Fibre to Fabric: Class 7 Science Q&A
22 free answers on Fibre to Fabric (Science) for Class 7 students, across CBSE, ICSE and State boards. Includes questions such as “Write various steps for processing fibres into wool.”, “How does the hair of certain animals help in keeping their bodies warm?”, “Silkworms secrete fibre made of (a) fat (b) cellulose (c) protein (d) nylon”.
Question & Answer
Questions
- ScienceClass 7CBSE
Write various steps for processing fibres into wool.
Soln: Step I: The fleece of the sheep along with a thin layer of skin is removed from its body [Fig. 3.8 (a)]. This process is called shearing. Machines similar to those used by barbers are used to shave off hair. Usually, hair is removed during the hot weather. This enables sheep to survive without their protective coat of hair. The hair provides woollen fibres. Woollen fibres are then processed to obtain woollen yarn. Shearing does not hurt the sheep just as it does
- ScienceClass 7CBSE
Explain the phrase – “Unity is Strength” on the basis of the making of fabric from the fibre.
trong>Soln: Fabric is made of a thin hair-like strand called fibres. It is easy to break a fibre thread as it is fragile and easy to break as well. On the other hand, fabric is the accumulation of many fibre threads which are hard to break and needs an enormous amount of energy to break the fabric. Hence, based on making of fabric from fibre it is said that unity is strength.
- ScienceClass 7CBSE
Paheli went to the market to buy sarees for her mother. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. One thread burnt with the smell of burning hair and the other burnt with the smell of burning paper. Which thread is from a pure cotton saree and which one from a pure silk saree? Give a reason for your answer.
Soln: A thread which burns with the smell of burning paper is of cotton because both paper and cotton are cellulose which is carbohydrate and hence they burn with similar odour. Similarly, the thread which is burnt with the smell of burning hair is silk because silk, as well as hair, are proteins hence they burn with a similar characteristic smell.
- ScienceClass 7CBSE
Complete the paragraph related to the life history of silk moth by filling in the blanks. The ____(a)___ silk moth lays ___(b)___, from which hatch ____(c)___ called ___(d)____ or ___(e)____. They grow in size and when the caterpillar is ready to enter the next stage of its life history called ___(f)____, it first weaves a covering to hold itself, which is known as ___(g)____.
Soln: The a)femalesilk moth lays b)eggs, from which hatch c)larvaecalled d)caterpillarsor e)silkworms.They grow in size and when the caterpillar is ready to enter the next stage of its life history called f)pupa, it first weaves a covering to hold itself, which is known as g)cocoon.
- ScienceClass 7CBSE
20. A wholesale woollen fibre dealer gets the woollen fibre of different textures sorted for various purposes. Match the items in Column I with the woollen fibre in Column II. Column I Column II a) Pashmina Shawl i) Camel Wool b) Woollen carpet ii) Angora wool c) Baby blanket iii) Kashmir Goat d) Woollen Sweater iv)Sheep wool
Soln: Column I Column II a) Pashmina Shawl iii) Kashmir Goat b) Woollen carpet i) Camel Wool c) Baby blanket ii) Angora wool d) Woollen Sweater iv)Sheep wool
- ScienceClass 7CBSE
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) Fibers 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.
Soln: (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 eating and start spinning cocoons. (f) Cocoons are kept under the sun or boiled in water. (b) Fibers are taken out from the cocoon.
- ScienceClass 7CBSE
Some words related to silk are jumbled up. Write them in their correct form. (a) TURECULRISE (b) WILSMORK (c) BELMURRY (d) RINGLEE
Soln: (a) sericulture (b) silkworm (c) mulberry (d) reeling
- ScienceClass 7CBSE
Various steps involved in obtaining wool from fleece are given here. (i) Picking out the burrs (ii) Dyeing in various colours (iii) Shearing (iv) Scouring (v) Sorting Write the above steps in the correct sequence in which they are carried out.
Soln: (iii) Shearing (iv) Scouring (v) Sorting (i) Picking out the burrs (ii) Dyeing in various colours
- ScienceClass 7CBSE
Match the items of Column I with the items given in Column II. Column-I Column-II a) Yak Wool i) Sheared hair b) Angora Goat ii) Silkworm c) Mulberry Leaves iii) Tibet and Ladakh d) Scouring iv) Jammu and Kashmir
Soln: Column-I Column-II a) Yak Wool iii) Tibet and Ladakh b) Angora Goat iv) Tibet and Ladakh c) Mulberry Leaves ii) Silkworm d) Scouring i) Sheared hair
- ScienceClass 7CBSE
How does the hair of certain animals help in keeping their bodies warm?
