Lakhmir Singh Manjit Kaur Class 7 Science 3rd Chapter Fibres To Fabric Solution

Lakhmir Singh Manjit Kaur Class 7 Science 3rd Chapter Fibre To Fabric Solutions

Lakhmir Singh and Manjit Kaur Science solution: Fibre To Fabric Chapter 3. Here you get easy solutions of Lakhmir Singh and Manjit Kaur Science solution Chapter 3. Here we give Chapter 3 all solution of class 7. Its help you to complete your homework.

• Board – CBSE
• Text Book – SCIENCE
• Class – 7
• Chapter – 3.

Very Short Type Questions Solution:

(1) Ans:- Two fibres obtained from animals are wool and silk.

(2) Ans:- Yak wool is common in the hilly regions of Tibet and Ladakh.

(3) Ans:- Angora goats found in Jammu & Kashmir.

(4) Ans:- Kashmiri goat.

(5) Ans:- Llama and Alpaca are found at South America.

(6) Ans:- The two breeds of sheep found in India are Lohi and Rampur bushair.

(7) Ans:- Sheep are herbivores.

(8) Ans:- (a) Shearing.

(b) Scouring

(c) Sorting.

(9) Ans:- Bacteria called anthrax.

(10) Ans:- Shearing.

(11) Ans:- Silk

(12) Ans:- The adult silk moth spins cocoons from which silk is obtained. (False).

(13) Ans:- Mulberry trees.

(14) Ans:- The natural colours of the fleece of sheep and goats are white, brown or brown.

(15) Ans:- Larva.

(16) Ans:- Larva.

(17) Ans:- Sericulture.

(18) Ans:- The two fibres which are made of proteins are Wool, fur.

(19) Ans:- Plant Fibre.

(20) Fill in the following blanks with suitable words :

Ans:- (a) breeding

(b) goat

(c) wool

(d) herbivores

(e) sheep

(f) cocoon

(g) protein

(h) larvae (or caterpillars).

(i) cocoon

(j) reeling

Short Answer Type  Questions Solution:

(21) Ans:- Mostly sheep eat grass. Except of grass sheep are also fed mixture of pulses, corn, jowar, oil cakes and minerals.

(22) Ans:- Rearing of sheep means to look after the sheep by providing them food, shelter and health care.

Breeding of sheep is done to obtain such breeds of sheep which yield good quality wool in large quantities.

(23) Ans:- The various steps involved in the production of wool from sheep are Shearing, Scouring, Sorting, Dyeing, Combing, Spinning.

(24) Ans:- Wool yielding animals like sheep have a thick coat of hair on their body because to keep them warm during cold winter season.

(25) Ans:- Woolen clothes keep us warm during winter because wool is a poor conductor of heat and it has air trapped in between the fibres.

(26) Ans:- The risks faced by people working in any industry due to the nature of their work are called occupational hazards.

Sorter’s disease is an occupational hazard.

(27) Ans:- The rearing of silkworms for obtaining silk is called sericulture.

(28) Ans:- The most common silkmoth is mulberry silkmoth.

Silk fibres obtained from the cocoons are spum to form silk threads called silk yarn. The silk yarn is then woven on looms into silk cloth by the weavers.

(29) Ans:- We can distinguish between natural silk and artificial silk by performing burning test.

(30) Ans:- The process of taking out silk fibers from the cocoons for use as silk is called reeling.

Reeling is done in special machines which unwind the fibers of silk from cocoons.

(31) Match the words of column I with those given in column II :

(ii) Mulberry leaves- (c) Food of silkworms.Ans:- (i) Scouring- (e) Cleaning Sheared wool.

(iii) Yak- (b) wool yielding animal.

(iv) Cocoon- (a) Yields silk fibres.

(32) Ans:- Wool is most commonly obtained from sheep.

(33) Ans:- silk is an animal fibre.

(34) Ans:- The cocoon is made by silkworm to protect its development as Pupa.

(35) Ans:- Shearing > Scouring > Sorting > Dyeing > Combing > Spinning.

Long Answer Type Questions:

(36) Ans:-

 (37) Ans:- (a) Shearing:- The process of removing hair from the body of a sheep in the form of fleece is called Shearing.

(b) Scouring:- The process of washing the fleece thqat removes dust, dirt, dried sweat and grease is called scouring.

(c) Sorting:- The process of separating the fleece of a sheep into sections according to the quality of woolen fibres is called sorting.

(38) Ans:- Egg -> Larva (or Caterpillar) -> Pupa -> Silk Moth.

