Extra Questions for Class 7 Science Chapter 3 Fibre to Fabric

Extra questions for Class 7 Science Chapter 3 Fibre to Fabric with answers is given below. Our subject expert prepared these solutions as per the latest NCERT textbook. These questions will be helpful to revise the all topics and concepts. CBSE Class 7 extra questions are the most simple and conceptual questions that are prepared by subject experts for the students to study well for the final exams. By solving these extra questions, students can be very efficient in their exam preparations.

Fibre to Fabric Class 7 Science Extra Questions and Answers

Very Short Extra Questions and Answer

1. Of which nutrient silk fibre is made?

Answer:  Protein

2. What are silkworms?

Answer:  Silkworm are caterpillars of silk moth.

3. Which parts of the black sheep have wool?

Answer: The hairy skin of the sheep has wool.

4. What is meant by the white fleece of the lamb?

Answer: The white fleece of the lamb means white color hairy skin.

5. What is Sericulture?

Answer: The rearing of silkworms for obtaining silk is called sericulture.

6. What is the scientific name of mulberry?

Answer: Scientific name of mulberry is Morus alba.

7. Name some animals which give us wool.

Answer: sheep, goat and yak

8. Which leads the world in silk production?

Answer: China leads the world in silk production.

9. Is silk a good conductor of heat?

Answer: Silk is a protein fibre and is a non-conductor of heat.

10. What do you mean by yarn?

Answer: Yarn is a long continuous thread that is made up of fibre.

11. Name some Indian breed of sheep.

Answer: Lohi, Rampur bushair, Nali, Bakharwal, Marwari and Patanwadi

12. What are the different types of silk?

Answer: mulberry silk, tassar silk, eri silk, mooga silk, etc.

13. Define spinning.

Answer: The process of making yarn from fibres is called spinning.

14. What is the most common silk moth?

Answer: The most common silk moth is the mulberry silk moth.

15. What do you understand by wool?

Answer: Wool is a fibre obtained from sheep, goat, yak and some other animals.

Short Extra Questions and Answers

1. What do you mean by occupational hazards?

Answer: Risks faced by workers in any industry are called occupational hazards.

2. What is cocoon?

Answer: The caterpillar completely covers itself by silk fibres and turns into pupa. This covering is known as cocoon.

3. Where does angora wool come from?

Answer: Angora wool is obtained from angora goats, found in hilly regions such as Jammu and Kashmir.

4. What are silkworms?

Answer: The female silk moth lays eggs, from which hatch larvae which are called caterpillars or silkworms.

5. What is weaving?

Answer: Weaving is the process of arranging two sets of yarns together to make a fabric.

6. What is Rearing?

Answer: Rearing of animal includes day-to-day care, selective breeding and the raising of animal.

7. What is called reeling the silk?

Answer: The process of taking out threads from the cocoon for use as silk is called reeling the silk.

8. Why caterpillars need to shed their skin when they grow bigger?

Answer: Caterpillars’ bodies grow but their exoskeleton doesn’t grow. Hence, they have to shed their exoskeletons when they grow bigger.

9. What do you mean by shearing?

Answer: The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing.

10. Write the sequence of steps involved in the processing of wool.

Answer: Steps involved in the processing of wool are: Shearing, Scouring, Sorting, Picking out burrs, Dyeing of fibres, Making of yarn.

11. How are Pashmina Shawls made?

Answer: Wool is also obtained from goat hair. The under fur of Kashmiri goat is soft. It is woven into fine shawls called Pashmina shawls.

12. Why sheep have a thick coat of hair?

Answer: Hair trap a lot of air. Air is a poor conductor of heat. So, thick coat of hair keeps these animals warm.

13. What is fibre?

Answer: A fibre is a long strong thread, which is obtained from natural sources like plants or manmade sources like synthetic fibres.

14. How and when shearing is done?

Answer: Machines similar to those used by barbers are used to shave off hair. Usually, hair are removed during the hot weather.

15. Why shearing does not hurt the sheep?

Answer: Shearing does not hurt the sheep because the uppermost layer of the skin is dead. Also, the hair of sheep grow again just as our hair does.

