Fibre to Fabric Class 7 Science Extra Questions Very Short Answer Type Question 1. Name the sources of obtaining fibres. The sources of obtaining fibres are plants and animals. Question 2. Name some wool yielding animals. Wool yielding animals are sheep, yak, llama, alpaca, angora goat, angora rabbit and camel. Question 3. in which part of India, yak wool is common? Yak wool is common in the hilly regions of Ladakh. Question 4. Rampur bushair and Bakharwal are the breeds of which animal-sheep or goat? Rampur bushair and Bakharwal are the breeds of sheep. Question 5. How do the hair of certain animals help in keeping their bodies warm? [NCERT Exemplar] Hair traps a lot of air which is a poor conductor of heat resulting their body warm. Question 6. Write the name of the animal from which wool for pashmina shawls is obtained. Kashmiri goats. Question 7. Name the goats which are found in Tibet and Ladakh. In Tibet and Ladakh, angora goats are found. Question 8. wool is obtained from which body part of sheep? Wool is obtained from the fleece or hair of sheep. Question 9. Name the natural fibre obtained from insects. Silk. Question 10. In which part, the wool yielding animals liama and alpaca are found? Liama and alpaca are found in South America. Question 11. For what purpose, rearing of sheep is done? The main aim to rear the sheep is to obtain wool. Question 12. What term is used for the following process? Washing of sheep’s fleece to remove dust, dirt, dried sweat and grease. Scouring. Question 13. Out of scouring or shearing, which process comes first in the production of wool from sheep? The first step is shearing then scouring. Question 14. To which class, animal fibre or plant fibre, artificial silk belongs to? Artificial silk is a plant fibre. Question 15. Two fibres are made up of proteins. Name them. Silk and wool are two fibres which are made up of proteins. Question 16. Name the process of taking out silk fibres from the cocoon for use as silk. The process of taking out threads from the cocoons for use as silk is called reeling the silk. Question 17. Name the stage next to caterpillar in the life cycle of silk moth. The stage next to caterpillar in the life cycle of silk moth is called pupa. Question 18. which stage in the life cycle of silk moth is called cocoon? The covering of silk fibres inside which the caterpillar covers itself is called cocoon. Question 19. Write the maximum length of continuous silk thread that can be obtained from a cocoon. 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. Question 20. Define the term ‘selective breeding’. 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. Question 21. Silk fibre belongs to which class of organic substance? Protein. Question 22. In the life history of silk moth as Egg ➝ Larva (or caterpillar) ➝ Pupa ➝ Silk moth which actually makes the silk fibre? [HOTS] The larva (or caterpillar) of a silk moth makes the silk fibre.Fibre to Fabric Class 7 Science Extra Questions Short Answer Type Question 1. Sheep are herbivores, so which type of feed (or food) is provided by shepherds? [HOTS] Sheep are herbivores, and prefer grass and leaves of various trees. Their food also contain a mixture of pulses, corn, jowar, oil cakes (material left after taking out oil from seeds) and minerals. Question 2. Write a caption for each of the figures given as figure (a-d). (a) Eggs of silk moth on mulberry leaves (b) Silkworm (c) Cocoon (d) Cocoon with developing moth Question 3. Silk yarn of different textures can be prepared. Define the statement. 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. Question 4. Write the difference between natural silk and artificial silk. 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 giving a smell of burning hair while artificial fibre burns giving a smell of burning paper. Question 5. Sorter’s disease is an occupational hazard. Explain. 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. Question 6. Write a short note on how first silk industry began in China. 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. Question 7. Various steps involved to obtain wool from fleece are given here.Picking out the burrsDyeing in various coloursShearingScouringSorting Write the above steps in the correct sequence in which they are carried out. [NCERT Exemplar] Question 8. Steps for the production of silk are given below in a jumbled order. Arrange them in their proper sequence. [NCERT Exemplar] (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. 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 caterpillers 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. Question 9. Cocoon is used to obtain silk thread. How? A pile of cocoon is used for obtaining silk fibre. The cocoon are kept under the sun, boiled water 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. Question 10. Name different types of silk. Which variety of silk is most common and how it is obtained? Different types of silk are mulberry silk, tassar silk, mooga silk and kosa silk. The most common variety of silk is mulberry silk. It is obtained from the cocoons of mulberry silkworm and is made up of protein. It is a natural silk and is an animal fibre. Question 11. Four different types of fibres are given to us. Out of these, two fibres (1 and 2) are obtained from plants and other two (3 and 4) fibres are obtained from animals. Fibre (1) is used in filling quilts and the yarn made of fibre (2) is used in making gunny bags, The yarn made from fibre (3) is used for knitting sweaters and yarn of fibre (4) is used for weaving saries. Name the four given fibres marked 1,2, 3 and 4. [HOTS] Fibre (marked 1) which is used in filling quilts is cotton and fibre (marked 2) is jute. (cotton and jute are plant fibres). Fibre (marked 3) is wool and fibre (marked 4) which is used for weaving saris is silk. (wool and silk are animal fibres). Question 12. Why caterpillars need to shed their skin when they grow bigger but humans do not? Do you have any idea? [HOTS] 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. During the feeding period, a silkworm sleeps four times (24 h each time) at intervals of six days. While sleeping, its skin cracks and on awakening, the worm leaves the old skin and comes out in a new one. So, it sheds skin and this phenomenon is called moulting. After the final moulting begins, the last feeding period (of about ten days) after which the worm grows to its full size. Question 13. Radhika 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. [HOTS] Artificial (synthetic) silk called rayon is obtained from wood pulp and it is made of modified plant material cellulose. Synthetic silk can be prepared at a large scale in factories/mills. So, it is cheap. For obtaining pure silk, we have to rear silk moth, their larvae to get pupa. To get silk thread, we have to dip cocoon in hot water to get silk thread which is wrapped over the cocoon. The pupa inside the cocoon dies. To obtain silk for commercial purposes, a large number of cocoons (containing living pupa) are killed. As a result, natural silk is costly. Question 14. From what type of health problems the workers suffered while working in a wool industry? [HOTS] 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. It leads to a fatal blood disease called sorter’s disease. Question 15. Write the different types of fibres that form the hair of sheep. There are following two types of fibres that form the hair to sheepThe coarse beard hair.Fine soft under hair close to the skin. Question 16. Name the most common silk moth. What are the characteristics of silk fibres obtained from the cocoons of this silk moth? The most common silk moth is the mulberry silk moth. The silk obtained from the cocoons of mulberry silk moth is called mulberry silk. Mulberry silk is soft, lustrou