Taking the Ice Bucket Challenge With Liquid Nitrogen 182
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.
so the T-1000 shouldn't have frozen? (Score:2)
Does this mean Terminator 2 is debunked by Leidenfrost?
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No, it works for a few seconds, the evaporation of the nitrogen still extracts energy from the skin. If you pour it for more than a few seconds your hand will freeze and then crack.
Re:so the T-1000 shouldn't have frozen? (Score:5, Funny)
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No, the T-1000 was a liquid metal. Due to it's heat conduction (we can assume from the metal) it would conduct heat and thus not create a protective gas layer.
Now if you want to start talking about Armageddon's bad physics, we could be here all day.
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Whoosh the humor went over my head, or "Whoosh!" the sound of a hundred NASA rocket scientists groaning at bad science in movies?
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Whoosh the humor went over my head, or "Whoosh!" the sound of a hundred NASA rocket scientists groaning at bad science in movies?
The Point
------------- (Dear moronic Slashfilter, It's not fucking "ASCII Art", it's a fucking line)
Your Head
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it tingles (Score:3, Informative)
Re:it tingles (Score:5, Informative)
In my old job we used a lot of liquid nitrogen - mainly to transfer carbon dioxide around in various scientific apparatus (a mass spectrometer, for one).
Anyone who has worked extensively with the stuff will tell you it is NOT safe unless you are careful. The Leidenfrost effect works... for a relatively short duration. But the co it used application of liquid nitrogen to a specific area rapidly cools the immediate surroundings, and then the effect stops working - especially if the nitrogen doesn't have a way to skitter away on that layer of gas (if you were to pour it into a cupped palm, for example).
Also, small droplets (such as are generated from the stuff boiling when you're freezing carbon dioxide into a cold finger) don't seem to have much difficulty reaching one's skin, Leidenfrost or no. Most of us in the lab frequently had small burns on the thumb sides of our hands.
Re:it tingles (Score:5, Informative)
He stopped the last one after it went slightly wrong, and all his teeth cracked. His dentist suggested he not do it any more.
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His dentist suggested he not do it any more.
It took a dentist to tell him that?
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I think we had the same physics book, because this article brought back memories of the story. In my memory he cracked one rear molar and not *all* of his teeth, but it's otherwise similar.
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Re:it tingles (Score:5, Funny)
Anyone who has worked extensively with the stuff will tell you it is NOT safe unless you are careful.
Gee, and there I was, going to tell those Knoxvillesque folks to try the "Liquid Nitrogen Enema Challenge."
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Anyone who has worked extensively with the stuff will tell you it is NOT safe unless you are careful.
Gee, and there I was, going to tell those Knoxvillesque folks to try the "Liquid Nitrogen Enema Challenge."
Some things are worth the risk.
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At least they'll be in the running for a Darwin Award.
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Re:it tingles (Score:5, Funny)
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I can confirm you can use a thermos. You don't need to drill the hole if you don't screw the lid down. Heat rises, cold descends so all you might want to do is prevent drafts which can be done by placing the cup on top (assuming it does not create an airtight seal). You'll get some radiative warming but it'll be fairly negligible (the small dewars we used to cart liquid nitrogen around in were open full-width at the top).
Is it really the Leidenfrost effect? (Score:3)
Re:Is it really the Leidenfrost effect? (Score:5, Informative)
It really is this time. The Leidenfrost effect comes into play when a surface is much hotter than a given material's boiling point. The Leidenfrost effect explains safe contact of hot skin with liquid nitrogen, wet hands surviving molten lead, and why water skitters on a hot skillet. Any time a liquid contacts a surface much hotter than its boiling point, such that it can be suspended in the air by convection currents, the Leidenfrost effect is responsible. In the LN2 case, your skin is far enough above the -195C boiling point that the nitrogen boils off before it touches your skin. In the molten lead case, the water on your hands must evaporate before your hands can start burning, this creates a temporary steam bubble that insulates your hand much like a winter coat. The water on a hot skillet case is the simplest case, where radiative and convective heat transfer is so intense that hot air and water vapor form a convective bubble underneath the boiling water bubble and instabilities in the air bubble then cause the water bubble to flow towards a theoretical edge and skitter around the pan.
The firewalking claim is a little dubious, it seems more likely that the short contact time combined with the small surface area exposed during normal walking is responsible for the undamaged feet. Most firewalkers don't seem to sit around getting their feet good and sweaty before firewalking.
