[rmh47]

Many years ago, when I was a technician in a lab that designed and tested air conditioners for a major appliance manufacturer, we used liquid nitrogen for pulling the charge out of units to measure the amount of freon in them.

The stuff was neat to work with. You could plunge your hand into the dewar flask without any problem as long as you pulled it right back out. You could cup your hand as you brought it out and hold a small amount of it in your hand as long as you kept tilting your hand back and forth to keep the liquid nitrogen from sitting in one place.

Apparently, the temperature differential between your body and the liquid nitrogen is so great that the radiant heat from you hand causes the stuff to instantly boil and forms an insulating layer of gas between them.

[supercat]

Apparently, the temperature differential between your body and the liquid nitrogen is so great that the radiant heat from you hand causes the stuff to instantly boil and forms an insulating layer of gas between them.

The Leidenfrost effect. If your dip your hand in water, you can then very briefly dip it in molten lead with similar non-effects, but only if the lead is hot enough. Otherwise very bad.

[Hillarys Gate Cult]

Another use for nitrogen that's well known around aircraft maintenance circles is it's use in vehicle tires instead of compressed air. It stops most all slow leaks.

[Neologic]

Apparently, the temperature differential between your body and the liquid nitrogen is so great that the radiant heat from you hand causes the stuff to instantly boil and forms an insulating layer of gas between them.

You are referring to the Leidenfrost effect. It's really quite fascinating and you can do more than hold a ball of liquid nitrogen in your hands. It's even possible to dip your hand into molten lead or to gargle liquid nitrogen, if you know what you are doing. See this page for some interesting discussion and cool photos of the above.