http://www.youtube.com/watch?v=gjsMV1MglA4&feature=endscreen&NR=1
stick my hand (momentarily) directly into liquid nitrogen but don't suffer any injuries due to the Leidenfrost effect.
The
Leidenfrost effect is the formation of a gas barrier between a hot
surface and a boiling liquid if the temperature difference is great
enough. This gas barrier greatly slows the heat transfer between the two
and allows the liquid to last longer and consequently the hot surface
to remain hot longer. This effect can be seen in a frying pan as it's
being heated. At first the water quickly boils as it's dropped in but at
a hot enough temperature the Leidenfrost effect takes over and makes
the water skate around the surface lasting a very long time.
Liquid
nitrogen vs. a room temperature object will also exhibit the effect
preventing it from instantly freezing the object... such as my hand.
No comments:
Post a Comment