earth and atmosphere

• structure of the earth

  thin crust

  core- made of molten nickel & iron

  outer part liquid inner part solid

  mantle - properties of solid but can flow 


  average density of the earth is much higher than the crust so the inner core is very dense
• plate tectonics

  pangea- one giant continent

  split over years creating continents we know today

  plates of rock float in the magma below movement is explained by plate tectonics 


  Alfred wegners evidence for the change

  jigsaw fit of continents

  simular rock structure on different continents

  fossils found on different continents were similar

  COULDNT explain how plates moved -> convection currents found later in the mantle
• plate boundaries

  3 types which cause earthquakes/volcanic eruptions

  1. constructive plate boundary- plates move apart molten rock rises from mantle to fill gap cools forming new rock
  2. destructive plate boundary- plates come together the more dense oceanic plate moves under the less dense continental plate-> subduction mountains form
  3. conservative plate boundary- plates move past each other causing powerful earthquakes but no volcanos
• changing atmosphere

  stage 1 volcanos release carbon dioxide ammonia and steam

  stage 2- volcanos stop the earth cools steams and condenses forming seas and oceans

  stage 3- photosynthetic bacteria take in Co relase O so Co decreases and O increases

  stage 4- current atmosphere

  nitrogen 78%

  oxygen 21%

  inert gases 0.96%

  carbon dioxide 0.04%
• maintaining atmosphere

  repiration and photosynthesis maintained the balance for years

  combustion from human activity have upset this balance and deforestsation level rise 


  increased carbin dioxide

  changing weather patterns- drier hotter summers

  flooding due to greater rainfall

  rising sea levels as ice cups melt
• pollution

  •reducing carbon dioxide emissions

  reduce use of fossil fuels

  increase use of wind wave and solar power

  • add rain

  produced when sulphur dioxide in burnt when coal burns

  sulphur dioxide and water react -> sulphuric acid - damaging

  • biofuel

  fuel derived from organic materials

  •carbon neutral fuel eg bio ethanol

  amount of carbon dioxide taken in during photosynthesis = a released when bioethanol is burnt
• thermal decomposition

  uses heat energy to breakdown a compound. metal compounds are decomposed if heated strongly 


  measure how quick it occurs by

  timing colour change of the metal carbonate

  timing the colour change of the limescale
• limescale cycle 


  diagram |