Wool is a modified form of hair that grows with a waviness. Silk takes well to dyes, which results in colourful fabrics. Wool is the soft, wavy (or curly) hair which covers the body of a sheep. Wool is used to make sweaters, shawls, and other woollen fabric. Gravity: 1.48 - 1.51 g/cm 3. E) None of these . silk tends to fall naturally and hangs delicately on the body. Silk fibre reacts with acids more quickly. There are several types of silk . Fibres are very thin, thread-like strands from which fabrics (or cloths) are made. Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look luxurious. Silk takes well to dyes, which results in colourful fabrics. Ans: The two characteristics of wool fibre are - In the first place, this fiber is popular all over the world for its valuable and outstanding appearance.It is also popular to make children's wear, ladies' wear, tie suits, and other applications. Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look luxurious. The finest wool is obtained from Merino sheep. Characteristics of Silk Fibers and Products. Step 5: Dyeing: After sorting and picking out of burrs, these are dyed in desired colors. and its culture and weaving was a guarded secret for more than 2500 years by the Chinese. Natural Fibres. It is also very elastic, which means it can be stretched to its limits. Effect of alkalis: The silk fibres so obtained are weaved to make silk cloth. Because of the waviness of wool, the woollen fabrics have a greater bulk (than cotton fabrics) and hence trap more air. Silk is a strong natural fibre possessing good tensile strength. SILK. Ans. Uses of Silk Fiber: The silk fiber is a different type of textile fiber.When silk fiber has various uses in the textile and apparel manufacturing industry. Silk takes well to dyes, which results in colourful fabrics. (iii) The silk thread is used in surgical works . Strength: It is stronger than silk. The cocoons are put in boiling water to loosen the silk fibre. 3. Silk is a luxurious fabric spun from the cocoons of a moth, Bombyx mori. First of all, silk takes well to dyes, both natural and synthetic, which results in colorful fabrics. Main inner portion (70 80%) is made up of fibroin (true fibre) which is surrounded by a thin covering of . Question 1. They are very thin but strong having high elastic property. Very long filament (up to a mile long) Spun by a caterpillar called a silkworm (but not actually a worm). What are the characteristics of silk fibre? Silk culture began in china in 2640 BC, and later spread to Korea and Japan, westward to India and Persia, then to Spain, France and Italy. It is soft, but strong, and can be used in a variety of fabrics. The use of linen in Egypt between 3000and 2500B.C. Strength: Silk is that the strongest fibre. IV. When a cross section of the Silk thread is observed under microscope, it is roughly in the figure of 8. Answer (1 of 2): silk is one of the popular fabrics for apparel because of its unique properties. common silk moth among all is the mulberry silk moth . Silk textiles may be weakened if it is exposed to too much sunlight. The sub-topics covered are animals that yield wool, fibres to wool and the rearing and breeding of sheep. Name two varieties of cloth materials which are commonly used. It's cotton i.e. Maturity ratio: varies from 0.7-0.9. These cocoons are spun to produce a continuous silk filament with a natural gum that lends it to have an appealing sheen. c) It is the strongest natural fibre. Silk cotton is a plant fibre from the KAPOK tree used for stuffing for pillows and lifejackets and insulation. Answer: Wool, jute, cotton, flax, etc. What Are The Characteristics Of Silk Fibre Class 7? Silk cotton tree has softwood, red flowers, a large number of seeds and smaller filaments. Why cannot a single silk fibre form a thread? Wool yielding animals are sheep, yak, llama, alpaca, angora goat, angora rabbit and camel. Use Code STAYHOME200 and get INR 200 additional OFF. Ans: Egg: The female silk moth lays large number of eggs. Wild silk fiber is very irregular and resembles flattened, wavy ribbons with longitudinal markings. The soft silk thread is as strong as a comparable steel thread. Answer: The thread-like materials used to make cloth or fabric are called fibres. silk tends to fall naturally and hangs delicately on the . All you need of Class 8 at this link: Class 8. Characteristics of Silk. Mention two characteristics of wool fibre. The addition of silk fibre (3-15 wt%) reduced the percentage mass loss (59.7-45.5%) . Properties of Silk. Silk is composed of 80% of fibroin, which is a protein substance and 20% of sericin, which is a silk gum. 2. Silk. Stronger than cotton or linen. So, silk is an animal fibre. Silk is often used for clothing such as formal dresses, shirts, blouses, ties, lining, pajamas, dress suits, lingerie, high fashion clothing and Eastern traditional costumes. Question 5. Silk fibers are made from a protein produced by the silkworm, Bombyx Mori. Question 2. 