Earth ScienceMarch 22nd, 2011

Mrs. Harris

Today’s Objectives

• Describe characteristics of Earth’s atmosphere.

• Describe the processes of radiation, conduction, and convection.

• Differentiate between various types of winds.

What is the atmosphere?

• All of the gases that surround the Earth

• Name some gases!

What is the atmosphere?

78%

21%

0.9%

0.1%

Under Pressure • You’ve got the whole atmosphere on

your shoulders!• Air pressure is the “force per unit area

that is exerted on a surface by the weight of the atmosphere”

• Like PSI (pounds per square inch)

Under Pressure • You’ve got the whole atmosphere on

your shoulders!• Air pressure is the “force per unit area

that is exerted on a surface by the weight of the atmosphere”

• Like PSI (pounds per square inch)

• Measured with a barometer• Think of all the air molecules over your

head! (~9 miles for the first layer)

Services of the Atmosphere

• Weather system that provides & delivers fresh water to the land

Services of the Atmosphere

• Weather system that provides & delivers fresh water to the land

• Holds heat to the surface of the Earth (without this daily temperatures would fluctuate at least by 80o)

Services of the Atmosphere

• Weather system that provides & delivers fresh water to the land

• Holds heat to the surface of the Earth (without this daily temperatures would fluctuate at least by 80o)

• Protects us from small meteors and debris

Services of the Atmosphere

• Weather system that provides & delivers fresh water to the land

• Holds heat to the surface of the Earth (without this daily temperatures would fluctuate at least by 80o)

• Protects us from small meteors and debris• Shields us from strong UV radiation

Layers of the Atmosphere

Layers of the Atmosphere

Where does weather happen?

Where is the ozone layer?

Where do auroras happen?

Where are the coldest temperatures?

Where are the hottest temperatures?

Where is most of the water vapor?

Any questions so far?

Radiation, Conduction, Convection

Transferring Energy

Energy: Electromagnetic Spectrum

Energy: Electromagnetic SpectrumRadiation is the transfer of energy as

electromagnetic waves.

Radiation

• Can be scattered, reflected, or absorbed.• Scattering is caused when radiation hits particles in

the atmosphere and is bent in all directions.• Reflection happens when radiation reaches the

earth’s surface and is reflected back into the atmosphere. (remember albedo?)

• Earth’s surface absorbs solar radiation and is what heats the surface of the earth.

• The transfer of thermal energy as heat through materials.

• This is how the atmosphere gets warmed.

Conduction

• The transfer of thermal energy as heat through materials.

• This is how the atmosphere gets warmed.

Conduction

What happens to warm air?

What happens to warm air?

Convection• The movement of molecules

in a fluid due to differences in density that are caused by temperature variations; can result in the transfer of energy as heat.

• The atmosphere behaves like a fluid.

What is a fluid? What makes it different from a solid or a gas?

Baking soda & vinegar

Moving Energy Around

• Some awesome benefits:

– Stablizes Earth’s average temperatures (greenhouse effect)

– Drives the water cycle (______, _______, ______ )– Creates wind/weather patterns tomorrow

• Before you leave, write something you learned.• Next class: why does my candle go out?

and how the atmosphere behaves like a fluid, humidity, clouds and fog, and precipitation.