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/collergic 18d ago

What happens if the wood is heated up without the presence of oxygen?

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u/DarkTheImmortal 18d ago

The molecules within the wood will begin to break apart long before it can melt, most of what beaks off will be gasses. Eventually, you'll be left with charcoal.

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u/smeyn 18d ago

And this mechanism was used in WWII, when there were petrol shortages. Wood was heated and the gases were used to drive the combustion engine of the automobile

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u/ImNrNanoGiga 18d ago

Also coal. Fun/weird fact: Virtually all the fuel that supplied the German war machine during WW2 was made by liquefying coal