what is scouring of wool class 7
5. Question 2. C becomes cold by the process of radiation. This is the process of making wool. The process of washing the fleece (cut hair of sheep) that removes dust, dirt, dried sweat and grease is called scouring. The various steps for processing fibres into wool: a) Shearing: The procedure of removing fleece of sheep is termed as a shearing. ii. It includes the processes of raw wool scouring, drying, carding, backwashing and preparer gilling. Question 5. Fibres are very thin, thread-like strands from which fabrics (or cloths) are made. 4 sekunder ago ; 0 Comments ; Okategoriserade The finest wool is obtained from Merino sheep. The process of washing the fleece (cut hair of sheep) that removes dust, dirt, dried sweat and grease is called scouring. Due to this, woollen fabrics keep us more warm during cold, winter days. Wool is obtained from the fleece (or hair) of sheep. Shearing: This is step one of processing fibre into wool. The cocoons are put in boiling water to loosen the silk fibre. Step 5. Short Q & A : Q1: Define wool. Carbonising is unique to the woollen system and breaks down any remaining impurities after scouring. Solution 1) Shearing- the process of removing hair from the body of a sheep. This makes the wool suitable for making fabric. It contains dust and dirt, therefore, requires thorough cleaning. The longer fibres are made into wool for sweaters and the shorter ones are spun and woven into the woollen cloth. (iv) Cleaning of Burrs: The small fluffy fibres, called burrs, are picked out from the hair . Also share it wi. Scouring & Carbonising. Email Address. B becomes cold by the process of convection. They grow in size and when the caterpillar is ready to enter the next stage of its life history called pupa, it first weaves a net to hold itself. It is done with the help of machines. 11. Each one of the USPTO's 45 international classes designates a specific category . You can choose to spend your time scouring the internet for resources, or you can invest your money wisely and get as good a resource as you'll need. Solution 1: (a) The skin of the black sheep has fur like hairs mainly at the back and abdomen, known as wool. Without this, further processes are impossible. Scouring is the process of washing and drying sheared wool in hot water and detergent. Answer: Leaves, grains . Q 17 - Two fibres are made up of proteins. (ii) 'Mary had a little lamb, whose fleece was white as snow. Name . In coarse wool scouring plants the final bowl of the scouring train is sometimes used for chemical treatments. Answer: Silk fibres are animal fibres obtained from cocoons of the silkworm. The skin hair affords the fibre to make wool. Meaning of Soil Consistency: Soil consistency is also an important physical and dynamic property which varies with the variation of soil moisture and applied stress. Answer: Silk is a protein fibre and is a non-conductor of heat. 3-sorting- the process of seperating good quality wool fromm inferior quality wool. The fleece is sorted according to its texture and type Since the fibres are mostly black, brown or white in colour, they can now be dyed in various colours. The system of creating fibre into wool follows a chain of processes: Shearing Scouring Sorting Dyeing Straightening, Rolling and Combing. Answer the following: Fleece: The covering of wool on the body of animals from which wool is extracted is called fleece. Choose the correct option. The larvae secrete very fine filaments made of protein. What is the process of scouring? Because of the waviness of wool, the woollen fabrics have a greater bulk (than cotton fabrics) and hence trap more air. If you have any other queries of CBSE Class 7 Science Fibre to Fabric MCQs Multiple Choice . Prev Question Next Question . Hope the information shed above regarding NCERT MCQ Questions for Class 7 Science Chapter 3 Fibre to Fabric with Answers Pdf free download has been useful to an extent. The first mechanical method the wool goes through, to extract grease and soil from the fleece, is scouring or cleaning. answered Mar 29 by ZoyaPatel (47.6k points) selected Mar 30 by . The small fluffy fibres called burrs are picked out and sent for reprocessing. Wool is a modified form of hair that grows with a waviness. Fleece (i) Woolly covering : We think the shed NCERT MCQ Questions for Class 7 Science Chapter 3 Fibre to Fabric with Answers