(39) Ans:- (a) Rearing of Silkworms to obtain Cocoons:

A female silk moth lays hundreds of eggs at a time. The eggs of silk moth are stored carefully and sold to the farmers. The farmers keep this egg at a suitable teperature and humidity so that these eggs can hatch.

After hatching silkworms comes out. Silkworms now fed up cut mulberry leaved. After 1 month silkworms stop eating and ready to spin cocoon. The silkworm now climb up the twigs place near them and spin cocoons of silk fibres.

(b) Processing of cocoons to obtain silk fibres:

All the cocoons are collected at one palce. The pile of cocoon is placed in hot water. Hot water separate out silk fibers of cocoons.

(c) Converting silk fibres into silk cloth:-

Silk fibres are then spun into silk threads, which are woven into silk cloth by weavers.

(40) Ans:- The shearing of sheep is done in hot season. This is because sheep may survive without their protecting coat of hair.

Shearing does not hurt the sheep because the uppermost layer of the skin is dead. Like when we cut our hear is their any pain of face? No. It is the same.

Higher Order Thinking Skills (HOTS)

56)

X = Wool

Y = Air

Z = Summer

Some animal have a thick coat of hair on their body. These hairs are used to make Wool (X) which is used in making cardigans after suitable treatment. The wool (X) traps a lot of air (Y) which prevents the body heat of these animals from being lost to surroundings and keep them warm in winter. The wool is removed from these animals at the beginning of summer.

Sheep, goat, yak and camel are some of the examples of these types of animals

57)

A = Sheep

B = Fleece

C = Shearing

D = Scouring

E = Wool

The hair of Sheep (A) is cut from the body in one piece along with a thin layer of its skin called Fleece (B). This process of removing hair in the form of Fleece is called Shearing (C). The Fleece of the sheep is then cleaned using a lot of soap and water and this process is called Scouring (D). The clean Fleece is then converted into yarn Wool (E) by a process of sorting, dyeing, combing and spinning. Yarn wools are used for knitting sweaters which have a particularly high demand.

58)

P = Wool

Q = Silk

R = Cotton

S = Jute

Wool (P), silk (Q), cotton (R) and jute (S) are all various type of fibres. The fibres of wool and silk are obtained from animals whereas the fibres of cotton and jute are obtained from plants. The Yarn made from Wool (P)is used for knitting sweaters whereas yarn made from silk (Q) is used for weaving sarees. The cotton (R) is used for filling quilts whereas the yarn made from jute (S) us used in making gunny bags.

59)

A = Silk moth

B = Larva

C = Caterpillar

D = Pupa

E = Silkworm

F = Silk

Silk moth (A) is an insect that resembles butterfly. Silk moths are not directly formedfrom eggs. There is an interesting process by which silk moths are formed. First the hatching of eggs produce a stage called larva (B) or caterpillar (C) and then an encased form pupa (D) which ultimately forms a Silk moth (A). The wormlike form of larva or caterpillar is also known as silkworm (E). Silkworm is an important form for silk production because it leads to the formation of silk (F). The main food for the silkworms is the leaves of Mulberry tree.

60)

A = Silk moth

B = Silk worm

C = Mulberry tree

D = Silk

E = Reeling

Here we have discussed the process of making silk yarn from silk moth is described briefly. The Silk moth (A) lays hundreds of eggs. The eggs hatch to produce Silk worm (B) which are fed cut-up leaves of Mulberry tree (C). After about 25 to 30 days the worms stop eating and spin cocoons of Silk (D). The silk is separated from cocoons by a process called Reeling (E). The spinning of these fibres produces a yarn which is woven on looms into fine cloth used for making sarees etc.

Next Chapters Solution Link:

• Chapter 1) Nutrition in Plants
• Chapter 2) Nutrition in Animals
• Chapter 4) Heat
• Chapter 5) Acids, Bases and Salts
• Chapter 6) Physical and Chemical Changes
• Chapter 7) Weather, Climate And Adaptations of Animals to Climate
• Chapter 8) Winds, Storms And Cyclones
• Chapter 9) Soil
• Chapter 10) Respiration in Organisms
• Chapter 11) Transport in Animals and Plants
• Chapter 12) Reproduction in Plants
• Chapter 13) Motion and Time
• Chapter 14) Electric Currents and Its Effects
• Chapter 15) Light
• Chapter 16) Water: A Precious Resource
• Chapter 17) Forests : Our Lifeline
• Chapter 18) Wastewater Story