Earth’s Water & Land Distribution: The Blue Planet

🌏 Introduction

From space, our Earth looks blue. This blue colour is not because of the atmosphere or clouds, but because nearly 71% of Earth is covered with water. The remaining 29% is land. Water appears as one continuous mass—the oceans—while land appears as large blocks called continents. Understanding how land and water are distributed helps us understand climate, rainfall, agriculture, settlement patterns, transportation routes, biodiversity, and even human history.

In this topic, we will explore why the Earth is called the Blue Planet, how oceans and continents are unevenly spread across the Northern and Southern Hemispheres, and why this unevenness matters for life. This understanding forms the base for later learning about oceans, continents, islands, climate, monsoons and disasters.

Practice MCQs

This MCQ module is based on: Earth’s Water & Land Distribution: The Blue Planet

This assessment will be based on: Earth’s Water & Land Distribution: The Blue Planet

🔸 Concept Notes / Theory

🔹 Earth — The Blue Planet

  • When astronauts first saw Earth from space, they called it the Blue Planet, because most of what they saw was water.
  • Water bodies appear blue, while land appears brown.

Name given to Earth because ¾ of its surface is covered with water.

🔹 Distribution of Water and Land on Earth

Component

Approx. % of Earth’s Surface

Colour on globe

Water (Oceans + seas + bays + gulfs)

~71%

Blue

Land (continents + islands + mountains + deserts)

~29%

Brown


  • Water is continuous — oceans are connected to each other.
  • Land is not continuous — it is broken into continents.

🔹 Water vs Land in Hemispheres

states that water and land are not evenly distributed. Using a globe:

Hemisphere

Dominant Feature

Key Understanding

Northern Hemisphere

More land

Called Land Hemisphere

Southern Hemisphere

More water

Called Water Hemisphere

When you look at the globe from the South Pole, you see mostly water.

This unequal distribution affects:

  • climate zones
  • wind patterns
  • rainfall
  • ocean currents

🔹 Why doesn’t Earth run out of water?

Because of the water cycle:

  • Oceans → evaporation → clouds → rain → rivers → oceans

However, most ocean water is salty, and cannot be used directly for drinking or farming.

🔹 Freshwater vs Saltwater

Type of Water

% Share on Earth

Found In

Saltwater

97%

Oceans

Freshwater

3%

Rivers, lakes, glaciers, underground water

Key Insight:
 Only 0.5% of freshwater is usable. The rest is locked in ice caps and glaciers.

🧠Think & Connect / Did You Know

✅ DID YOU KNOW?

  • If the whole Earth’s water were stored in a 1-litre bottle, only half a teaspoon of it would be usable freshwater.

✅ THINK & CONNECT

Why do cities with nearby oceans (e.g., Mumbai, Chennai, Kochi) have humid climates, while places far from water (e.g., Rajasthan) are dry?

Discuss: How does proximity to large water bodies influence weather?

🧩Questions – distribution of land and water

✅ MCQs

  1. Earth appears blue from space mainly because:
    • (a) It reflects blue light
    • (b) It is covered mostly by water ✅
    • (c) It has a blue atmosphere
  2. Which hemisphere has more land?
    • (a) Northern ✅
    • (b) Southern
    • (c) Both are equal

✅ Match the Following

Column A

Column B

71%

Water surface

29%

Land surface

Blue Planet

Earth

Freshwater

Glaciers, rivers, groundwater

✅ Cause & Effect

Cause

Effect

Only 3% of Earth’s water is freshwater

Water scarcity exists despite abundant water

✅ Relation Type

Earth : Blue Planet :: Northern Hemisphere : ________
 → Land Hemisphere

✅ Short Analytical Question

If most of Earth’s water cannot be used for drinking, why does water scarcity occur?

🌱 Olympiad Focus

🌊 Cross-disciplinary reasoning

  • More water in Southern Hemisphere → stable temperatures & less seasonal variation
  • More land in Northern Hemisphere → greater differences in summers/winters

Example HOTS Question (integrates geography + climate science + logic):

Q: If continents absorb heat faster than oceans, which hemisphere would heat up faster and why?

✅ Expected: Northern Hemisphere, because land heats and cools faster than water.

🔍 Summary Points

  • Earth appears blue because water covers ~71% of its surface.
  • Land covers ~29%, broken into continents & islands.
  • Northern Hemisphere → more land, Southern Hemisphere → more water.
  • Oceans are continuous; land is broken.
  • All freshwater is not usable → water scarcity exists.
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