They are very thin but strong having high elastic property. Question 3. Wool is the soft, wavy (or curly) hair which covers the body of a sheep. Silk's shine also makes it . What is shearing? What is silk give some characteristics of the silk fibre Class 7? Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look luxurious. The sub-topics covered are animals that yield wool, fibres to wool and the rearing and breeding of sheep. Wool and silk are hence animal fibres. 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. Silk takes well to dyes, which results in colourful fabrics. Silk is a natural fibre which is obtained from an insect (called silk moth). Some examples of fibres are cotton, wool, silk, flax, jute, nylon, polyester and polyacrylic. 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. Cultivation of silkworm is known as sericulture. Ans: The fibre of a single cocoon is too fine to handle as a result of which a single silk fibre cannot form a thread. It is a solid fiber. Properties of Silk. Ans: The two characteristics of wool fibre are - Silk fibers are made from a protein produced by the silkworm, Bombyx Mori. Step 6: Spinning: The fibers are then straightened, combed and rolled into yarns. Name some wool yielding animals. How is natural silk and artificial silk made? Gravity: 1.48 - 1.51 g/cm 3. The eggs took about 10 days to become larvae. it's a purpose of two.4 to 5.1 grams per denier. Answer: Fibre (marked 1) which is used in filling quilts is cotton and fibre (marked 2) is . 1. Silk is composed of 80% of fibroin, which is a protein substance and 20% of sericin, which is a silk gum. Suggest Corrections. 4. Silk fibres are converted into silk yarn . Silk is a luxurious fabric spun from the cocoons of a moth, Bombyx mori. Wool. What . It gets yellowish when it comes into contact of Nitric acid. Silk is an elastic fibre which can be stretched from 10% to 20% of its original length . 2. All you need of Class 8 at this link: Class 8. The bast fibers include flax, ramie, jute & hemp. The soft silk thread is as strong as a comparable steel thread. So, silk is an animal fibre. First of all, silk takes well to dyes, both natural and synthetic, which results in colorful fabrics. Characteristics of Silk. Silk fibre done clear. Detailed Solution for Important Questions Test: Fibre To Fabric - Question 2. Effects of Acids: Cotton fibers are weakened by cold weak dilute acids and degraded by strong acids. Silk cotton is softer than regular cotton. The fibres are spun into yarn (long continuous thread) which can then be woven on a loom to make a fabric (or cloth). The production of silk in Europe began in 590 AD and around 300AD in India. Ans. What Are The Characteristics Of Silk Fibre Class 7? Silk is resistant to organic acids but damaged by mineral acids. Maturity ratio: varies from 0.7-0.9. Fibre (1) is used in filling quilts and the yarn made of fibre (2) is used in making gunny bags, The yarn made from fibre (3) is used for knitting sweaters and yarn of fibre (4) is used for weaving saries. The rearing of silkworms to obtain silk is termed as sericulture. Properties of Silk: Silk threads are very fine, soft and light in weight. This strength comes from the continuous length of the fibre. c) It is the strongest natural fibre. A protein fiber. It derives from the stalk or stem of Linum suitatssimum. 5. It's filament density is 1.34 g/cm which make it a medium weight fiber. . silk tends to fall naturally and hangs delicately on the body. 3. Answer: Wool is the most commonly used animal fibre. b) It can be dyed easily and takes the highest lusture. 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. has been verified. Which characteristics of fibre are given below? The protein is called Sericanin and is solely produced by this insect. (ii) It is a natural fibre. Name two varieties of cloth materials which are commonly used. INTRODUCTION Silk is a natural protein fibre produced by the larve of a moth, like wool. Fibres obtained from plants and animals that can be spun into filament, thread or rope are termed as 'Natural fibres'. The fibre of a single cocoon is too fine to handle, so up to ten cocoons are wound together onto a reel by hand. Silk has a soft feel, and in appearance, it has a sheen and luminosity that makes it look luxurious. Ans: Egg: The female silk moth lays large number of eggs. What are the characteristics of silk fibre? The cocoons are put in boiling water to loosen the silk fibre. Very light weight silk textile materials may be manufacturing from silk filaments. 1. silk has good tensile strength,Silk is the strongest natural fibre and has moderate abrasion resistance. The sources of obtaining fibres are plants and animals. Silk is an elastic, lustrous protein fibre. The use of linen in Egypt between 3000and 2500B.C. (i) Soft in touch. This silk cloth is then used for making sarees and other dresses. Question 5. 1. Answer (1 of 2): silk is one of the popular fabrics for apparel because of its unique properties. Wool and silk are animal fibres. 