10. The female died immediately after producing the eggs while the male moth died a short period after that. Fineness: The value varies 3-6. Step 6: Spinning: The fibers are then straightened, combed and rolled into yarns. A silk saree. Silk is a natural protein fiber produced by silkworms that are kept in captivity. Fibre to Fabric Class 7 Science Extra Questions Very Short Answer Type. Differentiate between a biodegradable and a non-biodegradable material. Cultivated silk is smooth, cylindrical and generally uniform in thickness, like glass rods. They may be woven, knitted, matted or bonded. Silk fibre with the average fibre diameter of 100 m was supplied by Ocean Verve Ltd., Hong Kong. Ans: Shearing is the first step in the processing of wool. Silk is a fine, strong, soft and shining fibre obtained from silkworms. Different types of silk: Silk is usually referred to as the queen of the fibers. Properties of Silk Silk is an elastic, lustrous protein fibre. it's a purpose of two.4 to 5.1 grams per denier. To kill the pupa inside cacoons, these are boiled in hot water. The cost of silk varies widely, depending on the country in which it was produced, the method of collection, the nature of the fiber and so on. Fabrics made from silk fiber are light but it can keep its wearers warm. Below 7 is acid, and above 7 is alkaline. The bast fibers include flax, ramie, jute & hemp. Types of Silk Different types of silk moths yield different types of silk yarn, such as mulberry silk, tassar silk, eri silk and moonga silk.The most common silk moth is the mulberry silk moth. How is natural silk and artificial silk made? Answer: But there is a huge difference between silk vs wool. Resiliency: Wool is highly resilient and comes to its original shape when hanged after wrinkled or created. INTRODUCTION Silk is a natural protein fibre produced by the larve of a moth, like wool. Burr is the fiber that gives wool. Question 4. Most valued for its "silky" feel. This fiber, also called raw silk, is spun into silk yarn and threads. The biodegradable polymer-PLA as a matrix under investigation in the current study is a neat grade commercialized by Cargill-Dow under the brand name NatureWorks PLA Polymer. Silk fibres are converted into silk yarn which is used for making silk cloth. The soft looking silk yarn is as strong as a comparable thread of steel. Some examples of fibres are cotton, wool, silk, flax, jute, nylon, polyester and polyacrylic. 2. Silk is most luxurious fabric, the most comfortable fabric. Name some natural fibres. Silk is an elastic, lustrous protein fibre. It derives from the stalk or stem of Linum suitatssimum. Silk fibre is soluble in hot and concentrated sulphuric acid and hydrochloric acid. It is separated from cacoons of silkworms which is made of protein. Silk as a wearable fiber was first discovered by the Chinese emperor Xi Ling shi during 2,640 B.C. The rearing of silkworms to obtain silk is termed as sericulture. (ii) It is a natural fibre. The protein is called Sericanin and is solely produced by this insect. Silk fibres are converted into silk yarn . Saris and other garments are made from silk. Silk is a natural fibre which is obtained from an insect (called silk moth). Silk is a natural protein filament. D) All the above done clear. China is the largest silk producer and consumer in the world followed by India where Indian sarees made from silk are famous. Fibres obtained from plants and animals that can be spun into filament, thread or rope are termed as 'Natural fibres'. 2. Silk is a universally accepted luxury fibre. This silk cloth is then used for making sarees and other dresses. Detailed Solution for Important Questions Test: Fibre To Fabric - Question 2. Silk is an elastic, lustrous protein fibre. Wool is the most commonly used animal fibre. has been verified. Suggest Corrections. Explain the life cycle of the silk moth? The eggs took about 10 days to become larvae. 