4. Natural silk is one of the strongest textile fibres, and this can be accounted for by the stretched-out molecular form. Answer: Question 10. (a) a process of making silk reels During these movement of head, the silkworm secrets fibre made of protein which hardens on exposure to air and becomes silk fibre (or silk thread). The silk obtained from the cocoons of mulberry silk moth is called mulberry silk. 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.) …… and ……. Scouring. Answer: The wool which is used for knitting sweaters or for weaving shawls is the finished product of a long process. (a) What do you mean by occupational hazard? Wool is the fiber derived from the fur of animals of the Caprinae family, principally sheep, but the hair of certain species of other mammals such as goats, alpacas, and rabbits may also be called wool.. Alpaca. [NCERT Exemplar] Thus, tassar silk, mooga silk, kosa silk, etc are obtained from cocoons spun by different types of moths. Silk fibres come from cocoons of the silk moth. This process of washing of sheared hair is called scouring. 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. Burn them separately and observe the smell produced. The term sericulture is used for [NCERT Exemplar] The main aim to rear the sheep is to obtain wool. Silkworms secrete fibre made of The thread which burns giving a smell of burning paper will be cotton fibres. The empress found white worms eating up mulberry leaves. Rearing Silkworms Question 3. Fibre is a long thread like structure. (c) washing of sheep fibre to remove grease. Now-a-days scouring is done by machines. Answer: Give reason for your answer. Answer: Yak wool provides more warmth than sheep wool. Silk. Question: Write a caption for each of the figures given as figure (a-d). The silk fibre obtained from the cocoon of mulberry silk moth are soft and lustrous. She also noticed that they were spinning shiny cocoons around them. (c) protein Silk, wool, Question 2. Finally, we conclude that the sheep’s hair is sheared off from the body, scoured, sorted, dyed, combed and spun to obtain wool (for knitting sweaters) and woollen yarn (for weaving cloth). Selective breeding is a process of Rampur bushair and Bakharwal are the breeds of which animal-sheep or goat? Small racks or twigs may be provided in the trays to which cocoons get attached. The long woollen fibres are spun (or twisted) into thick yarn called wool which is used for knitting sweaters, etc. They are the smallest visible unit of a fabric and denoted by being extremely long in relation to their width. Question 6. Question 22. air, conductor, Question 5. Name different types of silk. Fibre and Fabric Wool and silk are animal fibres. Name some wool yielding animals. False, because silkworms feed on mulberry leaves. Question 12. (b) Yes, pure silk saree is more costly than an artificial one. Question 5. Silk is a …… conductor of heat. Wool fibre cannot be obtained from which of the following? Question 7. ... Shearing is the process in which fleece of sheep with thin layer is removed. Yak hair are not used to make woollen fabric. 2. (a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs. Write a short note on how first silk industry began in China. Explain in brief. Answer: Answer: The fleece of sheep is not the only source of wool. Explain the quality of wool they provide and the state where they are found. Across (A) 1. He advised his father to take care of their health and told him about the occupational hazards. Explain. (b) rearing of silkworm Selective breeding is a process of … B) done clear. Two fibres are made up of proteins. For obtaining pure silk, we have to rear silk moth, their larvae to get pupa. Answer: (c) Neha’s mother is intelligent and knowledgeable. [HOTS] larvae, Question 6. Question 5. [Value Based Question] How? (wool and silk are animal fibres). yarn, Question 13. (a) selecting the offsprings with desired properties Answer: As a result, natural silk is costly. ... of sheep or yak. Match Column I with Column II. Answers: Wool is an animal fiber obtained from shearing the fibrous covering of sheep. Now answer the following questions. (d) rolling of sheep fibre into yarn (d) Moth There are other sources of wool except sheep. Question1. [HOTS] China, Question 14. (c) sericulture, Question 2. Mulberry silk is soft, lustrous (shiny) and elastic and can be dyed in beautiful colours. (b) Tassar silk Silk is obtained by killing the pupae. Silk fibre is obtained from (a) fleece of sheep (b) cotton ball (c) cocoon (d) shiny jute stalk . A wholesale woollen fibre dealer gets the woollen fibre of different textures sorted for various purposes. Apart from sheep, wool also comes from the angora goat, yak, llama, alpaca, and even camels. Answer: Name some fibres obtained from animals; Wool and silk. (b) selecting the parents with desired properties, Question 7. [HOTS] The hair of the sheep are shaved off by using a saving machine similar to that used by barbers. Answer: When the silkworm (or caterpillar) is ready to enter the next stage of its development called pupa, it first weaves a net to hold itself. Answer: Thus, tassar silk, kosa silk, mooga silk, etc are obtained from cocoons spun by different types of moths. Do you have any idea? The rearing of silkworms for obtaining silk is called silviculture. The first step is shearing then scouring. (a) Goat (b) Llama (c) Alpaca (d) Moth . But her mother helped her in selecting a pure silk saree for her grandmother and she was quite elated about that. Question 6. Silk