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Taking the Ice Bucket Challenge With Liquid Nitrogen 182

Posted by samzenpus
from the coldest-shower dept.
Nerval's Lobster writes As a trend, the ALS Ice Bucket Challenge seems a bit played out—who hasn't yet dumped a bucket of icy water over his or her head for charity? But that didn't stop Canadian chemist Muhammad Qureshi from executing his own sublimely scientific, potentially dangerous variation on the theme: After donating to the ALS Association, he proceeded to douse himself with a bucket of liquid nitrogen. Anyone who's taken a chemistry class, or at least watched the end of Terminator 2, knows that liquid nitrogen can rapidly freeze objects, leaving them brittle and prone to shattering. Pouring it on your skin can cause serious frostbite. So what prevented that bucketful of liquid nitrogen from transforming Qureshi into a popsicle? In two words: Leidenfrost effect. Named after 18th century scientist Johann Gottlob Leidenfrost, the effect is when a liquid comes near a mass that's much warmer than the liquid's boiling point, which (in the words of Princeton's helpful physics explainer) results in an insulating vapor layer that "keeps that liquid from boiling rapidly." In other words, the vapor makes the liquid "float" just above the surface of the object, rather than coming into direct contact with it.
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Taking the Ice Bucket Challenge With Liquid Nitrogen

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  • by mark-t (151149) <markt@@@lynx...bc...ca> on Thursday September 04, 2014 @01:00AM (#47822999) Journal

    ... how long will it take before somebody dies?

    I don't mean to sound morbid here, I am just starting to think that this whole thing is pretty darn pointless, If you want to donate money to ALS, do it... but this ice bucket challenge thing is turning into a competition of who can one-up who in how they go about it, and I think it's now only a matter of time before somebody gets seriously hurt or killed.

  • by radtea (464814) on Thursday September 04, 2014 @01:12AM (#47823047)

    ... how long will it take before somebody dies?

    Already happened: http://news.nationalpost.com/2... [nationalpost.com]

    I've stuck my hand in liquid nitrogen (it feels strangely warm) and so can attest to the protective effect of the gas blanket (which is highly insulating) but it is insanely dangerous to pour a bucket of LN2 over your head, and doing so is an invitation to people who aren't as smart or careful as you to do even more stupid and risky things.

    Donate to ALS research [*], by all means! But please, please, don't participate in this ridiculous pyramid scheme of increasingly dangerous stupidity.

    [*] I do not donate to ALS because it is not one of my causes, but I encourage you to think carefully about what you care most about and sign up as a steady, long-term donor to a few causes that are really important to you... this is of far more long-term benefit than episodic giving. If ALS is what matters most to you, go for it!

  • I did it first ! (Score:5, Interesting)

    by dargaud (518470) <slashdot2@gd[ ]aud.net ['arg' in gap]> on Thursday September 04, 2014 @01:40AM (#47823127) Homepage
    In 1994 I had a liquid nitrogen tube break above my head while preparing an experiment for Antarctica [gdargaud.net]. About 30 liters poured on my head in a second. I felt it go instantly trough my clothing, run over me, and on the floor. Everybody else in the lab ran away, but I couldn't because it formed a dense could, I couldn't see anything and I was behind a lot of equipment and cables. Then the floor exploded: I couldn't see what was going on but very loud cracking and banging noises later proved to be the tiles shattering. Fortunately I was wearing security shoes and just stood my ground. After the fog cleared I saw some faces at the door: "Are you still alive?"
  • by BetterThanCaesar (625636) on Thursday September 04, 2014 @02:22AM (#47823223)

    Not only Germans. Have you seen the function named after Englishman Oliver Heaviside [wikipedia.org], which has one light and one heavy side?

  • by BlueLightning (442320) on Thursday September 04, 2014 @05:01AM (#47823545) Homepage Journal

    This is known as "nominative determinism"; here's a somewhat amusing article [scilogs.com] from a couple of years ago on the subject.

  • Re:I did it first ! (Score:4, Interesting)

    by drinkypoo (153816) <martin.espinoza@gmail.com> on Thursday September 04, 2014 @06:50AM (#47823741) Homepage Journal

    Seems kind of dangerous and that this stuff would be buried in the ground (as people would do with a tank of diesel, for instance)

    Which people? Gas stations, maybe. Everyone else stores diesel above ground. It's more stable than gasoline so the thermal cycling isn't as big of a worry, and you literally cannot light diesel on fire. You need a wick of some kind to even produce massive volumes of black smoke, with very little flame. You can extinguish lit cigarettes by dropping them into a can of diesel. It's legal to gravity-feed diesel, but you legally have to pump gasoline. (Obviously not out of a jerrycan, but in terms of tanks.)

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