Page 6 - SST Class 03

Know It!

v The eight planets in the order of increasing distance from the Sun are : Mercury, Venus,
Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

The Earth is also very big, but the Sun is far bigger than it. It is round

almost like a ball. It looks flat because it is very big and we can see only a
small part of it.

Long ago, people thought that the Earth is flat. One day in the year 1519,

Ferdinand Magellan set sail from Spain. He sailed his ship to the west
direction. He kept sailing for three years. Amazingly, he reached where he

had started from. This proved that the Earth is round.

In 1961, Yuri Gagarin went into the space. He was an astronaut from Russia.
From the outer space, he noticed that the Earth is round like a ball. Until

now, many people have gone into the space and seen the Earth as round.
Rakesh Sharma was the first Indian astronaut who went into the space in
1984.

Ferdinand Magellan Yuri Gagarin Rakesh Sharma

The Earth moves in two ways. It goes round the Sun. It is called revolution .
It takes 365¼ days for one revolution. We can see different seasons on the

Earth. They are caused by this revolution.

The Earth also rotates on its axis. It is called rotation . It takes 24 hours for
one rotation. Day and night occur due to rotation.

The Earth is enveloped by air. It is called atmosphere .

About three-fourth of the Earth’s surface is covered with water. The

6 Contemporary Social Science-3