Layers of the Layers of the AtmosphereAtmosphere

6-4.16-4.1Compare the composition and Compare the composition and structure of Earth’s atmospheric structure of Earth’s atmospheric layers (including the gases and layers (including the gases and differences in temperature and differences in temperature and pressure within the layers). pressure within the layers).

Essential QuestionEssential Question

How do each of the layers of the How do each of the layers of the Earth’s atmosphere compare to Earth’s atmosphere compare to each other?each other?

These are the layers in These are the layers in order from the Earth order from the Earth upwardsupwards TroposphereTroposphere StratosphereStratosphere MesosphereMesosphere ThermosphereThermosphere ExosphereExosphere

Create a saying to Create a saying to remember them remember them Such as “Try sending me to the Such as “Try sending me to the

exosphere!”exosphere!”

The TroposphereThe Troposphere Lowest layer.Lowest layer. Weather occurs here Weather occurs here

and therefore clouds.and therefore clouds. We live in it.We live in it. ““Tropo” means turning Tropo” means turning

or changing conditions.or changing conditions. Densest layer.Densest layer. Temperature is warmer Temperature is warmer

at the surface and at the surface and decreases with altitude.decreases with altitude.

Temperature/Density Temperature/Density and the Troposphereand the Troposphere Troposphere: Troposphere:

temperature at temperature at surface is warmed by surface is warmed by the earth absorbing the earth absorbing energy from the sun.energy from the sun.

Convection currents Convection currents carry the heat carry the heat upward, so the air upward, so the air cools as it rises.cools as it rises.

Density decreases Density decreases since there is less air since there is less air above.above.

The StratosphereThe Stratosphere

““Strato” means layer Strato” means layer or spreading outor spreading out

Contains the ozone Contains the ozone layer which absorbs layer which absorbs energy and causes energy and causes the temperature to the temperature to rise.rise.

The ozone layer The ozone layer protects the surface protects the surface from dangerous UV from dangerous UV rays (ultraviolet rays (ultraviolet radiation from the radiation from the Sun).Sun).

Temperature and the Temperature and the StratosphereStratosphere

Ozone, made of Ozone, made of oxygen, absorbs oxygen, absorbs ultraviolet radiation ultraviolet radiation from the sun, from the sun, causing the causing the temperature to temperature to increase.increase.

Density still Density still decreases.decreases.

The MesosphereThe Mesosphere

Drop in Drop in temperature temperature marks beginning marks beginning of mesosphereof mesosphere

““Meso” means Meso” means middlemiddle

Most meteors Most meteors burn up hereburn up here

Temperature and the Temperature and the MesosphereMesosphere

This layer does This layer does not absorb energy not absorb energy from the sun, so it from the sun, so it starts to cool starts to cool again.again.

Without Without greenhouse greenhouse gases, energy gases, energy pretty much pretty much passes straight passes straight through!through!

The ThermosphereThe Thermosphere ““Thermo” means heatThermo” means heat Very hot (over 1000Very hot (over 1000°C), but °C), but

since air is so thin (not very since air is so thin (not very dense) it would not feel warm dense) it would not feel warm at all.at all.

The space shuttle orbits here.The space shuttle orbits here. So even though it is very hot So even though it is very hot

(over 1000°C), it would feel (over 1000°C), it would feel cold because there are so few cold because there are so few particles to transfer heat to particles to transfer heat to you.you.

It takes special instruments It takes special instruments to measure the temperature.to measure the temperature.

Temperature and the Temperature and the ThermosphereThermosphere

Solar radiation first hits Solar radiation first hits this layer, so the few this layer, so the few particles that are here particles that are here can gain lots of energy. can gain lots of energy. They move rapidly, so They move rapidly, so they have a very high they have a very high temperature.temperature.

But the air is so thin here But the air is so thin here that it takes special that it takes special instruments to measure instruments to measure the temperature the temperature accurately.accurately.

The ExosphereThe Exosphere ““Exo” means Exo” means

outerouter Extends for Extends for

1000’s of miles1000’s of miles Satellites orbit Satellites orbit

herehere No definite edgeNo definite edge Molecules Molecules

gradually escape gradually escape out into spaceout into space

Atmospheric gasesAtmospheric gases

Two most Two most common?common?

Nitrogen is the Nitrogen is the most commonmost common

Oxygen is the Oxygen is the second most second most commoncommon

These gases are These gases are found throughout found throughout all the all the atmospheric atmospheric levels.levels.

Atmospheric gasesAtmospheric gases

Inflating exampleInflating example Air inside a ball Air inside a ball

pushes against the pushes against the sides. The more sides. The more air we put in a ball, air we put in a ball, the more the the more the molecules push. molecules push. So the pressure So the pressure increases as we increases as we add air.add air.

Air PressureAir Pressure

Air pressure is the Air pressure is the result of the column of result of the column of air that is above you.air that is above you.

There is so much air There is so much air above you that at sea above you that at sea level you have 14.7 level you have 14.7 lbs/inlbs/in22 pushing on you. pushing on you.

Gravity causes most of Gravity causes most of the air to be pulled the air to be pulled down to the surface.down to the surface.

Why are we not Why are we not crushed by air crushed by air pressure?pressure? Air pressure is Air pressure is

equal in all equal in all directions.directions.

So air pushes So air pushes equally in all equally in all sides of us. The sides of us. The forces are forces are balanced!balanced!

Altitude and DensityAltitude and Density As the air pressure As the air pressure

decreases, the density of decreases, the density of the air decreases. The air the air decreases. The air particles are not squashed particles are not squashed together as tightly the together as tightly the higher one goes. This is higher one goes. This is caused by gravity!caused by gravity!

The air at sea level and at The air at sea level and at 6km has the same 21% 6km has the same 21% oxygen, but at 6km there oxygen, but at 6km there are fewer molecules, so are fewer molecules, so you take in less oxygen you take in less oxygen with each breath.with each breath.

A journey through the Atmosphere - YouTube.wmv