Nature'S Treasures

Hello my dear students! I am so happy to be here with you today to learn about one of the most wonderful chapters in your Science book. Today we are going to learn about Chapter 11, which is called "Nature's Treasures." Now, isn't that a beautiful name? Nature's treasures! And what exactly are these treasures? Well, they are the things that nature gives us freely — air, water, sunlight, forests, soil, rocks, minerals, and so much more. Without these treasures, life on Earth would not be possible. So let's begin our journey and discover these amazing gifts of nature together.

Let me tell you a story first. There are two children in this chapter, their names are Bhoomi and Surya. They are visiting their grandmother, whom they call Ajji. Ajji lives in a village on the edge of a forest in the Western Ghats. Now, the Western Ghats are a beautiful mountain range in India, running along the western side of our country. You might have seen or heard about places like Maharashtra, Karnataka, Kerala, and Tamil Nadu which are part of the Western Ghats. So Bhoomi and Surya are having their vacation at Ajji's village, and they are having so much fun! The air is fresh and cool, they can see beautiful hills, streams, and many interesting plants, animals, and birds around them.

One afternoon, Bhoomi and Surya ask Ajji to tell them more about this beautiful place. And Ajji says something very important. She says, "Children, do you know that this place has several treasures of nature that enrich our lives? The pure air is refreshing and the soil is so fertile that it supports a variety of living beings. Moreover, this place gets plenty of sunlight which is useful in many ways. Different varieties of trees provide food and shelter to animals including various birds and insects."

Bhoomi immediately replies, "Ajji, we use water for drinking and growing vegetables." And Ajji says, "Yes. We need these treasures for our survival and for making our lives more comfortable. Without these treasures of nature, any form of life on Earth is not possible. We all are a part of nature."

Isn't that so true, students? We are all part of nature, and we depend on these treasures every single moment of our lives. So now, let us learn about each of these treasures in detail, one by one.

## 11.1 Air

Let us start with air. What is air? Air is the mixture of gases that surrounds the Earth. We cannot see air, but we can feel it when the wind blows. We cannot live without air, even for a few minutes. Let's see what Ajji teaches Bhoomi and Surya about air.

One morning, Bhoomi and Surya see Ajji performing some breathing exercises. Ajji asks them to join her. She says, "I am taking deep breaths in, and letting them out. This helps in getting more fresh air in the lungs to stay healthy." Bhoomi and Surya sit with Ajji and start taking deep breaths.

Now, let us also perform this breathing exercise together, shall we? First, take a deep breath in, and then breathe out slowly. Good! Now take a deeper breath in again. Hold your breath for as long as you can and then breathe out slowly. How long can you hold your breath? Maybe ten seconds, maybe twenty seconds, maybe less. How do you feel when you hold your breath? You feel uncomfortable, right? You feel like you need to breathe immediately. That is because your body needs oxygen, and when you hold your breath, you are not giving oxygen to your body.

From this activity, we find that it is difficult to hold our breath for a long time. The air which we breathe in has oxygen. Our body needs oxygen to perform its functions. When we hold our breath for a long time, the body does not get enough oxygen to perform its functions. Thus, we need oxygen for our survival. Similarly, most of the living beings also need oxygen for their survival.

Now here is something very important for you to remember: We can survive without food or water for a few days, but we cannot survive without oxygen for even a few minutes. That is why air is so precious!

Now, let us learn about what air is made of. The air which surrounds the Earth is a mixture of gases. Can you name some gases which are present in the air? Let me tell you. Air contains nitrogen, oxygen, argon, carbon dioxide and other gases in small quantities. Now, let me explain this with the help of a simple example. Imagine you have 100 small squares, like a hundred grid. Out of these 100 squares, 78 are occupied by nitrogen, 21 are occupied by oxygen, and 1 by argon, carbon dioxide and other gases. This is what we mean when we say the composition of air in percentage. Percentage is the number of parts in 100. It is denoted by the symbol '%'. So we say air contains 78% nitrogen, 21% oxygen, and 1% other gases.

So the biggest part of air is nitrogen, students! Nitrogen makes up about 78% of the air we breathe. Oxygen is about 21%, and the remaining 1% is a mixture of argon, carbon dioxide, and other gases. Isn't that interesting? The air we breathe is mostly nitrogen, but our body uses oxygen from the air. Plants, on the other hand, use carbon dioxide from the air to make their food. So each gas has its own importance!

Now, how do we know that air is all around us? You notice the presence of air when the leaves of a tree rustle, the clothes hanging on a clothes line sway, or the pages of an open book begin to flutter once a fan is switched on. All these happen because of moving air. Moving air is called wind. Sometimes it blows fast, for example, during a storm, and sometimes it blows gently as a breeze. You must have played with a firki, which is a paper pinwheel, many times. Let us make a firki by performing an activity.

