Chapter 2 – Oceans and Continents

Chapter 2 – Oceans and Continents

 

1. Earth: A Unique Planet

 

• Our earth is a  unique planet because it is the only planet where life is possible.
• This is because proper temperature, water, air, and land exist on earth, which are essential for life.
• About 71%  of the Earth’s surface is covered with water and about 29% is covered by land.
• Earth is  also called  the Blue Planet.

 Continents

• Large tracts of land on earth are  called  continents.
• There are seven major continents on Earth. These are separated from each other by large water bodies.
• They vary in size and may be related to each other (e.g. Europe and Asia).

 Seven Continents

1. Asia :

• It is the largest continent .
• It covers about one-third of the total land area of the Earth.
• It is located in the Eastern Hemisphere.
• Europe and Asia together are called Eurasia (separated by the Ural Mountains and the Ural River).

 

1. Europe :

• It is a very **small continent** from Asia.
• It is located in the west of Asia.
• It passes through the Arctic Circle.

 

iii. Africa :

• It is the second largest continent.
• The equator passes through its middle.
• Both the Tropic of Cancer and the Tropic of Capricorn pass through it.
• The world’s largest desert, the Sahara Desert, is located in Africa.
• The Nile River, the longest river in the world, is also in Africa.

    

1. North America:

• It is the third largest continent.
• It is connected to South America by a narrow isthmus called  the Isthmus of Panama.
• It is located entirely in the Northern and Western Hemisphere.

 

1. South America :

• Most of it is located in the Southern Hemisphere.
• The world’s longest mountain range, the Andes, lies on its western edge.
• The world’s largest river, the  Amazon, is located here.

   

1. Australia :

• It is **the smallest continent**.
• It is located entirely in the Southern Hemisphere.
• It is also called  the island continent because it is surrounded by water from all sides.

    

vii. Antarctica :

• It is a large continent that is completely located in the Southern Hemisphere near the South Pole.
• It is permanently covered with thick ice layers.
• There is no permanent human habitation here.
• Research stations of many countries are located here (g. Maitri and Bharati of India).

 

Oceans

• Oceans are the vast water bodies present on earth.
• All the oceans are interconnected.
• Ocean water is always in motion – waves, tides and ocean currents.

Five Major Oceans

(By Size):

1. Pacific Ocean:

• It is the largest ocean .
• It covers about one-third of the earth.
• The deepest part of the world, the Mariana Trench (11,022 meters deep), is located here.
• It is almost circular in shape.

1. Atlantic Ocean:

• It is the second largest ocean.
• Its shape is similar to the English letter ‘S’.
• Its coastline is heavily cropped, ideal for natural harbours.
• It is the busiest ocean for trade and commerce.

 

iii.  Indian Ocean:

• It is the only ocean that is named after a country, e. India.
• It is almost triangular in shape.
• It is bordered by Asia to the north, Africa to the west, and Australia to the east.

 

1. Southern Ocean :

• It surrounds the continent of Antarctica and extends northwards to 60° south latitude.

 

1. Arctic Ocean :

• It is **the smallest ocean**.
• It surrounds the North Pole and is located within the Arctic Circle.
• It is connected to the Pacific Ocean by a narrow stretch called the Bering Strait.
• It is covered with a thick layer of ice.