FIBRE TO FABRIC Class VII Chapter III (C.B.S.E.)

FIBRE TO FABRIC      Class 7      Chapter 3 (C.B.S.E.)

Introduction-The very thin strands of the thread is called fibre. Fibres are soft and they can be spun to form yarn or thread. The yarns are then woven to form the fabric i.e. clothes. The fibres are obtained from plants as well as from animals. Plant fibres are – cotton, jute, hemp, coir, some grasses fibres, linen from flax, bamboo, nettle etc. The hairs of animals called ‘fleece’ are used as fibres. The animal fibres are- Silk, Sheep Wool, Angora goat wool, camel hair, rabbit hair etc.

The plant and animal hairs are natural fibres while synthetic fibres are also there which are prepared in factories. e.g.- Rayon, Nylon, Polyester, Plastic, Acrylic etc.

Animal Fibres- Wool and Silk- Wool and silk are two well known animal fibres. The wool keep the animals warm in cold and protect from insect bites. The hairs (wool fibres) on the skin of sheeps are of two types- (i) outer coarse beard hairs and (ii) fine soft under-hairs close to skin.

The better quality sheeps like those having more soft under-hairs are selected for reproduction (or breeding) to form better quality of wool. This process is called ‘selective breeding’. The wool is obtained from different varieties (breed) of sheeps, Yaks, Angora Goats, Pashmina goats, Camel, Llama, Alpaca, Rabbits etc. Yaks are found in Himalayan regions like Ladakh, Nepal, Bhutan, Sikkim, Arunachal Pradesh, Tibet etc. Angora and Pashmina Goats are found in Jammu and Kashmir of India. The famous Angora wool is obtained from Angora goats. Pashmina shawls are prepared from the wool of Pashmina goats. Llama and Alpaca are South American wool yielding animals.  

                                                                                                                                                                                                                           

Yak

Converting Fibers to wool- The rearing and breeding of sheep is a good source of income. The hair of sheep is cut and different methods are adopted to get the wool. Lets us know it in details.

(a) Rearing and breeding of Sheeps– The sheeps are herbivores. They prefer grazing of grass, leaves, jowar, bajra, pulses, oil cakes etc. In summer season you must have seen the shepherds grazing the sheeps. In winter sheeps are kept indoors. Good quality wool are obtained from improved variety of sheeps. In India the common breeds of sheeps are-

S.N.	Breed Name	Quality of Wool	Location
1	Bakharwal	Good for shawls	Jammu and Kashmir
2	Lohi	Good quality wool	Rajasthan , Punjab
3	Nali	Carpet wool	Rajasthan, Punjab, Haryana
4	Rampur Bushair	Brown coloured hairs	Uttar Pradesh, Himachal Pradesh
5	Marwari	Coarse wool	Gujarat
6	Patanwari	For hosiery cloths	Gujarat

  (b) Processing of Fibres into wool-The making of wool yarn for preparing sweaters and shawls is a long process. This process can be simply divided into following six steps for convenience of study.

Step 1. Shearing– The cutting of the fleece of sheep along with dead outer skin is called as shearing. It is just like shaving of beard and cutting of hairs of ours. It does not harm the sheeps.

Step 2. Scouring– The sheared skin may contain dead skin, dust, dirt and grease. The through washing to remove dead skin, dust, dirt and grease is called as scouring. Earlier scouring was done in water tanks by stirring but scouring is nowadays done by machine.

Step 3. Sorting– The cleaned hairs (fleece) are sent to factories to sort out (separate) the hairs of different texture –length and thickness. This process is called as sorting. 

Step 4. Re-scouring and Resorting to Pickup Burrs– The sorted hairs are again cleaned i.e. scoured and dried. The small fluffy hair fibres called burrs are picked out i.e. sorted out. The remaining good fibres are ready to be drawn into yarns.

Step 5. Dyeing– The woolen fibres can be dyed in different desired colours as the colour of natural wool is black, brown or white.   

Step 6. Rolling into yarns– The woolen hairs fibres are straightened, combed and rolled into yarns. The shorter fibres are spun and woven into woolen cloths while the longer fibres are rolled into yarns for woolen sweaters, mufflers, cap etc.

Sorter’s Disease as an occupational hazard- The workers working in wool industry sometimes get infected by a fatal disease called ‘Sorter’s disease’. It is a blood infection caused by Anthrax bacteria.

Silk- Silk is a natural fibre obtained from silkworms. Silk is a protein secretion by the silkworm or larva or caterpillar. The protein secretion forms cocoon from which silk fibre is extracted. Silk yarns are different in texture i.e. they may be coarse, smooth or shiny. There are different kinds of silk found in India. e.g. – Tassar, Mooga, Kosa, Eri, Mulberry etc. The silk fibres are smooth, lustrous, and elastic. Silk fibres can be dyed to impart different colours. Silk fibres are very strong. The silk is costly so the artificial silk ‘rayon’ is used in place of natural silks.      

Sericulture- The rearing of silkworms to get silk is called sericulture.The soft leaf of mulberry tree (Morus alba) are usually used to grow the caterpillar.

