Notes For All Chapters – General Science Class 6
Natural Resources – Air, Water and Land
1. What are Natural Resources?
- Natural resources are things we get from nature.
- The three main natural resources are air, water, and land.
- These resources are very important for all living things.
2. The Earth’s Spheres
Our Earth has three main parts:
Atmosphere – The layer of air around the Earth.
Hydrosphere – All the water on Earth (seas, rivers, lakes, etc.).
Lithosphere – The land on Earth (soil, mountains, rocks, etc.).
Biosphere – All living things on Earth.
3. Air (Atmosphere)
Air is a mixture of different gases.
The main gases in air are:
Nitrogen (78%) – Helps plants grow.
Oxygen (21%) – Needed for breathing and burning.
Carbon Dioxide (0.03%) – Plants use it to make food.
Other gases – Argon, Helium, Neon, Krypton, Xenon.
Ozone Layer
The ozone layer in the atmosphere protects us from harmful ultraviolet rays of the Sun.
Some gases from factories and refrigerators damage the ozone layer.
Air Pollution
Air gets polluted by smoke from vehicles, factories, and burning fuels like coal and wood.
Air pollution causes health problems like breathing issues.
4. Water (Hydrosphere)
Water covers 71% of the Earth’s surface.
Freshwater is only 2.7% of all the water on Earth.
Water is found in oceans, rivers, lakes, ponds, and underground.
We use water for drinking, cooking, farming, and cleaning.
Why is Seawater Salty?
Seawater is salty because it has dissolved minerals.
Even though we cannot drink seawater, it is useful for fishing, transport, and making salt.
Water Shortage
People waste a lot of water, and fresh water is limited.
To save water, we should:
- Use water carefully.
- Store rainwater.
- Reuse water when possible.
5. Land (Lithosphere)
Land is made up of soil, rocks, and minerals.
We use land for:
- Building houses.
- Farming.
- Making roads and factories.
Soil is formed over thousands of years when rocks break down due to wind, rain, and heat.
Layers of Soil
- Humus – The top layer with dead plants and animals (makes soil fertile).
- Soil – Has small rocks and minerals.
- Bedrock – Hard rock deep underground.
How to Protect Soil?
Trees help stop soil erosion.
We should not cut too many trees.
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