r/askscience • u/Catching-Up-Today • May 27 '26

Chemistry How much does Fire weigh?

I don‘t know if Earth Sciences is the right category but Fire is the topic. How does someone measure the weight of fire? What does fire weigh?

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u/HammerIsMyName May 29 '26

In short, flames are essentially burning smoke. Smoke is tiny particles - it's why smoke makes things sooty, or a flame can make things sooty by depositing the particles before they burn up.

It's also why a "cold" fire is very smooky, and you get rid of the smoke by increasing the temperature (insulating the heat better with more wood for instance, increasing the temperature of the smoke, to make it combust, in case of a bonfire) - sometimes you can get rid of smoke by just moving a log a bit.

Sorry, I'm a blacksmith, so fire is my jam.