Fibre to Fabric Class 7 Extra Questions and Answers Science Chapter 3

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Class 7 Science Chapter 3 Extra Questions and Answers Fibre to Fabric

Extra Questions for Class 7 Science Chapter 3 Fibre to Fabric with Answers

Fibre to Fabric Class 7 Extra Questions Very Short Answer Type

Question 1.
Name three animals that yield wool.
Answer:
Sheep, goat, yak.

Question 2.
In which areas are yaks found in plenty?
Answer:
Tibet and Ladakh.

Question 3.
Which animal provides Pashmina shawls?
Answer:
Kashmiri goat.

Question 4.
What is the diet of sheep?
Answer:
Grass, leaves, mixture of pulses, corn, jowar, oil cakes and minerals.

Question 5.
In which season sheep are sheared?
Answer:
Summer.

Question 6.
What are burrs?
Answer:
Small fluffy fibres found in hair of sheep are called burrs.

Question 7.
What are silkworms?
Answer:
Larvae of silk moth are called silkworms.

Question 8.
Name one disease that occurs in sheep.
Answer:
Anthrax. It is a fatal blood disease.

Question 9.
What is cocoon?
Answer:
For pupa stage, the caterpillar completely covers itself by silk fibres. This covering is known as cocoon.

Question 10.
What is the most common silk moth?
Answer:
Mulberry silk moth.

Fibre to Fabric Class 7 Extra Questions Short Answer Type 1

Question 1.
What is selective breeding?
Answer:
The process of selecting parents for obtaining special characters in their offspring, is termed ‘selective breeding’.

Question 2.
Write about the food of sheep.
Answer:
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. In winter, sheep are kept indoors and fed on leaves, grain and dry fodder.

Question 3.
How is reeling of silk done?
Answer:
Reeling is done with special machines, which unwind the threads or fibres of silk from the cocoon. Silk fibres are then spun into silk threads.

Fibre to Fabric Class 7 Extra Questions Short Answer Type 2

Question 1.
How is shearing of wool done?
Answer:
Machines similar to those used by barbers are used to shave off hair. Usually, hair are removed during the hot weather. This enables sheep to survive without their protective coat of hair. The hair provide woollen fibres. Woollen fibres are then processed to obtain woollen yarn. Shearing does not hurt the sheep because uppermost layers of skin is dead.

Question 2.
How is silk processed?
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 are 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.

Fibre to Fabric Class 7 Extra Questions Long Answer Type

Question 1.
How is woollen cloth made after scouring hair of sheep?
Answer:

1. After scouring, sorting is done. The hairy skin is sent to a factory where hair of different textures are separated or sorted.
2. The small fluffy fibres, called burrs, are picked out from the hair. The fibres are scoured again and dried. This is the wool ready to be drawn into fibres.
3. The fibres can be dyed in various colours, as the natural fleece of sheep and goats is black, brown or white. The fibres are straightened, combed and rolled into yarn.
4. The longer fibres are made into wool for sweaters and the shorter fibres are spun and woven into woollen cloth.

Question 2.
Describe the life history of silk moth.
Answer:
The female silk moth lays eggs, from which hatch larvae which are called caterpillars or silkworms.

1. They grow in size and when the caterpillar is ready to enter the next stage of its life history called pupa, it first weaves a net to hold itself.
2. Then it swings its head from side to side in the form of the figure of eight (8).
3. During these movements of the head, the caterpillar secretes fibre made of a protein which hardens on exposure to air and becomes silk fibre.
4. Soon the caterpillar completely covers itself by silk fibres. This covering is known as cocoon.
5. The further development of the moth continues inside the cocoon.
6. Finally, it comes out of the cocoon as silk- moth.

Question 3.
Draw figures to describe life history of silk moth.
Answer:

Question 4.
How is rearing of silkworm done?
Answer:

1. 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.
2. The farmers keep eggs under hygienic conditions and under suitable conditions of temperature and humidity.
3. The eggs are warmed to a suitable temperature for the larvae to hatch from eggs.
4. This is done when mulberry trees bear a fresh crop of leaves. The larvae, called caterpillars or silkworms, eat day and night and increase enormously in size.
5. The worms are then kept in clean bamboo trays along with freshly chopped mulberry leaves.
6. After 25 to 30 days, the caterpillars stop eating and move to a tiny chamber of bamboo in the tray to spin cocoons.
7. 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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