I was curious why extremely cold substances, especially liquids, feel like they’re burning your skin when you come in contact with them. I read somewhere that it was because the heat was “flowing” through your skin and nerves as it left your body. This doesn’t seem logical to me though. What’s the real deal?
Dunno the answer to your question but
Part of the training for handling Anhydrous Ammonia is protecting skin from burns. Basicly rubber gloves and eye protection.
Several years ago my Father in Law was burnt from his upper chest to his knees.He spent several days in the hospital. He was lucky the valve was off and it was just the ammonia in the hose that burnt him.
It can be nasty stuff.
Perhaps I’d better qualify my post.
He was applying agricultural anhydrous ammonia and used the hose to pull himself up on the wagon.
It might have something to do with the various liquids freezing and bursting cells.
I think the person that said something about skin cells could be right.
In grade 9 science, I learnt that heat transfers from one object to another. It kinda spreads itself out. Like if you put cold milk into hot coffee.
Say you put something really cold on your arm. Heat will travel from your arm to the ‘something really cold’.
As for the burning sensation, it could be due to the extreme variant in temperature. It’s probably the same kind of thing that happens when you get sunburn or a burn from ‘something really hot’.
An acceptable answer? 
Burns are the result of injuries to cells and thereby, tissue. The original cause was heat. However, extreme cold, caustics such as lye or acids, radiation, etc. can also injure or kill cells and such injuries are similar to a burn from heat.
The nervous system doesn’t have a special receptor for “freezing cold that kills cells.” Ordinary cold, yes, and ordinary heat, but tissue damage, whether it’s physical, chemical, or thermal, is all pretty much the same.
Yeah, that’s the answer as I know it. Extremely cold substances don’t burn the skin, but they cause cellular damage. You kill a bunch of cells, it’s gonna hurt, no matter what the cause.
I think that you can tell the difference in feeling between a burn from heat and at least some other kinds of damage. So, there’s more than just “pain”.
The explanation about heat flowing through the skin sounds dumb to me, too.
Much liklier, I think, is that we didn’t have much evolutionary pressure - certainly not for long, anyway - to develop an ability to distinguish dangerously cold things from other things, and so we get senses that aren’t very well adapted to it.
We had even less pressure to notice radioactivity, for instance, and we have no sense at all of that. Whereas sharp and hot have been important - and sensible - for a long time.
So the consensus is that both burning and freezing damages nerves in the same way and thus cause the same type of pain? Any ideas why we feel like we’ve been burned in both instances? Perhaps it’s because people are more accustomed to being burned than they are to having their cytoplasm frozen, since liquids well below the freezing point of water don’t typically occur in nature.
I note that I’ve never touched anything cold enough to “burn” me. I’m just going by what people say.
I’ve also heard that burning and freezing have essentialy the same effect on skin. And I was told by my high school biology teacher that when skin is exposed to extreme hot or cold it causes both your hot and cold receptors to fire, and that is what causes the pain.
The wound caused by freezing the skin is treated like a burn caused by heat.
well if you think about it for a minute it makes sense. What is the evolutionary benefit of being able to sense hot or cold? Ouch that is hot, I shouldn’t touch it. Ouch that is extremely cold, probably shouldn’t touch it. In both cases your body is sending you a message to remove yourself from the situation. Does your brain really need to feel the difference between hot and cold in order to protect you from the damage they cause?
When I was a kid I thought I stepped on a lit cigarette (common back in they day) when I jerked my foot away I saw an ice cube on the grass. The immediate sensation was identicle to being burned.
Not really scientific proof, but I thought I’d throw out some personal experience.
Just to clarify, heat does indeed flow out of your body and into the cold object. There’s no denying that. But it is not really the flow of heat that causes the burning sensation. It’s just the extreme loss of heat, which kills cells, like everyone else said.