For this activity, you will need a square paper of size 15 cm by 15 cm, a pair of scissors, an all-pin, and a soft stick. Follow the instructions shown in your textbook to make a firki. Now, you can hold the firki in your hand and run. You can also blow air on it. What do you observe? Does the firki rotate? When you move it a little back and forth, the firki rotates. What makes a firki rotate? It is the wind that makes a firki rotate. When you blow air on it or run with it, the moving air pushes the blades of the firki and makes it spin around.

Now, the working of a windmill is similar to that of a firki. Wind rotates the wings of a windmill. Windmills can be used to run flour mills, to pull up water from a well, or to generate electricity. In India, there are many windmill farms. A windmill farm is an area that has a large number of windmills which use the energy of the wind to generate electricity.

Let me tell you about some famous windmill farms in our country. The Muppandal Wind Farm in Tamil Nadu is one of the largest wind farms in India. The Jaisalmer Wind Park in Rajasthan is another major wind farm. The Brahmanvel Wind Farm in Maharashtra is also very important. These wind farms generate a lot of electricity using the power of the wind. This is clean energy because it does not cause pollution! So the next time you see a windmill, remember that it is using the power of air, which is one of nature's treasures, to produce electricity.

Now, let me quickly recap what we have learned about air. Air is a mixture of gases, mainly nitrogen and oxygen. We need oxygen from air to survive. Moving air is called wind, and wind can be used to generate electricity through windmills. Air is a renewable resource because it is constantly renewed by natural processes.

Now, let us move on to the next treasure of nature.

## 11.2 Water

Bhoomi and Surya help Ajji in filling the troughs of water for the cows. They also help her in watering plants such as vegetables and medicinal herbs in the garden. Ajji teaches them how to water the plants so that every drop is used and none of it goes waste.

Can you think of some more uses of water in your daily life? Let me tell you some uses. We need water for drinking. We need water for many daily activities, such as cooking, bathing, washing and cleaning. It is also used for growing crops and for industrial purposes. So water is used in almost everything we do!

Now, where do we get water from? Make a list of the different sources of water. The main sources of water are rivers, lakes, ponds, wells, and underground water. Also, water from the sea and ocean, but that water is salty and cannot be used directly.

Water covers about two-thirds of the Earth's surface. That means if you look at the Earth from space, you would see that most of it is covered with water! Most of the water is found in oceans and seas. However, this water is saline or salty. This saline water is not fit for domestic, agricultural and industrial use. For all these activities, we need freshwater, which is present in the form of ice sheets or snow, rivers or lakes on the surface of the Earth, and underground. Freshwater present in ice sheets and snow, or underground water is difficult to access. A very small fraction of the freshwater present in ponds, rivers, lakes and wells is easily accessible. Water is precious, that is why Ajji guides them to use it with care.

Now, let us do an activity to understand water wastage better. This is Activity 11.3. We need to fill Column II and Column III in Table 11.1. Column I has activities like hand washing, washing clothes, washing utensils, taking shower, cooking, gardening, and brushing teeth. In Column II, we need to write how water is wasted in each activity. In Column III, we need to suggest ways to reduce wastage of water.

Let me help you fill this table. For hand washing, water is wasted when we keep the tap running while soaping our hands. To reduce wastage, we should close the tap while soaping. For washing clothes, water is wasted when we use too much water or when the washing machine runs unnecessarily. To reduce wastage, we should use the washing machine efficiently and reuse water for gardening. For washing utensils, water is wasted when we keep the tap running. We should use a bucket and mug instead. For taking shower, water is wasted when we take long showers. We should take short showers and close the tap while soaping. For cooking, water is wasted when we boil more water than needed. We should boil only the required amount. For gardening, water is wasted when we water plants during the hot afternoon or use too much water. We should water plants in the morning or evening and use water efficiently. For brushing teeth, water is wasted when we keep the tap running while brushing. We should use a glass of water for brushing.

What conclusion can we draw from this? We can see that water is wasted in many daily activities, but we can reduce this wastage by being more careful and using water wisely. There are many ways to reduce wastage of water. For example, turning off taps when not in use and fixing water leakages. Recycling water and water harvesting also help in saving water.

Now, let me tell you about water pollution. Our country is blessed with numerous rivers, streams and lakes. Have you ever noticed plastic bags and wrappers floating on the surface of water? We pollute freshwater sources by throwing trash in them. Waste from homes and industries pollute our water sources when it is dumped into them. Other human activities that lead to water pollution include dumping chemicals from factories, washing vehicles near water bodies, and using pesticides and fertilizers in farms that wash into rivers and lakes. Polluted water is not fit for consumption by living beings. We should never throw trash in water bodies and should always dispose of waste properly.

As freshwater sources are limited, there is a shortage of water in many parts of India. At some places, people have to walk long distances to fetch drinking water. Everyone does not have the same kind of access to water. It is important for us to conserve water and use it judiciously. We must also prevent it from being polluted so that water remains fit for consumption by all living beings.

Now, how can we conserve water? Water harvesting is one of the methods for conserving water. In many buildings, rainwater is collected and stored in large quantities for later use. This is called rainwater harvesting. Do you know that rainwater is also harvested in many homes, residential societies or schools? It is an age-old practice in India.

