Q 1 – Of which nutrient silk fibre is made?
Ans – Protein
Q 2 – Name the sources of obtaining fibres.
Ans – The sources of obtaining fibres are plants and animals
Q 3 – Name some wool yielding animals.
Ans – Wool yielding animals are sheep, yak, llama, alpaca, angora goat, angora rabbit and camel.
Q 4 – In which part of India, yak wool is common?
Ans – Yak wool is common in the hilly regions of Ladakh.
Q 5 – Rampur bushair and Bakharwal are the breeds of which animal-sheep or goat?
Ans – Rampur bushair and Bakharwal are the breeds of sheep.
Q 6 – How do the hair of certain animals help in keeping their bodies warm?
Ans – Hair traps a lot of air which is a poor conductor of heat resulting in their body being warm.
Q 7 – Write the name of the animal from which wool for pashmina shawls is obtained.
Ans – Kashmiri goats.
Q 8 – Name the goats which are found in Tibet and Ladakh.
Ans – In Tibet and Ladakh, angora goats are found.
Q 9 – wool is obtained from which body part of sheep?
Ans – Wool is obtained from the fleece or hair of sheep.
Q 10 – Name the natural fibre obtained from insects.
Ans – Silk
Q 11– In which part, the wool yielding animals liama and alpaca are found?
Ans – Liama and alpaca are found in South America.
Q 12 – For what purpose, rearing of sheep is done?
Ans – The main aim to rear the sheep is to obtain wool.
Q 13 – How is the reeling of silk done?
Ans – Reeling is done with special machines, which unwind the threads or fibres of silk from the cocoon. Silk fibres are then spun into silk threads.
Q 14 – What term is used for the following process? Washing of sheep’s fleece to remove dust, dirt, dried sweat and grease.
Ans – Scouring.
Q 15 – Out of scouring or shearing, which process comes first in the production of wool from sheep?
Ans – The first step is shearing then scouring
Q 16 – To which class, animal fibre or plant fibre, does artificial silk belongs?
Ans – Artificial silk is a plant fibre.
Q 17 – Two fibres are made up of proteins. Name them.
Ans – Silk and wool are two fibres that are made up of proteins.
Q 18 – Name the process of taking out silk fibres from the cocoon for use as silk.
Ans – The process of taking out threads from the cocoons for use as silk is called reeling the silk.
Q 19 – Name the stage next to the caterpillar in the life cycle of the silk moth
Ans – The stage next to the caterpillar in the life cycle of the silk moth is called pupa.
Q 20 – What are silkworms?
Ans – Silkworms are caterpillars of a silk moth.
Q 21 – What are larvae called?
Ans – Caterpillars or silkworms.
Q 22 – What is the process of taking out silk threads from the cocoon called?
Ans – Reeling the silk
Q 23 – Where is reeling done?
Ans – In special machines
Q 24 – What spins the cocoons inside which develops the silk moth?
Ans – Caterpillar or silkworm
Q 25 – How many eggs do a female silk moth lay at a time?
Ans – Hundreds of eggs
Q 26 – Where are the eggs stored?
Ans – The eggs are stored on strips of cloth or paper
Q 27 – which stage in the life cycle of the silk moth is called cocoon?
Ans – The covering of silk fibres inside which the caterpillar covers itself is called a cocoon.
Q 28 – Why are moths reared?
Ans – Moth are reared for obtaining silk
Q 29 – The covering of silk fibres inside which the caterpillar covers itself is called a cocoon.
Ans – The maximum length of continuous silk thread that can be obtained from a cocoon is more than that of 1000 feet (1000 to 1500 feet) continuous in length.
Q 30 – Define the term ‘selective breeding.
Ans – The process of breeding of selective parents for obtaining special characters in their offspring such as soft under hair in sheep, is termed as selective breeding.
Q 31 – Why are cocoons collected?
Ans – Cocoons are collected to get silk threads.
Q 32 – Silk fibre belongs to which class of organic substance?
Ans – Protein
Q 33 – Where are larvae kept in the process of rearing?
Ans – Larvae are kept in clean bamboo trays.
Q 34 –In the life history of silk moth as
Egg ➝ Larva (or caterpillar) ➝ Pupa ➝ Silk moth which actually makes the silk fibre?
Ans –The larva (or caterpillar) of a silk moth makes the silk fibre
Q 35 – In which country silk industry begun?
Ans – China
Q 36 – Sheep are herbivores, so which type of feed (or food) is provided by shepherds?
Ans – Sheep are herbivores, and prefer grass and leaves of various trees. Their food also contains a mixture of pulses, corn, jowar, oil cakes (material left after taking out oil from seeds) and minerals
Q 37 – What is the silk route?
Ans – The route, the traders and traveler travelled to introduce silk to other countries is called the silk route.
Q 38 – Name two wool yielding animals.
Ans – Yak, sheep.
Q 39 – Name three animals that yield wool
Ans – Sheep, goat, yak.
Q 40 – Name two finished products of wool
Ans – Sweater, shawl
Q 41 – In which areas are yaks found in plenty?
Ans – Tibet and Ladakh.
