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Why is it necessary to kill the pupae by boiling the cocoon in water?
Answers (1) To get silk, the cocoons are put in boiling water during the process of which pupae die. It is necessary to kill pupa by boiling cocoons so that the rest of the processes (I.e. scouring ,spurning and dying ) get easily carried off.
Why are silkworm pupae boiled?
Explanation: Silk is produced by silk worms when making their cocoons. To get the silk from the cocoons at the optimum time, before the worm makes a hole in the cocoon reducing it’s value, they are placed in boiling water to kill the worm and make it easier to unwrap the silk threads.
Who produce silk thread pupa or caterpillar?
It is the larva (or caterpillar) of a silk moth which produces silk and not the adult silk moth. The larva (or caterpillar) of a silk moth which produces silk is called silkworm. (2) The eggs hatch to form worm-like larvae. The larvae of silk moth are called caterpillars or silkworms.
What is the process of reeling?
Reeling is the process of unwinding raw silk filament from the cocoon directly onto a holder. When several filament strands, either raw silk or synthetic, are combined and twisted together, producing yarn of a specified thickness, the process is called throwing.
Why do we need to boil the cocoons for extraction of silk Class 7?
To obtain the silk, cocoons are treated with boiling water to kill the living pupa inside. Thread is recovered from the killed cocoons and this process is known as reeling . hope this helps you! !
Why are the cocoons boiled in hot water or treated in ovens?
The uniform cooking of the outer and inner layers of the cocoon can be easily attained by replacing the air of the cocoon cavity with water since water transfers heat faster than air. Thus, the wet cocoons from the soaking part are exposed to steam at about 90-95ºC at an appropriate steam pressure.
Why do we need to boil the cocoons for extraction of silk class 7th?
Why are the cocoons boiled in hot water or treated in oven?
Cocoons are boiled in hot water or treated in ovens so as to get the silk. Boiling with hot water or treating in ovens results in softening of the upper layer of of the cocoon or killing the pupa inside.
Why are cocoons boiled in hot water or treated in ovens?
Why are silkworm pupae killed by boiling water?
It is necessary to kill pupae by boiling cocoons in water because, if the pupae in the cocoons are not killed, they can develop into a silk moth and by this, the silk could not be obtained.
Why is it necessary to kill the pupae by boiling the cocoons?
Why it is necessary to kill the pupae by boiling cocoons in water at right time? It is necessary to kill pupae by boiling cocoons in water because, if the pupae in the cocoons are not killed, they can develop into a silk moth and by this, the silk could not be obtained.
What happens if cocoon is not boiled when harvesting silk?
Some cocoons are not boiled during the harvesting of silk thread because they are let to grow into pupae. This pupae will then help in the future harvesting of silk when they grow into a moth. Why do we not wait for the silk moth to hatch and then boil the cocoon?
How to boil a silkworm cocoon, step by step?
How do you boil a silkworm cocoon? 1 Cocoons are put into a pan of boiling water. The groping ends of the cooked cocoon can be completed with the stirring… 2 The cocoons contained in the wire cage are placed into the boiling water and then boiled for a few minutes. More