When a chemical burns or there’s a chemical reaction, electrons in the atoms get excited and jump up to higher energy levels, and release photons when they fall back into their original place. Different chemicals/ fuels release different frequencies of photons because they have different arrangements of electrons.
E: like others have pointed out, this explains the flame color, but not really the smoke color. Smoke no longer radiates light in the visible spectrum in the way I described above, so the color of the smoke is just the color of whatever byproduct the reaction produces.
“Smoke” is not one substance, it’s just the collection of whatever solid and liquid particles get airborne when something burns, a mix of burned and unburned material. Fire is a chemical reaction between oxygen and fuel (whatever is burning). So naturally, the chemicals you get out depend on the chemicals you put in.
Latest Answers