School vacations are always fun for Bhoomi and Surya. This vacation, they visit their Ajji (grandmother). Ajji lives in a village on the edge of a forest in the Western Ghats. The air in the village is fresh and cooler than in the city. 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 the place. Ajji 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 replies, "Ajji, we use water for drinking and growing vegetables." 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.
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."
- •Take a deep breath in, and then breathe out slowly.
- •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?
- •How do you feel when you hold your breath?
- •⚠️ Caution: Do not hold your breath for so long that you start feeling uncomfortable.
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. Thus, we need oxygen for our survival. Similarly, most of the living beings also need oxygen for their survival.
The air which surrounds the Earth is a mixture of gases. Air contains nitrogen, oxygen, argon, carbon dioxide and other gases in small quantities. The composition of air is approximately: Nitrogen 78%, Oxygen 21%, Argon, CO₂ and other gases 1%.
Fig. 11.1: Composition of Air
| Color | Gas | Percentage |
|---|---|---|
| Blue | Nitrogen | 78% |
| Red | Oxygen | 21% |
| Pink | Argon, carbon dioxide and other gases | 1% |
You notice the presence of air when the leaves of a tree rustle, the clothes hanging on a line sway, or the pages of an open book flutter when a fan is switched on. Moving air is called wind. Sometimes it blows fast (during a storm), and sometimes it blows gently as a breeze.
- •Take a square paper of size 15 cm × 15 cm, a pair of scissors, an all-pin and a soft stick.
- •Mark diagonal lines from corner to corner.
- •Use scissors to cut along the diagonal lines from the corners towards the center — but do NOT cut all the way to the center.
- •Fold every other corner tip towards the center point.
- •Secure the folded tips at the center with an all-pin and attach it to a soft stick.
- •Now hold the firki in your hand and run, or blow air on it. Does it rotate? What makes a firki rotate? It is the wind!
Bhoomi and Surya help Ajji fill the troughs of water for the cows and water plants in the garden. Ajji teaches them how to water plants so that every drop is used and none goes to waste. Water is used for many daily activities such as drinking, cooking, bathing, washing and cleaning. It is also used for growing crops and for industrial purposes.
Water covers about two-thirds of the Earth's surface. Most of the water is found in oceans and seas — however, this water is saline (salty) and not fit for domestic, agricultural and industrial use. For all these activities, we need freshwater, which is present in ice sheets or snow, rivers/lakes on the surface of the Earth, and underground. A very small fraction of 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.
- •Fill Column II and Column III in Table 11.1 to identify how water is wasted in daily activities and how this wastage can be reduced.
- •What conclusion can you draw from the information you gathered?
- •What can you and your family do to reduce wastage of water?
- •There are many ways to reduce wastage — for example, turning off taps when not in use, fixing water leakages, recycling water, and rainwater harvesting.
Table 11.1: Wastage of water in your daily activities
| Activity | How is water wasted? | Suggest ways to reduce wastage of water |
|---|---|---|
| 1. Hand washing | ||
| 2. Washing clothes | ||
| 3. Washing utensils | ||
| 4. Taking shower | ||
| 5. Cooking | ||
| 6. Gardening | ||
| 7. Brushing teeth |
Stepwells (commonly known as Bawadi in Rajasthan and Vav in Gujarat) are built for water harvesting. They store not only rainwater but also water seeping from nearby lakes, ponds and rivers. The walls of the trenches are lined with blocks of stones that allow seepage of water.
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. 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 — for plants to make food, drying clothes, cooking in solar cookers, heating water in solar water heaters, and generating electricity through solar panels.
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.
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.
One morning, Ajji takes Bhoomi and Surya for a walk in the forest. Ajji explains, "Forests are large areas with dense growth of various types of plants." On the way, they collect some nellikai (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."
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.
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."
