AP State Syllabus AP Board 7th Class Science Important Questions Chapter 3 Animal Fibre
AP State Syllabus 7th Class Science Important Questions 3rd Lesson Animal Fibre
7th Class Science 3rd Lesson Animal Fibre Important Questions and Answers
How silk weaving began ? Write the story behind it.
- Chinese traditions, along with the writings of Confucius tell the same 2700 BC tale. It states that the empress Leizu (Hsi – ling – shi) was having tea one day under a mulbery tree with her husband, emperor Huang-ti, when a silk worm’s cocoon fell into her cup.
- In an attempt to take it out, the thread of the cocoon began to unroll. So the Empress thought of weaving the thread.
- The Emperor encouraged his wife to study the life of silk worm, and so she learned the art of raising silk worms or what is called sericulture. Her finding was taught as well and thus the advent of the silk industry.
- However, archaeological evidences show that the origin of silk industry traces back to 3000 and 5000 BC.
- The sites of Yangshao culture in Xia Country; Shanxi reveal a cocoon of a bombyx mori or a domesticated silk worm along with silk weaving looms.
Write a note on The world of wool.
Woolen fabrics are as ancient as human civilization. According to archeological evidences domestication of woolly sheep may have started around 6000 BC by early Iranians. Earliest woven woolen garments are dated 2000 – 3000 years later. In 15th century, British made laws to control wool smuggling and at one time they punished people by cutting off their hands ! The industrial revolution introduced mass production of wool. Leaders of wool production are Australia and China.
What is the historical record of spinning and weaving?
Spinning and Weaving:
The spinning of animal or vegetable fibres into thread dates from about 7000 BC, from the Middle East; the earliest tools used were a distaff (a cleft stick holding a bundle of fibres) with a weighted spindle to twist them together. The oldest known textile, from Asia Minor, dates from around 7000 BC. The first looms for weaving wool dates from about 5000 BC.
Family Scene A Hittite lady spins wool in a bas-relief from the 8th century B.C.
Are caterpillars dangerous?
All caterpillars are not dangerous. Some are useful too.
From where do we get fibres? Explain.
- We get fibres from plants and animals.
- Cotton, Jute, Gongoora, Coconut plant fibres are useful to make different kinds of fabrics.
- In the same way we get fibres of silk and wool from animals like silk worms, sheep, goat, camel, and yak etc.
Who will purchase the tiny silk worms?
Farmers from Kurnool, Kadapa, Chittoor and some other places of our state come and purchase these tiny worms.
Why do farmers buy silk moths ? What is the name of the centres?
- Sometimes farmers buy silkmoths because to produce eggs from them.
- The eggs are produce by thermselves (by farmers) in their own centres.
- The egg producing centres are called Grinages’.
Narrate the stages of transformation from egg to cocoon in the sericulture. What do you do in this process?
- Large tray with leaves and larva feeding on them could be seen.
- Some trays had white and yellowish egg like structures.
- Farmers grow silk worms to get cocoons. They get 5-6 harvests of worms in a year.
- Farmers bought mulberry twigs from Palamaneru of Chittoor district, where sericulture (the whole process of obtaining silk starting from silk moth) is carried out.
- Farmers plant the twigs to get the mulberry crop.
- We purchased tiny white coloured silk worms (caterpillars) from seed growing centres at Horsely Hills.
- We place these worms in trays. We chop Mulberry leaves into small pieces to feed them.
- These worms eat leaves day and night. They need good hygienic conditions and proper light to grow.
- When they grow biggerin size, we transfer the worms into big sized cane frames called “Chandrikalu”.
- After 30-35 days the caterpillar stops eating and settles at a particular place. It weaves a net to hold itself.
- Caterpillar moves its mouth from side to side and secretes fibre-like substance.
- When it is exposed to air and heat it becomes strong.
- The net is woven completely to cover the body of the caterpillar. This seems to be a closed sack. This is called Pattukayalu’ (Cocoon).
- The larva of silk worm undergoes changes in the cocoon to change into a moth. After 2-3 weeks young moths come out from the cocoons and fly away.
- So we have to be very careful. Within 2-3 days of formation fo cocoon, we start removing them from the tray.
How is the process of reeling, fibre to yarn is done? Describe.
- Some people will attend to boiling and stirring something in large pots. (Fig. )
- Cocoons are being boiled in water.
- Cocoons are boiled to get silk fibre.
- Caterpillar of silk worm spins fibre which is mainly made up of two types of protein (sirisine and fibroin) and is very strong.
- The cocoons have to be boiled to loosen the fibre to be able to reel it.
- Obtaining silk fibre from cocoon is called reeling. It is done with special machines called reelers and twisters.
- The silk fibre is carefully collected from the cocoon and nearly 3 to 18 of such threads are wound together to make yarn from it which is reeled (Fig. )
How is silk yarn woven to fabrics?
- The reeled yarn is cleaned, bleached and coloured.
- The yarn is ready to be woven into a variety of designed fabrics, on looms.
- We can see reeling centres at Nandikotkur, Hindupur, Dharmavaram and Madanapalli etc.
Describe the process of scouring of wooL Why is cool air passed over it after washing?
- Sheared skin with hair is dipped in such tanks and stirred with a spade.
- Often it may be washed under a stream of water as well.
