sheep wool is its hairs why is it white or yellow like colourd which hormone is used in its formation
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1. Introduction
Overview
Objectives
2. Key Concepts
Animal Fibres - Wool and silk
3. Experiments and Experiences
Distinguish between artificial silk and natural silk.
4. Check your understanding
Quiz
5. Did You Know?
Interesting Facts
Classroom Activities
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Chapter 3 - Fibre to Fabric
Everything Is Everything - II
Animal Fibres - Wool and silk
Wool
Wool comes from sheep, goat, yak and some other animals. These wool-yielding animals bear hair on their body because hair keeps these animals warm and 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.
Some breeds of sheeppossess only fine under-hair. Theirparents are specially chosen to give birthto sheep which have only soft under hair.This process of selecting parentsfor obtaining special characters in theiroffspring, such as soft under hair insheep, is termed ‘selective breeding’.
Animals That Yield Wool
The fleece of sheep is not the only source of wool, though wool commonly available in the market is sheep wool.
Yak wool is common in Tibet and Ladakh and Angorawool 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 and It is woven into fine shawls called Pashmina shawls.
The fur (hair) on the body of camels is also used as wool. Llamaand Alpaca, found in South America,also yield wool.
From Fibres To Wool
For obtaining wool, sheep are reared.Their hair is cut and processed into wool.
Rearing and breeding of sheep :
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 and In winter, sheep are kept indoors and fed on leaves, grain and dry fodder.
Sheeps are reared in many parts of our country and Certain breeds of sheep have thick coat of hair on their body which yieldsgood quality wool in large quantities.
Once the reared sheep have developed a thick growth of hair, hair is shaved off for getting wool.
Processing Fibres Into Wool
Wool that is used for knitting sweaters and for weaving shawls is the product of a long process involving the following steps :
Step 1-
The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing.
Usually, hair are removed during the hot weather which enables the sheep to survive without their protective protective coat of hair.
The hair provide woollen fibres and Woollen fibres are then processed to obtain woollen yarn.
Step 2-
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 3-
After scouring, Sorting is done. The hairy skin is sent to a factory where hair of different textures are separated or sorted.
Step 4-
The small fluffy fibres, called burrs, are picked out from the hair. The fibres are scoured again and dried and the wool is ready to be drawn into fibres.
Step 5-
The fibres can be dyed in various colours, as the natural fleece of sheep and goats is black, brown or white.
Step 6-
The fibres are straightened, combed and rolled into yarn and the longer fibres are made into wool for sweaters and the shorter fibres are spun and woven into woollen cloth.
Silk fibres are also animal fibres.
Silkworms spin the ‘silk fibres’.
The rearing of silkworms for obtaining silk is called Sericulture.
Life History Of A Silk Moth
The female silk moth lays eggs, from which hatch larvae which are called Caterpillars or Silkworms.
They grow in size and when the caterpillar is ready to enter the next stage of its life history called pupa, it first weaves the net to hold itself and swings its head from side to side in the form of figure eight (8).
During these movements of head, the caterpillar secretes fibre made of a protein which hardens on exposure to air and becomes silk fibre.
The caterpillar completely covers itself by silk fibres and turns into pupa. This covering is known as Cocoon.
Silk fibres are used for weaving silk cloth. The silk yarn (thread) is obtained from the cocoon of the silk moth.
Thus, Tassar silk, mooga silk, kosa silk, etc. are obtained from cocoons spun by different types of moths and the most common silk moth is the mulberry silk moth.
The silk fibre from the cocoon of this moth is soft, lustrous, and elastic and can be dyed in beautiful colours.
Sericulture or culture of silkworms is a very old occupation in India.
From Cocoon To Silk
For obtaining silk, moths are reared and their cocoons are collected to get silk threads.
Rearing silkworms :
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