Q 42 – Name two types of fibres of the hairy skin of the sheep.
Ans – The coarse beard hair and the ¦ne soft under-hair close to the skin.
Q 43 – What are occupational hazards?
Ans – Risks faced by the workers in any industry are called occupational hazards
Q 44 – What is the diet of sheep?
Ans – Grass, leaves, a mixture of pulses, corn, jowar, oil cakes and minerals.
Q 45 – What keeps the wool yielding animals warm?
Ans – The wool yielding animals like sheep, goats, yak, etc., have thick hair on their body. Hair trap a lot of air. Air is a poor conductor of heat, which does not allow the heat absorbed to release from their body and keeps them warm.
Q 46 – Explain selective breeding.
Ans – In some animals, to get desired characters in off springs parents are selected having that desired characters for breeding. This process is known as selective breeding. For example, some breed of sheep are selected for their soft under-hair.
Q 47 – Write a caption for each of the figures given as figure (a-d).
Ans – (a) Eggs of silk moth on mulberry leaves
(b) Silkworm
(c) Cocoon
(d) Cocoon with developing moth
Q 48 – Which country leads the world in silk production?
Ans – China
Q 49 – Silk yarn of different textures can be prepared. Define the statement
Ans – The silk yarn is obtained from the cocoon of the silk moth. There is a variety of silk moths which look very different from one another and the silk yarn they yield is different in textures (coarse, smooth, shiny, etc.) Thus, tassar silk, mooga silk, kosa silk, etc are obtained from cocoons spun by different types of moths.
Q 50 – Name two varieties of silk.
Ans – Tassar silk and mooga silk.
Q 51 – Write the difference between natural silk and artificial silk
Ans – Natural silk is obtained from the cocoons of silkworms and it is made up of a protein. Natural silk is an animal fibre. Artificial silk is obtained from wood pulp and it is made up of modified plant material ‘cellulose’.
If we perform the burning test, then natural silk fibre burns to give a smell of burning hair while artificial fibre burns to give a smell of burning paper
Q 52 – What is the nature of silk fibre obtained from the cocoon of mulberry silk moth?
Ans – It is soft, lustrous and elastic
Q 53 – Sorter’s disease is an occupational hazard. Explain.
Ans – Wool industry is an important source of livelihood for many people in our country. The people who do the job of sorting (separating) the fleece of sheep into fibres of different qualities are called sorters. The sorter’s job is very risky because sometimes, they get infected by the bacteria called ‘anthrax’ which cause a deadly blood disease called sorter’s disease.
Q 54 – What is a pupa?
Ans – The next stage of caterpillar in the life cycle of the silk moth is called pupa
Q 55 – Write a short note on how the first silk industry began in China.
Ans – 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 in 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. This is how silk was discovered by chance. In this way, the first silk industry began in China
Q 56 – What is sericulture?
Ans – The rearing of silkworms for obtaining silk is called sericulture.
Q 57 – Various steps involved to obtain wool from fleece are given here.
- Picking out the burrs
- Dyeing in various colours
- Shearing
- Scouring
- Sorting
Write the above steps in the correct sequence in which they are carried out.
Ans –
Q 58 – What is a cocoon?
Ans – The silky covering spun by the larvae of silkmoth for protection as pupae is called a cocoon.
Q 59 – Steps for the production of silk are given below in a jumbled order. Arrange them in their proper sequence.
(a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.
(b) Fibres are taken out from the cocoon.
(c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons.
(d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.
(e) Female silk moths lay eggs.
(f) Cocoons are kept under the sun or boiled in water
Ans – The correct order is
(e) Female silk moths lay eggs.
(a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.
(d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.
(c) After 25 to 30 days, the caterpillars stop N eating and start spinning cocoons
(f) Cocoons are kept under the sun or boiled in water.
(g) Fibres are taken out from the cocoon.
Q 60 – There are other sources of wool except for sheep. Explain.
Or
Mention other sources of wool than sheep.
Ans – The fleece of sheep is not the only source of wool. There are some other sources for obtaining wool. As yak wool is common in Tibet and Ladakh. Angora wool is obtained from angora goats found in hilly regions. Wool is also obtained from camel hair. Llama and Alpaca found in South America also yield wool
Q 61 – Describe in brief the animals that yield wool.
Ans – The animals that yield wool are sheep, yak, goat, camel, etc. The wool commonly available in the market is sheep wool. Yak wool is common in Tibet and Ladakh. Angora goats yield angora wool, which is found in hilly areas such as Jammu and Kashmir.
The underfur of the Kashmiri goat is soft and so it is woven into fine shawls called Pashmina shawls. The hair on the body of camels is also used as wool. Llama and Alpaca also yield wool. They are found in South America. Wool obtained from different animals and based on their quality are used to make different kinds of woollen things.
Q 62 – What are the various steps for processing fibres into wool?
Ans –The processing of fibres into wool involves various steps such as shearing, scouring sorting, dyeing and rolling. They have been discussed below in brief:
Step 1 . Shearing: First of all, the woollen coat or fleece from the animals along with a thin layer of skin is removed from their body. The process is called shearing.
