Physics News

Protected By Science My hand is like a red-hot poker to the liquid nitrogen, but an insulating layer of nitrogen gas forms- a phenomenon known as the Leiden-frost effect- keeping my hand safe and warm for a fraction of a second. Mike WalkerA layer of bubbles protects the flesh from liquid nitrogen, though only for a split second. Need proof? Watch the video When I first saw this photograph of a man's hand submerged in liquid nitrogen at somewhere below -320° F, my immediate thought was, "That guy must be crazy! One second in that stuff, and you're shopping for new skin!" My shock was tempered only slightly by the fact that it was my hand, and we'd taken the picture just a minute earlier. I hadn't realized that my hand was quite so deep into the liquid. Amazingly, I barely felt the cold at all. My skin didn't get hurt for the same reason that water droplets dance on a hot skillet. An insulating layer of steam forms almost instantly between the water and the metal, keeping the droplets relatively cool