The Leidenfrost Effect
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The Leidenfrost effect is a physical phenomenon that happens when a liquid is exposed to an extremely hot substance.
It is named for Johann Gottlob Leidenfrost, who described the phenomenon in A Tract About Some Qualities of Common Water in 1796.
If you were to sprinkle a few drops of water on a warm frying pan, the drops would evaporate instantly into vapor.
If the pan keeps heating up until it hits the Leidenfrost Point (the point where a metal that is much hotter than the boiling point of water), the drops you splashed in the pan wouldn't just lie there. They would roll or skitter across the pan in beads, seemlingly hovering over the surface not knowing where to go next. Why? The water isn't actually rolling across the surface of the pan. It's rolling on a thin cloud of water vapor between it and the metal as evidenced in the gif above.
The physics behind the Leidenfrost effect are relatively straightforward. When liquid heats rapidly as a result of contact with something extremely hot, it forms a vapor layer. Vapor does not conduct heat very well, so it acts as a barrier between the heat of the pan and the remaining liquid. The droplets might appear to skim on the surface as the vapor drifts. Eventually, it steams away, as does the rest of the water.
This man is able to to dump his hand in liquid nitrogen (-196 degrees Celsius or -321 degrees Fahrenheit) and pull it out completely unharmed due to the Leidenfrost effect. This time, his hand being the object being exponentially hotter than the liquid.
In 2014 during the Ice Bucket challenge craze, where people poured ice cold water over their heads to promote awareness of ALS (amyotrophic lateral sclerosis or Lou Gehrigs's disease), Russians created their own unique version where they dumped even ice cold(er) liquid nitrogen over themselves.
Challenge:
So the next time your buddy falls asleep and you want to soak his hand in a glass of warm water so he'll piss his pants (myth?)... Dip it in liquid nitrogen instead and maybe he'll piss frozen piss popsicles for you and your buddies to enjoy. Now that you know the science behind it, any and all experimentation pertaining to the Leidenfrost effect should probably end well for all parties involved so by all means do try this at home and upload the results to youtube for everyone's entertainment.
The Leidenfrost effect - A person dipping his fingers into a pot of molten lead. Prior ... - http://t.co/shnrgS9tTx pic.twitter.com/i6WtFpEHtk
— Melbourneer (@_Melbourneer_) March 17, 2015
(Edit: But seriously, don't try this at home. Everyone is trying to find new ways to look cool and be the next internet viral sensation but wind up looking like this guy instead:
Hold my beer while I sit on an airbag. pic.twitter.com/cyTDWpzqh7
— Hold My Beer GIFs (@HoldMyBeerGif) March 12, 2015
except you'll be fucking dead, brah)
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