Let me tell you about some traditional water harvesting practices. For example, stepwells, commonly known as Bawadi in Rajasthan and Vav in Gujarat, are built for water harvesting as a response to the scarcity of water in these regions. These stepwells have a unique system of water harvesting. They store not only rainwater but also water seeping from nearby lakes, ponds and rivers. The walls of the trenches, which are long deep holes dug in the ground, are lined with blocks of stones that allow seepage of water. There are many such traditional water harvesting practices in different parts of India. You can find traditional water harvesting practices in your locality by discussing with your teachers and parents.

World Water Day is observed on 22nd March every year. This day is celebrated to raise awareness about the importance of freshwater and to advocate for the sustainable management of freshwater resources. It is a day to remember that water is precious and we must conserve it.

Now, let me recap what we have learned about water. Water is essential for all living beings. Most of the Earth's surface is covered with water, but most of it is salty seawater. We need freshwater for drinking, cooking, washing, and farming. Water is a renewable resource, but it can get polluted and wasted. We should conserve water by using it carefully, fixing leaks, and practicing rainwater harvesting.

Now, let us move on to the next treasure of nature, which comes from the Sun!

## 11.3 Energy from the Sun

On a sunny day, Bhoomi and Surya are helping Ajji dry chillies in the Sun. Ajji says, "We use the heat from the Sun to dry it. We can use dried chillies when fresh ones are not available. I will give you some to take home. Do you know that the Sun is the main source of energy on Earth? All plants and animals are dependent on it."

We use heat and light from the Sun for various purposes. What are some of the activities for which we need heat and light? Let me tell you some examples. Plants make food using sunlight. We dry our clothes in the Sun. We get warmth from the Sun during winter. The Sun helps us see during the day so we don't need artificial lights. The Sun helps in evaporating water to make salt from seawater. There are so many uses!

Now, there is an interesting conversation between Bhoomi and Surya about the Sun's energy. Let me read it carefully and answer the question.

Bhoomi says, "Look at this cow. It is getting energy from it." Meaning, the cow is getting energy from the grass.

Surya says, "No, I think this cow is getting energy from the Sun."

Bhoomi says, "The cow is standing in the Sun. But it does not mean that it is getting energy from the Sun."

Surya says, "The cow is eating grass. Grass leaves need sunlight to grow. So, the main source of energy is the Sun. This way the cow gets energy from the Sun."

Now, whose statement is correct and why? Surya is correct! The Sun is the main source of energy on Earth. Here is how it works: The Sun provides energy to plants to make food through a process called photosynthesis. The cow eats grass and gets energy from the grass. So, ultimately, the energy in the grass came from the Sun. Similarly, when we eat vegetables or fruits or any food, the energy in that food originally came from the Sun. So, the Sun is the ultimate source of energy for all living beings!

Sunlight helps plants prepare food. The Sun also provides all the living beings on Earth with heat and light. It is their main source of energy.

In many households in India, water is offered to the Sun early in the morning as an expression of gratitude to the Sun. This is a beautiful tradition!

Have you seen solar panels on rooftops, on top of street lights or on traffic signals? The solar panels capture the Sun's energy and produce electricity. Energy from the Sun can also be directly used for cooking in a solar cooker or for heating water in a solar water heater. Solar energy is clean and does not cause pollution!

Now, what will happen if the Sun is not visible for a few days? Let me think about this. First, we may have to depend on artificial lighting during daytime also. Second, plants would not be able to make food, so there would be no food for animals and humans. Third, it would become very cold because we wouldn't get heat from the Sun. There would be no solar energy for electricity. Life on Earth would be very difficult!

One cannot imagine life on Earth without the Sun. The Sun is the main source of energy on the Earth. Plants get energy from the Sun and produce food. Animals eat plants and grow. We get food from both plants and animals. This cycle on Earth is possible due to the Sun. So, we all are dependent on the Sun as the main source of energy.

Now, let me recap what we have learned about energy from the Sun. The Sun is the main source of energy on Earth. We use sunlight for drying clothes, drying food items, generating electricity through solar panels, and many other purposes. Solar energy is a renewable source of energy because the Sun will continue to shine for billions of years.

Now, let us explore where we can find a large variety of plants or animals. The answer is forests!

## 11.4 Forests

One morning, Ajji takes Bhoomi and Surya for a walk in the forest. They find a variety of herbs, shrubs and trees in the forest. Ajji explains, "Forests are large areas with dense growth of various types of plants." On the way, they collect some nellikai, which is the Kannada term for Indian gooseberries, that have fallen on the ground. Ajji tells them, "We have a tradition in the village not to pluck fruits from the trees; they are left for animals and birds to eat."

Now, let me ask you to discuss with your friends and make a list of at least five products that we get from forests. What do we get from forests? We get fruits like mangoes, bananas, and gooseberries. We get vegetables. We get medicinal plants and herbs. We get wood for furniture and building houses. We get rubber. We get spices like cinnamon, pepper, and cardamom. We get bamboo. We get honey from bees. We get fodder for animals. We get oxygen to breathe. There are so many products!

