When we were in high school, a friend of mine used to get liquid nitrogen from his father, who was a chemist, and put it on his tongue and blow smoke out his mouth and nose. I thought he was nuts! That he would crack a tooth, or some such, but he never did.
IIRC correctly, he stopped when he accidentally swallowed a TINY amount. I think it made him burp for a while, but other than that, he was apparently unharmed.
This is an old story (see the date of 1999?), as a WPI guy ive heard this one a few times
The guy was attempting to use a cute little physics trick. I'm no physics major, but the idea is similar to walking on coals. You can have the liquid nitrogen in your mouth briefly and it doesn't burn you. Swallowing it, however is a totally different story.
That was his point -- having liquid nitrogen in your mouth is safer than it sounds, since you get a gas layer insulating the liquid from the rest of your mouth.
But in addition to the danger of accidentally swallowing, I've also heard stories of people having teeth crack by doing this; so I'd say that "safer than it sounds" is still far from "safe".
> "Michael performed a stunt he and other students and teachers have been doing for years," says Thomas Keil, professor and head of WPI's Physics Department. "Only this time, for some reason, he swallowed the liquid nitrogen. That turned a trick into a life-threatening medical emergency."
The evaporating liquid nitrogen creates a buffer of nitrogen gas between the liquid nitrogen and your mouth. Nitrogen gas conducts heat very poorly, so you won't get burned, as long as you're careful.
Swallowing the liquid nitrogen is different, because the nitrogen gas is trapped inside your body. According to the article, they estimate that the liquid nitrogen he swallowed expanded to "3 or 4 liters" of nitrogen gas. That won't fit in your stomach, so it will go to other parts of the body, rupturing tissue as it goes. That's what hurt him -- 3-4 liters of nitrogen gas gave him ruptured organs.
From what I could gather, it's a common parlour trick in his circles to pour liquid nitrogen into your mouth, at which point it will sort of stay on your tongue (above an air cushion that protects the tissue) until it's evaporated. But this time he swallowed, and once it's inside your body the vapour cannot escape into the room as it expands, creating horrific amounts of pressure on your insides.
Putting a small amount of liquid nitrogen on your tongue does not cause any trouble, as long as you don't swallow it. I have a friend who used to do this frequently. See a comment I made elsewhere on this story for more details
IIRC correctly, he stopped when he accidentally swallowed a TINY amount. I think it made him burp for a while, but other than that, he was apparently unharmed.