The AtmosphereThe Atmosphere

What is the Earth’s AtmosphereWhat is the Earth’s Atmosphere?? OurOur atmosphereatmosphere is is the mixture of the mixture of

gases and particles that surround gases and particles that surround the Earththe Earth..

The atmosphere is held around the Earth by The atmosphere is held around the Earth by gravity.gravity.

Protects us from the sun’s most damaging Protects us from the sun’s most damaging rays.rays.

Helps maintain the right temperature range Helps maintain the right temperature range for life on Earth.for life on Earth.

The oxygen we need to breathe is an The oxygen we need to breathe is an important component of the atmosphere. important component of the atmosphere.

A Mixture of GasesA Mixture of Gases

Small Particles Small Particles Floating in the AirFloating in the Air

DustDust Volcanic AshVolcanic Ash Sea Salt / Sea SpraySea Salt / Sea Spray SmokeSmoke Small Pieces of SkinSmall Pieces of Skin PollenPollen BacteriaBacteria

Water in the AtmosphereWater in the Atmosphere

Liquid WaterLiquid Water (Water droplets (Water droplets forming clouds)forming clouds)

Solid WaterSolid Water (Snow, sleet, hail and (Snow, sleet, hail and ice crystals in clouds)ice crystals in clouds)

Water VaporWater Vapor (Changes into liquid (Changes into liquid and frozen water creating rain and and frozen water creating rain and snow)snow)

How do How do air pressureair pressure and and temperaturetemperature change as change as altitude increases in the altitude increases in the

atmosphere?atmosphere?

Gravity pulls the gas Gravity pulls the gas molecules in the atmosphere molecules in the atmosphere toward the Earth’s surface toward the Earth’s surface causing air pressure.causing air pressure.

Air pressure is the measure Air pressure is the measure of the force with which air of the force with which air molecules push on an area molecules push on an area of a surface.of a surface.

Air pressure is measured Air pressure is measured with a barometer.with a barometer.

Atmospheric PressureAtmospheric Pressure

As altitude increases, air pressure As altitude increases, air pressure and air density decreaseand air density decrease..

Temperature Change in the AtmosphereTemperature Change in the Atmosphere

As altitude increases, temperature changes.As altitude increases, temperature changes. These changes are mainly due to the way These changes are mainly due to the way

solar energy is absorbed in the atmosphere.solar energy is absorbed in the atmosphere. Some gases in the atmosphere absorb solar Some gases in the atmosphere absorb solar

energy while others do not.energy while others do not. Parts of the atmosphere where there are a Parts of the atmosphere where there are a

high percentage of these gases are warmer high percentage of these gases are warmer than the other parts of the atmosphere than the other parts of the atmosphere where these gases are absent. where these gases are absent.

Pressure and Temperature Change as Altitude IncreasesPressure and Temperature Change as Altitude Increases

This line indicates how temperature changes as altitude increases in the atmosphere.

As altitude increases, the atmospheric

pressure decreases.

Layers of Layers of the Earth’s the Earth’s AtmosphereAtmosphere

The TroposphereThe Troposphere1.1. The Lowest layer of the atmosphere. We live in The Lowest layer of the atmosphere. We live in

this layer.this layer.

2.2. The temperature gets colder as altitude The temperature gets colder as altitude increases.increases.

3.3. Is the densest layer containing almost 80% of the Is the densest layer containing almost 80% of the atmosphere’s total mass.atmosphere’s total mass.

4.4. ““Weather” occurs in this layer.Weather” occurs in this layer.

5.5. Almost all of the Earth’s COAlmost all of the Earth’s CO22, water vapor, , water vapor, clouds, air pollution, and life forms are in the clouds, air pollution, and life forms are in the troposphere.troposphere.

6.6. Clouds in upper part contain ice pellets.Clouds in upper part contain ice pellets.

The StratosphereThe Stratosphere

1.1. In this layer, In this layer, temperature temperature increases with increases with altitude.altitude.

2.2. The Ozone Layer The Ozone Layer occurs in the occurs in the stratosphere. stratosphere.

3.3. Ozone is 3 Oxygen Ozone is 3 Oxygen Atoms. (OAtoms. (O3)3)

4.4. Absorbs most of the Absorbs most of the ultraviolet radiation ultraviolet radiation from the sun.from the sun.

The MesosphereThe Mesosphere

1.1. ““Meso” means “middle,” as in middle sphere.Meso” means “middle,” as in middle sphere.

2.2. Coldest Layer. Temperatures are as low as -Coldest Layer. Temperatures are as low as -120120°C at the top of the Mesosphere. °C at the top of the Mesosphere.

3. Meteoroids begin to burn up in the 3. Meteoroids begin to burn up in the Mesosphere.Mesosphere.

ThermosphereThermosphere (Divided Into Two Sub Layers)(Divided Into Two Sub Layers)

1.1. The uppermost layer of the The uppermost layer of the atmosphere.atmosphere.

2.2. The temperature increases The temperature increases as altitude increases.as altitude increases.

3.3. The temperature in the The temperature in the Thermosphere can reach Thermosphere can reach over 1500over 1500°C.°C.

4.4. The air is thin because the The air is thin because the molecules are spread out.molecules are spread out.

5.5. No detectable outer limit.No detectable outer limit.

IonosphereIonosphere (Lower Part of the Thermosphere)(Lower Part of the Thermosphere)

1.1. Ions or charged Ions or charged particles in this layer particles in this layer reflect radio signals reflect radio signals back to the Earth.back to the Earth.

2.2. The Auroras are occur The Auroras are occur in the Ionosphere.in the Ionosphere.

ExosphereExosphere(Part of the Thermosphere)(Part of the Thermosphere)

1.1. Outer most layer of the thermosphere.Outer most layer of the thermosphere.

2.2. Phone calls and television signals often Phone calls and television signals often reach you by way of communication reach you by way of communication satellites that orbit the Earth in the satellites that orbit the Earth in the exosphere.exosphere.

Scale Model Scale Model of the Earth’s of the Earth’s Atmosphere:Atmosphere:

How does the atmosphere protect life on Earth?How does the atmosphere protect life on Earth?

By Absorbing or Reflecting Harmful solar radiation.By Absorbing or Reflecting Harmful solar radiation. The Earth’s atmosphere reflects or absorbs most of The Earth’s atmosphere reflects or absorbs most of

the radiation from the sun.the radiation from the sun. The Ozone Layer absorbs most of the radiation from The Ozone Layer absorbs most of the radiation from

the sun.the sun.

By maintaining the Right Temperature Range for living By maintaining the Right Temperature Range for living things.things.

The “greenhouse effect” is the process by which The “greenhouse effect” is the process by which gases in the atmosphere, such as water vapor and gases in the atmosphere, such as water vapor and carbon dioxide, trap the sun’s heat escaping from the carbon dioxide, trap the sun’s heat escaping from the Earth’s surface.Earth’s surface.

Unfortunately, the burning of fossil fuels adds too Unfortunately, the burning of fossil fuels adds too much COmuch CO2 2 and many scientists believe is causing and many scientists believe is causing global warming.global warming.