1. Ch.22 Atmosphere

2. Composition 78% nitrogen 21% oxygen 0.9% argon 0.1&other gasses

3. Air pressure As a result of gravity holding the gasses of the atmosphere together, air molecules are compressed together and exert force on earths surface. The pressure exerted on the surface is atmospheric pressure.

4. How air pressure changes The higher you go in the atmosphere, the less gravity acts on you. So at higher altitudes the air molecules are farther apart and do not exert as much force on each other. Meaning atmospheric pressure decreases as altitude increases. Atmospheric pressure an also change as a result of differences in temperature and amount of water vapor in the air. As temperature increases, the atmospheric pressure at sea level decreases.

5. Layer of atmosphere Troposphere- layer closest to the earths surface. As altitude increases in the atmosphere the temperature decreases. Most weather occurs in the area. Stratosphere- the ozone layer. Second layer. Mesosphere- third layer. Temperature decreases as altitude increases. Thermosphere- highest layer. Temperature increases with altitude. Auroras occur here.

6. Radiation Radiation travels through space to the earth from the sun. Visible, ultraviolet, X-rays, radio waves, infrared. Electromagnetic spectrum- all of the frequencies or wavelengths of electromagnetic radiation.

7. Greenhouse effect & co2