Notes of fibre to fabric chapter class 7.
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Natural Fibre
Natural fibres are threads obtained from plants and animals. Cotton, flax, and jute are examples of plant fibres and wool and silk are examples of animal fibre.
types-of-fibres
Animal Fibres (Wool and Silk)
Out of these two animal fibres wool comes from animals like sheep, goat, yak etc. and silk comes from silk warms. Animal fibres are made up of proteins (complex compound that form a major part of bodies of all animals).
Wool
Wool is the most used animal fibre. Wool is used for knitting sweaters , weaving shawls and other woven cloths.
Wool comes from the fleece (hair) of animals like sheep, goat, yak and some other animals. These animals bear hairs on their body. Hairs of wool yielding animals trap lot of air. Air is a poor conductor of heat. So hairs keeps these animals warm by shielding their body from cold during winter.
Wool is most commonly obtained from sheep.
The fleece of a sheep consists of two types of fibre:-
1. The coarse beard hair
2. The fine and soft under hair (hair that grows close to skin). These under hairs are used for making the wool.
Selective breeding:-
The process of selecting parents for obtaining special characters in their offspring, such as soft under hairs in sheep, is called selective breeding.
There are several breeds of sheep found in our country. Apart from sheep there are many other animals for obtaining wool. Some examples are
Yak wool is common in Tibet and Ladakh.
Angora wool is obtained from angora goats found in hilly regions (Jammu and Kashmir).
Under fur of Kashmiri goats is soft and is used to weave fine Pashmina shawls.
Fur of camel and Alpaca (found in South America) also yield wool.
From Fibres to wool
In market wool we generally get is the wool obtained from sheep. In order to obtain wool , sheep are reared. There hairs are then cut and processed into wool.
Rearing and breeding of sheep
By rearing of sheep or any other animal we means to look after it by providing them food, shelter and healthcare. The persons who look after sheep are called shepherds.
Sheep are reared mainly for wool. They are reared in areas with low rainfall. In India you would be able to see shepherds taking their herds of sheep to gazing in plains of states like Haryana, Punjab, Rajasthan, and Gujrat. You can also find herds of sheep to gazing in hilly states also for example Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Arunachal Pradesh and Sikkim.
Sheep have a lifespan of 10 to 12 years. Sheep are herbivores and prefer grass and leaves. Apart from this reared sheep are also fed on mixture of pulses, corn, jowar and minerals. In winters they are kept indoors and are fed on dry fodder, leaves and grains.
Processing fibres into wool
Processing fibres into wool involves the following steps:-
Processing fibres into wool
Step 1:- Shearing
The removal of wool from sheep is called shearing. It can be done manually with large razor or with a shearing machine. Shearing is usually done during hot season. It is important to note that shearing does not hurt sheep because uppermost layer of the skin of sheep is dead.
Step 2:- Scouring
The sheared hair is thoroughly washed in tanks to remove dust, dirt and grease. This process is called scouring. It is then passed through series of rollers and dryers.
Step 3:- Sorting
Clean hairs are then sent to factory where hairs of different textures are separated or sorted. This process is called sorting.
Step 4:- Removing burr
Burrs are soft fluffy fibres in the wool. These burrs are picked out from the hair.
Step 5:- Dyeing
The natural fleece of sheep is white, brown or black. These fibres are dyed in different colors.
Step 6:- Making Yarn
In this step the wool is straightened, combed and spun into yarn. After spinning the wool is either woven or knitted. Longer fibres are made into wool for sweaters.
Occupational Hazards
Occupational Hazards are the risks faced by people working in any industry due to the nature of their work.
Wool industry gives employment to many people in our country. But sorter’s job is risky as they sometimes get infected by a bacterium anthrax, which causes fatal blood disease called sorter’s disease.
Silk
Silk fibres are also animal fibres. Silk is a fine, strong, soft and shining fibre produced by silkworms in making their cocoons (something that covers or protects some insects while they grow). Silk is a naturally lustrous fibre. Silk does not conduct heat so it is a good insulator. It keeps person warm in winter and cool in summer.
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