question_answer Answers(1) edit Answer . NCERT Exemplar solutions for Class 7 Science Chapter 3 cover a variety of questions like MCQS, fill in the blanks, match the following and long answer questions. NCERT Exemplar for Class 7 Science Chapter 3 Fibre to fabric Explanation: Obtained from wool which does not required killing of animals. Watch Queue Queue. Class 1-5; Class 6; Class 7; Class 8; Class 9; Class 10; Class 11; Class 12; NCERT Solutions. They are very thin but strong having high elastic property. α-Keratin is a type of keratin found in vertebrates. n Class VI you have learnt about some fibres obtained from plants. CBSE Class 7 Revision Notes. Activity2: Yes! Followings are the physical properties of silk: Color: The color of silk fiber could be yellow, brown, green or grey. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. These are stored on strips of cloth or paper. NCERT Exemplar Class 7 Science Solutions Chapter 3 Fibre to Fabric. The most common silk moth is the mulberry silk moth. Sericulture, or silk farming, is the rearing of silkworms for the production of raw silk. The caterpillar covers itself completely with silk fibre and turns into a pupa, this covering is known as the cocoon. Properties of Silk Silk is an elastic, lustrous protein fibre. Naina Nisa. Image Courtesy: “Green wool texture” By M0tty – Own work (CC BY-SA 3.0) via Commons Wikimedia “white silk 5” By J E Theriot via Flickr. Silk is a natural protein fiber produced by silkworms that are kept in captivity. Learn all about wool. The bamboo trays are provided with small racks or twigs to which the cocoons can be attached. The raw silkmay now be used as is. Skip to main content; Skip to secondary menu; Skip to primary sidebar ; Class Notes. A cocoon accidentally dropped into the empress’s cup of hot tea, and the delicate tangle of threads separated from the cocoon, thus leading to the discovery of silk. The silk thread is then bleached and dyed into many shades. Other insects can also produce silk. When a cross section of the Silk thread is observed under microscope, it is roughly in the figure of 8. These woollen clothes are made of wool. CBSE Class 7 Sample Papers and Solutions. Mulberry leaves are the staple diet of silkworms. Once you find your worksheet, click on pop-out icon or print icon to worksheet to print or download. You can & download or print using the browser document reader options. Piles of cocoons are kept under the sun, boiled or exposed to steam. This video is unavailable. Types of Silk The soft silk thread is as strong as a comparable steel thread. Silk fibres come from cocoons of the silk moth. This was kept secret for hundreds of years. However, over 900 meters of filament can be obtained from a single cocoon. To prepare further for Class 7 Science subject you can get Revision Notes, Important Questions at aglasem.com for free. The next step is called reeling the silk, which is the process of delicately unwinding the fibre from the cocoon. When the mulberry tree bears a fresh crop of leaves, the eggs are warmed suitably so that the larvae hatch from them. CBSE Class 7 Textbook Solutions. Insulating Properties: Silk: Silk is not as good as wool in retaining warmth. Fibre to Fabric . TYPE OF FIBRES Natural fibers – The fibers which are produce from natural sources called natural fibres (cotton and jute from plant, silk and wool from animal.) Ans: Processing Silk: Extracting silk from the cocoon is called processing silk. This silk is then re-boiled in order to improve its luster. Class 7 - Science - CH3 - Fibre To Fabric NCERT Chapter Solutions and Q & A. We are talking about silk, the queen of textiles. Worksheet will open in a new window. So far, the maximum strength of spider dragline silk (dragline of Caerostris darwini ) up to 1.7 GPa, which exceeds that of steel (1.5 GPa), is in the range of high-tech materials [ 1 ]. Actually silkworms are not worms, but the larvae or caterpillars hatched from the eggs of the silk moth. CBSE Class 7 Videos. This process is known as reeling, The filaments are usually twisted to form a silk yarn of about 6 to 8 denier. These two factors permit many more hydrogen bonds to be formed in a much more regular manner. Nov 5, 2014. Question 1. Go to Activity It then swings its head from side to side, secreting a fibre that hardens on contact with air. This strength is due to its linear, beta configuration polymers and very crystalline polymer system. How is Silk Obtained? Learn all about silk. Living Science 2019 Solutions for Class 7 Science Chapter 4 Animal Fibres are provided here with simple step-by-step explanations. Silk fibre is made of a protein. This fibre is made of a protein and becomes the silk fibre. Processing Silk The silk moth develops inside these cocoons. Properties and Characteristics of Silk Fabric; Properties and Characteristics of Silk Fabric. Silk For Class 7. These properties of silk make it an attractive fabric. The warmth causes the silk fibre to separate from the rest of the cocoon. Satyanarayana Prasad. Showing top 8 worksheets in the category - Silk For Class 7. Properties of Silk Science . 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. The rearing of silkworms for obtaining silk is called Sericulture. Extracting silk from the cocoon is called processing silk. The route provided a means for Buddhist missions to travel from India to influence China. This video is highly rated by Class 7 students and has been viewed 13 times. Chinese legend has it that empress Si-lung-Chi was worried about the damaged mulberry leaves in her garden. However, only silk from the silkworms is used for textile purposes. Nov 25, 2020 - Types of Silk Class 7 Video | EduRev is made by best teachers of Class 7. Tensile Strength: Cotton is a strong fiber. The wool is obtained mainly from animals like sheep, yak and goat. However, it is generally thrown，or twisted, with two or thre… How is Silk Obtained? Sources of Wool (image credits: openclipart.org) Q1: You must be familiar with the following nursery rhymes: (i) ‘Baa baa black sheep, have you any wool.’ (ii) ‘Mary had a little lamb, whose fleece was white as snow.’ Answer the following: (a) Which parts of the black sheep have wool? Activity1: Figure 1: Animals that yield wool The end of the filament is brushed off the cocoon and, along with ends from one or two other cocoons, unwound. Larvae feed on mulberry leaves for about 20 to 25 days. over here on EduRev! Discovery of silk Springer.com has developed an interesting simulation regarding life cycle of silkworm through intersingf images and explanation for the each stage of silkworm life cycle. Mulberry silk is soft, lustrous (shiny) and … Thus, tassar silk, kosa silk, mooga silk, etc are obtained from cocoons spun by different types of moths. The Chinese guarded the making of this fabric with their life What fabric are we talking about? Go to Activity These silkworms feed on fresh mulberry leaves the silkworm grows in size and then becomes a pupa. During special occasions or functions, you like to wear silk clothes. 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. Do you know which part of the sheep’s body yields fibres? You can study other questions, MCQs, videos and tests for Class 7 on EduRev and even discuss your questions like Write any two properties of silk.? Wool is obtained from hairs of sheep, yak, camel, goat etc. Caterpillars may shed skin four or five times! Reeling is also done in special machines. Let us discuss about the life cycle of silk moth. The silk obtained from the cocoons of mulberry silk moth is called mulberry silk. The soft silk thread is as strong as a comparable steel thread. What is cool in summer and warm in winter? how_to_reg Follow . Pem.org has developed an about silkworm life cycle, silk cultivation and fashioned in silk with interseting images from the ancient times.
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