Methods of Separation in Everyday Life PDF

Chapter 9 Methods of Separation in Everyday Life साधु ऐसा चाहिए जैसा सपू सभु ाय । सार सार को गहि रहै थोथा दई उड़ाय ।।...

Chapter 9 Methods of Separation in Everyday Life साधु ऐसा चाहिए जैसा सपू सभु ाय । सार सार को गहि रहै थोथा दई उड़ाय ।।  —कबीर Just like winnowing makes the husk blow away while retaining the grains, similarly, sages let the virtues stay while discarding the vices. —Kabir Malli and his sister Valli are excited for their summer vacations. Their parents have planned a trip to visit their relatives and friends living across India. They always stay in touch with their relatives and friends. Do you also keep in touch with your loved ones? Their first halt is at their Nani’s (maternal grandmother’s) house in Haryana. It is surrounded by large fields. Malli and Valli are fascinated by the variety of grains piled up in the courtyard. Their Mami (maternal aunt) and Mama (maternal uncle), along with other community members, are busy separating small stones and husk from the grains with their hands. Malli and Valli are curious to know why this is being done. Their Nani notices their curiosity and explains, “We are removing these stones so that the grains are fit for cooking.” Chapter 9.indd 163 09-07-2024 12:11:51  They go around the house to see the fields and the cattle. To keep them busy, Nani gives them a challenge of handpicking small stones from grains while keeping their eyes closed. The method of picking by hand from a mixture (when two or more substances are mixed) such as small stones and husk from wheat and rice is called handpicking. It is done on the basis of differences in size, colour and shape of the particles. If the particles to be removed are present in small quantities and can easily be picked by hand, handpicking proves to be a convenient method. At lunch, Malli and Valli are served steaming hot vegetable pulao. While eating the pulao, Nani observes that Malli is separating whole black peppers from the pulao and is placing them Fig. 9.1: Handpicking aside on his plate (Fig. 9.1). Valli playfully teases, “Wow! This is a handpicking method, nice one!” Nani tells them about the benefits of black pepper and encourages Malli to eat it. Later in the day, their Mama takes them to the fields where they observe bundles of harvested wheat stalks lying in the fields. Some stalks are spread in the sun for drying. Both of them pick up a stalk each and notice numerous grains attached to it. A group of farmers are beating the stalks on a large wooden log. Curiously, Valli asks Mama, “Why are they Curiosity | Textbook of Science | Grade 6 doing this?” Mama explains, “They are beating the stalks to separate the grains” (Fig. 9.2). This process of separating grains from the stalks Fig. 9.2: Threshing is known as threshing. Farmers work hard, yet they enjoy their work. From time to time, they sing folk songs while working. Have fun Explore folk songs of your region and try to while sing along with your friends. you learn 164 Chapter 9.indd 164 08-07-2024 17:46:55  The separated grains get mixed with A small amount of piles of husk. puffed rice is mixed Valli whispers to Malli, “Will the farmers with chana dal. ? handpick the grains to remove them from Can you think of separating the mixture so much husk?” She wonders, “How much by any method other time will the farmers take to separate than handpicking? these?” Let us perform an activity to find out the answer to the questions raised by Valli. Activity 9.1: Let us explore ‹‹ Take a handful of roasted peanuts and rub them between your palms. What happens? ‹‹ Is it possible to separate the removed skin and the peanuts? ‹‹ Now, try blowing it. What do you observe? Which of these components—removed peanut skins or peanuts are blown away? You observe that blowing air separates the heavier and the lighter components. How do you think farmers separate so many grains from husk? Traditionally, a soop (bamboo tray) is used for separating heavier and lighter components of a mixture (Fig. 9.3). Next day, their Nana takes them to the fields to show this process at work. Malli and Valli observe a farmer standing on a raised platform. The farmer is moving the bamboo tray which contains threshed Fig. 9.3: Bamboo tray Methods of Separation wheat grains in the direction of air or wind (Fig. 9.4). in Everyday Life What do you infer from Fig. 9.4? Do both the components, wheat grains and husk, fall at the same place? Which of the two components get blown away? Can the wind separate the two components? 