Download The Early Atmosphere - Leon County Schools

THE ATMOSPHERE
Learning Goal:
Describe how the composition and structure of the
atmosphere protects life on Earth.
Essential Question:
How does the composition and structure of the atmosphere
protects life on Earth.
MAIN IDEAS:
 The atmosphere is divided into laters.
 The atmosphere protects life from harmful radiation
and regulates the planet’s temperature.
 Weather is caused by changes in the atmosphere due
to the transfer of energy in one form or another.
 This energy transfer is driven by the solar radiation
from the sun.
The Atmosphere
Atmosphere: the blanket of gasses that
surrounds our planet held by gravity
The Early Atmosphere
Thought to be mostly water vapor and
carbon dioxide.
Water vapor condensed and rained to fill the
oceans.
The first organisms used carbon dioxide to
perform photosynthesis which made
oxygen.
Today’s Atmospheric
Composition



78% Nitrogen (N)
21% Oxygen (O2)
1% Other Gasses
The atmosphere also contains:


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water vapor: which forms clouds and precipitation and
absorbs heat energy
particles: like dust, salt, pollen
ozone: a gas in the ozone layer that absorbs harmful UV
radiation.
Greenhouse gasses: gas molecules that absorb solar
radiation, trap heat, and can increase the temperature of the
atmosphere.
 Carbon dioxide: most worrisome
 Water vapor: most abundant
Atmospheric Layers


There are 5 layers of the atmosphere, divided
by temperature.
Temperature is a measure of the average
amount of kinetic energy of the particles in a
material. (motion)

Layers from top to bottom:




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Exosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere

Exosphere (“Exo”- means outer)


outermost layer with no clear boundary
It extends into space

Thermosphere (“therm-” means heat)

Very little air here

Known for its great range of temperatures (-112⁰
F - 2000 ⁰ F)

Layer where space shuttles orbit

Produces the Aurora Borealis (Northern Lights)

Mesosphere (“Meso-” means middle)



Air is very thin
Temperature decreases.
Where meteors burn up and make shooting
stars.

Stratosphere

Air is pretty thin

contains the “Ozone Layer” which is made of
ozone gas that protects us from harmful UV
radiation by absorbing it

This is why temperature in the stratosphere increases.

Troposphere



Bottom layer that contains most of the air.
Temperature decreases with altitude because
the Earth’s surface warms it.
Where all weather occurs
Where all weather occurs.
The Sun heats the Earth
through radiation.
The clouds block the sun
during the day and keep heat
in at night.
Water vapor and carbon
dioxide also absorb heat and
help keep it warm at night.
The ground
absorbs the Sun’s
radiation.
The ground heats
the air above it
through
conduction. It gets
cooler the farther
away you get from
the ground.
Convection TRIES to evenly distribute heat
in the troposphere.
Warm, moist air rises, and cool air sinks and
rushes in to replace it. This creates wind.
It is also how clouds form.
All three types of energy transfer happen in
the troposphere.


Altitude is the
height above sea
level.
The higher you go,
the less air there is.

Pressure is the
weight of the air
above you

The higher you
go, the less air
there is, so
pressure
decreases with
altitude.