6th Class Science Fibre to Fabric Silk

     Silk

Silk is also a natural fibre. It is obtained from cocoons of silkworm. Silk is a fine, strong, soft and shiny fibre. The rearing of silkworms for obtaining silk is called sericulture.

        Production of Silk

Eggs from the adult silk moth are kept at suitable temperature and humid conditions. During the hatching, silkworms come out in the form of larvae or caterpillar. After 25 to 30 days, they get ready to spin cocoons.

            Processing of cocoons for fibres

Reeling machine is used for unwinding the silk fibre from cocoons. Silk fibres are twisted to make silk yarn for waving the silk cloth. There are many varieties of silk obtained from different silk moth. A most common type of silk is mulberry silk which is soft, lustrous, elastic and can be dyed in different colours.

Look at the following picture to obtain silk from silk moth:

Eggs from female adult silk moth             Caterpillar form cocoons           Caterpillar covers themselves form silk  

           Natural and Artificial Fibre

Silk and wool are natural fiber. A type of fibre which is neither natural nor artificial is called rayon. Rayon is obtained from wood pulp (cellulose) which is a natural fibre. Some artificial or synthetic fibres are : nylon, polyester, acrylic, polyolefin, etc. The first artificial fibre known as viscose was produced in 1894.

Rayon came into being in the year of 1924.

The following are the method by which, we can find out whether the fibre is artificial or natural.

(i) Take a piece of fibre and burn it. If burning smell is same as the burning smell of hair then the taken piece of fibre is a natural fibre.

(ii) If the burning smell is same as the burning smell of paper then the taken piece of fibre is an artificial fibre.

      Consider the following statements:

Statement 1: Silk is obtained from silk worm.

Statement 2: Silk is obtained from plants.

Which one of the following is correct about the above statements?

(a) Statement 1 is true and 2 is false

(b) Statement 1 is false and 2 is true

(c) Both statements are false

(d) Both statements are true

(e) None of these

Answer: (a)

Explanation 

Silk is obtained from silkworm. Therefore option (A) is correct and rest of the options is incorrect.   

     Variety of silk depends upon which one of the following factors?

(a) Temperature at which eggs are stored

(b) Types of silk processing in the factory

(c) Types of silk moth

(d) All of these

(e) None of these

Answer: (c)

Explanation 

Verity of silk depends upon the types of silk moth from which silk is obtained. Therefore, option (C) is correct and rest of the options is incorrect.

incorrect.      

Plant fibres are obtained from plants and animal fibres are obtained from animals.

Wool and silk are animal fibres.

Silk is obtained from larva or caterpillars of silk moth.

Burning smell of a natural fibre is same as that of the burning of hair.

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