The Earth Class 3 Notes Science

Solar System

• Our solar system consists of the sun, eight planets and their moon. 
• The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. 
• All eight planets revolve around the sun. 

Solar System

The Earth

• The earth was formed from a giant cloud of dust and gas. 
• It is the third planet from the sun. 
• It is the fifth largest of the eight planets in the solar system. 

Earth

• Earth is the only planet that has life on it. 
• It consists of land, water and air. Approximately two-third of the earth is covered with water and the rest is land. 
• The earth is surrounded by a layer of air called the atmosphere. 
• The earth has no light of its own.

Shape Of The Earth

The earth seems to be flat. However, the shape of the earth is spherical with flat poles and a slight bulge in the middle like an orange. Evidences which show that earth is spherical in shape are –

• When the shadow of the earth falls on the moon, it is called  the eclipse of the moon. This shadow is round in shape. This shows that the earth is spherical in shape.
• When we observe a ship in the sea, we first see the top part of the ship and gradually the rest comes into view.

Viewing of ship

• Photographs of the earth taken by astronauts from space have also shown that the earth is spherical in shape.

Movement Of The Earth

1. Rotation of the earth

• The earth moves round and round just like a top. 
• It spins about an imaginary line passing through its centre called its axis. 
• The spinning of the earth on its own axis is called rotation. 
• The earth rotates from West to East and completes one rotation in 24 hours. 
• Rotation of the earth results in day and night.

Rotation of the Earth

Formation of day and night

• The earth rotates from West to East. 
• Half of the earth always faces the sun. 
• The part of the earth which faces the sun experiences day. 
• The other half which does not get light from the sun experiences night.
  
  Question for Chapter Notes: The Earth

  Try yourself:Axis is an actual line on Earth.

  • A.

    True
  • B.

    False

  Explanation

  In astronomy, an axis refers to the imaginary line that an object, usually a planet, rotates around. Earth's rotational axis is an imaginary straight line that runs through the North and South Pole.

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2. Revolution of the earth

Revolution of the Earth

• The earth goes around the sun on a fixed path called an orbit. 
• This movement of the earth around the sun is called revolution.
• The earth completes one revolution around the sun in 365¼ days (one year). 
• The revolution of the earth causes the change in seasons.