the questions are provided to make the concepts clear. Students can register and access the complete list of solutions for Important Questions Class 7 Science Chapter 3 on the website. 

Below given questions is the example of how the Important Questions Class 7 Science Chapter 3 with solutions is going to:

Question 1. The silkworm is 

 (a) a caterpillar 

 (b) a larva. 

Choose the correct option.

 (i) a 

 (ii) b 

 (iii) Both a and b 

 (iv) Neither a nor b

Answer 1. (iii) Both a and b

Explanation: Caterpillars are the larvae of silkworms.

Question 2. Selective breeding is a process of

 (a) Selecting the offspring with desired properties.

 (b) Selecting the parents with desired properties.

 (c) Selecting an area for breeding.

 (d) Selecting fine hair for good quality wool.

Answer 2. (b) Selecting the parents with desired properties.

Explanation: Selective breeding takes parents with particular traits of interest and breeds them together to get offspring with desirable characteristics.

Question 3. Name some of the wool-yielding animals.

Answer 3. Wool-yielding animals are Yak, Alpaca, Sheep, Angora goat, llama, Angora rabbit, and Camel.

Question 4. What is meant by the following terms?

 (a) Rearing 

 (b) Shearing 

 (c) Sericulture

Answer 4. 

(a) Rearing: Rearing is keeping, feeding, breeding, and medical care of domestic animals for commercial purposes. For example, Sheep are reared for wool, cows for milk, silkworms for silk threads, etc.

(b) Shearing: The process involves the shearer removing the woollen fleece(hair) of sheep along with a thin layer of skin to obtain wool. Shearing is generally done twice a year during the spring and autumn months.

(c) Sericulture: Sericulture is the process of breeding and managing silkworms to get the raw silk. Varieties of Silk moths produce different types of silk. Examples are mulberry silk and tussar silk.          

Question 5. Paheli wanted to buy a gift made of animal fibre obtained without killing the animal. Which of the following would be the right gift for her to buy?

 (a) Woollen shawl

 (b) Silk scarf

 (c) Animal fur cap

 (d) Leather jacket

Answer 5. (a) Woollen shawl

Explanation: Wool is obtained by shearing the fleece(hair) of Sheep, goats, or camels and does not require animal killing compared to other options where the killing of silkworms obtains silk. Animal fur and leather jackets also involve killing animals.

 Question 6. Fill in the blanks in the following statements.

 (a)  _________ and _________ fibres are obtained from animals.

 (b) Silk fibres come from _________ of silk _________.

 (c) Wool yielding animals bear _________ on their body.

 (d) Hair traps a lot of _________, which is a poor _________ of heat.

Answer 6.          

(a) Silk and wool

(b) Cocoons and moth

(c) Hair

(d) Air and conductor 

Question 7. Out of the following, which are the two terms related to silk production?

(a) Sericulture

(b) Floriculture

(c) Moriculture

(d) Apiculture

(e) Silviculture.

Hints: 

(i) Silk production involves the cultivation of mulberry leaves and rearing silkworms.

(ii) Scientific name of mulberry is Morus alba.

Answer 7. (a) Sericulture and (c) Mariculture.

Explanation:

Sericulture: The process of rearing silkworms to obtain raw silk.

Mariculture: Cultivation of mulberry plants to feed the silkworms.

Floriculture: Cultivation of flowering plants.

Apiculture: Method of rearing honeybees.

Silviculture: Art of managing the growth and quality of forest to meet diverse needs and values.

Question 8. Steps for the production of silk are given below in a jumbled order. Arrange them in their proper sequence.

 (a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.

 (b) Fibres are taken out from the cocoon.

 (c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons.

 (d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.

 (e) Female silk moths lay eggs.

 (f) Cocoons are kept under the sun or boiled in water.

Answer 8. Correct sequence:

 (e) Female silk moths lay eggs.

 (a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.

 (d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.

 (c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons.

 (f) Cocoons are kept under the sun or boiled in water. 

