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K12 LibreTexts

20.6: Fossil Fuel Formation

  • Page ID
    5615
  • Where is the energy coming from to power this bumper car?

    Bumper cars usually run on electricity. Much of the electricity we use comes from fossil fuels. Coal or other fuels are burned in a power plant. This powers a generator and creates electricity. So the car is probably running on fossil fuels!

    Formation of Fossil Fuels

    Fossil fuels are made from plants and animals that lived hundreds of millions of years ago. The plants used energy from the Sun to form energy-rich carbon compounds. As the plants and animals died, their remains settled onto the ground and at the bottom of the sea. Layer upon layer of organic material was laid down. Eventually, the layers were buried very deeply. They experienced intense heat and pressure. Over millions of years, the organic material turned into fossil fuels.

    Fossil fuels are compounds of carbon and hydrogen, called hydrocarbons (Figure below).

    Structure of methane

    Hydrocarbons are made of carbon and hydrogen atoms. This molecule with one carbon and four hydrogen atoms is methane.

    Hydrocarbons can be solid, liquid, or gas. Coal is an example of a solid form. Petroleum, or crude oil, is a liquid hydrocarbon. Natural gas is a gaseous hydrocarbon.

    The solar energy stored in fossil fuels is a rich source of energy. But because they take so long to form, they are nonrenewable. Fossil fuels also release a lot of greenhouse gases when they're burned.

    Summary

    • Hydrocarbons are molecules made of one carbon and four hydrogen atoms.
    • Ancient living organisms died and were buried quickly. Their remains were altered by intense heat and pressure. This formed fossil fuels.
    • Fossil fuels include solid coal, liquid petroleum, and liquid natural gas.

    Review

    1. Why are coal, petroleum, and natural gas called fossil fuels?
    2. How do fossil fuels form?
    3. Where did the energy in a fossil fuel come from originally?

    Explore More

    Use this resource to answer the questions that follow.

    1. What did fossil fuels form from? When did they form?
    2. What was Earth like during this period of time?
    3. What is the source of the fuel?
    4. Which four factors affect which type of fossil fuel forms?
    5. What leads to coal formation?
    6. What leads to oil formation?
    7. What is the difference in conditions that lead to the formation of natural gas rather than oil?
    8. Why are fossil fuels used as energy sources?
    9. What do we use fossil fuels for in terms of energy?
    10. What else do we use fossil fuels for?
    11. Why do geopolitical issues arise regarding fossil fuels? What does this really mean?
    12. Why are fossil fuels considered non-renewable fuel sources?
    13. Why is it harder to get at fossil fuels now?
    14. What does burning fossil fuels do to the environment?
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