Textbook-based subjective questions

— Just like winnowing makes the husk blow away while retaining the grains, similarly, sages let the virtues stay while discarding the vices. —Kabir

Their parents have planned a trip to visit their relatives and friends living across India.

Do you also keep in touch with your loved ones? Their first halt is at their Nani’s (maternal grandmother’s) house in Haryana.

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.” 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.

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.

It is done on the basis of differences in size, colour and shape of the particles.

At lunch, Malli and Valli are served steaming hot vegetable pulao.

9.1: Handpicking aside on his plate (Fig. This is a handpicking method, nice one!” Nani tells them about the benefits of black pepper and encourages Malli to eat it.

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. asks Mama, “Why are they doing this?” Mama explains, “They are beating the stalks to separate the grains” (Fig. This process of separating grains Fig.

This process of separating grains Fig. 9.2: Threshing from the stalks is known as threshing. Farmers work hard, yet they enjoy their work.

Farmers work hard, yet they enjoy their work.

Have fun Explore folk songs of your region and try to while sing along with your friends. you learn

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.

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. Next day, their Nana takes them to the fields to show this process at work.

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.

The farmer is moving the bamboo tray which contains threshed Fig.

Do both the components, wheat grains and husk, fall at the same place?

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. 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 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.

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.

Mami: To prepare a dish with flour, first we need to remove bran that may be present in the flour.

The bigger particles such as bran and small stones remain on the sieve.

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.

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? 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.

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 the seawater is kept in shallow pits and exposed to sunlight and air.

the seawater is kept in shallow pits and exposed to sunlight and air.

Find out about some water bodies in India that contain common salt.

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? 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.

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. Recall the chapter ‘A Journey through States of Water’. Let us probe further to get the answer.

Let us probe further to get the answer. 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?

Take some salt solution (prepared in Wire gauze Activity 9.2) in a china dish.

9.8: Heating of china dish Caution Be careful Allow the china dish containing salt solution while heating to cool down. the china dish. What do you observe?

You can feel the presence of salt in the china dish by touching the salt with your fingers. Does method through it answer the which I can get question?

Can back both salt you name the and water? process involved? (paternal grandparents) residing in Puducherry, located in southern India. They are excited to meet their old neighbourhood friend, Balan.

They 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. 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?

9.9: Decantation Dada: Leave the sauce pan (vessel) containing tea undisturbed for some time and gently pour the tea in a cup (Fig.

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. It means it is not a proper method of separation. 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.

This process of separating tea leaves from tea is called filtration.

Dada: Also, try to filter the muddy water through a piece of cloth and observe the difference.

These pores in the cloth can be used as a filter. People in 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.

Place it inside a funnel kept on a conical flask and pour muddy water into it (Fig. Do the mud particles pass through the filter paper? The water coming from the funnel will be collected in the conical flask. 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.

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.

Design and create a working model of water filter using low-cost materials.

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? As they cast the fishing net, water drains out through the mesh.

Malli is taken aback when he sees 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. Let us raise awareness about the issues related to 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?

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. Discuss with your parents A bowl of milk in your home has gone sour.

Discuss with your parents A bowl of milk in your home has gone sour.

Also, which method of separation will you use in the process?

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 Malli asks the shopkeeper about the big painting, hanging on the wall of the dhaba.

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.

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.

On their arrival at their Bua’s (paternal aunt’s) house in Shillong, they notice a carpenter making a wooden door.

The carpenter starts handpicking the iron nails.

They ask the carpenter to move the magnet through the sawdust. All the nails get attracted to it (Fig.

Recall the chapter ‘Exploring Magnets’. The substances which are attracted towards a magnet are called magnetic substances.

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.

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.

The scrap iron can be recycled and More to reused.

They not only enjoyed exploring different regions of India but also gained a lot of knowledge about various methods of separation of substances.

Taking out green chillies from cooked dalia (dish made of broken wheat) or poha (dish made of flattened rice). Sorting piles of sawdust and iron nails from a mixed heap of building material.

Separating coconut pieces from rice flour. 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. ny one of the te t w o di f f e o ve a co m ara re r em t is n ot us ef u ep a po s f u l c o mpo n nt To t h l n e To t use en bu ts This activity helps in assessing your understanding as to why we separate substances.

This activity helps in assessing your understanding as to why we separate substances. 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.

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.

Play a Game—WISE FISH Prepare your own fishing rod with locally available eco-friendly materials.

Fish out a red fish representing the method of separation first and then fish out one blue slip related to the red one. 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 apour on of water v insoluble particles get filtered as residue conversi state its liquid ed lighter compo dpick nent of mixtu s ar e han by blowing ai re is separate d article r rp large 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

(i) Oil from water (ii) Sand from water (iii) Cream from milk (iv) Oxygen from air Which factor is usually essential for the filtration? (i) Apparatus size (ii) Presence of air (iii) Pore size (iv) Temperature of the mixture 4.

(i) Apparatus size (ii) Presence of air (iii) Pore size (iv) Temperature of the mixture 4.

(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.

Can you relate the presence of nasal hair to any separation process? During the COVID-19 pandemic, all of us wore masks.

Generally, what material are they made of? A mixture containing potatoes, salt and sawdust has been given to you.

Outline a stepwise procedure for separating each component from this mixture. Read the following story titled ‘Intelligent Leela’ and tick the most appropriate options. Provide a suitable title of your choice for the paragraph.

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.

Before her father felt thirsty/hungry, she went to the nearby pond to fetch some water/grains.

Leela, then, cooled/boiled the water for about 10 minutes in a covered pan.

She served this water to her father while having food, who blessed her and appreciated her efforts. 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. 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 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.

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.

Encourage children of your community below the age of 14 to join a neighbourhood 180 school.

Think like a scientist: You are provided with a mixture of iron nails, sand, black pepper, stones, common salt and water.

The given steps may help you to think like a scientist. 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?

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? Hint: A mixture that has more than two components requires a combination of several methods of separation.