QUICK PHYSICS INFO: Not To Freeze; Leidenfrost Effect
If we touch any point of our body with -195 degrees, the thing that we will encounter is probably freezing where we touch and, it will be broken in a few seconds and fall to pieces. You can try this by inserting your hand into liquid nitrogen.
However, there is a man in the following video who takes his hand into liquid nitrogen and has no harm. This is a contradiction to what I said above. Before I explain the reason for this, I would like to give you some information about Nitrogen. Nitrogen starts to boil at -195.79 degrees Celsius, which in other words is liquid nitrogen. If you plunge an object into liquid nitrogen, it will freeze within seconds. Well, why does not this guy see a damage when he puts his hand through the liquid nitrogen?
We can explain this with Leidenfrost Effect. The average temperature the human body has is about 36.5 degrees centigrade. Contact with liquid nitrogen at this temperature causes a rapid boiling reaction. The evaporated liquid creates a protective wall between the hand and the liquid, providing superior protection for a few seconds. But this is very risky because if the man in the video touches the nitrogen for a few seconds more, it will probably have a frozen organ.