Grade 6 Chapter 1: Natural Resources – Air, Water and Land

Introduction

In this chapter, we will learn about the essential components of our environment that support life: air, water, and land. These are called natural resources because they come from nature and are crucial for all living things. We will explore their composition, importance, various uses, and the serious problem of pollution. Finally, we will understand why it is vital to conserve these precious resources for a healthy planet.

Key topics covered:

• What are Natural Resources?
• Air: Composition, Importance, and Uses
• Water: Distribution, Importance, and Water Cycle
• Land: Importance, Landforms, and Soil Layers
• Pollution of Natural Resources (Air, Water, Land)
• Conservation of Natural Resources

Air: The Blanket of Gases

Air is a mixture of various gases that surrounds the Earth, forming its atmosphere. This blanket of air is vital for the survival of all living organisms.

Composition of Air

Air is primarily composed of:

• Nitrogen ($\text{N}_2$): Approximately 78%
• Oxygen ($\text{O}_2$): Approximately 21%
• Argon (Ar): Approximately 0.9%
• Carbon Dioxide ($\text{CO}_2$): Approximately 0.03%
• Other gases (Neon, Helium, Krypton, Xenon, Methane, etc.), water vapor, and dust particles make up the remaining percentage.

Importance and Uses of Air Components

• Oxygen: Essential for respiration in all living beings (animals and plants). Also used in combustion (burning).
• Nitrogen: Used by plants for protein synthesis through nitrogen fixation. Important component in fertilizers.
• Carbon Dioxide: Used by plants for photosynthesis (making their own food). Used in fire extinguishers.
• Argon: Used in electric bulbs to prevent the filament from burning out quickly.
• Helium and Neon: Used in decorative lights and advertising signs due to their glow when electricity passes through them. Helium is also used in balloons and airships.
• Ozone Layer ($\text{O}_3$): Formed in the stratosphere, this layer absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth from skin cancer, cataracts, and other damages.

Water: The Elixir of Life

Water is one of the most abundant and essential natural resources. It covers about 71% of the Earth's surface.

Distribution of Water on Earth

• Oceans and Seas: Approximately 97% of the Earth's water is saline (salty) water found in oceans and seas. This water is not suitable for drinking or agriculture directly.
• Freshwater: Only about 3% of the Earth's water is freshwater.
  • Most freshwater is trapped as ice in glaciers and ice caps (about 2%).
  • Groundwater (water found beneath the Earth's surface in aquifers) and river/lake water (surface water) make up the remaining small percentage (less than 1%).

Importance and Uses of Water

Water is indispensable for life and human activities:

• Drinking and Domestic Use: Essential for human survival, cooking, bathing, and cleaning.
• Agriculture: Used for irrigation to grow crops, supporting food production.
• Industry: Used as a raw material, coolant, and solvent in various industries.
• Transportation: Rivers, lakes, and oceans are used for transport (boats, ships).
• Energy Generation: Used in hydroelectric power plants to generate electricity.
• Habitat: Provides a habitat for aquatic plants and animals.

The Water Cycle

Water on Earth continuously moves through a cycle, ensuring its availability:

1. Evaporation: Water from oceans, rivers, lakes, and soil turns into water vapor due to heat from the sun and rises into the atmosphere.
2. Condensation: As water vapor rises, it cools down and changes back into tiny water droplets, forming clouds.
3. Precipitation: When clouds become heavy with water droplets, water falls back to Earth as rain, snow, sleet, or hail.
4. Collection: This precipitation collects in oceans, rivers, lakes, and seeps into the ground to become groundwater, completing the cycle.

Land: The Solid Foundation

Land is the solid surface of the Earth that is not covered by water. It provides the base for all terrestrial life and human activities.

Importance of Land

• Living Space: Provides space for humans, animals, and plants to live.
• Agriculture: Used for farming and cultivation of crops.
• Minerals and Resources: Source of valuable minerals (e.g., iron, coal, gold), oil, and natural gas.
• Forests: Supports forests that provide timber, food, and habitat for wildlife.
• Industries and Infrastructure: Used for building factories, roads, railways, and cities.

Landforms

Land exists in various forms:

• Mountains: High, rocky landforms.
• Plateaus: Elevated flat lands.
• Plains: Flat and low-lying areas, often fertile for agriculture.
• Deserts: Dry regions with sparse vegetation.
• Valleys: Low areas between hills or mountains.

Soil Layers (Soil Profile)

Soil is the uppermost layer of the land, formed by the weathering of rocks and decomposition of organic matter. It is crucial for plant growth. A typical soil profile shows different layers:

1. Humus: The topmost layer, rich in decomposed organic matter (dead leaves, plants, animals). It is dark in color and makes the soil fertile.
2. Topsoil: Below humus, it is rich in minerals and nutrients. Most plant roots grow in this layer.
3. Subsoil: Contains less organic matter but more minerals, clay, and weathered rock particles.
4. Weathered Rock: Layer of partially broken down rock fragments.
5. Bedrock: The solid, unweathered parent rock below all other layers.

Pollution of Natural Resources

Human activities often lead to the contamination of natural resources, making them harmful for living beings. This is known as pollution.

Air Pollution

Introduction of harmful substances into the atmosphere, causing adverse effects on living organisms and the environment.

• Causes: Smoke from factories and vehicles, burning of fossil fuels (coal, petroleum), deforestation, agricultural burning.
• Effects: Respiratory problems (asthma, bronchitis), acid rain, global warming, damage to ozone layer, reduced visibility.

Water Pollution

Contamination of water bodies like rivers, lakes, oceans, and groundwater.

• Causes: Discharge of untreated sewage, industrial waste, agricultural runoff (pesticides, fertilizers), oil spills, dumping of garbage.
• Effects: Spread of water-borne diseases (cholera, typhoid), harm to aquatic life, destruction of ecosystems, scarcity of clean drinking water.

Land Pollution (Soil Pollution)

Contamination of soil by harmful substances, leading to reduced fertility and health risks.

• Causes: Dumping of solid waste (plastics, e-waste), excessive use of chemical fertilizers and pesticides, industrial waste, deforestation.
• Effects: Loss of soil fertility, contamination of groundwater, harm to soil organisms, reduced agricultural yield, health problems from contaminated food.

Conservation of Natural Resources

To ensure a sustainable future, it is crucial to protect and use our natural resources wisely. Conservation means using resources carefully so they are not wasted and remain available for future generations.

Measures for Conservation

• Reduce, Reuse, Recycle: Minimize waste, reuse items, and recycle materials like paper, plastic, and metal.
• Tree Plantation: Plant more trees (afforestation) to improve air quality, prevent soil erosion, and support biodiversity.
• Water Conservation: Save water by fixing leaks, using water-efficient appliances, practicing rainwater harvesting, and avoiding unnecessary water use.
• Control Pollution: Implement strict laws against industrial pollution, encourage public transport, use renewable energy sources (solar, wind), and properly dispose of waste.
• Sustainable Farming: Use organic farming methods, avoid excessive use of chemical fertilizers and pesticides.
• Awareness: Educate people about the importance of natural resources and the need for their conservation.