165 Chapter 9.indd 165 08-07-2024 17:46:55  Direction of air or wind Soop (bamboo tray) Husk Grains Fig. 9.4: Winnowing ? Valli is unable to This method of separating heavier and lighter separate husk components of a mixture by wind or by blowing from rice in a air is called winnowing. Have you seen any closed room. How similar kind of activity being done at your home? can you help her? Technological developments have resulted in developing of threshing machines called threshers. These machines are used for separating grains from the stalks and husk. They perform both the tasks of threshing and More to Curiosity | Textbook of Science | Grade 6 winnowing simultaneously. know! Next day, Malli and Valli board a train to Ahmedabad to visit their father’s friend Ghanshyam bhai. Before leaving, Valli requests her Mami to prepare meethi puri (sweet Indian bread made from wheat flour) for their journey. Valli: Shall I help you knead the wheat flour? Mami: To prepare a dish with flour, first we need to remove bran that may be present in the flour. Valli: How do we do it? 166 Chapter 9.indd 166 10-07-2024 10:49:00  Mami: We use a sieve for this purpose. Sieving allows the fine flour particles to pass through the holes of the sieve as shown in Fig. 9.5. The bigger particles such as bran and small stones remain on the sieve. Carefully observe a sieve. Are all the holes of the sieve the same size? Will sieving work if the holes of the sieve are larger than the substances? Is there any difference in the size between Fig. 9.5: Sieving the particles that pass through the sieve and the particles that remain on the sieve? Sieving is used when components of a solid–solid mixture have different sizes. Have you ever observed ? Upon reaching Ahmedabad, they visit sieves being used at Sabarmati Ashram along with Ghanshyam construction sites to bhai where they learn about the Namak separate pebbles and Satyagrah (Dandi March). stones from the sand? What is Sabarmati Ashram famous for? Draw a poster showing Dandi March and More to discuss why it was organised. do! Malli asks, “Where is namak (common salt) obtained from?” “From seawater”, replies Ghanshyam bhai. Seawater is a mixture of salts and some other Methods of Separation substances dissolved in water. To obtain salt, in Everyday Life the seawater is kept in shallow pits and exposed to sunlight and air. In a few days, the water Fig. 9.6: Obtaining salt from seawater 167 Chapter 9.indd 167 09-07-2024 14:44:47  evaporates completely, leaving behind the solid mixture (Fig. 9.6). Common salt is then obtained from this mixture by further purification. Find out about some water bodies in India that contain common salt. One such source is Sambhar Lake in Rajasthan. More to do! Let us explore how salt can be separated from a salt solution. Activity 9.2: Let us observe and create ‹‹ Take a bowl or any container and fill it half with Have you ever water. ? observed white patches on the ‹‹ Add 2-3 teaspoons of salt into it and stir till the dark coloured salt dissolves to form a solution. clothes you ‹‹ Take a small piece of black or dark coloured wear during hot thick paper and spread a few drops of the salt summers? How solution on it (Fig. 9.7a). are these patches ‹‹ You can also create any art of your choice with formed? this salt solution. ‹‹ Allow it to dry and then observe it (Fig. 9.7b and Fig. 9.7c). Curiosity | Textbook of Science | Grade 6 (a) Before drying (b) After drying (c) Art created Fig. 9.7: A few drops of salt solution spread on thick black paper Do you observe some patches on the paper? What do you think is left on the paper? You can feel the presence of salt by touching the paper. Where has the water disappeared? Recall the chapter on ‘A Journey through States of Water’. Let us probe further to get the answer. 