NCERT Solutions Class 7 Science Chapter 3 Fibre to Fabric
Question 1
You must be familiar with the following nursery rhymes:
(i) ‘Baa baa black sheep, have you any wool.’
(ii) ‘Mary had a little lamb, whose fleece was white as snow.’
Answer the following:
(a) Which parts of the black sheep have wool?
(b) What is meant by the white fleece of the lamb? Answer
(a) The hairy skin i.e. fleece of the black sheep has wool.
(b) White fleece means the white coloured hair of the lamb.
Question 2
The silkworm is
(a) a caterpillar
(b) a larva.
Choose the correct option.
(i) a
(ii) b
(iii) both a and b
(iv) neither a nor b Answer
(iii) both a and b Question 3
Which of the following does not yield wool?
(i) Yak
(ii) Camel
(iii) Goat
(iv) Woolly dog Answer
(iv) Woolly dog Question 4
What is meant by the following terms?
(i) Rearing
(ii) Shearing
(iii) Sericulture
Answer
i)
Rearing
It means taking care of herds of animals which includes feeding, grazing, breeding, etc. for economical purpose/commercial purpose like meat and other useful products.
For example, Sheep are reared mainly for the wool. They are mainly reared in areas with low rainfall. Reared sheep eat grass and leaves. In winters they are kept indoors and fed on dry fodder, leaves and grains.
ii)
Shearing
When sheep develops a thick coat of hair, it is shaved off to obtain wool hairs. The removal of fleece of the sheep along with a thin layer of skin from its body is called shearing. It is done by the machines similar to those used by barbers to remove.
iii)
Sericulture
The rearing of silkworms to obtain silk economically is called sericulture.
Question 5
Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, _________. Answer
Shearing, scouring, sorting, burrs picking, dying, rolling
Question 6
Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk. Answer
The two stages in the life history of the silk moth which are directly related to the production of silk:
Spinning of cocoon of silk threads around caterpillar.
Changing of caterpillar into pupa. Question 7
Out of the following, which are the two terms related to silk production?
Sericulture, floriculture, moriculture, apiculture and silviculture.
Hints:
(i) Silk production involves cultivation of mulberry leaves and rearing silkworms.
(ii) Scientific name of mulberry is Morus alba. Answer
Sericulture and moriculture Question 8
Match the words of Column I with those given in Column II:
Column I
Column II
1. Scouring
(a) Yields silk fibres
2. Mulberry leaves
(b) Wool yielding animal
3. Yak
(c) Food of silk worm
4. Cocoon
(d) Reeling
-
(e) Cleaning sheared skin
Answer
Column I
Column II
1. Scouring
(e) Cleaning sheared skin
2. Mulberry leaves
(c) Food of silk worm
3. Yak
(b) Wool yielding animal
4. Cocoon
(a) Yields silk fibres
Question 9
Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down
(D) 1: Thorough washing
2: Animal fibre
3: Long thread like structure
Across
(A) 1: Keeps warm
2: Its leaves are eaten by silkworms
3: Hatches from egg of moth
Answer Down
1. Scour
2. Silk
3. Fibre Across
1. Wool
2. Mulberry
3. Caterpillar
