NCERT Solutions for Class 7 Science Chapter 3 – Fibre to Fabric

Page No 32:

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) Wool is obtained from the hairy fibres (hair) of the sheep.

(b) White fleece of the lamb refers to 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: Rearing means helping someone to grow up.

(ii) Shearing: It is the process of removal of fleece along with a thin layer of skin from the body of sheep.

(ii) Sericulture: Sericulture refers to the rearing of silkworms to obtain silk.

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, __picking of burrs__, __dying of fibres__, making of yarn__

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 silk moth directly related to silk production are

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

(i)Scouring(a)Yields silk fibres
(ii)Mulberry leaves(b)Wool yielding animal
(iii)Yak(c)Food of silk worm
(iv)Cocoon(d)Reeling
(e)Cleaning sheared skin

Answer:

Column I

Column II

(i)Scouring(e)Cleaning sheared skin
(ii)Mulberry leaves(c)Food of silk worm
(iii)Yak(b)Wool yielding animal
(iv)Cocoon(a)Yields silk fibres

Page No 33:

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 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:

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