168 Chapter 9.indd 168 08-07-2024 17:47:31  In the traditional Indian system of holistic health and medicine called Ayurveda, the herbs or parts of plants are prescribed as remedies. These ingredients like roots, leaves, flowers or seeds of various medicinal plants are often dried in the shade. This practice facilitates the evaporation of excess water, leaving Do you behind the important part of the medicine. know? Activity 9.3: Let us investigate This activity may be demonstrated by the teacher. China dish ‹‹ Take some salt solution (prepared in Wire gauze Activity 9.2) in a china dish. If a china dish is not available, another suitable vessel may be used. ‹‹ Heat and let the water Spirit lamp boil away as shown in Fig. 9.8. Fig. 9.8: Heating of china dish Caution Be careful ‹‹ Allow the china dish containing salt solution while heating to cool. the china dish. ‹‹ What do you observe? What is left in the china dish? Did you get the salt back? You can feel the presence of salt in the china dish by touching the salt with your fingers. ? Observe the Is there any figure. Does method through it answer the which I can get question? Can back both salt you name the and water? process involved? Methods of Separation It is now time for them to visit Dada and Dadi (paternal in Everyday Life grandparents) residing in Puducherry, located in southern India. Malli and Valli are excited to meet their old neighbourhood friend, Balan. After reaching Puducherry, they start talking about the old times and do not realise that it is already evening, Dadi’s tea time. 169 Chapter 9.indd 169 09-07-2024 12:06:56  Dada: I shall prepare tea for you. Tea Children: We will also help you. leaves As Dada makes the tea, he shares tips on how to make a cup of tea. Balan: After preparing tea, how do you remove the tea leaves? Dada: Obviously, with a strainer. You know if we do not have a strainer, we can still remove most of the tea leaves. Valli: How? Fig. 9.9: Decantation Dada: Leave the sauce pan (vessel) containing tea undisturbed for some time and gently pour the tea in a cup (Fig. 9.9). Valli: Oh Yes! And then the tea leaves will be settled at the bottom. Oh! The process of settling down of heavier insoluble Decantation component at the bottom of a liquid is called sedimentation. is also used in When the water (liquid) is removed by tilting the vessel, washing and the process is called decantation. cleaning of rice and pulses. In the chapter ‘Materials Around Us’, you have studied ? that oil does not mix with water and forms a separate layer when left undisturbed for some time. Which method of separation would you use to separate oil and water? Dada: But I can still get a few tea leaves in my mouth because decantation does not completely separate all the tea leaves from the tea. Curiosity | Textbook of Science | Grade 6 Balan: Oh! It means it is not a proper method of separation. Dada: Yes, you are right. The tea is ready now. Malli picks up the tea-strainer from the shelf and gives it to his Dada. Dada: Let me pour the tea through this strainer. You can see all the tea leaves collected in the strainer. This process of separating tea leaves from tea is called filtration. Balan asks Malli if he could use a tea strainer to filter muddy water. Let us try and find out. Dada: Also, try to filter the muddy water through a piece 170 of cloth and observe the difference. Chapter 9.indd 170 09-07-2024 12:06:56  How many layers Malli: Why should we use a piece of cloth? of cloth do I need to use to get clear Dada: In a piece of cloth, there are very small holes water? or pores between the woven threads. These pores in the cloth can be used as a filter. People of ancient times also followed this practice. But if the water is still muddy, impurities can be separated using a filter with even smaller holes or pores. A filter paper is one such filter that has very fine pores in it. Activity 9.4: Let us experiment ‹‹ Try to fold the filter paper yourself and make a cone as shown in Fig. 9.10. A filter paper One-fold Two-folds Cone Fig. 9.10: Folding a filter paper to form a cone ‹‹ Place it inside a funnel kept on a conical flask and pour muddy water into it (Fig. 9.11). Filter paper Muddy water Funnel Tripod stand Conical flask Methods of Separation Fig. 9.11: Filtration in Everyday Life ‹‹ What do you observe? Do the mud particles pass through the filter paper? ‹‹ The water coming from the funnel will be collected in the conical flask. 