Answer the following questions in detail
1. How are fibers classified. Give
examples
2.Explain how wool is processed. Write the steps in sequence with help of diagram.
3. Explain life cycle of a silkworm with the help of a diagram.
4. Explain the process of obtaining silk from the cocoon.
5. How would you verify whether a silk dress bought by your mother is made from pure silk or artificial one.
6. Write one difference between the following
a. Plants fibers and animal fiber.
b. Marino wool and angora wool.
c. Sorting and scouting
d. Moulting and reeling
Answers
Answer:
1.
ans.Fibres can be classified as natural fibres and synthetic fibres.
Natural fibres are obtained from plants and animals. The examples of such fibres include cotton, jute, silk and wool.
Synthetic fibres are made from chemical substances, which are not obtained from plant or animal sources. Examples include polyester, nylon and acrylic.
Answer:
Introduction
A material which is composed of thin and continuous strands is known as fibre. Fibre can be of two types: natural fibre and synthetic fibre. The fibres which are obtained from plants and animals are known as natural fibres whereas synthetic fibres are man-made fibres. Examples of natural fibres are cotton and silk whereas examples of synthetic fibres are: nylon, polyester, etc. Silk is a type of natural fibre or animal fibre. Silkworm is responsible for spinning of silk and it is reared to obtain silk.
History of silk
Silk was discovered around 3500 BC in China. For a long period of time, silk was shipped to other parts of the world through trade. Technological advancement and new developments have enabled manufacturers to produce different types of silk from different silkworms on the basis of lustre and texture. Mulberry silk is the most common silk moth that is used for producing silk. Rearing of the silkworm is known as sericulture.
History of silk
History of silk
The life cycle of silkworm
The life cycle of silk moth starts when a female silk moth lays eggs. The caterpillar or larvae are hatched from the eggs of the silk moth. The silkworms feed on mulberry leaves and give rise to pupa. In the pupa stage, a weave is netted around by the silkworm to hold itself. After that it swings its head, spinning a fibre made of a protein and becomes a silk fibre. Several caterpillars form a protective layer around pupa and this covering is known as the cocoon. The silk thread (yarn) is obtained from the silk moth’s cocoon. The life cycle of the silkworm is explained below in detail.
Life Cycle of Silkworm
Stage 1: Egg
An egg is the first stage of the life cycle of the silkworm. The egg is laid by a female moth which is mostly the size of small dots. A female moth lays more than 350 eggs at a time. In the springtime, the eggs hatch due to the warmth in the air. This procedure happens once in every year.
Stage 2: Silkworm
A hairy silkworm arises after the eggs crack. In this stage of silkworms, the growth happens. they feed on mulberry leaves and consume a large amount of these leaves for around 30 days before going to the next stage.
Stage 3: Cocoon
In this stage, silkworms spin a protective cocoon around itself. It is the size of a small cotton ball and is made of a single thread of silk.
Stage 4: Pupa
The pupa stage is a motionless stage. In this stage, people kill the pupa by plunging the cocoon into boiling water and unwind the silk thread.
Stage 5: Moth
In this stage, the pupa changes into an adult moth. The female moth lays eggs after mating and thus the life cycle of silkworm begins again.
Processing of silk
Extracting silk from the cocoon is known as the processing of silk. Silk is separated from the cocoon by exposing it to sunlight. After the reeling of silk is done, the process of unwinding silk from a cocoon takes place. Silk thread is then bleached. The silk fibre is then spun into silk threads