Earth Y8

• Layer of the Earth that is 60km thick


  Crust
• Thickest layer of the Earth


  Inner Core
• Made of liquid iron and nickel

  Outer Core
• Made of magma

  Mantle
• Describe intrusive and extrusive rock forming

  Intrusive - magma cools down slowly as it rises through volcano, large crystals

  Extrusive - magma comes up and cools down quickly, small crystals
• Describe how metamorphic rock is formed

  When sedimentary rock travels further underground the heat and pressure becomes too much for the sedimentary to withstand, so it shifts to metamorphic rock
• Describe the formation of sedimentary rock


  Small bits of rock -sediments- are compacted and cemented together
• Earth's Percentage Atmosphere Makeup

  78% nitrogen

  21% oxygen

  1% argon and other gases
• The cause of water percentage decrease in atmosphere

  Condensed forming oceans
• The cause of a release of oxygen in the early atmosphere

  Photosynthesis
• Increase in oxygen led to what on Earth

  Animals could come to land
• Name three greenhouse gases

  Water vapour

  Carbon Dioxide

  Methane