Forests are a natural home for many wild animals, including birds and insects. Forests provide food and shelter to them. In nature, every animal depends on other life forms for survival. The diversity of life forms ensures food for every living being.

However, over the years, the forest cover has been decreasing, mainly due to human activities like large scale cutting of trees. It takes many years to grow a new forest or restore lost forests. Therefore, we must preserve and use forests responsibly so that they get enough time to regenerate.

Van Mahotsav is a week-long event celebrated across the country during the month of July. It is a forest festival during which new plants and trees are planted, and awareness about respecting forests is raised. The aim of the event is to increase the green cover. You too can plan a Van Mahotsav in your community!

Now, what are the consequences of cutting a large forest area? If we cut down trees on a large scale, many animals will lose their homes and food. There will be more soil erosion because tree roots hold the soil together. There will be less oxygen in the air. There will be changes in the climate. There will be floods because trees absorb rainwater. So, cutting forests has many bad effects. You can make a presentation or do a role play, or write a story or a poem that shows what could happen if we continue to cut down trees in our forests.

From ancient times, India had a tradition of respecting, protecting and preserving forests. Many efforts have been made by common people to prevent the cutting of trees, and thus, saving forests. One such effort is the famous Chipko movement. It started in the early 1970s in Uttarakhand, which was previously part of Uttar Pradesh. Local women actively participated in this movement. They encircled and hugged the trees to protect them from being felled. This movement became very famous and inspired many other environmental movements in India and around the world.

During their walk in the forests, Bhoomi and Surya notice that there are a lot of leaves on the ground and the soil feels damp. Ajji explains, "The roots of plants hold on to the soil and prevent it from being washed away. The leaves that fall from the trees decay and enrich the soil with nutrients. This soil is used by new plants and trees to grow. This is an example of recycling in nature." So, forests help in recycling nutrients in nature!

Now, let me recap what we have learned about forests. Forests are large areas with many types of plants and animals. Forests provide us with many products like fruits, wood, and medicines. Forests provide home to animals. Forests help prevent soil erosion. Forests help in the water cycle. Forests are renewable resources, but they take a long time to grow back. We should protect forests and plant more trees.

Now, let us investigate the soil in more detail.

## 11.5 Soil, Rocks and Minerals

Bhoomi, Surya and Ajji come back home from the forest. Bhoomi and Surya help Ajji in preparing the soil in the garden for planting some vegetables. Ajji asks them to dig the soil gently and loosen the lumps. You have already learnt in the chapter 'Living Creatures: Exploring their Characteristics' that for plants to grow, the space between the soil particles not only provides sufficient air but also space for the roots to grow easily. Bhoomi and Surya could see small pebbles, the roots of plants and a few earthworms too in the soil. Do you realise that earthworms are natural agents that help in turning and loosening the soil?

Now, let us do our own experiment by performing Activity 11.4. This activity is about investigating soil.

Caution: Remember to wash your hands thoroughly after touching the soil collected from different places. Sometimes soil that has garbage carries germs that may be harmful to us.

First, collect samples of soils from different areas around your home and school. Then, guess what could be there in different soils. Next, observe carefully each soil sample and note its colour. Touch each soil sample and feel its texture. Observe the soil samples with your naked eye. If you have a magnifying lens, look at the soil through it. Record your observations in Table 11.2.

Now, let me help you understand what to look for. When you observe soil with your naked eye, you might see its colour, whether it is dark or light, brown or red. You might feel if it is sandy, clayey, or loamy. When you use a magnifying lens, you might see small particles, tiny insects, or plant roots.

Now, let me ask some questions. Is there any difference between your guess and what you can actually observe when you look closely? Yes, usually our guesses are different from what we actually see! Do you see any differences in the soil samples taken from different places? Yes, soil from different places can be different in colour, texture, and composition. Do you see differences in what you are able to observe with your naked eye and what you can observe with a magnifying lens? Yes, with a magnifying lens, we can see more details!

There are many things in the soil, such as sand, insects and worms. There may be many small organisms that we cannot see with our naked eyes. Plants and animals also become part of the soil as they decompose and decay. The soil samples collected from different places may be of different colours because they may contain different materials.

Have you ever wondered how soil is formed? Soil is formed by the disintegration, which means breaking apart, of rocks by actions of the Sun, water and living organisms over a long time, thousands of years. There are different types of soils. Some are good for growing certain types of plants while some are good for making bricks for buildings. Forests have a variety of soils. Soil is a precious treasure that supports biodiversity.

Now, let us learn about rocks. You may have seen rocks in your surroundings. Rocks are used in the construction of houses, buildings, temples, roads, dams and table tops. Some rocks, like slate, are used for roofing. Laterite can be used as a building material, like bricks. Some of the important rocks are granite, sandstone and marble. Human beings have been using rocks to make tools such as hand axes and arrowheads since thousands of years. In the olden days, people used stones to make knives, axes, and arrowheads for hunting and cutting.

