stupid question i no, you burn logs of wood but where does the weight go?

[Lyndon]

ok yes this is stupid but the question is where does the weight go from wood? a fire place takes many logs of wood from a heavy pile & once burnt theres only light ash but the weight is a interesting mystery.

[david_bowman_sc]

The wood is burned. Most of the carbon in the wood is converted to carbon dioxide by combining with oxygen from the air. The water in the wood (if it's not completely dried out) turns into steam, then cools to become water vapor. A number of other gaseous compounds are formed in the burning of the wood. All of these take away the weight of the wood, leaving relatively little left as ash.

THERE ARE NO STUPID QUESTIONS. There are, however, a LOT of stupid answers.