7th Standard Science ( Fiber to Fabric )

 Fiber to Fabric

I Answer the following :

1. Which parts of the black sheep have wool?
Ans: The fine and soft under-hair that grows close to the skin of the sheep have wool. 

 

2. What is meant by the white fleece of the lamb?
Ans: White fleece refers to the white hair of lamb that is used to make wool.

 

3. Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Ans: Shearing, scouring, sorting, picking of burrs, dying of fibers, making of yarn.

II. Choose it:

1. The silkworm is (a) a caterpillar,  (b) a larva..
(i) a
(ii) b
(iii) both a and b
(iv) neither a nor b.

2. Which of the following does not yield wool?
(i) Yak
(ii) Camel
(iii) Goat
(iv) Woolly dog

 

3. What is meant by the following terms?
Answer) Rearing: Rearing is raising and taking care of livestock (eg. cows, buffaloes, goats, etc.); for commercial purposes. These animals are fed, provided shelters, and are bred for better yield like milk, meat, wool etc.

ii) Shearing: Once a sheep develops a thick coat of hair, it is shaved off to obtain wool. The process of cutting off the woolen fleece of sheep with a thin layer of skin is called shearing. It is done by the machines which remove the hair.

iii) Sericulture: The breeding and management of silkworms for the production of silk is known as sericulture. Different types of silk (eg. mulberry silk, Tassar silk, etc.) with different textures are obtained from different varieties of silk moths.

 

8.Match the words of Column I with those given in Column II:

Column I	Column II
1. Scouring	(a) Yields silk fibres
2. Mulberry leaves	(b) Wool yielding animal
3. Yak	(c) Food of silkworm
4. Cocoon	(d) Reeling
	(e) Cleaning sheared skin

Answers:
1 – e
3 – c
3 – b
4 – a

9. Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down
(D) 1 : Thorough washing
2 : Animal fiber
3 : Long thread like structure

Across
(A) 1 : Keeps warm
2 : Its leaves are eaten by silkworms
3 : Hatches from egg of moth

 

1. How many types of fibers found in sheep?
Answer: There are two types of fibers from sheep fleece.
They are

1.    the coarse beard hair

2.  the fine soft under-hair close to the skin.

 

2. What are the sources of wool?
Answer: Several breeds of sheep are found in different parts of our country. Sheep wool is very common. Yak wool from Tibet and Ladak Mohair is obtained from angora goats, wool from goat hair, The under fur of Kashmiri goats are soft and it is woven into fine shawls called Pashmina shawls. The fur on the body of camels is also used as wool. Llama and Alpaca found in South America also yield wool.

 

3. What is meant by selective breeding?
Answer: The process of selecting parents for obtaining special characters in their offspring such as soft under hair in sheep is termed as selective breeding.

 

4. Where and how the sheep are reared in India?
Answer: In Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Arunachal Pradesh, Sikkim, the plains of Haryana, Punjab, Rajasthan, Gujarat etc., the shepherds taking their herds of sheep for grazing. Sheep are herbivores and prefer grass and leaves. Apart from grazing, rears also feed them on a mixture of pulses, com, Jowar, oil cakes, etc., In winter Sheep are kept indoors and fed on leaves grain and dry fodder.

 

5. Define Shearing.
Answer: The fleece of the sheep along with a thin layer of skin is removed from its body is known as shearing.

 

6. What is meant by scouring?
Answer: The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt is called scouring.

 

7. What is sorting?
Answer: Sorting is the process of separating the different textures of hair.

 

8. Define Sericulture.
Answer: The rearing of silkworms for obtaining silk is called as sericulture.

 

9.Name some Indian breeds of sheep.
Answer:

Name of breed	Quality of wool	State where found
1. Lohi	Good quality wool	Rajasthan, Punjab
2. Rampur bushair	Brown fleece	Uttar Pradesh, Himachal Pradesh
3. Nali	Carpet wool	Rajasthan, Haryana, Punjab
4. Bakharwal	For woolen shawls	Jammu and Kashmir
5. Marwari	Coarse wool	Gujarat
6. Patanwadi	For hosiery	Gujarat

10. Explain the life-history of silk moth.
Answer: The female silk moth lays eggs from which hatch larvae which are called Caterpillars or silkworms. They grow in size and when the caterpillar is ready and enter pupa stage. The caterpillar secretes fiber made of a protein; soon the caterpillar completely covers itself by silk fibers and turns into pupa. This covering is known as Cocoon. The further development of the pupa into moth continues inside the cocoon. The silk yarn (thread) is obtained from the cocoon of the silk moth.

 

11. What are the various types of silk?
Answer: The types of silks are mulberry silk, tassarsilk,

Airsilk, moog silk etc.,

12. Explain the processing of silk.
Answer: A pile of cocoons is used for obtaining silk fibers. The Cocoons are kept under the sun or boiled or exposed to steam. The silk fibers separate out. The process of taking out threads from the cocoon for use as silk is called reeling the silk. Reeling is done in special machines, which unwind the threads or fibers of silk from the cocoon. Silk fibers are then spun into silk threads, which are woven into silk cloth by weavers.

13.Draw a neat diagram of the life-history of silk moth.

II. Fill in the blanks:

1.    Wool is obtained from the fleece (hair) of sheep or Yak.

2.  Parhmina shawls are woven from the soft wool of Kashmiri goat

3.  Yak wool is common in Tibet and Ladakh

4.  Mohair is obtained from angora goats.

5.  Llama and Alpaca found in South America.

6.  The rearing of silkworms for obtaining silk is called Sericulture.

7.  The soft silk yarn (thread) is as strong as the thread of steel.

8.  The most common silk moth is the mulberry silk moth.

9.  Sericulture or Culture of silkworms is a very Old occupation in India.

10.               China leads the world in silk production.

11. Sometimes the sorters get infected by the bacterium anthrax.

12.               The risks faced by workers in any industry are called occupational hazards.

13.               The process of taking out threads from the cocoon is known as reeling the silk.

14.               Silk fiber is chemically a Protein.

15.               The scientific name of mulberry is Morus alba.

16.               The small fluffy fibers of wool are called burrs.