NCERT Notes: Grade 9 Science - Chapter 14: Natural Resources

Introduction

Natural resources are nature’s gift to us. They play a pivotal role in supporting life and are critical for our sustenance. The judicious use and management of these resources will dictate the future of the next generations.

Classification of Natural Resources

Based on Availability:

1. Renewable Resources: Resources that can be replenished naturally within a short span, e.g., solar and wind energy.

2. Non-renewable Resources: Those that have a limited stock, once exhausted, can’t be replenished, e.g., coal, petroleum.

Based on Origin:

1. Biotic Resources: Derived from living beings and organic materials, e.g., forests, wildlife.

2. Abiotic Resources: Derived from non-living and non-organic material, e.g., water, air.

The Role of the Atmosphere

The atmosphere, a protective blanket of gases, plays an essential role in:

• Maintaining Earth’s temperature.

• Shielding Earth from harmful ultraviolet rays.

Composition of the Atmosphere:

1. Nitrogen (78%): Essential for protein synthesis in plants.

2. Oxygen (21%): Vital for the survival of most organisms.

3. Carbon Dioxide, Argon & Others (1%): Crucial for various ecological processes.

The Water Cycle

Water, essential for all forms of life, circulates between oceans, atmosphere, and land. The water cycle includes:

1. Evaporation: Conversion of water from liquid to vapor.

2. Condensation: Conversion of water vapor back into liquid form.

3. Precipitation: Rain, snow, sleet, or hail falling to the ground.

The Ocean Systems

Oceans cover 71% of Earth’s surface and act as a reservoir of water. They:

• Influence climate and weather patterns.

• Support a diverse range of marine life.

Marine Pollution:

With the rise in industrialization, pollutants get dumped into oceans, affecting marine life. Protecting oceans is vital for maintaining ecological balance.

Biogeochemical Cycles

Nature recycles resources in various biogeochemical cycles:

1. Carbon Cycle: Governs the flow of carbon in various forms.

2. Nitrogen Cycle: Ensures nitrogen availability and conversion in different forms.

3. Oxygen Cycle: Regulates the flow of oxygen through photosynthesis and respiration.

Soil - The Topmost Layer of Earth’s Crust

Soil, a mixture of rock particles, minerals, decayed organic material, water, and air, supports plant life. Soil formation depends on:

• Weathering of rocks.

• Decomposition of organic matter.

Types of Soil:

1. Alluvial: Rich in minerals, suitable for crops.

2. Black: Good for cotton cultivation.

3. Red & Yellow: Found in dry regions.

Soil Erosion:

Soil erosion, the removal of the top layer of soil, is primarily due to wind, water, or human activities. Conservation methods include afforestation, terrace farming, and contour plowing.

Conservation of Natural Resources

Over-exploitation of resources leads to their depletion. Conservation includes:

1. Judicious Use: Use resources sensibly without wastage.

2. Sustainable Development: Use resources in a way that they meet present needs without compromising the ability of future generations to meet their needs.

3. Recycling & Reusing: Minimize waste by recycling and reusing products.

Conclusion

Natural resources, whether renewable or non-renewable, are vital for the survival of life on Earth. It’s our collective responsibility to ensure they are preserved, protected, and used sustainably. Only then can we hope for a brighter, greener, and healthier future.

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Reference: NCERT Grade 9 Science - Chapter 14: Natural Resources

Note: This article is a summary and interpretation of Chapter 14 from the Science NCERT textbook for Grade 9. It’s recommended to refer to the original textbook for comprehensive details and understanding.