Earth and its Components
v
Percentage of Elements in the Atmosphere:
|
Nitrogen
|
78.09% |
|
Oxygen |
20.93% |
|
Argon |
0.93% |
|
Carbon
Dioxide |
0.03% |
v Percentage wise list of elements
present in Earth's Crust :
|
Oxygen |
47% |
|
Silicon |
28% |
|
Aluminium |
8% |
|
Iron |
5% |
|
Magnesium |
4% |
|
Calcium |
2% |
|
Potassium |
2% |
|
Sodium |
2% |
|
Others |
2% |
v Structure of the Earth’s
Atmosphere :
Ø Troposphere :
·
It
extends up to average height of 18 km. Its thickness varies from 8 km at poles
to 18 km at the equator.
·
This
layer contains clouds, rains, dust particles. All weather phenomena occur in this
layer only.
Ø Stratosphere :
·
This
layer is also known as Ozonosphere due to the presence of ozone layer in it. It
absords all ultraviolet rays coming from the sun which are harmful for the
living beings
·
Generally in the atmosphere as the altitude
increases there is decrease in the temperature but here in this layer, the
temperature rises in this layer from about -60° C to 0° C. This phenomena is
called temperature inversion.
·
This
layer is used by the pilots for the flying of jets and aircrafts.
Ø Mesosphere :
 |
| Earth's Atmosphere and its layers |
·
It is
considered as the coldest layer of the atmosphere.
·
The
temperature in this layer decreases rapidly from 0° C to -100° C
·
The
meteors burn in this layer which prevent them from colliding with the earth
Ø Ionosphere :
·
This
layer is called ionosphere because it contains electrically charged ions that
reflect the radio waves back to the earth surface , which is the reason why most
of the satellites are present in this layer.
·
The layer
helps in improving the communication through radio waves.
Ø Thermosphere :
·
In this
layer, the temperature increases with altitude. It is up to height of 600 km.
·
The day
temperature of this layer exceeds 1400° C while night temperature remain about
225° C
·
Only
lighter gases like helium and hydrogen are present in this layer.
Ø Exosphere :
·
The
outermost part of the atmosphere of the earth is called Exosphere.
·
This
layer acts as the transitional zone between earth’s atmosphere and outer space
Ø Magnetosphere :
· The outer part of exosphere is called as Magnetosphere.
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