171 Chapter 9.indd 171 08-07-2024 17:48:15  ‹‹ You will get mud as a residue on the filter paper and clear water as filtrate in the conical flask. Other than the filter paper, many materials such as cotton, charcoal, and sand can be used as filters. The More to choice of filter depends upon the size of the particles of the materials to be removed. know! Activity 9.5: Let us design and create Valli goes for a nature walk with her Dadi and collects some water from a pond in a container. She observes some unwanted substances in it. Design and create a working model of water filter using low-cost materials. Tea bags were initially made of soft cloth, like silk, because it could hold the tea leaves and let water pass through. Silk was strong and did not fall apart when it touched hot water. Later, people started using gauze or muslin. Eventually they began using filter paper, which is what most tea bags are made Do you of today. know? Malli and Valli go on a boat ride in a nearby river with their Dada and his Curiosity | Textbook of Science | Grade 6 friend, Otukkam. Otukkam is a fisherman. As they cast the fishing net, water drains out through the mesh. Valli recalls the filtration method she had learnt and realises that this method of catching the fish is somewhat similar. Malli is taken aback when he saw plastic bags, broken bottles, a large fish with a straw stuck in its mouth, and food wrappers along with the other fish trapped in the net. 172 Chapter 9.indd 172 10-07-2024 10:48:39  Let us raise awareness about the issues of river and ocean pollution by composing a poem. A few lines have been written here, add more lines— Piece of plastic in my neck, As in pain I cry, Koilas, Koilas…where are you dear? Papa fish cries and Mama fish has tears. Aware of the harm, yet they let it flow, Koilas faintly hears mother’s sorrow, Stop plastic pollution at source, Rivers are our huge resource. Discuss with your parents A bowl of milk in your home has gone sour. Discuss with your parents how you can use it in another way. Also, which method of separation will you use in the process? Malli and Valli take blessings from their Dada and Dadi, bid goodbye to Balan and travel to Madhya Pradesh. The train reaches Bhopal in Madhya Pradesh. The sun is rising and it is getting hot. On their way to Maasi’s (maternal aunt’s) home, they drink chhach Methods of Separation (buttermilk) in the dhaba (roadside in Everyday Life eatery). Malli asks the shopkeeper about the big painting, hanging on the wall of the dhaba. The shopkeeper explains that the picture shows a lady performing Churning 173 Chapter 9.indd 173 08-07-2024 17:48:36  the process of churning curd Can you name one using a big mathni (churner) kitchen appliance to separate butter. In this which runs on process, the butter being electricity that is lighter floats at the top, while used to prepare the buttermilk is left behind. buttermilk? Their stay at Maasi’s place has become enjoyable and they are looking forward to share all their memories with their friends upon returning home. Now, it is time for them to reach their final destination of the trip, Shillong, the capital of Meghalaya. On their arrival at their Bua’s (paternal aunt’s) house in Shillong, they notice a carpenter making a wooden door. While working, he accidentally drops a few iron nails in the sawdust. Curiosity | Textbook of Science | Grade 6 Fig. 9.12: Magnetic separation The carpenter starts handpicking the iron nails. The children tell the carpenter to wait. They get a magnet from their Bua. They ask the carpenter to move the magnet through the sawdust. All the nails get attracted to it (Fig. 9.12). Which method of separation did the carpenter use? Recall the chapter on ‘Exploring Magnets’. The substances which are attracted towards a magnet are called magnetic substances. Iron is a common example of 174 Chapter 9.indd 174 08-07-2024 17:48:37  a magnetic substance. Separation of magnetic and non- magnetic substances by using a magnet is called magnetic separation. Nowadays, recyclers use magnets to separate iron articles from a heap of waste. In many industries, the waste material often contains scrap iron. This is separated from the heap of waste materials using magnets fitted to a crane. The scrap iron can be recycled and More to reused. Magnetic separation know! Malli and Valli had delightful holidays and the ‘Bharat ki Yatra’ (tour of India) filled with fun will be a ever lasting memory for them. They not only enjoyed exploring different regions of India but also gained a lot of knowledge about various methods of separation of substances. Activity 9.6: Let us play Write the following phrases on small slips of paper— 1. Separating small stones from pulses. 