What is Fuel?
[[File:Diverse Kanisterformen.png|thumb|upright|right|Cans of petroleum. Petroleum is a type of fuel.]] A '''fuel''' is a [[substance]] that is changed in some way to produce [[heat]], [[electricity]], or other forms of [[energy]]. This is usually by being burnt in [[fire]], although there are exceptions, such as [[nuclear fuel]]. Fuel can be divided into two main types: [[fossil fuel]]s and other fuels. == Fossil fuel == {{Main|Fossil fuel}} There are several kinds of fossil fuels: * [[coal]] * [[oil]] and products that are [[refine]]d from oil ([[gasoline]], [[diesel fuel|diesel]], [[kerosene]]) * [[natural gas]] Some people do not want us to use fossil fuels because they may [[pollution|pollute]] the [[environment]]. Because all fossil fuels are made out of [[carbon]], burning them makes [[carbon monoxide]] and [[carbon dioxide]]. Too much carbon dioxide in the air causes a [[greenhouse effect]]. Carbon monoxide in the air is [[poison]]ous to humans and animals. Fossil fuels are also non-renewable, or renew extremely slowly (thousands to hundreds of millions of years). This means that we will eventually run out of fossil fuels. == Other fuels == Other fuels are not made from fossils. Some of these, like nuclear and hydrogen, do not have carbon in them. Others, like wood or ethanol, do have carbon in them. Some examples of these fuels are: * [[Nuclear fuel]] ([[uranium]], [[plutonium]], [[thorium]], etc.) * [[Hydrogen]] * [[Biofuel]]s from [[biomass]] ** [[Firewood]] ** [[Biodiesel]] (a diesel-type fuel made from [[plant]]s) ** [[Ethanol]] (made from [[grain]]s or other plants) These fuels are renewable. This means that we can make more of them if we run out. For instance, if we run out of ethanol, we can grow some more corn and make some more ethanol. == Other websites == {{commons|Fuel}} * [https://en.citizendium.org/wiki/Fuel Fuel] -Citizendium [[Category:Fuel]]