5. The finest wool is obtained from Merino sheep. Step 4: After sorting, fluffy fibers, called burr, are picked out from hair. (iii) The silk thread is used in surgical works . Another property of silk is its soft feel, and it retains it shape well, even after having . Silk is a fine, strong, soft and shining fibre obtained from silkworms. Fabrics made from silk fiber are light but it can keep its wearers warm. Silk is a filament spun by the caterpillars of various butter flies. These cocoons are spun to produce a continuous silk filament with a natural gum that lends it to have an appealing sheen. However, only silk from the silkworms is used for textile purposes. Question 4. Different types of silk: Silk is usually referred to as the queen of the fibers. It's Latin name is Bombyx mori. Flax is a bast fibera woody fiber obtained from the phloem of plants. The most. Then, the chapter moves on to explain a very useful fibre - wool. Silk is most luxurious fabric, the most comfortable fabric. 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. 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 . Wool is used to make sweaters, shawls, and other woollen fabric. 10. Todays major producers of silk are: China, India, Japan. Some most common Ccharacteristics of Silk Fibers are: (i) As the silk fibers can retain some moisture, the clothes made of silk can be used in both the winter and summer seasons. Wool is resistant to acids. 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 . Wool is a modified form of hair that grows with a waviness. It is also very elastic, which means it can be stretched to its limits. Natural Fibres. Effect of alkalis: It is also known as "bio steel" because of its strength. Silk is a natural protein filament. Burr is the fiber that gives wool. Fibres are very thin, thread-like strands from which fabrics (or cloths) are made. Artificial silk (called rayon) is obtained from wood pulp and it is made of modified plant material . Characteristics of Silk Fibers and Products. Silk fibre with the average fibre diameter of 100 m was supplied by Ocean Verve Ltd., Hong Kong. Wool yielding animals are sheep, yak, llama, alpaca, angora goat, angora rabbit and camel. It is slightly affected by diluted organic acids at room temperature. Fig. silk tends to fall naturally and hangs delicately on the . E) None of these . Name the four given fibres marked 1,2, 3 and 4. Explain the life cycle of the silk moth? Silk fibres are converted into silk yarn which is used for making silk cloth. The female died immediately after producing the eggs while the male moth died a short period after that. Flax fiber is not so fine as cotton, is longer than cotton. The document Test Paper - Synthetic Fibres & Plastics, Class 8, Science Notes - Class 8 is a part of Class 8 category. Fibre to Fabric Class 7 Science Extra Questions Very Short Answer Type. The soft silk thread is as strong as a comparable steel thread. a lot of over smoothness of the silk filament yarn reduces the matter of wear and tear from abrasion. The soft looking silk yarn is as strong as a comparable thread of steel. What are the characteristics of silk Class 7? The silk yarn is then woven on looms into silk cloth by the weavers. The concentrated organic acids dissolve the silk fibres. A silk saree. silk tends to fall naturally and hangs delicately on the body. This fiber, also called raw silk, is spun into silk yarn and threads. SILK. Ans: Shearing is the first step in the processing of wool. Answer: The thread-like materials used to make cloth or fabric are called fibres. Cultivated silk is from silkworms fed only mulberry leaves. Cellulose fibers are harmed by acids - even vinegar can do some damage. Strength: It is stronger than silk. Silk takes well to dyes, which results in colourful fabrics. Name the sources of obtaining fibres. 5. 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. Silk fibre is soluble in hot and concentrated sulphuric acid and hydrochloric acid. Silk is an elastic, lustrous protein fibre. Properties of Silk. Cultivated silk is smooth, cylindrical and generally uniform in thickness, like glass rods. Stronger than cotton or linen. Silk is a universally accepted luxury fibre. 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. Characteristics of Silk. Silk cotton tree has softwood, red flowers, a large number of seeds and smaller filaments. Very long filament (up to a mile long) Spun by a caterpillar called a silkworm (but not actually a worm). Differentiate between a biodegradable and a non-biodegradable material. If they are not killed and allowed to grow, they will break the . Silk takes well to dyes, which results in colourful fabrics. To kill the pupa inside cacoons, these are boiled in hot water. The raw silk threads undergo a series of processes such as rolling, warping and twisting before being woven into a fabric on a loom. . Ans. The soft-looking silk yarn is as strong as a comparable thread of steel. Question 1. Silk fibre is made of a protein. (ii) The silk is non-conductor of electricity, and therefore can be used as an insulator covering of electric wires. It's cotton i.e. 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. D) All the above done clear. Chemical, mildew & moth resistance - ph levels in your cleaning and dyeing baths can damage some of your fibers. Silk fiber is a protein fiber from silk glands of an insect. Silk. It is separated from cacoons of silkworms which is made of protein. common silk moth among all is the mulberry silk moth . The Class 7 Science, Chapter 3 - Fibre to Fabric helps us understand how the fabric that we use in our day-to-day lives is produced from the fibre.In this chapter, we study the concepts of natural and man-made fibres. Silk fibre is obtained from the cocoon of the silk moth. The filaments are 300-1800 yards long.
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