2. Churning curd to obtain butter. 3. Taking out green chillies from cooked dalia (dish made of cracked wheat) or poha (dish made of flattened rice). 4. Taking out seeds from watermelon. 5. Sorting piles of sawdust and iron nails from a mixed heap of building material. 6. Picking marigold flowers from a heap of other flowers Methods of Separation to make a garland. in Everyday Life 7. Separating pebbles from sand. 8. Separating coconut pieces from rice flour. 9. Separating oil from water. 10. Separating salt from salt solution. 175 Chapter 9.indd 175 10-07-2024 10:47:59  Now, take two baskets, each representing one of the two purposes for which we separate substances. Form two teams and see who will get the maximum correct entries. Think and start ny one of the te two diff e o ve a co m ara re r em t is n ot us ef u ep a po o s e ful compon nt To t h l n e T tu s en bu ts nt s This activity helps in assessing your understanding as to why we separate substances. Keywords Churning Mixture Create Decantation Sedimentation Design Evaporation Sieving Experiment Curiosity | Textbook of Science | Grade 6 Filtration Threshing Explore Handpicking Winnowing Infer Magnetic separation Investigate Observe 176 Chapter 9.indd 176 08-07-2024 17:49:00  Summary ‹‹ Handpicking is used for separating solid materials on the basis of differences in size, colour and shape from a mixture. ‹‹ The process in which the stalks are beaten to separate grains from them is called threshing. ‹‹ The method of separating lighter husk from heavier grains by wind or blowing air is called winnowing. ‹‹ The process of separating solids from a mixture based on variations in particle size using a sieve is called sieving. ‹‹ Evaporation is the process in which a liquid gets converted into its vapour. It can be used to separate a solid dissolved in a liquid. ‹‹ The process of settling down of heavier insoluble component at the bottom of a liquid is called sedimentation. When the liquid is removed by tilting the vessel, the process is called decantation. ‹‹ Filtration can be used to separate insoluble solid components from a liquid. ‹‹ Churning is used to extract butter from curd. ‹‹ Separation of magnetic and non-magnetic substances by using a magnet is called magnetic separation. Play a Game—WISE FISH Prepare your own fishing rod with locally available eco-friendly materials. Tie a thread to one end of the rod and a magnet to the free end of the thread. The Tank 1 has red cardboard fish and Tank 2 has blue cardboard slips attached to iron clips. Fish out a red fish representing a method of separation first and then fish out one blue slip related to the red one. Methods of Separation Watch out for your friends. Are they fishing out correctly? in Everyday Life 177 Chapter 9.indd 177 08-07-2024 17:49:02  Catch me first! Tank 1 Filtration Decantation Condensation Handpicking Churning Evaporation Winnowing Sedimentation Sieving Threshing Magnetic separation Then me! Tank 2 difference in siz e of solid particle s rties prope ma gnetic ence in differ d water extrac own of oil an t butte r from le d mixture curd s sett rp a rticle h eavie remove grains from seaw ater beating stalks to lt separate sa into ater vapour insoluble particles get filtered as residue on of w conversi a te st its liquid ed lighter compo dpick nent of mixtu s ar e han by blowing ai re is separate d article r rp large Curiosity | Textbook of Science | Grade 6 Let us enhance our learning 1. What purpose does handpicking serve in the process of separation? (i) Filtration (ii) Sorting (iii) Evaporation (iv) Decantation 2. Which of the following substances are commonly separated using the churning method? (i) Oil from water (ii) Sand from water (iii) Cream from milk (iv) Oxygen from air 178 Chapter 9.indd 178 08-07-2024 17:49:06  3. Which factor is usually essential for the filtration? (i) Apparatus size (ii) Presence of air (iii) Pore size (iv) Temperature of the mixture 4. State with reason(s) whether the following statements are True [T] or False [F]. Also, correct the False statement(s). (i) Salt can be separated from salt solution by keeping it under the Sun. [ ] (ii) Handpicking should be used only when the quantity of one component is less. [ ] (iii) A mixture of puffed rice and rice grains can be separated by