3. Fibre to Fabric | Natural Fibres and Synthetic Fibres Science class 7
3. Fibre to Fabric | Natural Fibres and Synthetic Fibres Science class 7
Natural Fibres and Synthetic Fibres
1. Natural fibres : The fibres which are obtained from plants and animals are called natural fibres.
Examples of natural fibres:
(i) Fibres obtained from plants : Cottons, Jute etc.
(ii) Fibres obtained from animals : Wool and silk.
2. Synthetic Fibres : Nylon, polyesters, Acrilyc etc.
Obtaining Wool: Wool is obtained from the fleece (hair) of sheep or yak.
Obtaining Silk : Silk fibres come from cocoons of the silk moth.
Animals by which obtain wool : Wool comes from sheep, goat, yak and some other animals.
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.
Selective breeding:
The process of selecting parents for obtaining special characters in their offspring, such a soft under hair in the sheep, is ‘termed selective’.
- sheep wool and Yak wool is common in Tibet and Ladakh.
- Angora wool is obtained from angora goats, Found in hilly regions such as Jammu and Kashmir.
- The fur (hair) on the body of camels is also used as wool. Llama and Alpaca, found in South America, also yield wool.
Pashmina shawls : Wool is also obtained from goat hair. The under fur of Kashmiri goat is soft. It is woven into fine shawls called Pashmina shawls.
Name of Animals which yield wool :
(i) Angora goat
(ii) Goat
(iii) Sheep
(iv) Camel
(v) yak
(vi) Llama
(vii) Alpaca
The steps of obtaining wool
The steps of obtaining wool :
(i) Shearing: The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing. In this process the hairs are shaved off. The hair provide woolen fibres.
(ii) Scouring : The sheared skin with hair thoroughly washed in tanks to remove grease, dust and dirt. This is called scouring.
(iii) Sorting: The hairy skin is sent to a factory where hair of different textures are separated. This ia called sorting.
(iv) Cleaning of Burrs: 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.
(v) Dyeing : The dyeing in various colours. as the natural fleece of sheep and goats is black, brown or white.
(vi) Rolling into Yarn : 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 : Sorter's job sometimes workers 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.
Timing to remove hair :
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Science Chapter List
1. Nutrition in Plants
2. Nutrition in Animals
3. Fibre to Fabric
4. Heat
5. Acids, Bases and Salts
6. Physical and Chemical Changes
7. Weather, Climate and Adaptations of Animals to Climate
8. Winds, Storms and Cyclones
9. Soil
10. Respiration in Organisms
11. Transportation in Animals and Plants
12. Reproduction in Plants
13. Motion and Time
14. Electric Current and its Effects
15. Light
16. Water : A Precious Resource
17. Forests: Our Lifeline
18. Wastewater Story
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