NCERT 7th Class (CBSE) Science: Fibre to Fabric

Question: Different between animals and vegetable fibres. Give two example for each.

Answer: Difference between Animal fibre and Vegetable fibre is as follows:

Question: How does wool fibres help in keeping our body warm?

Answer: Since air is a poor conductor of heat, this shields the body from cold and keeps it warm. That is why woolen clothes are worn in winters.

Question: What is meant by the following terms?

Answer: Rearing: The process of keeping, feeding, breeding and medical care useful animals is called rearing of animals. These animals produce one or more useful products for human beings.

Shearing: The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing.

Sericulture: The rearing of silkworms for obtaining silk is called sericulture.

Question: Name the process used for the removal of sheep hair.

Answer: Shearing.

Question: Why is scouring of the sheep’s hair done?

Answer: The scouring of the sheep’s hair is done to remove grease, dirt and dust.

Question: What is silk?

Answer: Silk is an animal fibre produced mainly by silkworms.

Question: What is wool?

Answer: Wool is an animal fibre obtained from the hair of some animals.

Question: What is sorting?

Answer: The process of removing any stained, damaged and inferior wool from fleece is called sorting.

Question: What do you mean by grading?

Answer: The process of sorting the wool according to the length, colour and texture of fibre is called grading.

Question: Name the fibre obtained from an organism that feeds on mulberry leaves?

Answer: Silk fibre.

Question: What are the uses of wool?

Answer: Wool is used for making fabrics, shawls, blankets, carpets, felt and upholstery.

Question: Write the properties of wool fibre.

Answer: Wool fibre is considerably resilient, has high tensile strength, light weight and is heat insulator.