Now, what are rocks made up of? They are made up of minerals. Important metals, such as aluminium, gold, copper and iron are extracted from minerals. Minerals are used in the manufacturing of airplanes, cars, jewellery, cosmetics, and electrical and electronic equipment. For example, the basic mobile phones that we use contain about a dozen minerals like gold, silver, copper, cobalt, and so on. So, minerals are very important for our daily lives!

Rocks play a vital role in our lives. It takes thousands to millions of years to form rocks. Therefore, it is important to conserve and them responsibly. Do you know how rocks and minerals are transported from one location to another? Most vehicles that we use for transportation use fossil fuels. Let us explore more about fossil fuels.

Now, let me recap what we have learned about soil, rocks, and minerals. Soil is formed from rocks over thousands of years. Soil contains many things like sand, insects, and decaying matter. Different soils have different colours and textures. Rocks are hard substances that are used in construction. Rocks are made up of minerals. Minerals are natural substances from which metals and other materials are extracted. Soil and rocks are non-renewable resources because they take a very long time to form.

## 11.6 Fossil Fuels

Now, let us learn about fossil fuels. Surya asks, "Why do different types of vehicles go to different filling stations?" The reason is that they use different types of fuels. For example, petrol and diesel.

Let us explore more about it by performing Activity 11.5. This activity is about conducting a survey of vehicles in your neighbourhood. First, conduct a survey of vehicles in your neighbourhood. Which types of vehicles are there? What types of fuels do they use? Record the information that you collect in Table 11.3.

Now, let me help you fill this table. Different types of vehicles use different fuels. Cars usually use petrol or diesel. Buses use diesel. Two-wheelers like scooters and motorcycles use petrol. Some vehicles use CNG, which is Compressed Natural Gas. Some vehicles now use electricity. So, the most common types of fuels used are petrol and diesel.

Now, what are the most common types of fuels used? Petrol and diesel are the two most widely used fuels for vehicles. Petrol, diesel and kerosene are obtained from petroleum. Petroleum along with natural gas and coal are commonly called fossil fuels. They are formed essentially from the remains of microorganisms and plants that got buried deep inside the earth, and were converted to petroleum, natural gas and coal. It takes millions of years for these fuels to form. That is why they are called fossil fuels — they are like fossils of ancient living things!

Natural gas is used for cooking and generating electricity. Nowadays, it is also used in the form of Compressed Natural Gas, which is CNG, as a fuel for vehicles. It is a cleaner fuel than petrol or diesel. Coal is mainly used for the production of electricity. It is found in several parts of India. The major coal-producing states in India are Jharkhand, Odisha, Chhattisgarh, West Bengal, and Madhya Pradesh.

Earlier, coal, wood and dung cakes were used as fuels for cooking. Nowadays, less polluting natural gas and Liquefied Petroleum Gas, which is LPG, have gradually replaced these domestic fuels.

Now, fossil fuels are found in limited quantities. Hence, we will soon run out of fossil fuels if we continue to use them in the manner that we currently do. To avoid such a situation, we need to explore alternate sources of energy. When fossil fuels are burnt, smoke and carbon dioxide gas are produced which pollutes the air. Over-dependence on fossil fuels for transportation and as domestic fuels has resulted in large scale air pollution.

Let us do our bit to conserve the fossil fuels by walking or cycling to nearby places, and using public transport. Can you suggest some more ways? We can carpool, use bicycles, use public transport like buses and trains, and switch to electric vehicles. We can also save electricity to reduce the need for coal-based power plants.

Now, let me recap what we have learned about fossil fuels. Fossil fuels are fuels like coal, petroleum, and natural gas that were formed from ancient plants and animals millions of years ago. They are non-renewable because they take millions of years to form and cannot be replaced quickly. Fossil fuels are used for transportation, cooking, and generating electricity. But they cause pollution and will run out one day, so we should use them wisely and find alternative sources of energy.

## 11.7 Natural Resources: Renewable and Non-renewable

Now, let us learn about natural resources and how they are classified. Nature's treasures fulfill our needs. They are essential resources to sustain all life forms on the Earth. For example, we get heat and light from the Sun, water from rivers, and food from plants and animals. These resources which we get from nature are called natural resources.

We also use natural resources to make many useful things for our convenience. For example, electric bulbs, furniture, solar panels, bicycles, and so on make our lives comfortable. All such resources created by human beings are called human-made resources.

You have learnt about various natural resources, such as air, water, energy from the Sun, forests, soil, rocks, minerals and fossil fuels. Now, let me tell you about an important classification of natural resources.

Some of these natural resources get replenished through natural processes over a period of time. If you remember, Ajji told Bhoomi and Surya that they could collect only those nellikai that had fallen on the ground. This makes sure that there would be enough fruits for other animals and birds. The seeds from the droppings of animals and birds would enable new trees to grow, though it would take some years before we get fruits from these new trees. Thus, resources which get renewed, replenished or restored within a reasonable period of time are called renewable resources. Air, water and forest are some of the examples of renewable natural resources. Nature renews them. We should use our natural resources judiciously.