Pdf free download will benefit you to the fullest. Scouring makes the fleece of sheep clean. (i) a (ii) b (iii) both a and b (iv) neither a nor b. Why scouring is done during processing of wool? Animal fibres are obtained from animals, e.g., silk and wool. The fibres, which are obtained from plants and animals are called natural fibres e.g., jute and wool. Wool is a modified form of hair that grows with a waviness. Topic 7: Wool Combing. This is called scouring. Wool and silk are animal fibres. What is scouring in the processing of wool? Free solutions for NCERT Solutions - Science , Class 7 Chapter 4 - Fibre to Fabric Exercise question 12. Hey there !Scouring. Then follows the actual combing operation and the sequence of topmaking processes . The most commonly used treatment is bleaching, in which hydrogen peroxide and formic or acetic acid are added to the bowl . This is referred to as grading. Scouring makes the fleece of sheep clean. Ans : Wool is the soft, curly fibres obtained from the fleece of sheep, goat and yak etc., it clothes made from wool keeps us warm. The fibres are dyed in various colours because the natural fleece of sheep and goats is black, brown or white. Wool comes from cattle, goats, yaks, and other beasts. Step-3 Sorting The process of separating the fleece of sheep into sections according to quality of woollen fibres such as fine, coarse , long, short is known as Sorting Home . 4. b) Scouring: The procedure of cleaning removed fleeces is termed as a scouring. Scouring is the process by which natural (oil, wax, gum, fat etc) as well as added (during fabrication process) impurities are removed completely as possible. (b) White hairs of a lamb are also known as white fleece. 5-dyeing- the fibres obtained after combing is dyed into various colours. Free JEE Main Mock Test . Wool is the soft, wavy (or curly) hair which covers the body of a sheep. 2: Differentiate between natural and man - made fibres. Ans : The fleece of sheep is the main source of wool .Apart from that, Angora wool is obtained from angora goats.The fur (hair) on the body of camels is also used as wool like Llama and Alpaca. Answer: Yarn is a long continuous thread that is made up of fibre. The amount of wool produced by one sheep varies from \(1\) to \(3\;\rm{kg}.\) Scouring. The preferred water temperature for washing wool is 140F. The process, of twisting of raw and dyed fibre, is known as sorting. Mulberry leaves. .A further, separate test called a Condition Test is used to determine the oven dry mass and calculated invoice weight of a batch of scoured or carbonised wool. Scouring : To remove dirt or grease from (cloth or fibres) by means of a detergent. Question 1. Answer: Fiber. Step-2 Scouring The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt .This is called scouring. 'Marry had a little lamb, whose fleece was white as snow'. Silkworm's feed on mulberry leaves. Answer: convection. Class 7 Science Chapter 3 MCQ. class 7th . The wool is also categorized by the length, colour, and texture of the fibres. Score: 4.7/5 ( 22 votes) To scour wool, fill a bowl with warm water (between 50 and 60 C), add some soap or washing up liquid and leave the wool to soak for two hours or overnight. Wool is a modified form of hair that grows with a waviness. Answer: Scouring: In scouring, the sheared skin with hair is thoroughly washed in soap solution in a number of tanks to remove grease, dirt and dust. Commercial processors may use a slight alkaline solution (by adding sodium carbonate) to aid in the scouring process. Wool straight off a sheep, known as "greasy wool" or "wool in the grease", contains a high level of valuable lanolin, as well as . Ask Us. Ans - Scouring. Ans - The first step is shearing then scouring. The fibres are spun into yarn (long continuous thread) which can then be woven on a loom to make a fabric (or cloth). Scouring: The process of washing of wool, shaved off from the body of animals, to remove grease, dust and dirt is called scouring. 1 Answer +1 vote . Scouring (b) Cleaning wool: 9. Carding: In carding process, selected curly . Sericulture. The process of removing dirt, dust, and grease from the sheared hair is called scouring. 