ANIMAL FIBRES CLASS 7 Q& A

ANIMAL FIBRES ( Q & A)

F.ANSWER THE FOLLOWING QUESTIONS IN DETAIL.

1. How do you classify fibres? Explain giving examples.

Fibres are classified into natural and synthetic fibres.

Natural fibres are obtained from natural sources such as animals and plants like silk from silkworm, cotton and jute from plants.

Synthetic fibres are man made fibres. they are made from petrochemicals. E.g. acrylic, polyester, nylon

2. List at least 4 animals other than sheep that give us wool.

Angora rabbit, goat, alpaca, yak, & camel

3. Explain the life cycle of silkworm by means of a neat diagram.

4. Explain the process to obtain silk from the cocoon.

The cocoons are obtained before the larvae mature by dipping the cocoons in hot water.

The process of obtaining silk threads from the cocoons that have been soaked in hot water is called REELING or FILATURE.

The filaments from 4 -8 cocoons are separated and slightly twisted to create a single strand.

Many strands together constitute a silk yarn.

These strands are then spun into silk cloth by weavers.

5. Differentiate between:

a. plant fibres and animal fibres                  b. Merino wool and angora wool

c. sorting and scouring                                  d. Moulting and reeling

a.

. plant fibres and animal fibres        

Plant fibres	Animal fibres
These are made of cellulose	These are made of proteins
These include cotton, flax, hemp, jute, etc.	These include silk & wool from yak,goat,sheep

         

b.

Merino wool and angora wool

Merino wool	Angora wool
This is obtained from sheep	It is obtained from angora rabbit.

c.

Sorting and scouring

sorting	scouring
The process of removing any damaged or inferior wool from the fleece           & Separating the wool obtained from different body parts is called sorting.	Washing the sheared wool in hot water and detergent to remove sand, dirt, grease    & Then drying is called scouring.
Moulting	Reeling
The process of shedding the skin 4 times by the larva is called as moulting	Te process of obtaining silk threads from the cocoons that have been soaked in hot water is called as reeling.

H. FILL IN THE CORRECT ORDER AND THE OBJECTIVE OF THE PROCESS INVOLVED IN WOOL PRODUCTION.

process	order	objective
sorting	shearing	Removal of the woollen coat or fleece from the animal.
carding	scouring	Washing wool with water and detergent to remove dirt etc.
scouring	sorting	Separating wool fibres detained from different parts of the body
shearing	carding	The wool fibres are passed through a series of metal teeth, to straighten the fibres.
spinning	spinning	Joining thin fibres together by machines to form one strand of yarn.

.