On the other hand, fossil fuels take millions of years to form. They are found in limited quantities and once used, they get exhausted. They are not produced or replenished within a reasonable period of time. These resources are called non-renewable resources. Examples of non-renewable natural resources are minerals, soil, rocks, coal, petroleum and natural gas.

So, the key difference is that renewable resources can be replaced within a reasonable time, while non-renewable resources cannot be replaced quickly once they are used up.

Now, let me recap what we have learned about natural resources. Natural resources are resources provided by nature that we need for survival. They include air, water, sunlight, forests, soil, rocks, minerals, and fossil fuels. Natural resources can be classified as renewable and non-renewable. Renewable resources can be replenished naturally within a reasonable time, like air, water, and forests. Non-renewable resources cannot be replenished quickly, like coal, petroleum, and minerals.

## 11.8 Resources We Use

It is time for Bhoomi and Surya to go back home after a wonderful holiday at their Ajji's home. Their Amma, which means mother, comes to pick them up. Bhoomi and Surya show her the vegetable plants that have started to grow in the garden and the dried chillies given by Ajji to take home.

They notice changes in the colour of the skyline and the smell of the air once they reach the city. There are very few trees. The air does not smell as good as the air at Ajji's place. They can smell smoke from the vehicles. The air is polluted.

Amma says, "Yes. When we use fossil fuels in our vehicles, smoke is generated. Now, there are vehicles which cause less pollution. For example, there are electric vehicles that do not release any smoke. So, people are making an effort to create alternatives."

Can you list some alternatives for reducing air pollution? Some alternatives are using electric vehicles, using public transport, cycling, walking, using solar energy, and using cleaner fuels like CNG and LPG.

Now, let us do an activity to identify the natural resources we use in our daily lives. This is Activity 11.6. We need to make a list of activities we do in our daily life and write down the natural resources used directly or indirectly for each activity. In Table 11.4, some items are already filled in. Let me help you fill the remaining blank rows.

For washing clothes, the natural resource used is water. For making clay toys, the natural resource used is soil. For collecting firewood, the natural resource used is wood from trees. For making kites, the natural resource used is paper, which comes from trees. For having breakfast, the natural resources used are food from plants and animals, water, and air to breathe.

How many natural resources did you list? Compare your list with that of your friend. You and your friends have listed many natural resources that we use everyday. These resources are air, water, soil, and food from plants and animals. We get these resources from nature and also make things using them for our consumption. Therefore, we must conserve our natural resources and use them responsibly without wasting them. This way, we can continue to fulfill our present needs while also saving for the future, without harming the environment.

Now, let me share a famous quote with you. "Earth provides enough to satisfy every man's need but not for every man's greed." This is said by Mahatma Gandhi. This means that nature gives us enough to meet our needs, but not enough to satisfy our greed. So, we should use natural resources wisely and not waste them.

Now, let me recap what we have learned in this chapter. We have learned about air, water, energy from the Sun, forests, soil, rocks, minerals, and fossil fuels. We have learned that these are all natural resources. We have learned about renewable and non-renewable resources. We have learned how to conserve these resources and use them responsibly.

Now, let us move on to the exercises at the end of the chapter. I will solve each question for you step by step.

## Let us enhance our learning

Question 1: Fig. 11.9 shows items related to natural resources. Match them with their jumbled up names. Make another table and write the names of these resources. Classify these resources as renewable or non-renewable.

The jumbled up names are: ocrk, refost, ndiw, atwre.

Let me unscramble them. "ocrk" is rock. "refost" is forest. "ndiw" is wind. "atwre" is water.

Now, let me classify them as renewable or non-renewable. Rock is a non-renewable resource because it takes millions of years to form. Forest is a renewable resource because trees can grow back. Wind is a renewable resource because it is constantly produced by natural processes. Water is a renewable resource because it is part of the water cycle and gets renewed.

Question 2: State whether the following statements are True or False. If False, correct them.

(i) Nature has all the resources to meet human needs. This is True. Nature provides us with air, water, sunlight, forests, soil, minerals, and fossil fuels to meet our needs.

(ii) Machines are a resource found in nature. This is False. Machines are human-made resources, not natural resources. They are made by humans using natural resources.

(iii) Natural gas is a non-renewable resource. This is True. Natural gas takes millions of years to form and is found in limited quantities.

(iv) Air is a renewable resource. This is True. Air is constantly renewed by natural processes like photosynthesis and wind.

Question 3: Fill in the blanks using the most appropriate option.

(i) A fuel that is commonly used in two wheelers like scooters or bikes is petrol. The answer is (b) Petrol.

(ii) An example of a renewable resource is water. The answer is (b) Water. Coal, natural gas, and petrol are all non-renewable.

Question 4: Classify the following as renewable or non-renewable resources: coal, natural gas, forests, and minerals.

