What is Fossil fuel?
[[File:Embers 01.JPG|thumb|220px|right|Coal burning to provide heat]] '''Fossil fuels''' are [[fuel]]s that come from old life forms that [[decomposition|decomposed]] over a long period of time. The three most important fossil fuels are [[coal]], [[petroleum]], and [[natural gas]]. Petroleum and gas are [[hydrocarbon]]s (molecules that have only [[hydrogen]] and [[carbon]] in them). Coal is mostly [[carbon]]. These fuels are called [[fossil]] fuels because they are dug up from underground. [[Coal mining]] digs up solid fuel; gas and [[oil well]]<nowiki/>s bring up liquid fuel. Fossil fuel was not much used until the [[Middle Ages]]. Coal became the main kind of fuel with the [[Industrial Revolution]]. == Uses == Most of the fuels people burn are fossil fuels. A big use is to make [[electricity]]. In [[power plant|power plants]] fossil fuels, usually coal, are [[combustion|burned]] to heat [[water]] into [[steam]], which pushes a fan-like object called a [[turbine]]. When the turbine spins around, [[magnet]]s inside the turbine make electricity. [[Crude oil]] (petroleum) can be separated to make various fuels such as [[liquefied petroleum gas|LPG]], [[gasoline]], [[kerosene]], jet fuel, and [[diesel fuel]]. These substances are made by [[fractional distillation]] in an [[oil refinery]]. They are the main fuels in [[transportation]]. That means that they are burned in order to move cars, trucks, ships, airplanes, trains and even spacecraft. Without them, there wouldn't be much [[transport]]. People also burn fossil fuels to heat their homes. They use coal less for this than they did long ago, because it makes things dirty. In many homes, people burn natural gas in a [[stove]] for [[cooking]]. Fossil fuels are widely used in [[construction]]. == Origin == All fossil fuels come from the periods in Earth's history when the Earth had huge [[rain forest|tropical forests]]. In those periods, plants lived, grew and died, faster than they decayed. In other words, they were times when much of the dead v