early atmosphere

• what produced the gases that formed earths early atmosphere

  volcanic activity
• how was earths early atmosphere formed

  initially , the earths atmosphere was molten with no atmosphere

  then global cooling caused land masses to form , then volcanoes formed on the land masses and released gases which formed the early atmosphere
• what did the earths early atmosphere contain

  little or no oxygen

  large amount of carbon dioxide

  water vapour

  small amounts of other gases
• how did oceans initially form

  condensation of water vapour as the earth cooled
• how did the amount of carbon dioxide in the atmosphere decrease after the oceans formed

  carbon dioxide dissolved into the oceans so the amount of carbon dioxide in the atmosphere decreased
• how did the amount of oxygen increase

  the growth of early plants uses carbon dioxide for photosynthesis , this meant that oxygen was released into the atmosphere , this increased the amount of oxygen in the atmosphere and decreased the amount of carbon dioxide
• what is the chemical test for oxygen

  insert a glowing splint into a test tube of gas , if oxygen is present , the splint will ignite
• what are greenhouse gases

  various gases in the atmosphere (such as carbon dioxide methane and water vapour) that absorb the heat radiated from earth , which subsequently releases energy keeping the earth warm
• what is the greenhouse effect

  electromagnetic radiation from the sun passes through the earths atmosphere

  the earth then absorbs some of the radiation and warms up

  heat is radiated from the earth as infrared radiation

  some of this infrared radiation is absorbed by greenhouse gases in the atmosphere which warms up the earths atmosphere
• how has human activity increased carbon dioxide concentration

  burning fossil fuels for energy releases carbon dioxide

  deforestation reduces the amount of photosynthesis occuring so less carbon dioxide is converted to oxygen
• evaluate the evidence that human activity is causing climate change

  there is a correlation between carbon dioxide concentration in the atmosphere , fossil fuel consumption and temperature change however correlartion doesnt mean causation

  there may be uncertainties in the data depending on the location of the measurements and historical accuracy
• what is the current composition of earths atmosphere

  nitrogen - 78 percent

  oxygen - 21 percent

  argon - 0.93 percent

  carbon - 0.04
• what are the effects of global warming

  melting of polar ice caps

  difficulties acquiring drinking water

  flooding

  forest fires

  destruction of ecosystems
• how has human activity increased the amount of methane in the surface

  raising livestock such as cows

  decay of organic waste in landfill sites
• how can the effects of global warming be mitigated

  construct flood defences in areas of low lying land

  the use of irrigation systems to provide water in drought

  produce alternative crops which are better adapted to the new environment