PSEB Punjab Board Class 7 Science Textbook Solution Chapter 3 Fibre to Fabric Exercise Questions and Answers
Chapter 3 Fibre To Fabric.
Q.1 Fill in the blanks:
1.) Wool is obtained from the ……… of sheep, goat, yak.
Answer:- Fleece
2.) Long hair on the body protect animals from ……..
Answer:- Extreme cold climate
3.) Removal of fleece from the skin of animal is called……..
Answer:- Shearing
4.) Rearing of silkworm is called……..
Answer:- Sericulture
5.) The process of unwinding the filaments from the boiled cocoons, is called……
Answer:- Reeling
Q.2.) Match the following:
Answers-
1.) Scouring – | v) Cleaning sheared fleece. |
2.) Sericulture – | iv) Rearing of silkworm. |
3.) Protein – | iii) Silk fiber made up of. |
4.) Mulberry leaves – | i) Food of silkworm. |
5.) Lohi | ii) Sheep found in Rajasthan and Punjab. |
Q.3.) Choose the correct option
1.) The fibre which is not produced by animals.
(a) Angora Wool
(b) Wool
(c) Jute
(d) Silk
Answer:- c. Jute
2.) Wool is commonly obtained from:
(a) Sheep □
(b) Goat □
(c) Yak □
(d) all of the above □
Answer:- a. Sheep
3.) Washing of sheared hair is called :
(a) Scouring □
(b) Sorting □
(c) Shearing □
(d) Dyeing □
Answer:- a. Scouring
4.) Wool is chemically:
(a) Fat □
(b) Protein □
(c) Carbohydrate □
(d) None of these □
Answer:- b. Protein
5.) The animal that does not yield wool is:
(a) Alpaca □
(b) Woolly dog □
(c) Camel □
(d) Goat □
Answer:- b. Woolly dog
Q.4.) True or false:
1.) Air is bad conductor of heat.(T/F)
Answer:- True
2.) Air trapped in long hair does not allow body heat to escape from body.(T/F)
Answer:- True
3.) In Tibet and Ladakh wool is obtained from yak.(T/F)
Answer:- True
4.) Rearing of silk moth is called apiculture.(T/F)
Answer:- True
5.) The cover around the body of caterpillar is called cocoon.(T/F)
Answer:- True
6.) Tassar silk and moonga silk are produced by silk moth who have been feeding onnon-mulberry trees.(T/F)
Answer:- False
Q.5.) Very short answer type questions:
1.) Name any two plants fibres and animal fibres?
Answer:- Animal fibers i) wool & ii) silk. Plants fibres i) jute & ii) cotton
2.) What is sericulture?
Answer:- The rearing of silkworm for obtaining silk is called sericulture.
3.) Name the common animals who yield fleece?
Answer:- Sheep, goat, rabbit, camel, yak, etc. are the common name of animal who yield fleece.
Q.6) Short answer type questions
1.) What do you understand by Angora and Kashmere wool?
Answer:- Angora wool is obtained from angora goats found in hilly region such as Jammu and Kashmir.
Kashmere wool obtain from under fur off Kashmiri goat which is soft.
2.) Write the states where the following breeds of sheep are found:- Lohi, Bakharwal, Nail and Marwari
Answer:- i) Lohi sheep found in Punjab Rajasthan and Haryana.
ii) Bakharwal sheep found in Jammu and Kashmir.
iii) Nail sheep found in Rajasthan and Haryana. iv) Marwari sheep found in Rajasthan.
3.) Write all the steps involved in processing of fibre into wool.
Answer:- The steps involved in processing of fibre into wool are as follow:
i) Shearing:- The fleece of sheep along with thin layer of skin is remove from its body is called as shearing. ii) Scouring:- The sheared skin with hairs is thoroughly wash is called as Scouring.
iii) Sorting:- After scouring the wool is sorted into various categories on the basis of their qualities is called as sorting. iv) Combing:- The he process of removing the lint from fleece is called as combing. v)Dyeing:- The fibres can be dye by various colours is called as dyeing. vi) Spinning:- The fibers are rolled in yarn is called as spinning.
4.) Why do some animals have a thick coat of hair?
Answer:- Hair straps a lot of air. Air is a poor conductor of heat, So hair keeps this animal warm.
5.) How is silk moth is reared?
Answer :- female silk moth lays hundreds of egg at a time. They are stored by the farmers at suitable temperature and humidity under hygienic conditions. When the eggs hatch silkworms come out of the eggs. The silkworms are fed mulberry leaves.
Q.7.) Long answer type questions:
1.) Write all the steps in processing silk from cocoons.
Answer:- Following are the steps involved in processing silk from cocoons,
Step I. Boiling: The cocoons are first boiled in hot water or treated in ovens to kill larvae inside. If the larvae are not killed and allowed to grow. they will break the cocoon, thereby reducing the length of silk fibre. The hot water soften the silk gum, so as to allow unwinding of silk fibre as one continuous thread.
Step II. Reeling: The process of taking out threads from the cocoon for use as silk is called reeling the silk. Reeling is done with special machines, which unwind the threads or fibres of silk from the cocoon.
Step III. Throwing: This process is similar to spinning of cotton. The raw silk is twisted to produce thrown silk. This process is called throwing. This prevents the silk from splitting into individual fibres.
Step IV. Dyeing: Thrown silk is then dyed for making coloured fabrics. The dyed silk fibres are then spun into silk threads, which are woven into silk cloth by weavers.
2.) Draw well labelled diagram and explain the life cycle of silk moth.
Answer: Diagram:-
The life cycle of the silk moth can be summarised in following steps:
Step I. The female silk moth lay eggs, on the leaves of mulberry tree.
Step II. The eggs hatch larvae in two weeks to form worm like structures which are called caterpillars or silkworms. They grow in size and then the caterpillar is ready to enter the next stage of its life cycle called pupa.
Step III. Pupa first weaves a net to hold itself. Then it swings its head from one side to another in the shape of O. During these head movements, the caterpillar secretes fibre made of a protein which hardens on exposure to air and becomes silk fibre. on the caterpillar completely covers itself by silk fibres. This covering is known as cocoon. The further development of moth continues inside the cocoon. The silk yarn (thread) is obtained from the cocoon of the silk moth. Silk fibres are used for weaving silk cloth. Can you imagine that the soft silk yarn is as strong as thread of steel.
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