fibres are spun into silk threads which are woven into silk cloth by weavers. (b) selecting the parents with desired properties Four different types of fibres are given to us. Name the sources of obtaining fibres. Fill in the blanks. Answer: The shearing (cutting the hair) of sheep is done in hot weather of summer so that sheep may survive without their protective coat of hair. NCERT Solutions for Class 7 Science: Chapter 3 – Fibre to Fabric are given below. Step II There are following two types of fibres that form the hair to sheep. Silk – derived from silkworms (the fibre is obtained from the cocoon of the silkworm) Cashmere – derived from the fur of the Cashmere goat Shearling – derived from the fur and skin of the shearling sheep Persian wool – derived from the fur of Karakul lambs (regarded by many to … (a) removal of fleece False, because mooga is the strongest variety of silk. (c) sericulture Answer. (b) Is the pure silk saree more costly than an artificial one? Answer: Silk fibres come from cocoons of the silk moth.. iii. (b) Llama Mohair Shawls. If we perform the burning test, then natural silk fibre burns giving a smell of burning hair while artificial fibre burns giving a smell of burning paper. Answer: The farmers keep eggs under hygienic condition. The eggs are stored carefully on strips of paper or cloth and sold to silkworm farmers. Neha was confused that how to distinguish between a pure silk and an artificial silk saree. Question 14. Shearing The process of removal of the fleece from an animal is called shearing. Answer: Some of the silkworms (as pupae) are however, allowed to live and mature into silk moths so that they can lay eggs to produce more silkworms. (d) nylon Silk fibre is obtained from (a) fleece of sheep (b) cotton ball (c) cocoon (d) shiny jute stalk asked Jan 22, 2018 in Science by Rohit Singh ( 64.3k points) fibre to fabric The process of taking out fibres from the cocoon for use as silk is known as reeling the silk. Answer: The thread which burns giving a smell a burning paper will be an artificial silk. Question 14. Natural silk is obtained from the cocoons of silkworms and it is made up of a protein. (c) making silk fabric from silk … Question 1. Question 4. In first saree, one thread which burnt with a smell of burning hair is from pure silk, silk and hair are protein fibres. Processing of fibres into wool involves the following steps: Step I The general process that takes place at a sheep shearing shed is (a) removal of fleece. Ajay’s father works in a wool industry. Answer: Fabric needs more energy to tear apart as compared to a single fibre. Name the process of taking out silk fibres from the cocoon for use as silk. Step V Answer: Wool is obtained from the fleece (hair) of sheep or yak. Question 1. Natural silk is an animal fibre. Weaving of fleece into yarn. Question 9. Wool and Silk Fibre. Pure silk is obtained from the cocoons of silkworm and it is made up of protein. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. Answer: [HOTS] i. (c) Alpaca 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. Mention other sources of wool than sheep. Processing of Fibres into Wool The silk fibres separate out. What are the characteristics of silk fibres obtained from the cocoons of this silk moth? Answer: True, Question 7. … (b) spinning of silk fibres Answer: (b) Fibres are taken out from the cocoon. From which parts of plants cotton and jute are obtained? So, on burning these threads, a smell of burning hair comes out. (b) Silkworm We're a family business selling a range of goodies including yarn, sheep locks, feltmaking fabrics, wool fibre, mohair shawls and felted goods. (a) Goat From what type of health problems the workers suffered while working in a wool industry? (f) Cocoons are kept under the sun or boiled in water. In order to produce silk, the silkworm developing inside the cocoon (as pupa) is not allowed to mature into an adult silk moth. Scouring makes the fleece of sheep clean. Fibre (marked 3) is wool and fibre (marked 4) which is used for weaving saris is silk. True. (a) Woollen shawl, Question 4. Question 15. (a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs. Answer: The fibres are straightened, combed and rolled into yarn. Silk fibres have fine draping qualities and are naturally crease-resistant and bring about a warm feel to the skin. (d) the process of taking silk threads from cocoon (i) Silk is a cellulosic fiber. Write the maximum length of continuous silk thread that can be obtained from a cocoon. Egg ➝ Larva (or caterpillar) ➝ Pupa ➝ Silk moth which actually makes the silk fibre? 2. (d) silviculture → Wool is obtained from the fleece (hair) of fleece sheep or yak. Question 16. You also learnt that wool and silk fibres are obtained from animals. Answer: 2. The process of taking out threads from the cocoon for use as silk is called reeling the silk. So, it is cheap. Question 1. (a)-(iii); (b)-(iv); (c)-(i); (d)-(ii). Question 6. (d) Moth, Question 6. Hair trap a lot of …… which is a poor …… of heat. Answer: Synthetic silk can be prepared at a large scale in factories/mills. The silk fibres separate out. