Question

Class Notes

Class: VII Topic: WORKSHEET BASED ON LONG

ANSWER TYPE QUESTIONS

Subject: SCIENCE

FOR PRACTICE

1. How the silk fibres are obtained from cocoon?

2. Write the steps to obtain wool fibres.

3. Differentiate between natural and artificial silk.

4. Define the following terms:

• Selective breeding

• Rearing

• Shearing

• Sericulture

• Scouring

5. Why an antacid tablet is taken when anyone suffers with acidity?



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Answer 1

Answer:

5 th ) because antacid is a base which when reacts with acid in our stomach neutralizes it and acidity in our stomach is relieved

Explanation:

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Answer 2

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QUESTION 1 :-

• Cocoons are first obtaining from the silkworm and then placed under the heat of sun.
• It can also be bioled at a high temperature.
• This process helps in the separation of silk fibres from the cocoon.
• This process of separation of silk fibres from the silk is known as reeling of silk.
• Then , finally the silk fibres obtained are cocoon are designed and moulded into the desired shape.

QUESTION 2 :-

➡️ Steps involved in the production of wool :

• Shearing : The process in which woolen material is removed from the body of animal.
• Scouring : The process of washing and cleaning of the wool.
• Sorting and grading : The process of separation of inferior wool from the whole stack of wool.
• Carding : The entangled fibres are taken out from the wool in order to convert it into continuous fibres . This process is called as Carding.
• Making Yarn ; The process in which the carded wool is turned and twisted to convert into thin rope called silver and stretchemnt of silver.
• washing and finishing : This is the final step of obtaining wool , in this process the yarn fabric is knitted or woven to make finished goods.

QUESTION 4 :-

• Selective breeding : The nourishment and rearing of the best quality of wool yielding parent so as to get good quality of wool is known as selective breeding.
• Rearing : Taking care of animals for their future use is called as rearing.
• Shearing : The process of removal of fleece of sheep accompanied by the removal of thin layer of sheep is called as shearing.
• Sericulture : The rearing of silkworm for the commercial use of silk obtained is called as sericulture.
• Scouring : The washing of unwanted dust , Greece and dirt from the raw wool is called scouring.

QUESTION 3 :-

• Artificial silk is synthesized and prepared by the man in the factory by the application of several chemicals . Whereas ,
• Natural Silk is acquired from Silkworm from the nature.