Life cycle of Silk moths- The male and female silk moths reproduce to lay eggs on leaves. The male silk moth is smaller than the female silk moth in size. The eggs hatch to form the larva/caterpillar/ silkworm. The caterpillar grows in size and starts forming a net like structure made up of protein fibres. Protein fibres dry up quickly. The shape of caterpillar becomes like figure of eight (8). The reserve food helps in this stage of development called Pupa stage. The covering over pupa is called cocoon. The Silk fibre is extracted from the cocoon using the sunlight or boiled water or steam.  

Life history of Silk moth

                     

Cocoons Caterpillar / Silkworm

                                            

Converting silk fibres of Cocoon to form silk- The silk moths are reared to collect their cocoons from which the silk fibres are obtained.  

(a) Rearing of Silkworm to get cocoons– Hundred of eggs are laid by the female silk moth at a time. The eggs are carefully stored on strips of paper or cloth. The suitable temperature, humidity and hygienic conditions are necessary for developing the eggs. The eggs hatch to form caterpillar/larva/ silkworm that eats day and night and enormously increase in size. The caterpillars are kept in clean bamboo trays and given freshly chopped mulberry leaves. After 25-30 days the caterpillars stop eating mulberry leaves and transform themselves in pupa stage as like shape of 8 inside cocoons. Cocoon is protein secreted by caterpillar around it.  

(b) Processing of silk fibres of cocoon (reeling of the silk) to form silk- the cocoons are put in boiled water or under the sunlight or exposed to steam to separate the silk fibres. The process of extracting the silk fibres from the cocoon is called reeling. Reeling is done by special machines which unwind the silk fibres from the cocoons. The silk fibres are then converted to silk yarns. The silk yarns are used to prepare silk clothes by weavers.

                                                  EXERCISE QUESTIONS-SOLVED

Q.1 You must be familiar with the following nursery rhyme:

(i) ‘Baa baa black sheep, have you any wool.’

(ii) ‘Mary had a little lamb, whose fleece was white as snow.’

Answer the following:

(a) Which parts of the black sheep have wool?

(b) What is meant by the white fleece of the lamb?

        Ans- (a) Wool is obtained from the hairy fibres of the sheep.

                 (b) The white fleece of the lamb denotes it’s white hairs.

       Q.2 The silkworm is (a) a caterpillar,  (b) a larva. Choose the correct option.

       (i)  a                    

      (ii) b                      

      (iii) both a and b               

      (iv) neither a nor b

       Ans-Both a and b

       Q.3 Which of the following does not yield wool?

       (i) Yak                

       (ii) Camel             

      (iii) Goat                             

      (iv) Woolly dog

       Ans- (iv) Woolly dog

      Q.4 What is meant by the following terms?

       (i) Rearing          (ii) Shearing        (iii) Sericulture

 Ans- (i) Rearing- All the activities involved in breeding and raising up of animals is called rearing.

(ii) Shearing –The process of shaving off of the fleece of wool producing animals is called shearing. It is done by scissors or machines. Dead outer skin may also come along with shaved hairs.

(iii) Sericulture-The rearing of silkworms to get silk is called sericulture.    

 Q.5 Given below is a sequence of steps in the processing of wool. Which are the    missing steps? Add them.

       Shearing, ……………., Sorting, ……………….., …………….., …………………

      Ans-scouring, re-scouring, dyeing, spinning

Q.6 Make sketches of the two stages in the life history of the silk moth which are    directly related to the production of silk.

      Ans- Draw figures of larva (caterpillar/Silkworm) and  Pupa.

Q.7 Out of the following, which are the two terms related to the silk production?

       Sericulture, Floriculture, Moriculture, Apiculture, and Silviculture.

Hints: (i) Silk production involves cultivation of mulberry leaves and rearing      silkworms.

 (ii) Scientific name of mulberry is Morus alba.

        Ans- Sericulture and Moriculture

      Q.8 Match the words of column I with those given in column II:

      Column I                        Column II

   1. Scouring                         (a) Yields silk fibres

   2. Mulberry leaves              (b) Wool yielding animal

   3. Yak                                  (c) Food of silk worm

   4. Cocoon                            (d) Reeling

                                               (e) Cleaning sheared skin

      Ans- 1.-V     2.-C      3.-Wool yielding animals       4.- Yields silk fibres

Q.9 Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.

           Down (D)                                                           Across (A)

       1. Thorough washing                                1. Keeps warm

       2. Animal fibre                                           2. It’s leaves are eaten by silkworms

       3. Long threads like structure                3. Hatches from egg of moth

       Ans

						1D		2D
			3D		1A
2A
3A

 

        Ans- 1A- Wool                    2A- Mulberry                3A- Caterpillar

                 1D- Scour                   2D- Silk                           3D- Fibre

 

 

 

CHECK YOUR PROGRESS      Time= 40 Minutes     Total Marks= 15

Q.1 What are the steps involved in processing of wool to prepare yarns?

Q.2 Describe the life-cycle of silk moths with a suitable diagram.

Q.3 Describe the steps in silk moths rearing to reeling of silk fibres.

GROUP PROJECTS –

1. Collection of silk made clothes. It’s history of making and traditional instruments used in making of silk clothes.

2. Collection of organisms of different stages in the life cycle of Silk moths.

3. Draw a labeled diagram of life cycle of silk moths and explain each stage.

4. Locate silk routes on the physical map of Asia. Write the history of origin of silk cloths making.

5. Visit a local Sericulture site and experience the making of silk yarns and silk clothes.

          

 

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