Atmosphere

• What is the atmosphere


  A layer of gas surrounding the Earth
• What was the early atmosphere composed of


  Mostly carbon dioxide
• How did the oceans form


  Water vapour condensing as the earth cooled
• How did the carbon dioxide in the atmosphere decrease to todays levels

  Dissolved in the ocean

  Photosynthesis

  Converted to fossil fuels
• When did life start to appear?


  About 2.7 billion years ago
• How did the appearance of life impact the atmosphere?

  Oxygen increased as it was released in photosynthesis
• How has the amount of nitrogen in the atmostphere changed over time?


  Increased slowly

  Stable molecule
• Scientists cannot be sure about the early composition of

  Earths atmosphere as it was billions of years ago and evidence is very limited
• Current composition of Earths atmosphere


  Approx. 80% nitrogen

  Approx. 20% oxygen

  Trace amounts of other gasses (carbon dioxide, water vapour..)
• Greenhouse gas


  Gas that traps radiation from the sun
• What type of radiation do greenhouse gasses absorb?


  longer wavelength infrared radiation
• 3 greenhouse gasses 


  Methane

  Carbon dioxide

  Water vapour
• 2 ways humans increased carbon dioxide in the atmosphere 


  burning fossil fuels

  deforestation
• 2 ways humans have increased the amount of methane in the atmosphere


  rice farming

  Cattle farming
• What is global warming


  Increase in overall global temperature
• What is global climate change


  The change in long term weather patterns across the planet
• Possible effects of climate change


  1. Sea levels rising
  2. Extreme weather events
  3. Changes to ecosystems and habitats
  4. Ice caps melting
• What is a carbon footprint


  Amount of carbon something releases into the atmosphere over its lifetime
• How is carbon monoxide formed?


  Incomplete combustion
• Why is carbon monoxide dangerous

  Difficult to detect (colourless + odorless)
• How are particulates formed?


  Incomplete combustion
• What are the dangers of particulates?


  Global dimming (decline of sunlight)

  Breathing problems

  Potential to cause cancer
• How is sulfur dioxide formed?


  Sulfur impurities react with oxygen during combustion
• What are the dangers associated with sulfur dioxide


  Acid rain

  Breathing problems
• How are oxides of nitrogen formed?


  Atmospheric oxygen and nitrogen react in the heat of a combustion engine
• What are the dangers of oxides of nitrogen?


  Acid rain

  Breathing