Step 2. Scouring: The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt from the wool. This is called
scouring.
Step 3. Sorting: It is done after scouring. The hairy skin is sent to a factory where hair of different textures are separated or sorted.
Step 4. The small fluffy fibres called burrs, are picked out from the hair. The fibres are scoured again and dried. Now the wool is ready to be drawn into fibres.
Step 5. The fibres are dyed in various colours because the natural fleece of sheep and goats is black, brown or white
Step 6. Finally, the fibres are straightened, combed and rolled into yarn. The longer fibres are made into wool for sweaters and the shorter ones are spun and woven into the woollen cloth.
Q 63 – Describe the life history of a silk moth with the help of figures of each stage.
Ans – Silk fibres are also known as animal fibre. They are soft, light in weight and strong. Silk fibres are obtained from the cocoons of the silkmoth or silkworm. The life history of the silk moth involves mainly four stages:
Eggs ➝ Caterpillars or Silkworms ➝ Pupa ➝ Adult silk moth
The female silk moth lays eggs, from which hatch larvae called caterpillars or silkworms. They grow in size and when they are ready to enter the next stage called pupa, they first weave a net to hold themselves. Then they swing their heads from side to side in the form of the figure.
During these movements, they secret fibre made of a protein which hardens on exposure to air and becomes silk fibre. Soon the caterpillars completely cover themselves with silk fibre and turn into pupae. This covering is known as cocoon. The further development of the pupae into moths continue inside the cocoons. Moths are reared and their cocoons are collected to get silk thread for obtaining Silk.
Q 64 – Why is silk obtained by mulberry silk moth most popular?
Ans – Silk obtained by mulberry silk moth is most popular because of its shimmering appearance which produces different colours.
Q 65 – You have been asked to buy a woollen sweater from the market. How will you check its purity.
Ans – We can test the purity of the woollen sweater by burning it. Take about 10 cm long thread (spareone). Hold it with the help of a tong and burn its one end. If the fibre smells like burning hair, it is wool but if . the fibre smells like chemicals or burning plastic, it is artificial wool.
On blowing out of the fame touch the end of the fibre. If the end turns to dust on touching then it is pure wool but if the end has melted and turned hard, then it is not pure wool.
Q 66 – Why natural fibres are costlier than synthetic fibres?
Ans – Natural fibres are obtained either from plants or animals. The process of obtaining fibres from these natural sources is a comparatively labour intensive process than the production of synthetic fibres on large scale from other raw materials or chemicals.
Q 67 – Compare the properties of silk and wool.
| Silk | Wool |
| (i) Silk is smooth, soft and lustrous. | (i) Wool is dense, soft, curly, elastic and resilient. |
| (ii) It is more sensitive to heat. | (ii) It is less sensitive to heat. |
| (iii) It is made up of a protein called fibroin. | (iii) It is made up of a protein called keratin. |
| (iv) It is the strongest natural fibre. | (iv) It is stronger but less than silk. |
| (v) Silk can be worn in both the hot and winter seasons. | (v) Wool is worn only in the winter season because it traps body heat and keeps us warm. |
Q 68 – What are occupational hazards? What occupational hazards are linked with wool and silk production?
Ans – Health risks faced by the workers of a particular occupation or industry are called occupational hazards. In the wool industry, wool sorter’ scan gets infected by a bacterium which causes fatal blood disease, called anthrax or sorter’s disease. In the silk industry workers handling dead worms with bare hands may get an infection. Fine hair on caterpillars may cause asthma or conjunctivitis.
Q 69 – Sania got upset on learning that for obtaining 1 kg of raw silk around 5,000 cocoons are killed. But her mother explained to her that silkworms are also conserved in this process for obtaining silk next time. Also, it is the source of income to many rural and needy person
(a) Why silk is famous?
(b) Whom do you agree with- Sania or her mother? Why?
(c) If you get an option to select between a silk dress and a dress made of synthetic fibre which one will you select and why?
(d) What value of Sania is shown here?
Ans – (a) Silk is famous for its smooth and lustrous fibre which is also strong.
(b) Do it yourself.
(c) Hint: While selecting dress one should always keep in mind the advantages and disadvantages of natural and synthetic fibres.
(d) Sania is eco-friendly, sensitive and concern for other creatures
Q 70 – Many occupational hazards are associated with wool and silk production. Most of these hazards can be prevented by just having a proper awareness and knowledge of how to tackle such conditions. The main reason for occupational hazards in India is due to poverty, illiteracy and poor hygienic conditions.
(a) What occupational hazards are associated with the wool and silk industries?
(b) How can most of the occupational hazards be minimised?
(c) What values of people are shown here?
Ans – (a) 1.Wool industry: Anthrax or sorter’s disease
2. Silk industry: Infections, asthma and conjunctivitis
(b) Occupational hazards can be minimised by
1. taking precautions while handling animals like wearing gloves, mask, using disinfectants, washing hands, etc.
2. having proper knowledge and awareness of signs and symptoms of diseases of humans and animals.
(c) People are ignorant, careless and illiterate.