A video circulating on Reddy shows that a person has the apparent ability to shake hands with molten metal without being injured. In the footage, he walks into a stream of liquid metal, removes his safety gloves and moves his hand forward into the red-hot liquid. Then, he left that it was no big deal, completely injured.
Do not try it at home, even if you have an industrial molten metal sluice in your home. So how is he able to do this without melting his own hands or without extreme burns? Is he some kind of reverse-terminator that is resistant to molten metal? However, the answer is still quite great. The potential is probably due to the Leidenfrost effect. The Leidenfrost effect is that the water droplets instantly dance around to become very hot instead of steam.
When a liquid dumped on a hot plate, the bottom layer of the liquid evaporates instantly. This leaves a protective layer of gas between the hot plate and the remaining water droplets, preventing contact between the two and slowing the heat transfer. This is rather neatly explained in this video from the British TV show QII hosted by Stephen Fry.
The same effect protects the person in the video who swaps hands like a normal tap by molten metal. For a very short time, the moisture in her skin instantly boiled over, forming a protective layer on her skin and preventing it from being in direct contact with the liquid metal. This allows him to swipe his hand through it without burning. If he does this for more than a second, he will probably burn badly. So do not try it at home.
The same effect observed with liquid nitrogen. Liquid nitrogen boils at -196°C (-321°F) and evaporates when it comes contact with a warm surface (such as a floor or a human hand). This creates a layer of gas between itself and the surface. As a result, there are very cool videos on YouTube of people putting liquid nitrogen in their hands and horribly few videos where people put their hands in nitrogen for too long and it all went badly. Here is one of the coolest videos, where the Leidenfrost effect was fully effective.
