What do fossil fuels have to do with energy?
Can you be more specific about what you are trying to ask?
Any matter has to do with energy with E=mc^2
If you are thinking about using fossil fuel as the driver of heat engines, than it just means that there is chemical energy left in these fossils during the days when they underwent photosynthesis. They don't dissapear from millions of years underground. Engines burn these fossils which the fossils in turn release energy as the chemicals rearrange themselves to form more stable bonds. Altough this can only be achieved when an intial amount of energy is provided to kickstart this reaction. It is the released energies mainly in the form of thermal energy that drives heat engines.
So in terms of machinary, fossil fuel is to do with thermal energy or heat. It is the heat that keeps the engines going.
Fuels are used to create energy - usually through burning, or in the case of nuclear energy, splitting and joining. Fossil Fuels are just a sub-type of fuel, the ones which are thought to be created through fossils sitting around for years (coal, oil, etc).
Well, fossil fuels don't actually create energy; they release it. You can think of them basically as stored solar energy. Some are vegetation-based, and some are animal-based. The plants directly converted sunlight, and the animals ate the plants (or other animals that had eaten plants), so it all comes down to the sun in the final analysis.
You can think of fossil fuels as a form of potential energy. You can think of potential energy like this: If you lift a rock up three feet, the rock has aquired a certain amount of potential energy in the gravitational field. Then if you let it drop, some of that potential energy will turn to sound energy when the rock hits the ground. That is what you hear.
Fossil fuels are the same except that the potential energy they contain is in their molecular bonds (how their atoms are put together). They need just a little push (like a rock on the edge of your desk) and the potential energy in their molecular bonds will be released creating heat (energy).
Which is why I said they're -used- to create it :)
No, that't no true (energy cannot be created except by nuclear means) . And uranium and plutonium are not fossil fuels so that doesn't count.
By the way, the original question "What do fossil fuels have to do with energy?" looks to me like an obvious homework problem so I'm moving it.
As HallsOfIvy said, fossil fuels do not create energy; they simply release the chemical energy stored by the chemical bonds between elements or compounds.
Excuse me for not getting into the semantics of the difference between create and release. And even energy "produced" by nuclear means is still just a conversion.
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