The document discusses the importance of Earth's atmosphere and its composition and structure. It is composed primarily of nitrogen and oxygen and helps protect the planet from radiation. The atmosphere is divided into five layers - the troposphere, stratosphere, mesosphere, thermosphere and exosphere - with properties like temperature and pressure changing with altitude. Each layer plays an important role in regulating the planet's climate and shielding its surface.

1. Earth’s Atmosphere
Why is it so important to life
on earth?
Kinara Kumudesh
Methodist College

2. What is atmosphere… ?
• The envelope of gases surrounding the earth or another
planet.
• Composition
 composed of nitrogen (about 78%) oxygen (about 21%)
 argon (about 0.9%) with carbon dioxide other gases in
trace amounts (Eg: hydrogen, helium, and other "noble"
gases).
• Atmospheric pressure
 Force per unit area that is applied
perpendicularly to a surface by the
surrounding gas.
 It is determined by a planet's
gravitational force in combination with
the total mass of a column of gas.kinara 2017 2

3. Uses of Atmosphere
• The atmosphere helps
protect living organisms
from genetic damage by
solar ultraviolet radiation
• The atmosphere is an
evolutionary agent
essential to the shaping of
a planet
• composition of the
atmosphere determines the
climate and its variations
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4. Use of Gasses
• Oxygen is used by most organisms for
respiration
• Nitrogen is fixed by bacteria and
lightning to produce ammonia used in
the construction of nucleotides and
amino acids
• Carbon dioxide is used by plants,
algae and cyanobacteria for
photosynthesis.
• Protect living organisms from genetic
damage by protect living organisms
from genetic damage by solar
ultraviolet radiation, solar wind and
cosmic rayskinara 2017 4

5. Earth’s
atmosphere
is made up
of 5 different
layers…
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6. • Atmosphere is not
uniform, its properties
change with altitude.
• Two properties change
with altitude, the air
pressure and the air
temperature
• Lets look at each layer
individually.
Why is the atmosphere divided into 5
different layers?
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7. The troposphere
• The layer of the atmosphere
nearest to earth.
• The troposphere goes from
0km to 16km.
• All weather happens in the
troposphere.
• More than half the air in the
total atmosphere is in this
layer.
• The temperature drops as
the altitude increases.
• Harmful ozone is found
here…IT CREATES SMOG!
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8. OZONE: A gaseous layer in
the upper atmosphere that
protects the earth from
harmful UV radiation. At lower
levels, ozone becomes a
major pollutant.
SMOG: Pollution formed by the
interaction of pollutants and
sunlight (photochemical smog),
usually restricting visibility, and
occasionally hazardous to health
• OZONE and SMOG
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9. • The temperature goes
up with altitude.
• Most jets fly in this layer.
• The protective ozone is
at the top of the
atmosphere (It protects
us from the ultraviolet
radiation of the sun.)
• Rivers of air, called Jet
Streams, can be found
at the base of this layer.
The stratosphere
from 16km to 50 km
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10. • In the mesosphere, the
temperature drops with
altitude.
• The coldest layer of
the atmosphere.
• Meteors burn up in this
layer.
• Radio waves are
reflected back to earth
in the mesosphere.
The Mesosphere
from 50km to 90km)
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11. • In the thermosphere the
temperature goes up with
altitude.
• The hottest layer of the
atmosphere.
• Curtains of light called
auroras occur in this
layer.
• The Ionosphere is found
in the thermosphere.
• The component of the
thermosphere that makes
the auroras.
The thermosphere
from 90km to 300km
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12. Exosphere • The exosphere is
the outermost layer
of the atmosphere.
• The temperature in
the exosphere
goes up with
altitude.
• Satellites orbit
earth in the
exosphere.
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13. Did you know that The Science Monkey’s
Took Evan?
 The
 Science
 Monkey’s
 Took
 Evan
Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere
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14. kinara 2017 14