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BTW it seems the only requirement to fire walking is just don't stop.
I never understood the mystique surrounding firewalking. It's basic heat transfer. You see the effects all the time.
Touch the coin on your desk. It feels a bit "cool," right? Now touch the wooden part of the desk. That feels more like the temperature of the room, right? But they're obviously both at the same temperature. Our bodies are sensitive to rate of heat transfer, absolute temperature is irrelevant.
It's the reason why no one ever worries about getting his tongue stuck to a wooden post in w
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It helps that the coals for firewalking are typically ashed over nicely. The ash actually serves as a pretty decent short term insulator. If you just blew the ash off the coals I imagine it would be a very different experience.
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I'd have preferred (Score:4, Informative)
If he were to turn into a popsicle.
I'm starting to wonder... (Score:5, Interesting)
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.
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Just so it's clear, ALS causes a person to lose feeling in their body. The ice bucket challenge's purpose is to simulate that effect so that you know what they go through in a much less permanent way. How it "feels" to have ALS (hint: it doesn't).
I agree, although I can't imagine how someone would die from it unless they had a pre-existing condition, in which case they shouldn't be doing it to begin with.
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I think that excuse was made up after the fact.
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Someone would die from it because it has escalated to a game of one-upmanship where people add extra bits.
Like using nitrogen. Or gasoline. Or massive ice cubes. Or while at driving a speeding car. Or in a swimming pool shackled to a sack of concrete.
You get the idea. People think that somehow it's not dangerous or idiotic because it's for charity.
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Yep - darned right. Five gallon bucket full of water == 40 pounds. Lifted straight over your head, then twisted to dump it on you. Not the easiest thing in the world to do.
Re:I'm starting to wonder... (Score:5, Interesting)
... 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!
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Donate to ALS research [*], by all means!
So IOW, don't give your money to the ALS foundation, since only around a quarter of it at best will go there.
Re:I'm starting to wonder... (Score:4, Informative)
So IOW, don't give your money to the ALS foundation, since only around a quarter of it at best will go there.
Demonstrably false with about 5 seconds of Google searching.
http://www.snopes.com/politics... [snopes.com]
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Demonstrably false with about 5 seconds of Google searching.
I read an article about that Snopes article this morning already, and hilariously, that snopes article is attacking a straw man and you are also using it to attack a straw man. I said research, and that's what the articles that snopes was responding to say as well, but snopes attacks the claim "research and services"
That is to say, English... YOU FAIL IT
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I recommend the Free Software Foundation.
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I recommend the Free Software Foundation.
dump a bucket of microsoft disk cases and old win95 floppies on your head for the FSF challenge
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It will even help with things like ALS (or any other medical condition) as people will look for solutions instead of wishing at the sky.
One slight flaw in that argument: the millions of religious doctors and researchers all over the world who are constantly looking for practical solutions to diseases such as ALS.
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Wait - an entire organization that's centered around imposing your beliefs on other people? Sounds like a circular argument waiting to happen.
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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.
Actually this is the perfect way to collect donations for a good cause: create a silly meme and create a culture of making a donation when doing it. People love this kind of shit.
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Re:I'm starting to wonder... (Score:4, Insightful)
By weeding out the ones that don't know when to quit.
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By weeding out the ones that don't know when to quit.
Hey, I haven't died yet!!!
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Stupid breeds.
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How is it that we managed to evolve in the first place, exactly?
Because it is relatively rare and relatively unusual. But without the wish to go further and take risks we wouldn't have ever harnessed fire, let alone achieved civilisation. Life is about *doing things*, not eliminating all possible risk.
Some people want to live a long boring life, and some people want to go to the moon, even if it means there's a high chance of death in the process.
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But without the wish to go further and take risks we wouldn't have ever harnessed fire, let alone achieved civilisation.
Or expanded beyond our "natural" habitat to cover nearly every corner of the globe while we were still building tools out of rocks.
Possible hair lost (Score:2)
After dipping a rose into liquid nitrogen, the petals are flaky as potato chips.
Then the guy combed his hair to remove anything frozen there. Such action
might break those hair frozen by the LN. I don't think he would like to show it
in the video.
I did it first ! (Score:5, Interesting)
Re:I did it first ! (Score:5, Funny)
Did you take the chance to reply "I'm not feeling so hot"?
Re:I did it first ! (Score:4, Funny)
Did you take the chance to reply "I'm not feeling so hot"?
Nah, someone else said - "that was cool!"