 (b) Fibres are taken out from the cocoon.

Question 9. Complete the paragraph related to the life history of the silk moth by filling in the blanks.

 The ____(a)___ silk moth lays ___(b)___, from which hatch ____(c)___ called ___(d)____ or ___(e)____. They grow in size, and when the caterpillar is ready to enter the next stage of its life history called ___(f)____, it first weaves a covering to hold itself, which is known as ___(g)____.

Answer 9. (a) Female (b) Eggs (c) Larvae (d) Caterpillars (e) Silkworms (f) Pupa (g) Cocoon

Question 10. Describe the life history of silk moths with the help of figures of various stages.

Answer 10. The complete life cycle of a silkworm takes 50 to 60 days. There are five stages in the life history of a silkworm.

Stage 1: Eggs:

The adult female silkworm lays more than 350 eggs in this first lifecycle stage.

Stage 2: Hatchlings:

In the warm weather during springtime, the eggs hatch to form larvae called caterpillars or silkworms. This stage requires 10 to 14 days.

Stage 3: Larvae:

After the eggs hatch, a caterpillar arises. These caterpillars feed on mulberry leaves in a vast quantity and grow for around 30 days before entering the next stage, which is Pupa.

Stage 4: Pupa(Cocoon):

In this stage, the caterpillar stops eating the mulberry leaves and starts to swing its head to spin a silk fibre from its saliva made of a protein that acts as a protective layer for the Pupa. This covering is known as a cocoon. The size of a cocoon is like a small cotton ball. This stage requires 10 to 14 days. During this stage, the cocoon bodies become slightly yellow, and the skin tightens.

Stage 5: Adult Silkworm:

In the final stage of its lifecycle, the moth emerges as an adult silkworm after one or two weeks from the Pupa stage. The silkworm moth is hairy and has a wingspan of about 50 mm. The male moth is smaller than the female. The female moth releases pheromones to attract the male moth. With the help of longer antennae, the male moth detects pheromones from a distance. They mate when the two find each other, and the life cycle begins again.

Question 11. Match the words of Column I with those given in Column II:                                  

Answer11. Below is the matched column

Question 12. You must be familiar with the following nursery rhymes:

 (i) ‘Baa baa black sheep, do you have any wool.’

 (ii) ‘Mary had a little lamb, whose fleece was white as snow.’

Answer the following:

  (a) Which parts of the black sheep have wool?

  (b) What is meant by the white fleece of the lamb?

Answer 12. (a) Fleece(hair) of the Black Sheep.

                      (b) The white fleece of the lamb is white coloured hairy skin of the lamb.

Question 13. Rohan’s father works in the wool industry. In his line of work, he sorts the fleece of Sheep into fibres of different qualities. Rohan noticed that his father and other workers doing similar jobs faced several health problems.

Rohan discussed this problem with his friends and learned that his father was facing health issues due to his work.

Rohan is worried about his father’s health. He advised his father to take care of his health and told him about the occupational hazards.

Now answer the following questions.

(a) What do you mean by occupational hazard?

(b) Name the disease that workers may risk.

(c) What values are shown by Rohan?

Answer 13.

(a) Occupational hazards are the risks faced by people working in any industry due to the nature of work. These include physical safety hazards, chemical hazards, biological hazards, physical hazards, and ergonomic risk factors.

(b) In the wool industry, the workers inhale small hair while sorting or scouring, leading to respiratory diseases like asthma, bronchitis, etc. Some other health issues include sprains and strains, wrist and back problems, cuts and bruising, fatigue, and dehydration.

(c) Rohan is caring and cautious.

Question 14. Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.

Shearing, __________, Sorting, __________, __________, _________.

Answer 14: The missing steps are  Scouring, Cleaning of burrs, Dyeing, Rolling

Question 15. State whether the following statements are True or False. If false, correct them

(a) Silkworms are caterpillars of silk moths.

(b) In India, camels and goats are generally reared for obtaining wool.

