[AdmSmith]

lit match (small input of energy) + gasoline vapor = explosion (output of energy greater than input)

No, you are releasing energy in the chemical bonds. The energy is conserved.

[aruanan]

No, you are releasing energy in the chemical bonds. The energy is conserved.

You're missing the point of the author's superficial understanding of the conservation of energy. In the overall, universe-as-the-system view, there is conservation of energy; you can't take out of a system any more energy than you put into it. From a practical and local point of view, however, we're always seeking to discover the means by which the input of a small amount of energy on our part can be used to release (usually via oxidation) or to exploit (usually via juxtaposition of an artifact with a natural force--windmills, watermills, hydroelectric dam, solar panels, etc--or the concentration and arrangement of a natural substance by technical means, such as "fuel" for a nuclear reaction) a much greater amount of energy to then be used to our advantage. People too often characterize "conservation of energy" to mean, "We can't get any more energy out of a system than we put into it." This is simply not true. We're constantly devising systems by which our energy input is considerably less than what we get out of it. This is the difference between cheap and expensive energy.

[SunkenCiv]

Thanks.