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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