Can Solids Really Burn Underwater?

[UMath1]

I was cooking oats in water yesterday and the oats at the bottom of the pot got scorched. How is this possible? Doesn't the water smother the oats from oxygen?

 

[Borek]

You don't need oxygen for the thermal decomposition of the organic substances.

In other words: nothing was burnt.

 

[UMath1]

But doesn't a combustion reaction proceed?

 

[Bystander]

https://en.wikipedia.org/wiki/Chemical_decomposition

 

[Borek]

But doesn't a combustion reaction proceed?

No.

 

[UMath1]

Alright. So thermal decomposition can produce the same burnt smell and charred look that burning can?

 

[Borek]

Yes. Charring is part of the burning - heat decomposes organic matter even before it starts to react with the oxygen.

 

[Ygggdrasil]

See https://en.wikipedia.org/wiki/Pyrolysis especially https://en.wikipedia.org/wiki/Pyrolysis#Cooking

 

[UMath1]

Thanks!

 

[hilbert2]

There are some substances that can actually "burn" under water because they are more powerful reducing agents than hydrogen and can therefore take the bound oxygen from water molecules. Magnesium metal is one example of this.