Fossil fuels

• What are the three types of fossil fuels?

  Coal, oil, and gas
• How are fossil fuels formed?

  Over millions of years from organic remains
• Why are fossil fuels considered non-renewable?

  They will run out if used continuously
• What is the process of coal formation?

  • Remains of ferns and trees
  • Die in marshy wetlands
  • Lack of oxygen or acidic conditions prevents decomposition
  • Covered with sediment and compressed
  • High temperature and pressure create coal
• How is crude oil formed?

  • Formed from plankton in the sea
  • Plankton die and settle in mud on the seabed
  • Lack of oxygen prevents decomposition
  • Compressed by sediment and heat
  • Converted into crude oil
• What is the formation process of natural gas?

  • Mainly composed of methane
  • Formed from plankton like oil
  • Often found near oil deposits
  • Created under heat and pressure
• What key fact is associated with old fossil fuels?

  They contain trapped carbon from carbon dioxide
• What process takes in carbon dioxide and produces oxygen?

  Photosynthesis
• What happens to carbon in fossil fuels when they are burned?

  It is released into the atmosphere
• What was the composition of the early atmosphere?

  High carbon dioxide, virtually no oxygen
• What is the current composition of the atmosphere?

  Plenty of oxygen, small carbon dioxide
• How does the lack of oxygen affect decomposition in fossil fuel formation?

  It prevents bacteria from decomposing organic matter