- This water contains some chemicals to remove grease, dirt and dust.
- This process ¡s called washing or scouring.
- Alter washing, cool air is Passed over the wool to makes it softer.
Explain the process of sorting wool.
- People sorting coarse and soft ones as well as broken and long ones and making separate piles of them.
- Unwanted materials like twigs or hits of leaves etc., that may he present with the wool are also separated out.
- This process is called sorting or wool classing. Fleece is the soft mass of wool.
How do these woolen fibres get different colours? What is there in the tubs? Explain the process of spinning.
- There are beaches and dyes in the tubs. Woolen fibres are bleached and then dyed with different colours.
- The coloured fibres are used to make yarn. These fibres are then combed.
- There is a machine for combing or carding wool. Wool is pulled through many teeth of the combing machine (Fig. )
- From there, a machine rolls and pulls it out into a thick rope and still another pulls and twists it into a long thread.
- This is the process of spinning.
- Flere you can see it being wound on whirling spools as well. (Fig. )
- Thus we get the yarn which may be dyed before weaving.
What is the advantage of stiffling?
- Stiffling helps to store the cocoons for a long period.
- This process is usually done in reeling centres.
Where are the cocoons sold ? In which places rfites of cocoon are usually enquired ?
- These cocoons are kept in sealed bags and sold at the cocoon market.
- If not stiffled, we sell them off within a week.
- Usually enquiries about rates of cocoons are made in the market at Hindupur, Madanapally, Dharmavaram, Kadiri, Palamaneru and Raychoti.
What are the different silks produced in our state ? What is tasar silk ? Where do the silk plantation is mainly concentrated?
- Apart from Mulberry, Tasar silk (Desali Pattu) is produced in our State.
- Some species of silk moths that lay eggs on termanalia (oak) plantation produce tasar silk.
- Mostly tribal people rear these kind of cocoons.
- This silk plantation is concentrated in coastal regions of East Godavari and Visakhapatnam.
What are the different places famous for silk? What are the different types of silk available to us?
- Dharmavaram – silk city of Andhrapradesh.
- People weave silk fabric by using silk yarn on handlooms.
- For there people, weaving is a traditional occupation.
- They get silk yarn from reeling centres to weave a variety of sarees.
- Venkatagiri pattu and Dharmavaram are famous types produced by our state.
- Dharmavaram is famous for its wide border and rich buta or dots.
- Banaras, Kanchipuram, Dharmavaram, Narayanpet, Kothakota, Pochampally are all types of silk fabrics.
- They get their names from the places where they are made.
- We also have heard the names of tasar silk, mooga silk, kosa silk, eri silk etc.
- These are all several varieties of silk. Some chemicals add strength to silk fibres.
- Silk is used to make other products as well like satin and crepe. We have both handlooms and power looms to weave silk.
What is the difference between silk and cotton?
|1. Mainly protein
|1. Mainly a carbohydrate called cellulose
How are we protected from heat and cold by wool?
- Wool is a poor conductor of heat. Air trapped in between the woolen fibres and our body prevents the flow of heat from our body to our surroundings.
- So we feel hot and are protected from cold.
- Woolen cloth also helps to douse fire.
- That is why it is good to wrap a person, who is caught in fire, with a blanket.
How much of yarn do we get from cocoons? How many people are involved in this process? Are they safe with this?
- The thread you get from the average cocoon ranges from about 1,000 to 3,000 feet, and about 2,000 to 3,000 cocoons are required to make 500 gm of silk.
- That is about 5,000,000 feet or more than 1,000 miles!
- That’s not all. People involved in the process suffer from skin as well as respiratory problems due to continuous handling of the silk worm and the silk fibres.
From where wool is obtained?
- Clothes like sweaters, mufflers, hats, long coats, table covers etc. are some woolen varieties.
- There were different types of animals like sheep, goat, yak, llama, camel, alpaca etc.
- Wool is obtained from hair of all the animals.
- It is also called fleece or fur collectively.
- It is mainly a protein. Good quality wool is obtained from Merino sheep.
- They are specially reared. The fleece is 3-5 inches long and very fine and most valuable.
- A merino sheep may yield about 5 to IS kg of wool per year.
Do we find any difference between hairs of all animals?
- Certainly, hair of camel that lives in Rajasthan is not same as Angora goat that lives in Kashmir.
- Camels have rough and coarse hair.
- Under this rough hair some animals usually have soft hair as well.
- Angora goat or the Merino sheep have soft hair.
Where do we find sheep or goat that give us wool?
In Jammu & Kashmir, Himachal Pradesh, Uttaranchal, Arunachal Pradesh, Sikkim, Haryana, Punjab. Rajasthan and Gujarat. They are often reared on large farms.
What do the people do with scissor in removing fleece of sheep?
- A shear is used to cut fleece from sheep.
- During spring season fleece of sheep is removed from its body using this type of razor.
- This process is called shearing (Fig.). To prevent damage to skin, grease is used.
If you are going to visit Ooty, a hill station in the month of November, which type of clothes would you carry
- Ooty is the cold place as it is a hill area.
- I would like to keep woolen clothes in my luggage in order to protect myself from cold condition.
- I would carry sweaters, gloves, scarfs and shoes to protect myself during cold days.