The Leidenfrost effect is where you can stick your hand into molten lead and not get your shit burned if you do it quickly enough. It also works with a bunch of other really hot liquids. Try it at home to impress your friends.
The Leidenfrost effect is a physical phenomenon in which a liquid, close to a surface that is significantly hotter than the liquid's boiling point, produces an insulating vapor layer that keeps the liquid from boiling rapidly. Because of this repulsive force, a droplet hovers over the surface, rather than making physical contact with it. The effect is named after the German doctor Johann Gottlob Leidenfrost, who described it in A Tract About Some Qualities of Common Water.