16. What is scouring?

Answer: The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt. This is called scouring.

17. Where does angora wool come from?

Answer: Angora wool is obtained from angora goats, found in hilly regions such as Jammu and Kashmir.

18. What is silk route?

Answer: Traders and travellers introduced silk to other countries. The route they travelled is still called the ‘silk route’.

19. What do sheep feed on?

Answer: Sheep are herbivores and prefer grass and leaves. Apart from grazing sheep, rearers also feed them on a mixture of pulses, corn, jowar, oil cakes (material left after taking out oil from seeds) and minerals.

20. Where rearing and breeding of sheep is popular in India?

Answer: Rearing and breeding of sheep is popular in Jammu & Kashmir, Himachal Pradesh, Uttaranchal, Arunachal Pradesh and Sikkim, or the plains of Haryana, Punjab, Rajasthan and Gujarat.

21. What are the two types of fibres that form the fleece of a sheep?

Answer: The hairy skin of the sheep has two types of fibres that form its fleece:
(i) the coarse beard hair, and
(ii) the fine soft under-hair close to the skin.

22. Why caterpillars should not be collected with bare hands?

Answer: Caterpillars should not be collected with bare hands because they have thick stingy hair which may causes irritation to our skin. So, use a paper napkin or a paper to hold a caterpillar.

Long Extra Questions and Answers

1. Why sorter’s job in wool industry is a risky job?

Answer: Wool industry is an important means of livelihood for many people in our country. But sorter’s job is risky as sometimes they get infected by a bacterium, anthrax, which causes a fatal blood disease called sorter’s disease.

2. What is selective breeding?

Answer: Some breeds of sheep possess only fine under-hair. Their parents are specially chosen to give birth to sheep which have only soft under hair. This process of selecting parents for obtaining special characters in their offspring, such as soft under hair in sheep, is termed ‘selective breeding’.

3. Explain the process of obtaining silk from cocoon.

Answer: A pile of cocoons is used for obtaining silk fibres. The cocoons are kept under the sun or boiled or exposed to steam. The silk fibres separate out. The process of taking out threads from the cocoon for use as silk is called reeling the silk. Reeling is done in special machines, which unwind the threads or fibres of silk from the cocoon. Silk fibres are then spun into silk threads, which are woven into silk cloth by weavers.

4. What do you know about discovery of silk?

Answer: The exact time of discovery of silk is perhaps unknown. According to an old Chinese legend, the empress Si-lung-Chi was asked by the emperor Huang-ti to find the cause of the damaged leaves of mulberry trees growing in their garden. The empress found white worms eating up mulberry leaves. She also noticed that they were spinning shiny cocoons around them. Accidentally a cocoon dropped into her cup of tea and a tangle of delicate threads separated from the cocoon. Silk industry began in China and was kept a closely guarded secret for hundreds of years.

5. Explain various steps involved in the process of making wool?

Answer: Steps

Shearing – The fleece of the sheep along with a thin layer of skin is removed from its body using shearing machine.

Scouring – The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt. It is done by machines.

Sorting- The hairy skin is sent to a factory where hair of different textures are separated or sorted.

Picking of Burrs – The small fluffy fibres, called burrs, are picked out from the hair.

Dyeing – The fibres can be dyed in various colours.

Combing and Rolling – The fibres are straightened, combed and rolled into yarn.

6. Write a note on rearing silkworm.

Answer: Rearing silkworms:

  • A female silk moth lays hundreds of eggs at a time. The eggs are stored carefully on strips of cloth or paper and sold to silkworm farmers.
  • The farmers keep eggs under hygienic conditions and under suitable conditions of temperature and humidity.
  • The eggs are warmed to a suitable temperature for the larvae to hatch from eggs. The larvae are kept in clean bamboo trays along with freshly chopped mulberry leaves.
  • After 25 to 30 days, the caterpillars stop eating and move to a tiny chamber of bamboo in the tray to spin cocoons.
  • Small racks or twigs may be provided in the trays to which cocoons get attached. The caterpillar or silkworm spins the cocoon inside which develops the silk moth.
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