Clothes are an important part of our lives. We wear clothes to cover us, to protect us from extreme weather condition and harmful insects and animals. Clothes worn by people also give information about their social, geographical and economic conditions. In this chapter we will learn about Natural fibres - silk and wool.
Fibre - Fibre is the basic material from which the fabric that you use is made. Fibres are spun into yarn. This yarn is then woven or knitted into a fabric.Fibres are classified into two types:
Silk
Properties of Silk:History
According to a Chinese Legend, around 5000 years ago, the queen of Emperor Huang-ti was having tea in the garden when one yellow colored cocoon feel into her tea and strands of thread separated from it. She discovered the thread to be strong and started weaving it into fabric. Hence, started the silk industry of China. The Chinese kept the silk production a secret for many years while trading it with other civilizations and making huge profits. The route taken by the Chinese traders for the exchange of silk is known as silk route. Eventually silkworms were smuggled out of China and production of silk began in other countries. China till date remains the largest producer of silk in the world.
Making of Silk
Silk is made from cocoons which silkworms spin around themselves. A single thread of a cocoon can be upto 1600 metres long. The structure of silk is like protein. It is a poor conductor of heat and keeps the body warm in winter and cool in summer. The silk producing insects are actually the larvae of silk moth, Bombyx mori, are domesticated for large production of silk.
Raising silkworms
A silk moth lays about 200-300 eggs and dies. The eggs are kept in temperature range of 25 to 31 C in highly humid conditions, for a gestation period of about three weeks. After that worms hatch out. The worms are then kept in bamboo trays and fed on mulberry leaves. The worms are protected from harmful insects by wrapping the trays with cotton cloth. The worms are continuously fed, cleaned and moved for 2-3 weeks, after that worms stop feeding, each silkworm now secretes liquid silk from an opening under its mouth. Within 2-3 days, they form a full cocoon around themselves called pupa. The pupa undergoes many changes inside the cocoon. A few weeks later, the adult moth comes out of the cocoon.
Extracting thread
The cocoons are then put in pots of boiling water to kill the insect inside and to make the outer coating soft and loose. Then the threads are pulled out by a special technique called reeling of silk.
Dyeing and spinning
The silk after reeling is dyed in different colors and spun into yarn. Different qualities of silk are separated based on the length and texture of the yarn.
Weaving
The yarn is then woven into beautiful fabrics.
Wool
Sources and Making of wool
Animals like sheep, yak, llama, alpaca, few breeds of goats etc. bear fine hair on their bodies to keep them warm. These fibres are the source of wool for us. Sometimes, special breeds of sheep are chosen to produce offspring which have very fine hair. This is called selective breeding.
Rearing and breeding
Sheep are reared and bred in herds in the mountains and open areas. Sheep feed mostly on grass and leaves; they are also given grains, corns and oil cakes. When the sheep have a thick layer of hair on their body, they are ready for shaving.
Shearing
Shearing is the process of removing the hair coat from a sheep’s body. The hair coat is removed using mechanical razors. Shearing is mainly done in summer as the temperature is hot and sheep can live without the fur. The hair removed from the sheep’s body is called fleece.
Scouring
The fleece contains lot of grease, skin and other waste materials. It is thoroughly washed with soap or detergents or diluted acid solution so that the fleece is clear of waste. This is called scouring.
Sorting
After washing and drying, wool fibres are separated into different categories based on the texture. This process is known as sorting.
Removing of burr
Here the fluffy fibres known as burr are removed and the wool is washed again.
Dyeing
The wool is then dyed into different colors.
Making yarn
After dyeing, the wool is combed either manually or in machines. Lastly the fibres undergo spinning to form the woolen yarn. The woolen warn is then knitted into clothes.
Occupational Hazards
Exposure to chemical agents
Many chemicals are used during the process of making wool from fleece and silk from silkworm. The chemicals are primarily used during dyeing, bleaching, washing etc. such chemicals can pose health hazards like respiratory disorders, skin problems, allergies, cancer etc.
Exposure to dust and fibres
The exposure of workers to dust from materials like silk, wool, cotton, flax, jute during weaving, spinning, cutting, packaging can cause allergies, nasal or bladder cancer.
| S.No. | 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 |
Practice Time
Objective Type Questions
- Fill in the blanks:
- Silk is produced by
- The production of silk is called
- The silkworms feed on
- The hair obtained from sheep is called
- Scouring of fleece is done after
- True or False:
- Sorting refers to washing of fleece:
- Silkworms are actually larvae of silkmoths:
- Shearing can kill the sheep:
- To obtain silk, the silkworms are killed:
- Wool is an insulator of heat:
- Choose the correct answer
- Which kind of cloth can be used in both summer and winter?
- a.silk
- b.wool
- c.both a and b
- Why are cotton clothes more common than silk cloth?
- Cotton is less expensive than silk
- Cotton clothes can be used in all seasons
- both a and b
- Is the fleece obtained from sheep is wool?
- yes
- no, it contains waste material
- What is the difference between wool and beard of sheep?
- wool is coarse
- beard is coarse
- there is no difference
- Does silk need to be detangled like wool?
- no, silk is obtained directly as thread from cocoon
- yes
- Match the following
Answers
1.silkworms
2.sericulture
3.mulberry leaves
4.fleece
5.shearing
| Column A | Column B |
|---|---|
| 1. Mulberry leaves | a. goats |
| 2. Sericulture | b. silkworms |
| 3. Scouring | c. silk thread |
| 4. Reeling | d. fleece |
| 5. Angora | e. making silk |
Very Short-Answer Questions
- Answer in a word or two:
- Name two wool yielding animals.
- Name the plant on whose leaves silk worm feed on.
- Nane one occupational hazard related to wool industry.
- Name the moth used for obtaining silk.
- Write two properties of silk.
Short-Answer Questions
- Answer the following in brief:
- Define sericulture
- Why are sheep shaved in summer?
- Why is shearing not painful for sheep?
- How does the silkworm product silk?
- What is meant by sorting in wool production?