(c) The rearing of silkworms for obtaining silk is called silviculture.

(d) In obtaining wool from fleece, sorting is done after scouring.

(e) Yak hairs are not used to make woollen fabric.

Answer 15. 

 (a) True.

 (b) False: Sheep are generally reared to obtain wool in India.

 (c) False silkworms are used for obtaining silk, called Sericulture.

 (d) True.

 (e) False. Yak hair is also used to produce woollen fabric.

Question 16. Which of the following is not a type of silk?

   (a) Mulberry silk

   (b) Tussar silk

   (c) Muga silk

   (d) Moth silk

Answer 16. (d) Moth Silk

Explanation: Mulberry Silk, Tussar Silk and Muga silk are the silk produced from the fibre that comes from different silkworms, whereas Moth silk is not a variety of that silk. 

Question 17. Explain the phrase “Unity is Strength” based on making fabric from fibre.

Answer 17. Fabric is made by weaving many thin strands of fibre. A single fibre is delicate and easy to break. However, the fabric cannot be torn easily as it is a collection of many fibre threads. Hence, it implies that with togetherness comes unity and with unity comes strength which proves the phrase –“Unity is Strength.

Question 18. Write various steps for processing fibres into wool.

Answer 18. The steps involved in processing fibres into wool are as follows:

Step I: Shearing.

Sheep’s fleece(hair) and a thin layer of skin are removed. Shearing does not hurt the Sheep as it is similar to a normal haircut humans get all the time. Also, the hair of Sheep grows again.

Step II: Scouring.

The sheared skin with hair is washed thoroughly through a machine to remove the impurities like dust, dirt and grease.

Step III: Sorting.

The sorting is done in the factory to separate or sort out the hair of different textures.

Step IV: From the sorted hair, small fluffy fibres called burrs are picked out and scoured again. Wool obtained from this is converted into fibres.

Step V: The fibres are dyed in various colours in this step.

Step VI: The fibres are straightened, combed and rolled into yarn. The longer fibres are made into wool for sweaters, and the shorter fibres are spun and woven into woollen cloth.

  Question 19. Reeling of silk is

  (a) a process of making silk reels

  (b) the spinning of silk fibres

  (c) the weaving of silk cloth

  (d) the process of taking silk threads from a cocoon   

  Answer 19. (d) The process of taking silk threads from the cocoon.

Benefits of Solving Important Questions Class 7 Science Chapter 3

Practicing questions from the Chapter 3 Class 7 Science Important Questions, after reading the chapter helps students understand the concepts more effectively and gain confidence to score well in examinations. MCQs, short answers, medium answer, and long answer questions are provided with step-by-step solutions to make you familiar with the question pattern and mark the weightage of this chapter. 

Furthermore, some other benefits of referring to Important Questions Class 7 Science Chapter 3 are:

• Important Questions Class 7 Social Science Our Pasts 2 Chapter 4  covers all the chapter-end questions along with their comprehensive answers explained with proper instances.
• These solutions help students save time while preparing for the upcoming examination as students don’t have to waste time looking for different resources for their exam preparation. Extramarks proves to be a one stop solution
• Students can entirely rely upon these important questions as these are made following all the guidelines laid by CBSE.
• Important Questions Class 7 Science Chapter 3 follow the latest CBSE syllabus and guidelines.
• The questions are collated from various sources, including NCERT textbooks, CBSE sample papers,  CBSE extra questions, NCERT Exemplars, past years’ question papers, etc.
• By practising these advanced level questions thoroughly, students can analyse their shortcomings and overcome them before facing the examinations.

To refer and practice on the Important Questions Class 7 Science Chapter 3, register on the Extramarks website right away.

Furthermore, students can get access to other study materials for various Classes from Classes 1 to 12 by clicking on the below links:

• NCERT books
• CBSE Revision Notes
• CBSE syllabus
• CBSE sample papers
• CBSE past year’s question papers
• Important formulas 
• CBSE extra questions