The Atmosphere

• Phase 1 - Volcano's erupting

  • For Millions of years the earths crust was mainly molten
  • Eventually a thin crust formed
  • The volcano's kept erupting and "degassing" the inside of the earth
  • Carbon Dioxide, Steam, Methane and Ammonia was being released into the atmosphere
  • When things settled down it was mainly CO2 In the atmosphere
  • The water vapour condensed to make oceans
• Phase 2 - Green plants producing Oxygen

  • A lot of CO2 dissolved into the oceans
  • Green plants started evolving and started photosynthesizing and removing the CO2 and started producing O2
  • Eventually the amount of O2 in the air increased and the CO2 got locked up in fossil fuels and sedimentary rocks
• Phase 3 - Ozone layer & Complex animals

  • The build up on oxygen allowed the evolution of complex organisms that made use of the oxygen
  • The O2 created the ozone layer which blocks harmful rays from the sun
  • It also enabled even more complex organisms to form
  • There is now virtually no CO2 left
• Todays atmosphere is made up of Approximately

  • 78 % nitrogen
  • 21 % oxygen
• Test for oxygen

  -> Checking If a glowing splint relights at the open end of the test tube