Class-7th ‘B’ [week 8] Sub.-science Chapter3-Fibre to Fabric

 The materials used to make clothes are called fabrics.  Fabrics are made from that are woven or knitted from hair-like strands called fibres.  Fibres are two types: 1. Natural Fibres 2. Artificial Fibres  Natural fibres are obtained from plants and animals.  Artificial fibres are made by humans.

Wool:-  is an animal fibre obtained mainly from fleece of some animals.  Wool fibres trap air in the spaces between them.  As air is bad conductor of heat, this prevents the loss of heat from the body, which helps in keeping the body of these animals warm. Characteristics of wool Fibre:-  It appears mostly creamy white in colour.  It does not wrinkle easily.  It is durable and elastic.  It is a bad conductor of heat.  It absorbs moisture.

Animals that yield wool are as follows:- Sheep:-  They are the main wool-yielding animals. Two types of fibres are obtained from the fleece of a sheep: 1. The coarse beard hair. 2. The soft and fine under hair that usually grows close to the Skin. Goat:-  Wool is also obtained from the under of some goats.  The Angora and cashmere breeds are the ones that yield wool.  Angora goats are mostly found in the (Angora) region of Turkey.  Fine, soft and lustrous wool fibre known as is obtained from Angora goats.  Cashmere goats are mostly found in the mountains of Tibet and China.  They produce very soft and warm fibre called Cashmere.

Camel:-  The fleece of camel gives soft, warm and light weight wool.  Annually 12-13 kg of wool is obtained from a male camel.  6-8 kg of wool is obtained from a female camel.  The best quality of wool is obtained from Bactrian camels of Siberia, Mongolia and China.  , Vicuna and are the animals that belong to the camel family and mostly found in South America.

Rabbit and :-  A very fine, silky wool called Angora wool is obtained from the .  Wool is also obtained from yak mostly found in Ladakh and Tibet.

Rearing and Breeding of sheep:-  Sheep live and move in groups called flocks and a big group of sheep is called a Herd.  The process of domestication and raising of sheep is known as rearing.  In India, sheep are mostly reared in Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Arunachal Pradesh, Sikkim, Haryana, Punjab, Rajasthan and Gujarat.  Sheep are herbivores and feed on grass and weeds.  The process of selecting parents for obtaining desirable characters in their off springs are known as selective breeding. The bred animals are known as breeds.

Name of breed Quality of wool Name of the states where it is found Lohi Good quality wool Rajasthan, Punjab Rampur bushair Brown fleece Uttar Pradesh, Himachal Pradesh Nali Carpet wool Rajasthan, Haryana, Punjab Bakharwal For woollen shawls Jammu and Kashmir Marwari Coarse wool Gujarat Patanwadi For hosiery Gujarat

Processing of fleece to Fabric (wool Production):- The processing of woollen fabric from the Sheared fleece involves the following steps:- 1. Shearing:-  The process of removal of fleece from the body of animals like sheep is known as Shearing.  It is done with the help of clippers or a pair of scissors or a shearing machine.  The person who removes the wool is called a Shearer.  Shearing is done during summer months to prevent from cold.

2. Scouring:-  The process in which the shorn hair is treated to remove grease and dirt is called scouring. 3. Sorting:-  The process of removal of any damaged and stained wool from the fleece is known as Sorting. 4. Grading:-  The process of grouping of wool according to their length, colour, texture and ease of dyeing is known as grading. 5. Dyeing:-  The process of colouring sheared wool in various colours is called Dyeing. 6. Drying:-  The process of drying dyed wool is called Drying. 7. :-  The fibres after drying are oiled, straightened, combed, washed, twisted and spun into yarns. 8. and knitting:-  The process of spinning into and knitting for making sweater. Health hazards in wool industry:-  The major health hazard faced by people working in wool industry is an infection called anthrax. It is common bacterial disease of goat and sheep. It is also known as ‘sorter’s disease’. This disease leads to skin, lung and intestinal disorder.  The usage of chemical dyes may result in irritation of eyes, infection of skin, lungs and breathing problems.  Hearing loss due to loud noise made by machines during processing of wool. Answer the following questions:- 1. What do you mean by fibre? 2. Write the characteristics of wool fibre. 3. Name the animals that yield wool. 5. What do you mean by rearing and breeding of sheep? 6. Explain the steps involved in the production of wool in detail.