Now, when you dip your hand into liquid nitrogen, it would hurt. But what would happen if you splashed it all over your face? Well, according to Grant Thompson, absolutely nothing!
But there is a scientific reason to his madness. When he splashed the liquid nitrogen on his face it didn’t hurt him because of the Leidenfrost effect.
It simply means when a substance evaporates so quickly, it actually sits on a thin layer of vapor. So in this case, the liquid nitrogen never really comes in contact with his face. So no damage is done.