Sheltered by science-based on the Leiden effect, liquid nitrogen forms a layer of isolated gaseous layer on the surface of my skin, thus keeping my hands safe and warm in an instant.
When I first saw a man's hand dipping in a photograph of liquid nitrogen (down to minus 320°), the first reaction was: This guy must be crazy! Put your hands in that thing for a second, you'll have to buy new skins! "But when I realized that the hand in the photo was my own hand, and this picture was just the fact that we took it a minute ago, my shock eased."
I never realized that my hands were so deep in liquid nitrogen bottles. Surprisingly, I didn't even feel the presence of the air conditioner. My skin is not harmed at all, and this is consistent with the principle of the small water droplets dancing on a frying pan--the instant the waters contact the metal creates a layer of vapor that allows the droplets to float for a few seconds without touching the hot surface of the metal. In my experiment, for liquid nitrogen, the skin that was hundreds of degrees higher than its boiling point was the frying pan. So when I was intimately exposed to liquid nitrogen, it produced a layer of nitrogen vapor, like the vapor layer produced by a frying pan. It gave me enough time to reach out. And if the time is longer, frostbite is inevitable.
Water droplets take longer to evaporate on the surface of a very hot pan than those that are not too hot and do not form an insulating vapor layer. Photography:
This phenomenon, known as the Leiden Frost effect, was first discovered and named by Dr. Johann Gottlob Leidenfrost in 1756. I know this science theorem has been around for some years, but when I personally verify it, I have to admit that I used a left hand that I might miss less.
I did not use another classic experiment to verify this effect. The book says that if you move fast enough, you can stick a wet finger in the melted lead and probably not get burned. After careful consideration, plus remembering the number of times I was burned by molten lead, I decided to give up, after all, that would not necessarily be perfect.
Warning! Imitation is strictly forbidden! If liquid nitrogen soaks up your clothes, you won't be blessed by the Leiden effect. You will be immediately frostbite.
http://article.yeeyan.org/view/165940/132497/
Picture: Hand to liquid nitrogen instantly