7th Class Science Fibre to Fabric Fibres

       Fiber

Fibres are the natural substances, slender, elongated and of threadlike structures. They are obtained from both plants and animals, and are also manufactured in factories. Fibres can be classified into two main groups, that is, natural Fibres and synthetic fibres. Natural fibres are obtained from natural sources, such as animals and plants. Fibres, which are not obtained from natural sources, are called synthetic fibres. Let us study about them in detail

         Natural Fibres

Fibres obtained from plants and animals are called natural fibres. Cotton, flax and jute are obtained from plants, therefore these are called plant fibres. Wool and silk are obtained from animals, and called animal fibres.

           Animal Fibers

There are mainly two types of animal fibers, that is, Wool and Silk. Wools are obtained from animals like sheep, yak and goat. They are actually thin hairs of the animals, which give protection to them from cold. Woolen cloths are mostly used in winter season. Silks are mainly used for making sarees and other dresses.

Look at the following pictures of fiber producing animals

                  Yak                                                                              Sheep

            Goat                                                                                  Alpaca  

During the winter season, thin hairs on animal’s body keep them warm. After winter, these hairs are shaved off, which again start growing during non-winter season.

           Production of Wool from Sheep

Wool is obtained from sheep through the following process: Shearing, Scouring,

Dyeing, Combing and Spinning.                                       

The process by which the hair of a sheep is removed along with a thin layer of N skin in one piece is called shearing. Removed hair along with thin layer of skin of a sheep is called fleece.                                               

Look at the Following Picture of Shearing of Sheep

Dust particles are present on haired skin of sheep, therefore, fleece of sheep must be scoured by soap or detergent.

Look at the following picture of process of making Wool from fleece of sheep

The natural colour of fleece of a sheep is white, brown and black. White colour of fleece can be dyed into different colours. A metal comb is used for the combing of fleece of sheep, after dying. In the process of spinning, the long woollen fibres are spun into thick yarn called wool. The short woollen fibres are spun into fine yarn and then woven on a loom to make woollen cloth.

           Production of Silk

Silk is a natural fiber produced by silkworms. The rearing of silk moth, for obtaining silk from them, is called sericulture. The clothes of silk are popular because of its shiny threads and strong structure.

Look at the Following Pictures

Eggs of silk moth                                         Larva or caterpillar or silkworm  

Left - Cocoon, Right - Pupa                                        Adult silk moth  

The adult female of silk moth lays eggs. The second stage of an egg of silk moth is larva. After completing the stage of larva, it wears a thin layer of silk around its body, which is called cocoon. The process of taking out silk from cocoons is called reeling. Reeling is done by a machine.

     Silk is obtained from:                                           

(a) Pupa

(b) Cocoon

(c) Silk moth

(d) All of these           

(e) None of these

Answer: (b)

      Wool is mostly obtained from which one of the following sources?

(a) Cellulose

(b) Plants

(c) Fruits of plants

(d) Sheep

(e) None of these

Answer: (d)

            Plant Fibres

Every plant produces less or large amount of fibres. Fruits, leaves and flower part of plants contain fibre. Fibres from bamboos are used for the making of paper and other house hold appliances. Cotton plants produces huge amount of cotton Fibres. Dresses made from cotton are light and comfortable to wear. Silk is obtained from insects and they depend on plants. Therefore, without plants the production of natural fibre is not possible.

Look at the following pictures of fibre producing plants

   Cotton                                                           Flax