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The source of energy is fuel!
Fuel: is a substance that provides a form of energy, such as heat, light, electricity, or motion, as the result of a chemical change
Energy can be converted from one form to another.
Ex: rubbing your hands together(mechanical energy) creates heat (thermal energy)
Combustion: the process of burning a fuel because fuels contain stored chemical energy
Ex: gasoline must be burned in car to get the car to move
Production of electricity: energy stored in fuels can be used to generate electricity
What are Fossil Fuels?
Most of our energy that we use today comes from organisms that lived hundreds of millions of years ago.
As these plants, animals & other organisms died, their remains piled up.
Layers of sand, rock, & mud buried the dead organisms.
Over time, heat & pressure changed the material into other substances.
Fossil Fuels are the energy-rich substances formed from the remains of the once-living organisms.
There are three major fossil fuels: coal, oil, and natural gas.
Fossil Fuels are made of hydrocarbons which are energy-rich chemical compounds that contain carbon and hydrogen atoms. During combustion, carbon & hydrogen combine with oxygen to release energy.
Fossil Fuels have more hydrocarbons per kilogram than most other fuels therefore they are an excellent source of energy!

Coal is a solid fossil fuel formed from plant remains
Coal provides 23% of the energy used in the U.S.
Coal’s main use is to fuel electric power plants
Coal Mining
To use coal it must be removed from the ground or mined
Reserves: known deposits of coal (and other fossil fuels) that we get using technology
Coal as an Energy Source
Coal is the most plentiful fossil fuel in the U.S.
Advantages:
It is easy to transport provides lots of energy when burned
Disadvantages: increases erosion water pollution air pollution coal mining is dangerous job (accidents, black lung disease)
Oil is a thick, black liquid fossil fuel
Forms from remains of small animals, algae, and protists that lived in oceans
Petroleum: another name for oil
Most oil deposits are located underground in tiny holes of sandstone or limestone
Petroleum accounts for 33% of the energy produced in the world
Fuel for cars, planes, trains & ships is from oil
U.S. consumes 33% of the world’s oil
Locating Oil Deposits
Finding oil is hard because it is located deep underground
Scientists use sound waves to locate oil deposits
They are only successful 1/6 of the time at locating them
Refining Oil
Crude oil: when oil is first pumped out of the ground, is usually runny or thick liquid
To become a useful fuel, crude oil has to be refined
Refinery: factory where crude oil is separated into fuels and other products by heating
Petrochemicals: compounds made from oil; used in plastics, paints, medicines, cosmetics
Natural Gas: mixture of methane & other gases
Forms from same organisms as petroleum
Natural gas air pockets are often found above oil deposits because it is less dense than oil
Transported through pipelines
Natural gas can be compressed into a liquid to be used for truck & bus fuel
Advantages:
Produces large amounts of energy with low pollution

Easy to transport once pipelines are built
Disadvantage:
Highly flammable
Natural gas has no odor, gas companies add an odor so you can tell there is a leak
Fuel Supply and Demand
Fossil fuels are considered nonrenewable resources
Fossil fuels take hundreds of millions of years to form
We will run out of fossil fuels if we use them up before more are formed over millions of years