Coal is non-renewable. Natural gas is non-renewable. Forests are renewable. Minerals are non-renewable.

Question 5: Why do we say that petroleum is a non-renewable resource?

We say that petroleum is a non-renewable resource because it takes millions of years to form from the remains of ancient plants and animals buried deep inside the Earth. It is found in limited quantities and once used, it cannot be replaced within a reasonable period of time.

Question 6: It is difficult to regrow forests. Justify this statement.

It is difficult to regrow forests because trees take many years to grow to their full size. A forest has many different types of plants, animals, insects, and microorganisms that all work together in a complex ecosystem. Rebuilding such a diverse ecosystem takes a very long time, often decades or even centuries. Also, once the soil quality degrades due to deforestation, it becomes harder for new trees to grow. So, it is very important to protect existing forests rather than cutting them down and trying to regrow them.

Question 7: Make a list of five daily activities in which you use natural resources. Suggest ways by which you can reduce their use.

Five daily activities in which we use natural resources are: taking a shower, brushing teeth, washing clothes, using electricity, and traveling by car.

Ways to reduce their use: For taking a shower, we can take shorter showers and use a bucket instead of a running shower. For brushing teeth, we can turn off the tap while brushing and use a glass of water. For washing clothes, we can use a washing machine efficiently and reuse water for gardening. For using electricity, we can switch off lights and fans when not in use and use LED bulbs. For traveling by car, we can walk or cycle to nearby places, or use public transport.

Question 8: List four activities that are possible due to the presence of air.

Four activities that are possible due to the presence of air are: breathing, flying kites, sailing boats, and drying clothes in the wind. Also, windmills generate electricity, and birds can fly.

Question 9: How can you contribute towards enhancing the green cover of your locality? Make a list of actions to be taken.

We can contribute towards enhancing the green cover by: planting more trees in our school and neighborhood, taking care of existing trees by watering them and protecting them from being cut, participating in tree plantation drives like Van Mahotsav, encouraging our family and friends to plant trees, and avoiding the use of plastic bags that harm the environment.

Question 10: In the given illustration, we see that food is being cooked. Answer the following questions.

(i) What type of energy is being used for cooking? The type of energy being used for cooking could be solar energy if it is a solar cooker, or it could be heat energy from burning gas or firewood.

(ii) Name one benefit and one drawback of using this type of energy for cooking. If it is solar energy, one benefit is that it is clean and does not cause pollution. One drawback is that it cannot be used at night or on cloudy days. If it is gas or firewood, one benefit is that it is convenient and can be used anytime. One drawback is that it causes pollution and produces smoke.

Question 11: Cutting down trees on a large scale impacts the quality of the soil. Why do you think it is so?

Cutting down trees on a large scale impacts the quality of the soil because tree roots hold the soil together and prevent soil erosion. When trees are cut down, the soil becomes loose and can be washed away by rain. Also, the leaves that fall from trees decay and enrich the soil with nutrients. Without trees, the soil loses these nutrients and becomes less fertile. Additionally, trees help in absorbing rainwater and preventing floods. Without trees, the soil may become waterlogged or too dry.

Question 12: Explain two ways in which human activities pollute the air. Propose one action which can help in reducing air pollution.

Two ways in which human activities pollute the air are: burning fossil fuels in vehicles, which releases smoke and harmful gases like carbon monoxide and nitrogen oxides; and burning garbage or crop residues, which releases toxic fumes and particles into the air. Another way is emissions from factories and industries.

One action which can help in reducing air pollution is using public transport or cycling instead of private vehicles. This reduces the number of vehicles on the road and therefore reduces the amount of smoke released into the air. Another action is using clean energy sources like solar or wind energy instead of fossil fuels.

Question 13: A family uses solar panels to generate electricity, a gas stove to cook food and a windmill for pumping water from a well. What would happen if there were no sunlight for a week?

If there were no sunlight for a week, the solar panels would not generate electricity because they need sunlight to produce energy. The family would have to rely on other sources of electricity, like the grid or batteries. The gas stove would still work because it uses natural gas or LPG, which does not depend on sunlight. The windmill would still work if there is wind, but if there is no sunlight, there might be less wind as well. Also, without sunlight, plants would not be able to grow, so there would be a shortage of fresh food. The overall environment would become colder and darker. Life would be very difficult without sunlight!

Question 14: Fill up the blanks using the following terms: fossil fuels, forest, air, petroleum, coal, water and non-renewable resource.

Natural Resources: Air, water, forest, coal, petroleum, and fossil fuels are all natural resources.

Renewable Resources: Air, water, and forest are renewable resources.

Natural gas: This is a non-renewable resource.

Now, let me fill in the blanks properly. The question seems to be asking to classify the given terms. Let me do that:

Renewable Resources: Air, water, forest. Non-renewable Resources: Coal, petroleum, natural gas, fossil fuels.

Question 15: There is an increasing demand of trees to meet the requirements of industries and for housing. Therefore, trees are being felled. Is it justified? Discuss and prepare a brief report.

