AtmosphereAtmosphere

Importance: 1) balance between heat absorbed from Sun and amount that escapes back (extreme temperatures) 2) protects Earth from Sun’s harmful rays

Early Atmosphere: Volcanoes produced nitrogen and carbon dioxide and little oxygen 2 billion years ago simple organisms started making oxygen

Early Atmosphere: Ozone layer formed protecting the Earth from Sun’s rays Green plants then released more oxygen

Makeup of Atmosphere: Nitrogen 78% Oxygen 21% Argon Carbon dioxide1% Other gases and water vapor 1) Gases

Gases Atmosphere changing because of pollutants increasing CO 2 Pollutants mix with water droplets & chemicals = smog

2 Solids Dust Salt Pollen

3 Liquids Water droplets Droplets from volcanoes

Troposphere All life Weather occurs Jets fly here Lowest layer

Troposphere Air pressure greatest near surface decreases as you go up Contains ¾ (75%) of atmospheric gases Nearly all water vapor (99%) Temperature decreases

Stratosphere Jet Stream Jets fly here to avoid storms Temperature increases

Stratosphere Ozone layer (O₃) Protects Earth from Sun’s harmful rays (UV) Molecules of ozone absorb Sun’s energy so as altitude increases; the temperature increases

Mesophere Meteor showers (shooting stars) Temperature decreases

Thermosphere Highest temperature 1 st to receive sun’s rays  few molecules 2 parts: ionosphere & exosphere

Ionosphere Temperatures increase reflects AM radio waves at night

Ionosphere Northern lights

Exosphere Space shuttle Satellites International Space Station Temperature increases

Importance of Ozone Life depends on ozone km above Earth’s surface Made of 3 atoms of oxygen Absorbs ultraviolet radiation (UV rays)

Importance of Ozone Air pollutants destroying ozone CFC’s (chlorofluorocarbons)in fridges, air conditioners, aerosol Sprays, & some foam packing

Chlorine is broken off CFCs by UV rays into regular oxygen that can’t absorb UV rays

creates a hole in ozone over Antarctica increase of UV rays kills life and causes skin cancer