CBSE Class 7 Science Fiber to Fabric Assignment

L-3 Fibre to Fabric

Question 1. Cut & paste or draw & colour any four wool yielding animals.
Answer: Four common wool yielding animals are:
1. Sheep (such as Marwari, Patanwadi, or Bakharwal breeds)
2. Goat (such as Angora goats which yield mohair, and Cashmere goats)
3. Yak (commonly found in Tibet and Ladakh)
4. Alpaca or Llama (found in South America)
In simple words: Animals with thick coats of hair or fleece give us wool.

Exam Tip: Remember that fleece consists of two types of fibres: the coarse beard hair and the fine soft under-hair close to the skin.

Question 2. Given below is a cross word puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
(D) Down Hints:
1) Removal of fleece of a sheep
2) Thorough washing of sheep's hair
3) Rearing of silk worms.
(A) Across Hints:
i) Separation of hair of different textures
ii) Covering of a pupa
iii) Its leaves are eaten by silk worms.
Answer: Completed crossword puzzle solutions based on the hints:
Down:
1D: Shearing
2D: Scouring
3D: Sericulture
Across:
i) Sorting
ii) Cocoon
iii) Mulberry
In simple words: These terms describe the various steps involved in processing wool and silk fibres.

Exam Tip: Learn the exact sequence of processing wool: Shearing \(\rightarrow\) Scouring \(\rightarrow\) Sorting \(\rightarrow\) Cleaning of burrs \(\rightarrow\) Dyeing \(\rightarrow\) Spinning.

Question 3. You must be familiar with the following rhyme remember and recite this infront of your class.
"Baa baa black sheep, have you any wool"
Answer: Recite the complete traditional nursery rhyme clearly and with proper expressions in front of the class:
"Baa baa black sheep, have you any wool?
Yes sir, yes sir, three bags full!
One for the master, and one for the dame,
And one for the little boy who lives down the lane."
In simple words: This classic rhyme highlights that sheep provide wool used to make warm clothes.

Exam Tip: Memorize this rhyme as a fun way to remember that sheep are primary sources of natural animal fibre.

Question 4. Cut & paste a small piece of -
A) Silk Cloth
B) Cotton Cloth
C) Woollen Cloth
Answer: Description of the three types of cloth fabrics to be collected and pasted:
1. Silk Cloth: A smooth, shiny, and luxurious fabric obtained from the cocoons of silk moths (animal fibre).
2. Cotton Cloth: A soft, breathable, and light fabric obtained from cotton plant bolls (plant fibre).
3. Woollen Cloth: A thick, warm fabric knitted or woven from animal fleece like sheep hair (animal fibre).
In simple words: Different fabrics come from different sources like plants and animals.

Exam Tip: Be able to distinguish burning smell or texture between plant fibres (like cotton) and animal fibres (like silk and wool).

Question 5. Lifecycle of silk moth (Colour all these diagram with your favourite colurs.)
Answer: The life cycle of a silk moth consists of four distinct stages:
1. Eggs: Female silk moth lays tiny eggs on mulberry leaves.
2. Caterpillar (Larva): The eggs hatch into larvae called caterpillars or silkworms, which feed voraciously on mulberry leaves.
3. Pupa (Cocoon): When the caterpillar is ready to enter the next stage, it spins a protective covering around itself called a cocoon.
4. Adult Silk Moth: Inside the cocoon, the pupa develops into a fully formed adult silk moth which emerges later.
In simple words: A silk moth changes its form completely from an egg to a caterpillar, then a cocoon, and finally an adult moth.

Exam Tip: Silk thread is obtained from the spun cocoon of the silkworm before the adult moth emerges and breaks the continuous thread.