Transcript Characteristics of the Atmosphere

Characteristics of the
Atmosphere
Unit 4: Sixth Grade
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Steven has an uninflated balloon.
He fills the balloon with a gas and ties it closed.
When he lets it go, it floats up into the sky.
Steven wonders what happens to the mass of the
uninflated balloon compared to the inflated, floating
balloon.
What do you think?
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Does the floating balloon have more mass?
Does the floating balloon have less mass?
Do the uninflated and the floating balloon have the same
mass?
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Explain your thinking
Floating Balloon
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The atmosphere is
the mixture of
gases that
surrounds the
Earth.
It provides you
with:
◦ The oxygen you need
to breathe
◦ Protection from the
Sun’s rays
Atmosphere
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Our atmosphere is
mostly made up of
nitrogen gas (78%)
The oxygen that we
depend on only
makes up 21% of
our atmosphere
The other 1% is
made up of argon,
CO2, water vapor
and other gases.
The Composition of the
Atmosphere
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What would carrying a column of air that
is 700 km high feel like?
You carry this load every day!
While air is not heavy, its weight adds up.
At sea level, a square inch of surface area
is almost 15 lb of air.
Carrying this much air on such a small
surface is like carrying a large bowling
ball on the tip of your finger!!!
Atmospheric Pressure and
Temperature
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Our atmosphere is
held around the
Earth by gravity.
Gravity pulls gas
molecules in the
atmosphere toward
the Earth’s surface,
causing air
pressure.
As Altitude Increases, Air Pressure
Decreases
Air pressure is the
measure of the force
with which air
molecules push on a
surface.
 Air pressure is
strongest at Earth’s
surface because more
air is above you.
 As you move farther
away from the Earth’s
surface, fewer
molecules are pushing
down on you, so air
pressure decreases.
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As Altitude Increases, Air Pressure
Decreases
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Think of air
pressure as a
human pyramid.
The people at the
bottom of the
pyramid can feel all
the weight and
pressure of the
people on top.
Air pressure works
in a similar way.
As Altitude Increases, Air Pressure
Decreases
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Air temperature
changes as altitude
increases.
This difference is due
to the way the sun’s
energy is absorbed as
it moves through the
atmosphere.
http://www.youtube.
com/watch?v=2RqmT
h3K6yk
Atmospheric Composition Affects
Air Temperature
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Some parts of the
atmosphere are
warmer because
they contain a high
percentage of gases
that absorb solar
(sun) energy.
Other parts contain
less of these gases
and are cooler.
Atmospheric Composition Affects
Air Temperature
Layers of the Atmosphere
http://www.youtube.com/watch?v=fyfN9t_E0w8&safety_mode=true&persist_safety_mode=1
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Based on temperature changes, the Earth’s
atmosphere is divided into four layers: the
Troposphere, the Stratosphere, the
Mesosphere and the Thermosphere.
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Try Saving Much Time
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These words may sound complicated, but the
name of each word gives you some clues
about its features.
Layers of the Atmosphere
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“Sphere” means “ball” which suggests that each layer
surrounds the Earth like a hollow ball.
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“Tropo” means “turning” or “change” and the Troposphere
is the layer where gases turn and mix.
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“Strato” means “layer” and the Stratosphere is where the
gases are layered and do not mix very much.
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“Meso” means “middle” and the mesosphere is the middle
layer
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“Thermo” means “heat”, and the thermosphere is where
the temperatures are the highest.
Layers of the Atmosphere
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The lowest layer of the
atmosphere, which lies next
to the Earth’s surface is the
troposphere.
◦ Altitude 0- 12,000 Km, 07.5miles
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It is the densest layer
◦ 90% of the atmosphere’s total
mass!
Almost all CO2, water vapor,
clouds, air pollution, weather
and life-forms exist here.
 Temperatures vary.
 Air pressure varies because
of differing temperatures
causes the gases to mix
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The Troposphere --- Our Layer!
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Gases in the stratosphere
are layered and do not
mix as much as the gases
in the troposphere.
◦ Altitude: 12,000-50,000
km,
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The air is very thin and
dry.
The lower stratosphere is
very cold (-60 C, -76F),
but the temperature rises
as altitude increases.
This rise happens because
ozone in the stratosphere
absorbs the ultraviolet
from the sun.
The Stratosphere --- Home of the
Ozone Layer
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The gases in the ozone layer rarely mix
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One of these gas layers within the
stratosphere is the ozone layer.
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Ozone is a natural gas that forms a thin
shield high up in the sky. It protects life on
Earth from the sun's ultraviolet (UV) rays.
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Stratospheric ozone is found most often
between six and 30 miles above the Earth's
surface.
The Stratosphere’s Ozone Layer
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Above the
stratosphere is the
mesosphere.
The mesosphere is
the middle layer of
the atmosphere.
◦ Altitude: 50,000 km80,000 km The
temperature
decreases as altitude
increases.
The Mesosphere --- The Middle
Layer
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The uppermost
layer of the
atmosphere is
called the
thermosphere.
◦ Altitude 80,000500,00 km
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The temperature
increases with
altitude.
◦ 1,000 C, 1800 F
The Thermosphere
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If you said “yes” you are wrong(so wrong)
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This is because temperature and heat are
NOT the same thing!
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Temperature is the measure of how quickly
particles are moving.
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Heat is the transfer of thermal energy
between objects of different temperatures.
You would think with such a high
temperature, the thermosphere
would be hot, right?
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Particles must touch each other to transfer thermal
energy.
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The density of the thermosphere is so low that there
is a lot of space between particles.
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Since there is so much space between the particles,
they rarely touch each other.
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Since they rarely touch, they cannot transfer heat.
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Therefore, while the temp is high, the heat is low in
the thermosphere!
Temperature vs. Heat
The uppermost layer of
the Earth's atmosphere
is known as the
exosphere.
In the exosphere, the
atmosphere becomes
very thin, and atoms
and molecules escape
into space.
It is thought of as the
region where the
atmosphere of Earth
merges with space.
One last layer --- The Exosphere
If you were lost in the woods, you could
survive for a few days without food and
water.
 But you wouldn’t last for more than a five
minutes without the atmosphere.
 So, if the atmosphere is soooo important
that you can’t live without out it for even
five minutes --- WHAT IS ATMOSPHERE?
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Former lead slide