Atmosphere

2/18/2013

Bell Ringer

What do the following videos have in common? http://www.youtube.com/watch?v=upDYed0rYvk http://www.youtube.com/watch?v=ANm_4k7OLDk http://www.youtube.com/watch?v=FWG7x04ZfGE

Lightning, meteorites, and airplanes (also sunburn, global warming, and space exploration)

Atmospheric Composition

99% of the atmosphere is nitrogen and oxygen 78% is nitrogen, 21% is oxygen

1% is carbon dioxide, argon, hydrogen, water vapor, and other gases

Percentages of nitrogen and oxygen are essential to life on earth

Carbon dioxide and water vapor levels regulate the energy absorbed by the atmosphere

Atmospheric Composition

Dust and salt particles, carried into the atmosphere by wind, relate to cloud formation

Ozone is a molecule with three oxygen atoms bonded together (regular oxygen is two atoms).

Ozone protects the surface of the earth from ultraviolet radiation, but the ozone layer may be thinning

Layers of the Atmosphere REVIEW

Troposphere

Where weather forms Makes up 75% of the total amount of air in the

atmosphere

Stratosphere

Airplanes fly here Contains the ozone layer (this will be very

important when we talk about climate in the next few weeks)

Another 20% of the air in the atmosphere is contained here

Mesosphere

Middle layer of the atmosphere Shooting stars burn up here due to friction

Thermosphere

Air is thin, but warm because of solar radiation (closer to the sun than inner layers are)

Two layers, ionosphere and magnetosphere Aurora Borealis (Northern Lights) happens here

Exosphere

Outer layer of the atmosphere, very thin (little air)

Borders space

Solar Fundamentals

Radiation: transfer of energy through space by light (visible, etc)

Conduction vs. Convection

Conduction is energy transfer through direct contact between substances.

Conduction affects only a very thin atmospheric layer near Earth's surface.

Convection is energy transfer by the flow of a heated substance.

As pockets of air near Earth's surface are heated, they become less dense and rise. Then the rising air expands and starts to cool, sinking when it is cooler than the air around it.

These air currents are called convection currents, very similar to what happens with magma below tectonic plates.

Exit Quiz

1) Which layer of the atmosphere is closest to the Earth's surface?

2) Which layer of the atmosphere contains the ozone layer?

3) Ultraviolet light is an example of what type of energy transfer?

4) What percentage of solar energy is reflected (by the atmosphere, clouds, or Earth's surface)?

5) What percentage of solar energy is absorbed by the Earth's surface?