The Ever Changing Earth

The Ever Changing Earth

1. The Earth's Structure

   • 3 main layers
     • Outer and Inner core
       • The inner core is a solid ball of iron and nickel
       • Whereas the outer core is a layer of molten iron and nickel
     • The mantle
       • Made up of magma and is around 2900km thick
     • The crust
       • Made up of plates which are made up of oceanic and continental crust
   • Plate Boundaries
     • Divergent
       • Plates move apart at mid-ocean ridge, volcanic activity produces new igneous rock
     • Convergent
       • At a destructive plate boundary, the more sense plate is pushed down into the mantle, where it melts to form magma, causing explosive volcanoes
     • Transform
       • Plates slide past each other, powerful eqs are generated, no volcanoes as melting doesn't occur

2. The Rock Cycle

   • Igneous
     • Made from molten rock e.g. Basalt
       • Magma rises to fill a gap, cools and solidifies making new igneous rock
   • Sedimentary
     • Made from layers of sediment squashed together e.g. Limestone
   • Metamotphic
     • Made from other rocks exposed to heat and and pressure e.g. Marble
   • Tectonic plates move together, denser plate pushed down, may melt or deform, so it's destroyed/deformed. If it cools to form new rock it would be said to be recycled.

3. The Original Atmosphere

   • Methane
     • Reacted with early Oxygen
       • (Process happened v quickly, levels of CO2 dropped)
         • CO2 dissolved in oceans then concentrated into the shells of the sea creatures as calcium carbonate
           • Sedimentary rocks - Limestone and Chalk
   • CO2
     • Photosynthesis
       • Some carbon trapped as fossil fuels
       • Oxygen built up very slowly
         • Oxygen (21%)
           • Our Atmosphere now
   • Ammonia
     • Reacted with oxygen + denitrifying bacteria in soil
       • Nitrogen (78%)
   • Steam
     • Condensed as the Earth cooled down to form oceans

4. Composition of Original Atmosphere

   • 1. Earth is a ball of molten rock. No atmosphere
   • 2. Earth is still too hot for any surface water. Surface is covered in volcanoes
   • 3. Earth starts to cool down. Water vapour condenses and oceans are formed
   • 4. Life begins in oceans. Simple plants use CO2 in photosynthesis. Ozone forms and oxygen levels start to rise
   • 5. Land plants start to appear. Oxygen levels rise rapidly
   • 6. Animals evolve due to increase in oxygen
   • 7. Balance between CO2 and oxygen is achieved
   • 8. CO2 levels rise due to pollution. Global warming starts - weather patterns are affected

5. Acid Rain

   • 1. Fossil fuels are burned which release gases (CO2)
   • 2. Radiation from sun enters the atmosphere
   • 3. This heats up the Earth's surface
   • 4. Beams bounce off the surface, some get trapped while others escape out of the atmosphere
   • 5. Beams bounce back to surface, process repeats

6. The Earth's Structure

   • 3 main layers
     • Outer and Inner core
       • The inner core is a solid ball of iron and nickel
       • Whereas the outer core is a layer of molten iron and nickel
     • The mantle
       • Made up of magma and is around 2900km thick
     • The crust
       • Made up of plates which are made up of oceanic and continental crust
   • Plate Boundaries
     • Divergent
       • Plates move apart at mid-ocean ridge, volcanic activity produces new igneous rock
     • Convergent
       • At a destructive plate boundary, the more sense plate is pushed down into the mantle, where it melts to form magma, causing explosive volcanoes
     • Transform
       • Plates slide past each other, powerful eqs are generated, no volcanoes as melting doesn't occur

7. The Rock Cycle

   • Igneous
     • Made from molten rock e.g. Basalt
       • Magma rises to fill a gap, cools and solidifies making new igneous rock
   • Sedimentary
     • Made from layers of sediment squashed together e.g. Limestone
   • Metamotphic
     • Made from other rocks exposed to heat and and pressure e.g. Marble
   • Tectonic plates move together, denser plate pushed down, may melt or deform, so it's destroyed/deformed. If it cools to form new rock it would be said to be recycled.

8. The Original Atmosphere

   • Methane
     • Reacted with early Oxygen
       • (Process happened v quickly, levels of CO2 dropped)
         • CO2 dissolved in oceans then concentrated into the shells of the sea creatures as calcium carbonate
           • Sedimentary rocks - Limestone and Chalk
   • CO2
     • Photosynthesis
       • Some carbon trapped as fossil fuels
       • Oxygen built up very slowly
         • Oxygen (21%)
           • Our Atmosphere now
   • Ammonia
     • Reacted with oxygen + denitrifying bacteria in soil
       • Nitrogen (78%)
   • Steam
     • Condensed as the Earth cooled down to form oceans

9. Composition of Original Atmosphere

   • 1. Earth is a ball of molten rock. No atmosphere
   • 2. Earth is still too hot for any surface water. Surface is covered in volcanoes
   • 3. Earth starts to cool down. Water vapour condenses and oceans are formed
   • 4. Life begins in oceans. Simple plants use CO2 in photosynthesis. Ozone forms and oxygen levels start to rise
   • 5. Land plants start to appear. Oxygen levels rise rapidly
   • 6. Animals evolve due to increase in oxygen
   • 7. Balance between CO2 and oxygen is achieved
   • 8. CO2 levels rise due to pollution. Global warming starts - weather patterns are affected

10. Acid Rain

    • 1. Fossil fuels are burned which release gases (CO2)
    • 2. Radiation from sun enters the atmosphere
    • 3. This heats up the Earth's surface
    • 4. Beams bounce off the surface, some get trapped while others escape out of the atmosphere
    • 5. Beams bounce back to surface, process repeats