threshing. [ ] (iv) A mixture of mustard oil and lemon water can be separated by decantation. [ ] (v) Sieving is used to separate a mixture of rice flour and water. [ ] 5. Match the mixtures in Column I with their method of separation in Column II. Column I Column II (i) Gram flour mixed with (a) Handpicking black gram (b) Magnetic separation (ii) Chalk powder mixed with (c) Decantation water (d) Sieving (iii) Corn mixed with potatoes (e) Filtration (iv) Iron powder mixed with sawdust (v) Oil mixed with water 6. In what situations would you use decantation instead of Methods of Separation filtration to separate solids from liquids? in Everyday Life 7. Can you relate the presence of nasal hair to any separation process? 8. During the COVID-19 pandemic, all of us wore masks. Generally, what material are they made of? What is the role of these masks? 179 Chapter 9.indd 179 08-07-2024 17:49:06  9. A mixture containing potatoes, salt and sawdust has been given to you. Outline a stepwise procedure for separating each component from this mixture. 10. Read the following story titled ‘Intelligent Leela’ and tick the most appropriate options. Provide a suitable title of your choice for the paragraph. Leela was working in the farm with her father when she realised that they left their drinking water at home. Before her father felt thirsty/hungry, she went to the nearby pond to fetch some water/grains. After obtaining some water in the container, she noticed that the water was muddy and fit/unfit for drinking. To purify the water, she kept it for some time and then she filtered/ churned the muddy water using a piece of paper/muslin cloth. Leela, then, cooled/boiled the water for about 10 minutes in a covered pan. After cooling/boiling, she filtered/churned it again and made it fit/unfit for drinking. She served this water to her father while having food, who blessed her and appreciated her efforts. Learning further ‹‹ Fun with parents: We are proud of our Indian heritage. Under supervision of your elders, try to prepare some herbal remedies using various parts of plants. For example—tulsi kadha. Which methods of separation will you use while preparing herbal kadha? ‹‹ Stage play: Imagine you and your friend are Malli and Valli. Write dialogues of a play presenting their entire ‘Bharat ki Yatra’, highlighting the different methods of separation of Curiosity | Textbook of Science | Grade 6 substances that they observed. Enact the play in your school assembly. ‹‹ Group activity: Observe and list separation methods you employed and noticed in your surroundings throughout a week. Explain the reasons behind using these methods and compile the ones you utilised or observed the most. Compare your observations with your group members. ‹‹ Be a stalwart of your community: Interview a ragpicker(s) and prepare a case study about the method(s) of separation he/she uses in his/her daily life. Encourage children of your community below the age of 14 to join a neighbourhood 180 school. Chapter 9.indd 180 08-07-2024 17:49:10  ‹‹ Be a reporter: (i) Gather newspaper clippings and articles related to various methods of separation implemented in your society, such as in agricultural fields or at construction sites. (ii) Conduct interviews with local farmers to explore the latest agricultural separation methods that they use. ‹‹ Think like a scientist: You are provided with a mixture of iron nails, sand, black pepper, stones, common salt and water. Which steps will you follow to separate each component of a mixture? The given steps may help you to think like a scientist. Reflection Steps I observe. I wonder. You might have wondered about questions such as— „„ Which component should I separate first? „„ What method of separation should I use first? „„ How can we separate these components effectively? „„ Will some of the components be soluble in water? „„ What properties of the components can help us in their separation? „„ What is the most appropriate sequence? Activity Steps ‹‹ Some possible answers to the questions which occurred in my mind are. ‹‹ I performed the following methods of separation— Methods of Separation ‹‹ My findings are. in Everyday Life Hint: A mixture that has more than two components requires a combination of several methods of separation. 181 Chapter 9.indd 181 08-07-2024 17:49:10  Notes Chapter 9.indd 182 08-07-2024 17:49:11