CBSE NOTES for class 7 th
3. Fibre to Fabric : Science class 7 th:English Medium NCERT Book Solutions
NCERT Books Subjects for class 7th Hindi Medium
3. Fibre to Fabric
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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See other sub-topics of this chapter:
1. Natural Fibres and Synthetic Fibres Science class 7
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