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 Walker
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 as they float for several seconds without actually touching the hot surface. To liquid nitrogen, flesh is like that skillet—a surface hundreds of degrees above its boiling point. So the moment my hand touched the liquid, it created a protective layer of evaporated nitrogen gas, just as the skillet created a layer of steam. That gave me just enough time to put my hand in and pull it out again. Any longer than that, and frostbite would have set in.
Hot Water: Droplets on a very hot skillet take longer to evaporate than they would on a less-hot surface where no insulating gas layer forms. Mike Walker
The phenomenon is called the Leidenfrost effect (after Johann Gottlob Leidenfrost, the doctor who first studied it in 1756). I’d known about it for years, but when it came time to test it in real life, I have to admit that I used my left hand, the one I’d miss less.
I drew the line at another classic example of the effect. According to the books, it’s possible to stick a damp finger directly into molten lead without getting burned, if you do it fast enough. After some consideration, and remembering the times I’ve been burned by molten lead, I decided that it probably wouldn’t make a very good picture anyway.
ACHTUNG! Do not try this. If liquid nitrogen soaks into your clothes, you will not be protected by the Leidenfrost effect, and you can get frostbite very quickly.
Scary Times For California Farmers As Snowpack Hits Record Lows 2015-04-02 2:45
The water outlook in drought-racked California just got a lot worse: Snowpack levels across the entire Sierra Nevada are now the lowest in recorded history â€” just 6 percent of the long-term average. That shatters the previous low record on this date of 25 percent, set in 1977 and again last year.
Morning traffic makes its way toward downtown Los Angeles ...
Sharia Policeman in Swedish School 2015-04-02 0:58
Editor's Note: Unfortunately this is not an April Fools story.
On monday morning emergency services were called to Eductus in BorĂĄs, a school specialized in teaching Swedish to immigrants, after a Muslim student threatened classmates who did not abide by his strict interpretation of Islam. They were reprimanded for laughing and a Christian woman who refused to wear a veil fainted ...
â€śUsâ€ť and â€śThemâ€ť 2015-04-01 22:30
Iâ€™ve decided to translate yet another one of Julia Caesarâ€™s popular Sunday chronicles available in Swedish on the website Snaphanen. This one is named â€śUs and Themâ€ť and concerns a scandal of epic proportions, the Swedish governments â€śsociety coachâ€ť program. The plan was for the coaches to assist newly arrived immigrants with getting jobs and becoming integrated into society.
The Expulsion and Extermination of Eastern European Germans: An Overview 2015-04-01 17:40 "Since the end of the war about 3,000,000 people, mostly women and children and overaged men, have been killed in eastern Germany and south-eastern Europe; about 15,000,000 people have been deported or had to flee from their homesteads and are on the road. About 25 per cent of these people, over 3,000,000 have died. About 4,000,000 men and women have ...
Your Smartphone Could be Tracking You Every 3 Minutes, Study Says 2015-04-01 2:24
Your apps want to know where you are
Smartphone apps regularly collect large amounts of data on usersâ€™ locations, sometimes as often as every three minutes, new research suggests.
Researchers at Carnegie Mellon University conducted a study where they asked 23 people to use their Android smartphones normally, and tracked location data requests from each device with specially designed software, the Wall ...