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[Short Notes – E&B] NCERT Class VII – Science – Fibre to Fabric – Chapter 3 – Part 1

by Wonder Boy · Published June 20, 2015 · Updated June 2, 2016

[Short Notes – E&B] NCERT Class VII – Science – Nutrition in Animals – Chapter 2 – Part 2

Read complete book (must) at : NCERT Class VII – Science – Fibre to Fabric – Chapter 3

Wool is obtained from the fleece (hair) of sheep or yak.

Silk fibres come from cocoons of the silk moth.

Animal fibres — wool and silk

Wool comes from sheep, goat, yak and some other animals.

These wool-yielding animals bear hair on their body.

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

Wool is derived from these hairy fibres.

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.

The fine hair provide the fibres for making wool.

SELECTIVE BREEDING

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’

Animals that yield wool

Apart from Sheep Wool

Yak wool is common in Tibet and Ladakh.

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

Wool is also obtained from goat hair. The under fur of Kashmiri goat is soft.

It is woven into fine shawls called Pashmina shawls.

The fur (hair) on the body of camels is also used as wool.

Llama and Alpaca, found in South America, also yield wool.

Rearing and breeding of sheep:

Shepherds take their herds of sheep for grazing

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.

In winter, sheep are kept indoors and fed on leaves, grain and dry fodder.

Certain breeds of sheep have thick coat of hair on their body which yields good quality wool in large quantities.

These sheep are “selectively bred” with one parent being a sheep of good breed.

Processing fibres into wool

Step I: The fleece of the sheep along with a thin layer of skin is removed from its body.

This process is called shearing.

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.

The uppermost layer of the skin is dead. Also, the hair of sheep grow again.

Step II: The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt.

This is called scouring.

Nowadays scouring is done by machines

Step III: After scouring, sorting is done. The hairy skin is sent to a factory wherehair of different textures are separated or sorted.

Step IV: The small fluffy fibres, called burrs, are picked out from the hair.

These are the same burrs which sometimes appear on sweaters.

The fibres are scoured again and dried.

This is the wool ready to be drawn into fibres.

Step V: The fibres can be dyed in various colours, as the natural fleece of sheep and goats is black, brown or white.

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.

Occupational hazard

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.

Such risks faced by workers in any industry are called occupational hazards.

Some Indian breeds of sheep
S.No.	Name of breed	Quality of wool	State where found
1	Lohi	Good quality wool	Rajasthan, Punjab
2	Rampur bushair	Brown fleece	Uttar Pradesh,Himachal Pradesh
3	Nali	Carpet wool	Rajasthan, Haryana, Punjab
4	Bakharwal	For woollen shawls	Jammu and Kashmir
5	Marwari	Coarse wool	Gujarat
6	Patanwadi	For hosiery	Gujarat