Bhoomi, Surya and Ajji come back home. They help Ajji prepare the soil in the garden for planting vegetables (Fig. 11.5). They dig the soil gently and loosen the lumps. They could see small pebbles, roots of plants and earthworms in the soil. Earthworms are natural agents that help in turning and loosening the 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.
- •Collect samples of soils from different areas around your home and school.
- •Guess what could be in each soil sample.
- •Observe each soil sample carefully 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.
- •Is there any difference between your guess and what you actually observe? Do you see differences between soil samples from different places? Do you see differences between observation with naked eye and with magnifying lens?
Table 11.2: Soil samples
| Location from which soil sample was collected | What I guessed about the soil? | Observation (colour and texture) with naked eye | Observation with magnifying lens |
|---|---|---|---|
Rocks are made up of minerals. Important metals such as aluminium, gold, copper and iron are extracted from minerals. Minerals are used in manufacturing of airplanes, cars, jewellery, cosmetics, and electrical and electronic equipment. For example, basic mobile phones contain about a dozen minerals like gold, silver, copper, cobalt, etc.
It takes thousands to millions of years to form rocks, so it is important to conserve and use them responsibly.
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.
- •Conduct a survey of vehicles in your neighbourhood.
- •Which types of vehicles are there? What types of fuels do they use?
- •Record the information you collect in Table 11.3.
- •What are the most common types of fuels used?
Table 11.3: Types of vehicles and fuels used
| Type of vehicle | Type of fuel used |
|---|---|
Coal: Mainly used for the production of electricity. Found in several parts of India.
Petroleum: Petrol, diesel and kerosene are obtained from petroleum. Used for vehicles and for lighting/cooking.
Fossil fuels are found in limited quantities. When burnt, they produce smoke and carbon dioxide, polluting the air. Over-dependence on fossil fuels has resulted in large-scale air pollution.
Resources created by human beings to meet their needs are called human-made resources — e.g., electric bulbs, furniture, solar panels, bicycles.
Ajji told Bhoomi and Surya to collect only those nellikai that had fallen on the ground — ensuring enough fruits remain for animals and birds, whose droppings would enable new trees to grow. Nature renews these resources. We should use them judiciously.
It is time for Bhoomi and Surya to go back home after a wonderful holiday at their Ajji's home. As they enter the city, they notice changes in the colour of the skyline and the smell of the air. There are very few trees. They can smell smoke from the vehicles. Amma (mother) says, "When we use fossil fuels in our vehicles, smoke is generated. Now, there are vehicles which cause less pollution — for example, electric vehicles that do not release any smoke. So, people are making an effort to create alternatives."
- •Make a list of activities you do in your daily life and write down the natural resources that were used directly or indirectly for each activity.
- •In Table 11.4, some items are already filled in — use them as a guide to fill the remaining blank rows.
- •How many natural resources did you list? Compare your list with that of your friend.
- •We must conserve our natural resources and use them responsibly without wasting them. This way, we can continue to fulfill our present needs while saving for the future.
Table 11.4: Natural resources used
| Activity | Natural resource |
|---|---|
| Washing clothes | Water |
| Making clay toys | |
| Collecting firewood | |
| Making kites | |
| Having breakfast | |
Keywords
- 1Resources required for our survival are provided by nature.
- 2Resources provided by nature are called natural resources.
- 3Some important natural resources are air, water, energy from the Sun, forests, soil, rocks, minerals and fossil fuels.
- 4Resources created by human beings to meet their needs are called human-made resources.
- 5Natural resources can be classified as renewable resources and non-renewable resources.
- 6Resources that get renewed, replenished or restored by natural processes within a reasonable period are called renewable resources.
- 7Resources that are in limited quantities and do not get replenished within a reasonable period are called non-renewable resources.
- 8All living beings, including humans, depend on natural resources for their survival so we should use them judiciously.
- 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.
- 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.
- Prepare a list of the names and uses of important minerals and rocks that are used in your village/town/city for various purposes.
- 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.
