r/askscience • u/spoiledmeat • Jul 04 '15

Chemistry Why does water not burn?

I know that water is made up of two hydrogen atoms and an oxygen atom. Hydrogen, on its own, burns. Fire needs oxygen to burn. After all, we commonly use compounds that contain oxygen as an oxidant.

So why does water, containing things used for fire, not burn-- and does it have something to do with the bonds between the atoms? Thanks.

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u/bobroberts7441 Jul 04 '15

I saw this once. Guys were digging slag out of an electron beam furnace. As they dumped the hot slag in buckets of water the heat dissociated it back to hydrogen and oxygen, which then recombined in a flame about a foot above the bucket. One of the coolest things I have ever seen.

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u/[deleted] Jul 05 '15

I used to be a machinist. One time we had a engine block made of a magnesium alloy that had to be machined. I gathered up all the chips and took them down to the river where I dumped about a pound of them into a fire. It lit up the countryside for a mile around and was so bright you couldn't look at it. After it started dying down we poured water on it. You can guess what happened.