Nature’s TreasuresClass 6 Science Notes

Nature's Treasures

Nature provides several treasures that enrich our lives and are essential for our survival and comfort. These natural resources include pure air, fertile soil, plenty of sunlight, various trees, and water. Without these, life on Earth would not be possible.

Air

Air is essential for our survival. We take deep breaths to get fresh air into our lungs to stay healthy. The air we breathe in contains oxygen, which our body needs to perform its functions. It is difficult to hold our breath for a long time because the body does not get enough oxygen. Most living beings also need oxygen for their survival. While we can survive without food or water for a few days, we cannot survive without oxygen for even a few minutes.

The composition of air in percentage is:

• Nitrogen: $78\%$
• Oxygen: $21\%$
• Argon, Carbon Dioxide, and other gases: $1\%$

We can observe the presence of air when leaves rustle, clothes sway on a line, or pages of a book flutter when a fan is switched on.

Moving air is called wind. Wind can blow fast, like during a storm, or gently, as a breeze. Wind can be used to make a paper pinwheel (firki) rotate. Similarly, the working of a windmill is based on wind rotating its wings. Windmills are used to run flour mills, pull water from wells, or generate electricity. Areas with many windmills for electricity generation are called windmill farms.

Water

Water is another essential and precious natural resource. We need water for many daily activities, such as drinking, cooking, bathing, washing, and cleaning. It is also used for growing crops and for industrial purposes.

Most of the Earth's surface (about two-thirds) is covered by water, primarily in oceans and seas. However, this water is saline (salty) and not suitable for domestic, agricultural, or industrial use. We need freshwater, which is found as ice sheets, snow, rivers, lakes, and underground. Freshwater in ice sheets, snow, or underground is difficult to access. Only a very small fraction of freshwater in ponds, rivers, lakes, and wells is easily accessible.

It is important to use water with care and reduce its wastage. Ways to reduce water wastage include:

• Turning off taps when not in use.
• Fixing water leakages.
• Recycling water.
• Water harvesting.

Human activities often lead to water pollution. Throwing trash (plastic bags, wrappers, waste materials) from homes and industries into freshwater sources pollutes them. Polluted water is not fit for consumption by living beings.

Rainwater harvesting is a method for conserving water where rainwater is collected and stored for later use. This is an age-old practice in India. For example, stepwells (known as Bawadi in Rajasthan and Vav in Gujarat) are traditional water harvesting systems. They store rainwater and water seeping from nearby lakes, ponds, and rivers, with stone-lined trenches allowing water seepage.

Energy from the Sun

The Sun is the main source of energy on Earth, and all plants and animals are dependent on it. We use both heat and light from the Sun for various purposes.

Uses of heat and light from the Sun include:

• Drying things (e.g., chillies, clothes).
• Plants use sunlight to prepare their food through photosynthesis.
• Providing warmth to living beings.

Solar energy can be harnessed for various uses:

• Solar panels on rooftops, street lights, or traffic signals capture the Sun's energy to produce electricity.
• Solar cookers use direct solar energy for cooking.
• Solar water heaters use solar energy to heat water.

Life on Earth is unimaginable without the Sun. Plants derive energy from the Sun to produce food, which is then consumed by animals, and humans get food from both plants and animals. This entire cycle is sustained by the Sun's energy.

Forests

Forests are large areas characterized by a dense growth of various types of plants, including herbs, shrubs, and trees. They are a significant treasure of nature.

Forests provide:

• Food and shelter for many wild animals, birds, and insects.
• Various products that humans use.

In nature, every animal depends on other life forms for survival, and the diversity of life forms in forests ensures food for all. However, human activities, particularly large-scale cutting of trees, have led to a decrease in forest cover. Growing a new forest or restoring lost ones takes many years. Therefore, it is crucial to preserve and use forests responsibly, allowing them enough time to regenerate.

India has a long tradition of respecting, protecting, and preserving forests. The Chipko movement, which started in the early 1970s in Uttarakhand, is a famous example of common people's efforts to save forests. Local women actively participated by encircling and hugging trees to prevent them from being felled.

Forests also play a vital role in soil health. The roots of plants hold onto the soil, preventing soil erosion (being washed away). Additionally, leaves that fall from trees decay and enrich the soil with nutrients, which are then utilized by new plants and trees, demonstrating a natural recycling process.

Soil, Rocks and Minerals

Soil is a precious natural treasure that supports biodiversity. It is essential for plants to grow, as the space between soil particles provides sufficient air and room for roots to expand. Soil contains small pebbles, plant roots, and organisms like earthworms, which are natural agents that help in turning and loosening the soil.

