The AtmosphereThe Atmosphere

The atmosphere is the blanket of air that surrounds the Earth.

The Earth System

Composition of the AirComposition of the Air

Nitrogen 78%

Oxygen 21%

Other gases 1%

*greenhouse gases: carbon dioxide, water vapor, methane, etc.

Layers of the AtmosphereLayers of the Atmosphere

1. Troposphere

2. Stratosphere

3. Mesosphere

4. Thermosphere (ionosphere)

The TroposphereThe Troposphere• the bottom layer of the atmosphere

• stretches to about 11 km

• temperature decreases with altitude

• where weather conditions happen

• with vertical air currents (turbulent)

• contains 75% of the air

• mostly N2 and O2

Temperature GraphTemperature Graph

The StratosphereThe Stratosphere• the second layer of the atmosphere

• up to about 50 km

• with horizontal air currents

• temperature increases with altitude

• contains the ozone (O3) layer in the upper region

• where most jet planes travel through

• contains about 24% of the air

Temperature GraphTemperature Graph

The MesosphereThe Mesosphere

• the third layer of the atmosphere

• up to about 80 km

• temperature decreases with altitude

• the coldest layer

• where most meteors burn up

Temperature GraphTemperature Graph

The Thermosphere (Ionosphere)The Thermosphere (Ionosphere)• the fourth layer of the atmosphere

• to about 1000 km

• the hottest layer (due to ions, H+ and He-, that directly absorb the sun’s radiation)

• temperature increases with altitude

• where radio waves are reflected

Temperature GraphTemperature Graph

Importance of the AtmosphereImportance of the Atmosphere provides the necessary gases for living things to survive

regulates the heat from the sun to just the right temperature for life on Earth

plays an important role in the water cycle

the ozone layer protects the Earth from the sun’s harmful UV rays

protects the Earth from small meteors

Points to PonderPoints to Ponder

What is air pollution? Where does it come from?

How does air pollution affect us?What can we do about air pollution?What is the Clean Air Act all about?

Let’s summarize…Let’s summarize…

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

1. Composed of hydrogen and helium.

Thermosphere

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2. Most affected by air pollution.

Troposphere

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3. Protects the organisms from the

harmful rays of the sun.

Stratosphere

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

4. Contains the most dense air.

Troposphere

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5. Contains the least dense/thinnest air.

Thermosphere

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

6. Coldest layer of the atmosphere.

Mesosphere

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

7. Contains ozone (O3).

Stratosphere

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

8. Where meteors burn up.

Mesosphere

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9. Where air planes and jet planes fly.

Stratosphere

Identify the layer of the Identify the layer of the atmosphere being described:atmosphere being described:

10. Where weather changes happen.

troposphere

True or false:True or false:

1. Nitrogen (N2) gas is the most abundant gas in the atmosphere.

True

True or false:True or false:

2. Methane (CH4) is not a greenhouse gas.

False

True or false:True or false:

3. Thermosphere and Mesosphere are the hottest layers of the atmosphere

False

True or false:True or false:

4. Air pressure is highest in the troposphere layer.

True

The EndThe End