MP Board Class 7th Science Solutions Chapter 3 Fibre to Fabric

October 11, 2021

Fibre to Fabric Intext Questions

Question 1.
Boojho is wondering why it hurts when someone pulls his hair but not when he goes for a haircut?
Answer:
When someone pulls his hair, it hurts because it’s roots is connected to the skin which has sensation. But, during haircut the tip of the hair is cut which is dead and does not have any sensation. Thus, hair cut does not hurt.

Question 2.
Boojho is wondering why a cotton garment cannot keep us as warm in winter as a woollen sweater does?
Answer:
Cotton cloths are thin and does not trap air. Wool is thicker than cotton and have spaces in which air traps. Air is a poor conductor of heat and so it prevent heat coming out of our body. Thus, wool gives better protection than cotton.

Question 3.
Paheli wants to know if the cotton thread and silk thread are spun and woven in the same manner?
Answer:
No.

Fibre to Fabric Text book Exercises

Question 1.
You must be familiar with the following nursery rhymes?

‘Baa baa black sheep, have you any wool.’
‘Mary had little lamb, whose fleece was white as snow.’

Answer the following:

Which parts of the black sheep have wool?
What is meant by the white, fleece of the lamb?

Answer:

Basically the abdomen and back of the sheep have wool.
The white fleece refers to the white hair of lamb that is used to make wool.

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?

Rearing
Shearing
Sericulture

Answer:
1. Rearing:
The bringing up and looking after the sheep is called rearing.

2. Shearing:
The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing.

3. Sericulture:
The rearing of silkworms for obtaining silk 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:
Scouring, drying, dying, spinning, weaving.

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:

Question 7.
Out of the following, which are the two terms related to silk production? Sericulture, floriculture, moriculture, apiculture and silviculture.
Hint:

Silk production involves cultivation of mulberry leaves and rearing silkworms.
Scientific name of mulberry is Morus alba.

Answer:

Sericulture
Moriculture.

Question 8.
Match the words of Column I with those given in Column II:

Answer:

(i) (e)
(ii) (c)
(iii) (b)
(iv) (a)

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?

Extended Learning – Activities and Projects:

Question 1.
Paheli wants to know the maximum length of continuous silk thread that can be obtained from a cocoon. Find out for her?
Answer:
980 m.

Question 2.
Boojho wants to know why caterpillars need to shed their skin when they grow bigger but we humans do not. Do you have any idea?
Answer:
During its growing stage, the caterpillar eats own shed skin. It has no other food option.

Question 3.
Boojho wants to know why caterpillars should not be collected with bare hands. Can you help him?
Answer:
Because caterpillar’s skin can cause alergy.

Question 4.
Paheli wanted to buy a silk frock and went to the market with her mother. There they found that the artificial (synthetic) silk was much cheaper and wanted to know why. Do you know why? Find out.
Answer:
The cost of production for artificial silk is very low. The raw materials used for artificial silk are available at very low cost and are available in huge quantity. Also, the production time is very less. Thus artificial silk is cheaper.

Question 5.
Someone told Paheli that an animal called ‘Vicuna’ also gives wool. Can you tell her where this animal is found? Look for this in a dictionary or an encyclopaedia?
Answer:
Vicuna is found in Spain.

Question 6.
When handloom and textile exhibitions are held, certain stalls display real moths of various varieties of silk and their life Stories. Try and visit these stalls with elders or teachers and these moths and stages of their life history.
Answer:
Do yourself.

Question 7.
Look for eggs of any moth or butterfly in your garden or park or any other place full of plants. They look like tiny specks (dots) laid in a cluster on the leaves. Pull out the leaves containing eggs and place them in a cardboard box. Take some leaves of the same plant or another plant of the same variety, chop them and put them in the box.

Eggs will hatch into caterpillars, which are busy eating day and night. Add leaves everyday for them to feed upon. Sometimes you may be able to collect the caterpillars. But be careful. Use a paper napkin or a paper to hold a caterpillar. Observe everyday. Note the:

Number of days taken for eggs to hatch.
Number of days taken to reach cocoon stage and
To complete life cycle. Record your observations in your notebook.

Answer:
Do yourself.

Fibre to Fabric Additional Important Questions

Objective Type Questions

Question 1.
Choose the correct alternative:

Question (i)
Silk is a –
(a) Rough fibre
(b) Way fibre
(c) Staple fi bre
(d) Filament fibre.
Answer:
(d) Filament fibre.