There are different types of soils, some suitable for growing specific plants, while others are used for making bricks. Soil samples from various places can differ in color and texture due to different materials present.

Rocks are natural materials found in the Earth's crust. They are used extensively by humans for:

• Construction: Houses, buildings, temples, roads, dams, table tops.
• Specific uses: Slate for roofing, laterite as building bricks.
• Tools: Ancient humans used rocks like hand axes and arrowheads.

Examples of important rocks include granite, sandstone, and marble.

Rocks are made up of minerals. Minerals are naturally occurring solid substances with a definite chemical composition. Important metals like aluminium, gold, copper, and iron are extracted from minerals. Minerals are crucial for manufacturing various products, including:

• Airplanes
• Cars
• Jewellery
• Cosmetics
• Electrical and electronic equipment (e.g., mobile phones contain minerals like gold, silver, copper, cobalt).

Since rocks and minerals take thousands to millions of years to form, it is important to conserve and use them responsibly.

Fossil Fuels

Fossil fuels are natural resources that provide energy. Common fossil fuels include petroleum, natural gas, and coal.

• Petroleum is the source of fuels like petrol, diesel, and kerosene, widely used for vehicles.
• Natural gas is used for cooking, generating electricity, and as Compressed Natural Gas (CNG) for vehicles, being a cleaner fuel than petrol or diesel.
• Coal is primarily used for generating electricity and is found in several parts of India.

Fossil fuels are formed over millions of years from the remains of microorganisms and plants that were buried deep inside the Earth.

Burning fossil fuels produces smoke and carbon dioxide gas, leading to air pollution. Over-dependence on fossil fuels for transportation and domestic use has caused large-scale air pollution.

To conserve fossil fuels and reduce pollution, we can:

• Walk or cycle to nearby places.
• Use public transport.
• Explore alternate sources of energy.

Natural Resources: Renewable and Non-renewable

Nature's treasures are essential resources that sustain all life forms on Earth. These resources, which we get directly from nature, are called natural resources (e.g., air, water, energy from the Sun, forests, soil, rocks, minerals, fossil fuels). Resources created by human beings for convenience (e.g., electric bulbs, furniture, solar panels, bicycles) are called human-made resources.

Natural resources can be classified into two main types:

1. Renewable Resources: These are resources that get renewed, replenished, or restored through natural processes within a reasonable period of time.

   • Examples: Air, water, forests, energy from the Sun.
   • Nature constantly renews these resources, but they must still be used judiciously to ensure their availability for the future. For example, allowing fallen fruits to remain for animals helps in seed dispersal and new tree growth.

2. Non-renewable Resources: These are resources found in limited quantities and take millions of years to form. Once used, they get exhausted and are not produced or replenished within a reasonable period of time.

   • Examples: Minerals, soil, rocks, coal, petroleum, natural gas (all fossil fuels).
   • These resources must be conserved and used responsibly due to their finite nature and extremely slow formation rate.

All living beings, including humans, depend on natural resources for survival. Therefore, we must use them judiciously.

Resources We Use

We use many natural resources in our everyday life. For example, washing clothes uses water, making clay toys uses soil, collecting firewood uses wood from forests, making kites uses paper (from trees), and having breakfast uses food from plants and animals, and water.

The difference in environments, such as a village on the edge of a forest versus a city, highlights the impact of human activities on natural resources. Cities often have fewer trees and polluted air due to smoke from vehicles, which burn fossil fuels. Efforts are being made to find alternatives, such as electric vehicles that cause less pollution.

It is crucial to conserve natural resources and use them responsibly without wasting them. This approach allows us to fulfill our present needs while safeguarding resources for future generations and protecting the environment. As M. K. Gandhi said, "Earth provides enough to satisfy every man's need but not for every man's greed."

Keywords

• Natural resources: Resources required for our survival and provided by nature.
• Human-made resources: Resources created by human beings to meet their needs.
• Renewable resources: Resources that get renewed, replenished, or restored by natural processes within a reasonable period.
• Non-renewable resources: Resources that are in limited quantities and do not get replenished within a reasonable period.
• Air: A mixture of gases surrounding Earth, essential for life.
• Water: Essential for survival and daily activities.
• Energy from the Sun: Main source of energy on Earth, providing heat and light.
• Forests: Large areas with dense plant growth, providing food and shelter for wildlife.
• Soil: Formed from disintegrated rocks, supports plant growth and biodiversity.
• Rocks: Natural materials used in construction and tools, made of minerals.
• Minerals: Components of rocks, source of metals, used in manufacturing.
• Fossil fuels: Non-renewable resources like coal, petroleum, and natural gas, formed over millions of years from organic remains.