This is not justified because cutting trees on a large scale causes many problems. When trees are cut down, animals lose their homes and food. Soil erosion increases because tree roots hold the soil together. The air becomes polluted because trees help clean the air by absorbing carbon dioxide. The climate changes because trees help regulate the temperature. We should find a balance between meeting our needs and protecting the environment. We can use alternative materials, recycle paper, and plant more trees to compensate for the ones we cut. We should also use wood and other forest products wisely and not waste them.

Question 16: Propose a plan to use less water in your school. What steps would you take to make this plan happen and how would it help the environment?

A plan to use less water in school could include: fixing all leaking taps and pipes, using bucket and mug instead of running water for cleaning, collecting rainwater for gardening, using water-efficient appliances, and creating awareness among students about saving water.

Steps to make this plan happen: First, we would check all taps and pipes in the school and fix any leaks. Second, we would put up signs reminding students to turn off taps. Third, we would start a rainwater harvesting system. Fourth, we would teach students about the importance of water conservation in assemblies and classes.

How it would help the environment: Saving water reduces the strain on freshwater sources, helps preserve ecosystems, and reduces energy used in pumping and treating water. It also teaches students to be responsible citizens who care for the environment.

Now, let me also tell you about the Learning Further section. This section has some additional activities you can do to learn more.

First, Rainwater harvesting is an age-old practice in India. Find out some of the traditional rainwater harvesting techniques being used in your state or in other parts of the country. Some examples are Bawadis in Rajasthan, Vavs in Gujarat, and many other local practices.

Second, investigate the effect of air pollution on human health by interacting with your elders or community members and identify the main sources of air pollution in your local area. Based on your findings, suggest two practical steps that your school or community could take to help reduce air pollution.

Third, prepare a list of the names and uses of important minerals and rocks that are used in your village, town, or city for various purposes. For example, granite is used for building, marble is used for flooring, iron is used for making tools, and so on.

Fourth, you are an eco-club monitor. Organise a tree plantation drive in your school with the help of your teacher. List the steps required for organising this activity. Prepare a one-page report listing the names of the trees planted along with their importance. Some steps would be: getting permission from the principal, selecting a suitable location, choosing the right type of trees, arranging for saplings, involving students and teachers, planting the trees, and taking care of them afterwards.

Now, let me give you a complete summary of everything we have learned in this chapter.

## Summary

In this chapter, we have learned about the treasures of nature that are essential for our survival. Let me summarize all the key points:

Resources required for our survival are provided by nature. Resources provided by nature are called natural resources. Some important natural resources are air, water, energy from the Sun, forests, soil, rocks, minerals and fossil fuels.

Resources created by human beings to meet their needs are called human-made resources, like tables, chairs, books, and bicycles.

Natural resources can be classified as renewable resources and non-renewable resources. Resources that get renewed, replenished or restored by natural processes within a reasonable period are called renewable resources. These include air, water, and forests. Resources that are in limited quantities and do not get replenished within a reasonable period are called non-renewable resources. These include minerals, rocks, coal, petroleum, and natural gas.

We learned about air: Air is a mixture of gases, mainly nitrogen and oxygen. We need oxygen to breathe. Moving air is called wind, and wind can be used to generate electricity through windmills.

We learned about water: Water is essential for all living beings. Most of the Earth's water is in oceans and is salty. We need freshwater for drinking, cooking, and farming. We should conserve water and prevent water pollution. Rainwater harvesting is a traditional practice to conserve water.

We learned about energy from the Sun: The Sun is the main source of energy on Earth. Plants use sunlight to make food. We use solar energy for drying clothes, generating electricity, and cooking. Solar energy is a clean and renewable source of energy.

We learned about forests: Forests are large areas with many types of plants and animals. Forests provide us with fruits, wood, medicines, and many other products. Forests provide home to animals and help prevent soil erosion. We should protect forests and plant more trees. The Chipko movement is an example of people's efforts to protect forests.

We learned about soil, rocks, and minerals: Soil is formed from rocks over thousands of years. Soil contains many things that help plants grow. Rocks are used in construction. Rocks are made up of minerals. Minerals are used to extract metals and other materials.

We learned about fossil fuels: Fossil fuels like coal, petroleum, and natural gas were formed from ancient plants and animals millions of years ago. They are non-renewable and cause pollution when burned. We should use them wisely and find alternative sources of energy.

We learned about the importance of conserving natural resources. We should use natural resources judiciously without wasting them. We should walk or cycle to nearby places, use public transport, turn off taps and lights, and plant more trees. By conserving natural resources, we can fulfill our present needs while also saving for the future, without harming the environment.

Remember the words of Mahatma Gandhi: "Earth provides enough to satisfy every man's need but not for every man's greed." Let us all do our part to protect nature's treasures!

Thank you so much for listening to this lesson, my dear students. I hope you have learned a lot about nature's treasures and how to conserve them. Do practice the exercises and activities we discussed, and remember to be kind to our environment. See you next time!