Page 126 - SST Class 07

There are a large number of seaports along its
coastlines. The Atlantic Ocean comprises of a
number of seas such as the Gulf of Mexico , the
Caribbean Sea , the Mediterranean Sea , the North
Sea and the Baltic Sea . Its average depth is about
3,736 m with the deepest point at Puerto Rico
Trench measuring 9,460 m deep.
Indian Ocean
The Indian Ocean lies to the south of India and
has been named after our country. It covers nearly
20 percent of the total sea area. It is bounded by
Africa on the west, Asia on the north, Australia on
the east and Antarctica on the south. Its average
depth is about 4,900 m with the deepest point at
Java Trench which is about 7,542 m deep. It
comprises a number of seas, such as the Red Sea , and groundwater.
the Arabian Sea , the Bay of Bengal and the
Andaman Sea . OCEAN WATERS AND THEIR CIRCULATION
Arctic Ocean
The Arctic Ocean lies to the north of Asia, Europe
and North America within the Arctic Circle. It
remains frozen throughout the year. It is the
smallest ocean. It is less saline due to a number of
rivers flowing into it.
Quiz Time
Fill in the blanks :
1. ___________ and ___________ are the largest
water bodies.
2. The ___________ is the deepest of all oceans.
3. Indian Ocean covers only ___________ of the
total sea area.
4. ___________ is the smallest ocean.
Southern Ocean
It is the fourth largest of the world’s five oceans.
The Pacific, Atlantic and Indian Ocean merge at a
place and are collectively known as the Antarctic
or Southern Ocean. It surrounds the landmass of
Antarctica and remains frozen throughout the
year. Its deepest point is South Sandwich Trench
at 7,235 m.
Contemporary Social Science-7
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Info Bits
Info Bits
In 2000, the International Hydrographic
Organisation again included the Southern Ocean as
its own ocean.
Other Water Bodies
In addition to the oceans, there are a number of
seas , bays and gulfs . These bodies have saline
water. The seas are also vast bodies of seawater,
but they are smaller in size, and form a part of the
oceans. A gulf is an inlet of seawater which
reaches deep into land. A bay is an inlet of
seawater with an opening, wider than a gulf.
The freshwater sources are rivers, lakes, streams
It is so enchanting when you walk on the
seashore. The waves keep rising, the air keeps
blowing, and there is before your eyes infinite
mass of water appearing to rise in the distant
horizon. The sea is never static. It keeps moving,
rising and falling. A number of factors contribute
in the movement of ocean waters—difference in
temperature and salinity between different places,
and winds. The movement of ocean waters can be
broadly classified as waves , tides and currents .
Waves
The ocean is an open area covered with water,
where the wind moves without any hindrance.
The wind moves along the water and pushes it in
the direction to which it is blowing. It results in
the rising and falling of water. You may be
surprised to note that water particles do not move
with the wind; they only rise and fall; it is only the
wave movement which is transported. Just put a
piece of wood; you will find that it goes up and
down with the wave
movement, but it
remains where you put
it, it does not move
forward. The rise of
waves is called crest and
the fall is called trough .
Ocean waves