Topic 1.4: Everchanging Earth

• What is global warming?

  Gradual increase in the earth's atmospheric temperature.
• What process takes in CO2 from the atmosphere

  Photosynthesis
• what processes release CO2 into the atmosphere

  combustion of fossil fuels and respiration
• Combustion of fossil fuels

  Takes in oxygen and gives out carbon dioxidecarbon dioxide levels increase and oxygen levels decrease
• Volcanoes


  Give out carbon dioxidecarbon dioxide levels increase
• Deforestation


  Cutting down trees means that they are no longer able to take in carbon dioxide and gives out oxygenoxygen levels decrease and carbon dioxide levels increase
• Respiration


  Takes in oxygen and gives out carbon dioxidecarbon dioxide levels increase and oxygen levels decrease
• Photosynthesis


  Takes in carbon dioxide and gives out oxygenoxygen levels increase and carbon dioxide levels decrease
• What were the three main gases that made the original atmosphere like? What changed?

  Volcanic activity released CO2, water vapour and ammonia. Eventually Eath's surface temperature decreased below 100 degrees celsius, water vapour condensed forming the oceans, CO2 decreased due to photosynthesis and 'locked up'/trapped in fossil fuels. photosynthesis produced oxygen which reacted with the ammonia and produced nitrogen.
• Sulfur scrubbing


  Removes sulfur dioxide from waste gases in order to reduce acid rain
• solutions for acid rain

  add weak alkali (slaked lime) to soil to neutralise acidic soilsulphur scrubbing
• Disadvantages of CCS

  High costs of seperation, Fuel needed in transporting CO2 burns fossils, Could leak back into the atmosphere
• carbon capture and storage (CCS)

  Carbon dioxide is trapped and seperated from other gases produced in coal-powered electricity plants. The captured carbon dioxide is transported to a storage location and finally stored underground eg. In old oil fields) or deep in the ocean using a pipeline.
• solutions for global warming

  - reduce burning of fossil fuels, by using alternative energy sources - wind, solar, water, geothermal energy, and fuel cells- reduce deforestation, plant trees-carbon capture (CCS)
• Consequences of global warming

  MORE heat energy trapped in atmosphere results in: Polar ice caps melting, Rising sea levels, Habitat loss, More extreme weather e.g. drought, flooding hurricanes, Changing weather patterns
• Factors that affect climate change

  Deforestation, Photosynthesis, Respiration, Burning fossil fuels
• What is the main cause of global warming?

  Burning MORE fossil fuels means an increase in carbon dioxide emissions.Increase in deforestation.
• What happens at a destructive Plate Margin

  A plate margin where two different plates collide. The denser oceanic plate is subducted into the mantle where old crust is destroyed and magma erupts on the Earth's surface creating igneus rock.
• What happens at a Constructive Plate boundary

  plates move apart, magma rises through the gap to the surface, cools and solidifies to form new igneous rock.
• What happens at a Conservative Plate boundary

  when two tectonic plates slide past each other. Location of catastrophic earthquakes.
• Composition of present day earth's atmosphere

  composed of 78% N2, 21% O2, 0.9% argon, 0.035% CO2
• What are the effects of acid rain?

  Problems such as INCREASED METAL CORROSION eg.Bridges, metal statutesINCREASED LAKE ACIDITY by lowering pH. HARMING AQUATIC LIFE, DAMAGES FORESTS AND VEGETATION, DAMAGE LIMESTONE BUILDINGS.
• What causes acid rain to form?

  Coal contains sulphur impurities. When coal is burned sulphur reacts with oxygen to form sulphur dioxide. Sulphur dioxide reacts with the moisture in the air to form dilute sulphuric acid which is acid rain.
• What is acid rain?

  Rain containing nitric and sulfuric acids PH 2-4.
• Theory of Plate Tectonics


  The theory that the Earth's crust is divided into tectonic plates that moves very slowly due to convection currents in the mantle.
• What did scientists later on suggest as a possible cause of continental drift?

  Convection currents in the earth's mantle act like a conveyor belt making the continents to move.
• Why did scientists not believe Wegener's theory?

  He was unable to explain how the continents moved
• Wegener's 3 pieces of evidence of continental drift


  The coastlines of continents fit together like a jigsaw, Similar rock patterns on different continents, Similar fossil patterns on different continents
• Continental drift


  The hypothesis that states that the continents once were joined together as a single landmass, supercontinent called Pangaea, broke up, and drifted to their present locations over time.
• Outer Core


  Liquid, made of mainly iron and some nickel
• Inner Core


  A dense sphere of solid iron and some nickel at the center of Earth
• Name the two inner-most parts of the Earth and their composition.


  Molten iron outer core, Solid iron inner core
• Mantle


  contains semi-molten rock called magma.It is also the layer of molten rock where convection currents occur
• Crust


  The thin and solid outermost layer of the Earth above the mantle
• Structure of the Earth

  crust, mantle, outer core, inner core