1. silk has good tensile strength,Silk is the strongest natural fibre and has moderate abrasion resistance. b) It can be dyed easily and takes the highest lusture. Todays major producers of silk are: China, India, Japan. As of . CBSE Class 7 Science Notes Chapter 3 Fibre to Fabric. Name the sources of obtaining fibres. (i) Soft in touch. Name the four given fibres marked 1,2, 3 and 4. Silk: Silk is a protein fiber and only one natural continuous filament made by the silkworm, produced by caterpillars belonging to the genus Bombyx.The most beautiful among all textile fibers is silk, which is claimed as the queen of textiles. Heat conductivity: Wool fibre is a part that is a poor conductor of heat and therefore the fabrics made from the fibre are considered most suitable for winter wear. The raw silk threads undergo a series of processes such as rolling, warping and twisting before being woven into a fabric on a loom. Wool and silk are animal fibres. It is also known as "bio steel" because of its strength. Like animal hair, silk does not conduct heat and is . A protein fiber. It is a solid fiber. e. Why are the cacoons boiled in hot water or treated in ovens. Cultivated silk is from silkworms fed only mulberry leaves. Silk fibre done clear. The soft-looking silk yarn is as strong as a comparable thread of steel. Silk is an elastic, lustrous protein fibre. Decades later even though the methods used to make fabrics from fibres may have changed greatly, their functions remain the same: Most natural fibres are still . 4. Microscopic properties of silk. d) It can be stretched to almost 25% of its original length. Ans. Other insects can also produce silk. Wool. Step 4: After sorting, fluffy fibers, called burr, are picked out from hair. Artificial silk (called rayon) is obtained from wood pulp and it is made of modified plant material . Properties of Silk. The filaments are 300-1800 yards long. What is silk give some characteristics of the silk fibre Class 7? The fibres are spun into yarn (long continuous thread) which can then be woven on a loom to make a fabric (or cloth). What is shearing? a lot of over smoothness of the silk filament yarn reduces the matter of wear and tear from abrasion. Question 3. Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look . Shape and appearance: Silk filaments square . 5. Name some wool yielding animals. 4. Properties of Silk: Silk threads are very fine, soft and light in weight. Flax is a bast fibera woody fiber obtained from the phloem of plants. The sources of obtaining fibres are plants and animals. A female silk moth produces about 300-400 eggs at once. Which characteristics of fibre are given below? Characteristics of silk fibre:-(i) It is the strongest natural fibre. Silk's shine also makes it . 5. This decrease in mass loss and the resultant increase in thermal stability is attributed to the higher thermal stability of silk fibres, which on interaction with the polymer matrix act as barriers for better heat insulation and lower the rate of . It gets yellowish when it comes into contact of Nitric acid. The strength of the spun silk yarns depends on the length of silk staple. Flax fiber is not so fine as cotton, is longer than cotton. If they are not killed and allowed to grow, they will break the . Effects of Alkali: Unaffected or undamaged by alkaline solution. Chemical, mildew & moth resistance - ph levels in your cleaning and dyeing baths can damage some of your fibers. According to a survey, a lot of silk was collected from silkworm farms instead of the wild as of 2010. It's filament density is 1.34 g/cm which make it a medium weight fiber. . Silk takes well to dyes, which results in colourful fabrics. Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look luxurious. The soft silk thread is as strong as a comparable steel thread. Silk is an elastic fibre which can be stretched from 10% to 20% of its original length . The document Test Paper - Synthetic Fibres & Plastics, Class 8, Science Notes - Class 8 is a part of Class 8 category. 5. Price of Silk Fabric. Natural silk is obtained from the cocoons of silkworms and it is made of a 'protein'. Silk cotton is softer than regular cotton. The following are the two most significant animal fibres: Wool is derived from animals such as sheep, goats, and yaks, among others, whereas silk is derived from silkworms. Characteristics of Silk. silk tends to fall naturally and hangs delicately on the body. Moisture Content: 8.5%. What are the characteristics of silk Class 7? Fig. Wool and silk are hence animal fibres.