When a fire burns out, where does it go?
(Lansing State Journal, July 1, 1992)
When you turn off the electricity to a light bulb, the light does not go anywhere; when the electricity stops going through the bulb, the bulb simply stops emitting light.
A fire works similarly. Fire consists of hot gases created by a chemical reaction between a burn able material (such as wood or gasoline) and oxygen from the air. A wood fire begins when the wood is heated enough (example: a match) to start a chemical reaction between carbon in the wood and oxygen. This reaction produces a hot gas that emits a large amount of heat and light. The gas forms the "flames".
Heat produced by the chemical reaction raises the temperature of unburned wood, which can start burning - in such a case, we say that the fire is "self-sustaining." The fire continues until all the wood is burned or until the wood can no longer burn. The fire can be stopped by throwing enough water on the wood to cool it, or by covering wood with foam from a fire extinguisher. All of these things stop the reaction, no more heat or light is emitted and the flame dies.
So when a fire burns out, it does not go anywhere. It just stops.