The Leidenfrost effect

Probably everyone who has cooked in a kitchen has seen this effect without knowing it had a name or a sophisticated explanation.

The video above is brief and to the point. This longer and more comprehensive video -

shows that the same principle applies when the person sticks his bare hand into liquid nitrogen.

Addendum: I just found a description of this same phenomenon, published back in 1868, dealing with boiling tar. You can read it at Futility Closet.