Soln: Hairs are bad conductors of heat; hence they will not allow the escape of heat from the body, which ensures their bodies are kept warm.
- ScienceClass 7CBSE
State whether the following statements are True or False. If false, correct them. (a) Silkworms are caterpillars of the silk moth. (b) In India, camels and goats are generally reared for obtaining wool. (c) The rearing of silkworms for obtaining silk is called silviculture. (d) In the process of obtaining wool from fleece, sorting is done after scouring. (e) Yak hair is not used to make woollen fabric.
Soln: True False- In India, sheep are reared for obtaining wool. False- The rearing of silkworms for obtaining silk is called sericulture True False- Yak hair is used to make woollen fabric.
- ScienceClass 7CBSE
Fill in the blanks in the following statements. (a) _________ and _________ fibres are obtained from animals. (b) Silk fibres come from _________ of silk _________. (c) Wool yielding animals bear _________ on their body. (d) Hair trap a lot of _________, which is a poor _________ of heat.
Soln: (a)SilkandWoolfibres are obtained from animals. (b) Silk fibres come fromcocoonsof the silkmoth. (c) Wool yielding animals bearhairon their body. (d) Hair trap a lot ofair, which is a poorconductorof heat.
- ScienceClass 7CBSE
Silkworms secrete fibre made of (a) fat (b) cellulose (c) protein (d) nylon
Soln: The answer is (c) protein Explanation: A salivary gland of silkworm releases a protein which is used as silk.
- ScienceClass 7CBSE
Reeling of silk is (a) a process of making silk reels. (b) the spinning of silk fibres. (c) the weaving of silk cloth. (d) the process of taking silk threads from the cocoon.
Soln: The answer is (d) the process of taking silk threads from the cocoon.
- ScienceClass 7CBSE
The term sericulture is used for (a) culture of bacteria. (b) rearing of the silkworm. (c) making silk fabric from silk yarn. (d) production of sarees.
Soln: The answer is (b) rearing of the silkworm. Explanation: Breeding and management of silkworms for obtaining silk are called sericulture.
- ScienceClass 7CBSE
The general process that takes place at a sheep shearing shed is (a) removal of fleece. (b) separating the hair of different textures. (c) washing of sheep fibre to remove grease. (d) rolling of sheep fibre into yarn.
Soln: The answer is (a) removal of fleece. Explanation: Removal of fleece from sheep is known as shearing. Shearing will be done manually by razors or by shearing machines.
- ScienceClass 7CBSE
Selective breeding is a process of (a) selecting the offsprings with desired properties. (b) selecting the parents with desired properties. (c) selecting an area for breeding. (d) selecting fine hair for good quality wool.
Soln: The answer is (b) selecting the parents with desired properties. Explanation: Selective breeding is the process of the crossing of two selected varieties having different traits to produce a hybrid having good traits of both, e.g., some breeds of sheep possess only soft under-hair.
- ScienceClass 7CBSE
A wool fibre cannot be obtained from which of the following? (a) Goat (b) Llama (c) Alpaca (d) Moth
Soln: The answer is (d) Moth Explanation: Wool can be obtained from animals like sheep, goat, camel, yak, rabbit, etc. A moth is a type of insect.
- ScienceClass 7CBSE
The silk fibre is obtained from (a) fleece of sheep (b) cotton ball (c) cocoon (d) shiny jute stalk
Soln: The answer is (c) cocoon Explanation: Silk is a fibre obtained from the cocoons of silkworms.
- ScienceClass 7CBSE
Paheli wanted to buy a gift made of animal fibre obtained without killing the animal. Which of the following would be the right gift for her to buy? (a) Woollen shawl (b) Silk scarf (c) Animal fur cap (d) Leather jacket
Soln: The answer is (a) Woollen shawl Explanation: Obtained from wool which does not require the killing of animals. Wool is obtained from hairs of sheep, yak, camel, goat, etc. Silk is obtained after killing silkworm, Animal fur cap is obtained from fur which requires the killing of an animal. A leather jacket is obtained from the skin of animals which needs killing of animals.