Earth and atmospheric science

• The gases produced by volcanic activity formed the Earth’s early atmosphere.
• What did Earth's early atmosphere contain?

  • Little or no oxygen
  • A large amount of carbon dioxide
  • Water vapour
  • Small amounts of other gases
• Explain how condensation of water vapour formed oceans:


  • Earth's atmosphere contained water vapour and gases from volcanic activity.
  • Cooling of Earth's surface led to the condensation of water vapour.
  • Condensed water droplets formed oceans over time.
  • Oceans are part of the water cycle, stabilizing Earth's climate.
  • Oceans provided habitat for early life forms and influenced biodiversity.
  • Geological processes further shaped Earth's surface and oceans.
• Explain how the amount of carbon dioxide in the atmosphere was decreased when carbon dioxide dissolved as the oceans formed:

  • CO2 dissolved in oceans as water vapour condensed.
  • Carbonates precipitated, forming sediments on the seabed.
  • Marine life used carbonates to form shells and skeletons.
  • Green plants and algae absorbed CO2 during photosynthesis.
• The growth of primitive plants used carbon dioxide and released oxygen by photosynthesis and consequently, the amount of oxygen in the atmosphere gradually increased.
• What is the chemical test for oxygen?

  The oxygen test is the glowing splint.
• Various gases in the atmosphere, including carbon dioxide, methane and water vapour, absorb heat radiated from the Earth, subsequently releasing energy which keeps the Earth warm: this is known as the greenhouse effect.
• What is the correlation between human activity and climate change?


  • An increase in atmospheric CO2 correlates with fossil fuel consumption and temperature rise.
  • Burning fossil fuels releases CO2, contributing to the greenhouse effect and warming.
  • Temperature records show consistent global warming in line with CO2 increase and fossil fuel use.

  
• What is the composition of today's atmosphere?

  • Nitrogen (78%)
  • Oxygen (21%)
  • Trace gases like argon, carbon dioxide, and methane.
• Effects of increased CO2 and methane:

  • Greenhouse effect
  • Global warming
  • Melting polar ice caps
  • Extreme weather events
  • Ocean acidification
  • Methane emissions from livestock farming.
• Strategies to combat climate change:

  • Transition to renewable energy
  • Sustainable agriculture practices
  • Afforestation and reforestation
  • Carbon capture and storage technologies.