Question (ii)
Which country is the largest producer of silk –
(a) India
(b) Pakistan
(c) China
(d) None of these.
Answer:
(c) China

Question (iii)
Which country is the largest producer of wool –
(a) India
(b) Australia
(c) Pakistan
(d) China.
Answer:
(b) Australia

Question (iv)
Mooga is the strongest variety of –
(a) Silk
(b) Wool
(c) Cotton
(d) None of these.
Answer:
(a) Silk

Question (v)
An International trade mark for new and pure wool is –
(a) ISI
(b) ISO
(c) Woolmark
(d) Agmark.
Answer:
(c) Woolmark

Question (vi)
Virgin wool is obtained from –
(a) Adult sheep
(b) Dead sleep
(c) Lamb
(d) Carnal.
Answer:
(a) Adult sheep

Question 2.
Fill in the blanks:

Silk is a natural ………….. fibre.
Silk fibres come from …………….. of the silk moth.
The fine hair provide the fibres for making ……………
Yak wool is common in Tibet and ………….
Angora wool is obtained from …………. goats.
Sheep are herbivores and prefer grass and …………….
Sericulture of silk worms is a very old …………….. in India.
…………… leads the world in silk production.
……………… is a dried perspiration found is the raw wool.
The science of raising silk worms so as to obtain silk cocoons is …………..

Answer:

Protein
Cocoons
Wool
Ladakh
Angora
Leaves
Occupation
China
Suint
Sericulture

Question 3.
Which of the following statements are true (T) or false (F):

Silk worm feeds an mulberry leaves.
A yarn is not a long continuous thread.
The wool and cotton are staple fibres.
Silk is a good conductor of heat.
The high grade silk is obtained from the filaments of damaged cocoons.
A female silk moth lays 100 of eggs at a time.
Sheeps are reared is many parts of our country for wool.
Lohi and Nali are the breeds of sheep.
Nowadays scouring is done by machines.
Sheep hair is sheared off from the body, scoured, sorted, dried, dyed, spun and woven to yield wool.

Answer:

True (T)
False (F)
True (T)
False (F)
False (F)
True (T)
True (T)
True (T)
True (T)
True (T)

Question 4.
Match the items in Column A with Column B:

Answer:

(i) (b)
(ii) (d)
(iii) (f)
(iv) (e)
(v) (c)
(vi) (a)

Fibre to Fabric Very Short Answer Type Questions

Question 1.
Write the name of some wool yielding animals.
Answer:
Sheep, goat, angora goat, camel, yak, lamb, etc.

Question 2.
Feel the hair on your body and arms and these on your head. Do you find any difference? Which are seems coarse and which are is soft?
Answer:
Yes, hairs in arms are soft.

Question 3.
In which area a yak found in plenty?
Answer:
Tibet and Ladakh.

Question 4.
What are the sources of obtaining fibres?
Answer:
Animals and plants are the sources of obtaining fibres.

Question 5.
What do you meant by shearing?
Answer:
The fleece of the sheep along with a thin layer of skin is removed from its body. This process is known as shearing.

Question 6.
Which animal provides pashmina shawls?
Answer:
Kashmiri goats.

Question 7.
Define wool?
Answer:
Wool is the common name of applied to soft curly fibres obtained chiefly from the fleece of domesticated sheep.

Question 8.
In which season, sleep sheared?
Answer:
Summer season.

Question 9.
What are the uses of wool?
Answer:
Wool is used for making fabrics, blankets, shawls, carpets, felt and upholstery.

Question 10.
What are the properties of wool fibre?
Answer:
Wool fibre is considerably resilient, has high tensile strength, light weight and is heat insulator.

Question 11.
What are silkworms?
Answer:
The female silk moth lays eggs from which hatch larvae are called silkworms of caterpillars.

Question 12.
What is the most common silk moth?
Answer:
Mulberry silk moth.

Question 13.
Name the strongest variety of silk.
Answer:
Mooga.

Question 14.
Name the different varieties of processed silk.
Answer:
Gepe, Tram, Organize, Trown singles are different varieties of processed silk.

Question 15.
What is reeling of silk?
Answer:
A pile of cocoons is used for obtaining silk fibres. This process is called reeling the silk.

Question 16.
Name some Indian breeds of sheep?
Answer:
Lohi, Rampur bushair, Nali, Bakharwal, Marwari and Patanwadi.

Question 17.
Where are sheep reared in India?
Answer:
Sub – Himalyan region because this area has a cooler climate.

Question 18.
Name one disease caused to sheep.
Answer:
Anthrax.

Fibre to Fabric Very Short Answer Type Questions

Question 1.
Name the animals that yield wool?
Answer:
The fleece of sheep is not the only source of wool, though wool commonly available in the market is sheep wool. Yak wool is common in Tibet and Ladakh. Angora wool is obtained from angora goats, found in hilly regions such as Jammu and Kashmir. Wool is also obtained from goat hair. The under fur of Kashmiri goat is soft. The fur (hair) on the body of camels is also used as wool. Uama and Alpaca, found in South Africa, also yield wool.

