Nature’s Treasures

Class 06 Science

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.

Air

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 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.

Moving air is called wind. Sometimes it blows fast, for example, during a storm, and sometimes it blows gently as a breeze. 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.

Water

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 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.

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 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.

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. It is an age-old practice in India. For example, step wells, 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 step wells 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 (long deep holes dug in the ground) are lined with blocks of stones that allow seepage of water.

Energy from the Sun

Sunlight helps plants prepare food. The Sun also provides all the living beings on Earth with heat and light. 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.

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.

Forests

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.

Soil, Rocks and Minerals

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.

Soil is formed by the disintegration (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.

Rocks are used in the construction of houses, buildings, temples, roads, dams and table tops. Some rocks, like slate, are used for roofing and laterite can be used as a building material, like bricks. Some of the important rocks are granite, sandstone and marble.

Rocks 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.

Fossil Fuels

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.

Natural gas is used for cooking and generating electricity. Nowadays, it is also used in the form of Compressed Natural Gas (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.

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.

Natural Resources: Renewable and Non-renewable

The 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, etc., make lives comfortable. All such resources created by human beings are called human-made resources.

Some of these natural resources get replenished through natural processes over a period of time. 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.

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.