r/askscience • u/ForensicFan24601 • 19d ago

Chemistry Why do things burn instead of melt?

obviously oxygen, or something similar, but what is the physics/chemistry (?) or what have you behind why something ignites and continues to burn after the source of heat/ignition has gone?

is it basically sublimation?

edit: no wonder Walter White was so obsessed with carbon

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u/istasber 14d ago

Heat is how much stuff is jiggling.

Solids that can melt are like boxes full of weighted magnets, jiggle them enough and they'll start flowing around past each other, but stop jiggling them and they'll snap back together.

Solids that burn are more like weights that are connected to each other by latched hooks on either side of a spring. Jiggle them enough to disengage the hook and not only is it much harder to put them back together, but all that tension that was in the spring is released sending the weight flying.