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. Question 27: Explain the formation of silk fibre during the pupa stage of the life cycle of the insect. Wool is mainly obtained by shearing fleece from living animals, but pelts of slaughtered sheep are sometimes treated to loosen the fibre, yielding an inferior type called pulled wool. So, it sheds skin and this phenomenon is called moulting. Answer: Question 1. The process of taking out threads from the cocoons for use as silk is called reeling the silk. The most common variety of silk is mulberry silk. Solution: The fruits or bolls of cotton plants are used to obtain cotton fibre and jute is obtained from the stems of the jute plants. The shopkeeper was showing sarees of different varieties of silk but her mother wanted to take only a pure silk saree and not an artificial one. Question 8. (a) Woollen shawl 3. The general process that takes place at a sheep shearing shed is: (a) removal of fleece. Wool fibre cannot be obtained from which of the following? Arrange them in their proper sequence. [NCERT Exemplar] The main difference between Wool and Silk is that the Wool is a natural fibre from the soft hair of sheep or other mammals and fine, lustrous, natural fiber produced by the larvae of various silk moths, especially the species Bombyx mori The silk yarn is obtained from the cocoon of the silk moth. Question 20. (c) protein, Question 1 . Question 21. Question 3. (a) Neha’s mother took a thread of natural silk fabric and another thread of artificial silk fabric and burn them separately. Write the above steps in the correct sequence in which they are carried out. The finest wool is obtained from Merino sheep. Answer: (c) Cocoon Answer: In sorting, the hairy skin is sent to a factory where hair of different textures are separated or sorted. Which thread is from a pure cotton saree and which one from a pure silk saree? Wool is obtained from the fleece or hair of sheep. The general process that takes place at a sheep shearing shed is Answer. You can specify conditions of storing and accessing cookies in your browser. C) done clear. In Tibet and Ladakh, angora goats are found. 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. Mulberry leaves are food of silk worms. Wool → Wool comes from sheep, goat, yak and some other animals who are having hair on their body. (b) rearing of silkworm, Question 9. The thread which burns giving a smell of burning hair will be pure silk thread. Mulberry silk is soft, lustrous (shiny) and elastic and can be dyed in different colours. It leads to a fatal blood disease called sorter’s disease. Kashmiri goats. of silk moth. Ajay discussed this problem with his friends and he came to know that his father is getting health problems due to the nature of his work. (f) Cocoons are kept under the sun or boiled in water. Match the items in Column I with the woollen fibre in Column II. (cotton and jute are plant fibres). [NCERT Exemplar; HOTS] Question 13. The caterpillar eats day and night the leaves of mulberry tree and grows big in size whereas its skin does not increase in size, shape or length. acids and bases, Question 10. Fibre to Fabric Q1. The cocoons are put in boiling water to loosen the silk fibre. Answer. Answer: (a) Eggs of silk moth … One thread burnt with a smell of burning hair and the other burnt with the smell of burning paper. Sheep are commonly shorn for his or her fleece once or twice a year. 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. It was the first fibre to be spun into yarn and it provides more warmth than other animal fibres. Answer: Name the natural fibre obtained from insects. (a) The risks faced by people working in any industry due to the nature of their work are called occupational hazards. Wool yielding animals bear …….. on their body. Practice more on Fibre to Fabric Page - 4 www.embibe.com. The female silk moth lays eggs on mulberry leaves. Silk fibre belongs to which class of organic substance? It comes from the fleece/hair of wool yielding animals such as sheep, goat, yak, camel, rabbit, etc. Alpaca fiber is sourced from alpacas.It is warmer than sheep's wool and lighter in weight. The fleece of sheep (or cut hair of sheep) contains dust, dirt, dried sweat and grease, etc. A single fibre is too weak to break but when it once made a fabric it is difficult to tear. There are some other sources for obtaining wool. Answer: Answer: The larvae are kept in clean bamboo trays along with young and freshly chopped mulberry leaves. It is soft, fine, glossy, and luxurious. The angora rabbit yields best variety of wool Write the difference between natural silk and artificial silk. (a): Wool can be obtained without killing the animal. While sleeping, its skin cracks and on awakening, the worm leaves the old skin and comes out in a new one. Name some breeds of sheep reared in our country. Soon the silkworm (or caterpillar) covers itself by silk fibres and turns into pupa. Answer: False, it is sericulture. To scour is to wash thoroughly. wool is obtained from which body part of sheep? Question 3. The most common silk moth is the mulberry silk moth. Wool is obtained from this fleece. protein, Question 1. (b) Silk scarf Silk fibres come from cocoons of the silk moth. In which part, the wool yielding animals liama and alpaca are found? Angora wool is obtained from angora goats found in hilly regions. Answer: Question 10. Answer: Answer: After the final moulting begins, the last feeding period (of about ten days) after which the worm grows to its full size. (d) Leather jacket Yak wool is common in Tibet and Ladakh.. iv. Answer (d) Question 6. People working in the wool industry sometimes get infected by a bacterium called anthrax, during the sorting (separating) the fleece of sheep into fibres of different qualities. Answer: The resulting fibre is known as raw silk. Define the term ‘selective breeding’. 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