Question 2.
What is raw silk?
Answer:
After brushing, filaments from four to eight cocoons are joined and twisted. They are then combined with a number of other similarly twisted filaments, to make a thread that is wound on a reel. The thread is called raw silk.

Question 3.
How is shearing of .wool done? Describe.
Answer:
The fleece of the sheep along with a thin layers of skin is removed from its body .This process is called shearing. Machines similar to those used by barbers are used to shave off hair. Usually, hair are removed during the hot weather. This enables sheep to survive without their protective coat of hair. The hair provide woolen fibers. Woolen fibres are then processed to obtain woollen yarn. Shearing does not hurt the sheep just as it does not hurt when you get a hair cut or your father shaves his beard.

Question 4.
Name the some breeds of sheep reared in our country. Also indicate the quality and texture of the fibre, obtained from them?
Answer:
Some Indian breeds of sheep are given in following table:

Question 5.
Why do the wool fibres have greater bulk as compared to other fibres?
Answer:
The scales and crimps is the wool fibre make it possible to spin and felt the fleece. They help the individual wool fibres grab each other so that they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles. They can retain lot of air and hence wool fabrics are good insulators of heat. The heat insulation also works both ways.

Question 6.
How is silk processed?
Answer:
A pile of cocoons is used for obtaining silk fibres. This process is called reeling of silk. The cocoons are kept under the sun or boiled or exposed to steam. The silk fibres separate out. The process of taking out threads from the cocoon for use as silk is called reeling the silk. Reeling is done in special machines, which unwind the threads or fibres of silk from the cocoon. Silk fibres are then spun into silk threads, which are woven into silk cloth by weavers.

Question 7.
Write a short note on’”discovery of silk”?
Answer:
The exact time of discovery of silk is perhaps unknown. According to an old Chinese legend, the empress Si – lung – Chi was asked by the emperor Huang – ti to find the cause of the damaged leaves of mulberry trees growing their garden. The empress found white worms eating up mulberry leaves. She also noticed that they were spinning shiny cocoons around them. Accidentally a cocoon dropped into her cup of tea and a tangle of delicate threads separated from the cocoon.

Silk industry began in China and was kept a closely guarded secret for hundreds of years. Latter on, traders and travellers introduced silk to other countries. The route they travelled is still called the ‘silk route’.

Fibre to Fabric Long Answer Type Questions

Question 1.
How wool is produced from fibres?
Ans. For obtaining wool. Sheep are reared. Their hair is cut and processed into wool. Sheep are herbivores and prefer, grass and leaves. Apart from grazing sheep, rearers also feed them on a mixture of pulses, corn, jowar, oil cakes (material left after taking out oil from seeds) and minerals. In winter, sheep are kept indoors and fed on leaves, grain and dry fodder.

Sheep are reared in many parts of our country for wool. The quality and texture of the fibres obtained from different sheeps are different. Once the teared sheep have developed a thick growth of hair, hair is shaved off for getting wool.

Question 2.
Define with diagram the process of scouring?
Answer:

MP Board Class 7th Science Solutions Chapter 3 Fibre to Fabric img-9

Question 3.
Define the process of sorting and rolling of fibres into wool?
Answer:
After scouring sorting is done. The hairy skin is sent to a factory where hair of different textures are separated or sorted. The small fluffy fibres, called burrs, are picked out from the hair. These are the same burrs which sometimes appear on your sweaters. The fibres are scoured again and dried. This is the wool ready to be drawn into fibres.

The fibres can be dyed in various colours, as the natural fleece of sheep and goats is black, brown or white. The fibres are straightened, combed and rolled into yarn (Fig.). The longer fibres are made into wool for sweaters and the shorter fibres are spun and woven into woollen cloth.

Question 4.
How we can obtain silk from cocoon? Explain.
Answer:
For obtaining silk, moths are reared and their cocoons are collected to get silk threads. A female silk moth lays hundreds of eggs at a time. The eggs are stored carefully on strips of cloth or paper and sold to silk worm farmers. The farmers keep eggs under hygienic conditions and under suitable conditions of temperature and humidity.

The eggs are warmed to a suitable temperature for the larvae to hatch from eggs. This is done when mulberry trees bear a fresh crop of leaves. The larvae, called caterpillars or silkworms, eat day and night and increase in size enormously.

The worms are kept in clean bamboo trays along with freshly chopped mulberry leaves. After 25 to 30 days, the caterpillars stop eating and move to a tiny chamber of bamboo in the tray to spin cocoons. Small racks or twigs may be provided in the trays to which cocoons get attached. The caterpillar or silkworm spins the cocoon inside which develops the silk moth.

MP Board Class 7th Science Solutions

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