NCERT Solutions for Class 7 Science Chapter 3 Fibre to Fabric
NCERT solutions for class 7 science chapter 2 : Solved Exercise Questions:
1. You must be familiar with the following nursery rhyme:
(i) ‘Baa baa black sheep, have you any wool.’
Answer the following:
(a) Which parts of the black sheep have wool?
Answer:
(a) Black sheep have wool in the skin part.
1. You must be familiar with the following nursery rhymes:
(ii) ‘Mary had a little lamb, whose fleece was white as snow.’
Answer the following:
(b) What is meant by the white fleece of the lamb?
Answer:
(b) White fleece means the hair (from where the wool is obtained) of lamb.
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:
The female silk moth lays eggs, from which hatch larvae which are called caterpillars or silkworms
Hence correct option: (iii) both a and b
3. Which of the following does not yield wool?
(i) Yak
(ii) Camel
(iii) Goat
(iv) Woolly dog
Answer:
(iv) Woolly dog does not yield wool.
4. What is meant by the following terms?
(i) Rearing
Answer:
Rearing means helping animals to grow includes grazing, feeding or breeding for some profit or other pleasure. It also helps animals from the problems of itching, odour, and waste.
4. What is meant by the following terms?
(ii) Shearing
Answer:
The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing.
4. What is meant by the following terms?
(iii) Sericulture
Answer:
The rearing of silkworms for obtaining the spinned silk is called sericulture.
5. Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, _________.
Answer:
The complete steps for the processing of the wool.
Shearing, scouring , sorting, cleaning of burrs , dyeing , rolling .
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 are:
Silkworm and cocoon
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 are related to silk production.
Sericulture: Rearing of silkworms to obtain silk.
Moriculture: The science of cultivation of mulberry leaves for silk production.
Therefore, the silk industry is dependent on sericulture which in turn is dependent on moriculture. Hence, both are related to silk production.
8. Match the words of Column 1 with those given in Column 2:
Column 1 Column 2
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 1 |
Column 2 |
|
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 |
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 Across
(D) 1: Thorough washing (A) 1: Keeps warm
2: Animal fibre 2: Its leaves are eaten by silkworms
3: Long thread like structure 3: Hatches from egg of moth.
Answer:
|
Down |
Across |
|
1. SCOUR |
1. WOOL |
|
2. SILK |
2. MULBERRY |
|
3. FIBRE |
3. CATERPILLAR |