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
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?