3. Silk threads are made from a sticky secretion secreted by the larvae of the silkworms. Asked by: Mr. Ali Schroeder DDS. Pashmina is soft wool obtained from Kashmiri goat. Chemistry Fibre to Fabric Part 4 (Wool Processing: Shearing, Scouring, Sorting) Class 7 VII Class 7 Science Chapter 3 | Fibre to Fabric. https://www.meritnation.com/ask-answer/question/scouring-means-abrasive-means/chemistry-in-everyday-life/3397710 Question 3. Use a mild soap. Wool scouring typically uses water and alkali, although scouring with an organic solvent is also possible. Why scouring of wool is a necessary step during. class-7; Share It On Facebook Twitter Email. White fleece refers to the white hair of lamb that is used to make wool. class7-science-fibre-to-fabric . Silk comes from silkworms and wool is obtained from sheep, goat and yak. A process and plant for scouring wool, wherein the wool is treated with a dry cleaning agent, such as for instance trichloroethylene or perchlorethylene, and used cleaning agent is separated from the wool and washed with a mixture of water and alcohol, the cleaning agent containing wool, grease being then separated from the water and alcohol and recovered in a solvent recovery low pressure and . by Taniya Unbeaten Ingenious (35.1k points) asked in Science-7 Jan 14, 2021 18 views +2 votes . Prev Question Next Question . Wool is obtained from the fleece (or hair) of sheep. The hair of sheep along with a thin layer of skin (called fleece) are removed from the body of sheep. 1 Answer +1 vote . 2) Scouring- the process of washing the fleece of a sheep to remove dirt,dust and greece. The woolen fibers are thoroughly washed in big tanks to remove grease, dust and dirt by fully mechanized machines before the wool can be used for commercial purposes.. Class 7 Science Chapter 3 MCQ (Multiple Choice Questions) of Fibre to Fabric. Hence silk and wool are animal fibres. Some examples of fibres are cotton, wool, silk, flax, jute, nylon, polyester and polyacrylic. Free chapter wise worksheets with answers have been designed . What is class 7 scouring wool? Scouring involves washing the shorn . Question 6. Fiber (especially wool)scouring involves the use of hot water and detergents to remove soil, vegetable impurities, grease and other contami User qa_get_logged_in_handle sort. Download printable Science Class 7 Worksheets in pdf format, CBSE Class 7 Science Fibre to Fabric Worksheet Set A has been prepared as per the latest syllabus and exam pattern issued by CBSE, NCERT and KVS. 2. Interested In CBSE Class 7 Science Notes Chapter 3 Fibre to Fabric. The silkworm is . 4) Combing- the process of removing burrs [tiny knots] from the fleece. Question 8. In which part of India is Yak wool commonly seen ? The scoured fleece (or washed fleece) is then dried. 4. Q2: What are the different sources of wool? What is wool How is it produced Class 7? Because of the waviness of wool, the woollen fabrics have a greater bulk (than cotton fabrics) and hence trap more air. After scouring, fleece of different textures are separated. (ii) Scouring : The sheared skin with hair thoroughly washed in tanks to remove grease, dust and dirt. What is wool How is it produced Class 7? Plant fibres and animal fibres and synthetic fibres. Science-7 . The silkworm is (a) a caterpillar, (b) a larva. Its other end. Answer: The female silk moth lays eggs, from which hatch larvae which are called caterpillars or silkworms. Dyeing, Combing and Spinning. Wool scouring: - The main purpose of scouring is to remove the impurities in wool like dust, dirt, perspiration, and natural oily matter. Is silk a good conductor of heat? Answer: Lohi, Rampur bushair, Nali, Bakharwal, Marwari and Patanwadi. Question 7. During the growth of the wool fibre it becomes coated with grease, salt and contaminated with dirt, dust and other matter. Define sericulture. Reeling: Reeling is the process of unwinding silk threads from cocoon using machines. Why is sorting of wool fibres is done after scouring? The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt. (iii) Sorting: The hairy skin is sent to a factory where hair of different textures are separated. Fibre to Fabric class 7 Science Main Points/Notes. Class 7 2 See answers Once the dyeing process is complete, the fibres are straightened, combed and rolled into yarn. This is called scouring. 2-scouring- the pocess of washing the fleece of a sheep to removr dirt,dust and greece. Ans - Artificial silk is a plant fibre. 7. In this technique, the fleece of the sheep at the side of a skinny layer of pores and .
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