Chapter 11: Nature's Treasures

11.1 Air

Air is a mixture of gases surrounding the Earth.
Composition of Air: Nitrogen (78%), Oxygen (21%), and Argon, carbon dioxide, and other gases (1%).
Oxygen: Essential for the survival of most living beings to perform bodily functions.
Wind: Moving air. High-speed wind is called a storm, while gentle wind is a breeze.
Windmills: Devices that use wind energy to generate electricity, pump water, or run flour mills. Large clusters of these are called windmill farms (e.g., Muppandal in Tamil Nadu, Jaisalmer in Rajasthan).

11.2 Water

Water covers about two-thirds of the Earth's surface, but most of it is saline (salty) ocean water, unfit for domestic or agricultural use.
Freshwater: Found in ice sheets, glaciers, rivers, lakes, and underground. Only a very small fraction is easily accessible.
Rainwater harvesting: The practice of collecting and storing rainwater for future use.
Traditional Water Harvesting: Age-old structures like stepwells, known as Bawadi in Rajasthan and Vav in Gujarat, store rainwater and seepage water.

11.3 Energy from the Sun

The Sun is the primary source of heat and light energy for all living organisms on Earth.
Plants use sunlight to prepare food, which in turn sustains animals.
Solar Panels: Capture solar energy to generate electricity.
Direct uses of solar energy include solar cookers and solar water heaters.

11.4 Forests

Forests: Large areas with dense growth of various types of plants, providing food and shelter to wildlife.
Van Mahotsav: A week-long forest festival celebrated in July across India to plant trees and raise awareness.
Chipko Movement: A famous forest conservation movement started in the early 1970s in Uttarakhand, where local women hugged trees to protect them from being felled.

11.5 Soil, Rocks and Minerals

Soil: Formed by the disintegration (breaking apart) of rocks by the action of the Sun, water, wind, and living organisms over thousands of years.
Rocks: Used in construction (e.g., slate for roofing, laterite for bricks, granite, sandstone, and marble).
Minerals: Naturally occurring substances from which important metals like aluminium, gold, copper, and iron are extracted.

11.6 Fossil Fuels

Fossil Fuels: Coal, petroleum, and natural gas. Formed from the buried remains of ancient plants and microorganisms over millions of years.
Petroleum: Refined to obtain petrol, diesel, and kerosene.
CNG (Compressed Natural Gas): A cleaner alternative fuel for vehicles compared to petrol or diesel.
LPG (Liquefied Petroleum Gas): Commonly used as a domestic cooking fuel, replacing highly polluting fuels like wood and coal.

11.7 Natural Resources: Renewable and Non-renewable

Natural Resources: Resources obtained directly from nature (air, water, sunlight, forests, soil, minerals).
Human-made Resources: Useful items created by humans using natural resources (bicycles, buildings, solar panels).
Renewable Resources: Resources that get replenished or restored naturally within a reasonable period (e.g., solar energy, wind, water, forests).
Non-renewable Resources: Resources that exist in limited quantities and take millions of years to form, getting exhausted with use (e.g., fossil fuels, minerals, rocks).

Let us enhance our learning

True or False:
- Nature has all the resources to meet human needs. (True - for needs, but not for greed)
- Machines are a resource found in nature. (False - they are human-made)
- Natural gas is a non-renewable resource. (True)
- Air is a renewable resource. (True)
Multiple Choice:
- A fuel commonly used in two-wheelers is: Petrol
- An example of a renewable resource is: Water
Key Concept: "Earth provides enough to satisfy every man's need but not for every man's greed." – M. K. Gandhi