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Is it normal to have liquid nitrogen stored up high?
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)
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That's where plumbing goes (Score:2)
It's perfectly normal for plumbing in a commercial or industrial setting to be run underneath the ceiling. Burying stuff under a concrete floor is expensive to install, weakens the floor, and is difficult to maintain. A raised floor has limited load-bearing capacity and is also expensive vs. a suspended ceiling (if you care about aesthetics at all... you don't really need one of those either.)
You see plumbing buried in the floor of slab houses because it's cheap to install when the slab is being poured.
Re:I did it first ! (Score:4, Interesting)
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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Genuine potential risk of asphyxiation depending on circumstances.
Why do German scientists have fitting names? (Score:5, Funny)
Serious. Mr. Schwarzschild ("black shield") only kinda-sorta fits his radius, but Mr. Leidenfrost ("suffering frost") really takes the cake here.
Re:Why do German scientists have fitting names? (Score:4, Interesting)
Not only Germans. Have you seen the function named after Englishman Oliver Heaviside [wikipedia.org], which has one light and one heavy side?
Re:Why do German scientists have fitting names? (Score:5, Interesting)
This is known as "nominative determinism"; here's a somewhat amusing article [scilogs.com] from a couple of years ago on the subject.
fuck you and the bucket challenge (Score:5, Insightful)
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I would mod you up, but my recent post count isn't good enough, and I'm not being allocated any mod points. This should solve the problem; though not for you, unfortunately! ;-)
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Idiocracy was right on. The fucking bucket challenge is no better than ow my balls. Mod me down at will.
Don't feel bad for yourself though, they're modding you down because you're using 'idiocracy' for no good reason, criticizing people who are doing good things.
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criticizing people who are doing good things.
Actually no. Doing a good thing would be donating to charity. Most of the people doing this are just doing it because they saw it online or have a friend that did it and they want to be cool. Monkey see, monkey do. I bet a large number of the people doing the "challenge" don't even know the reason behind it. Instead of sharing stupid videos of clowns pouring water over their heads maybe we should be sharing videos of people writing checks to the charity. Of course that isn't as "exciting" for the ADD/ADHD generations.
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There's nothing apart from your assumption saying that people aren't also giving to charity. Even if alot of them aren't, increasing awareness has its own benefits.
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Actually, you're assuming that he said that, when in fact he didn't.
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Whu? The clear implication from his post is that people are making videos instead of giving to charity.
Instead of sharing stupid videos of clowns pouring water over their heads maybe we should be sharing videos of people writing checks to the charity.
If he thought people were doing both then he wouldn't have a problem would he?
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I cant even fathom the complaints about this.
Hasn't ALS hit like 100 times their usual funding for the year due to all these people dumping ice on themselves? Saying the popularity and viral nature of it aren't a benefit in itself seems short sited.
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Re:fuck you and the bucket challenge (Score:5, Insightful)
It's slacktivism at its best. Seriously the whole point of the challenge was do something that causes discomfort and donate a little or forgo the discomfort and donate a lot. Yet we have an internet full of loaded celebrities like Oprah (who has a freezer draw of ice in her kitchen, like seriously how much money does one need to make before they can install something like that in their house?) who then go and douse themselves.
So far the only one I have seen who did it right was Patrick Stewart [youtube.com]. Write a big check instead of putting yourself through the discomfort.
The financial results of the campaign would be amazing if it weren't for the fact that many of the people participating make more money in a year than was donated in the entire campaign.
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Thank you for apologising on behalf of all the celebs. You demonstrated it perfectly. 99.9% of people raised less money then a few celebs could have if they put the correct effort in instead of simply trying to look like a fool in the name of ALS
This was my last Facebook straw (Score:2)
Agree. I think this was the fad that finally allowed me to give up Facebook. Just looking forward to signing on one more time in mid-February and replying to all my friends' challenges with, "sorry, I've been offline for a while, but if you're still up for it I'd be happy to kick in a dollar."
clothes are the problem (Score:2)
who hasn't yet dumped a bucket of icy water... (Score:2)
Lots of celebrities. They used warm water with plastic icicles.
BTW a german politician was dumb enough to film himself doing it beside his Marihuana plant.
I would prefer liquid nitrogen instead of water (Score:2)
Liquid nitrogen might be colder, but does not seem to have much heat capacity. When I had access to it, I 'played' a bit with it... who does not? Instant ice cream... putting finger in it... hand. No problem. Once I had a wet rag on the floor and I poured half a 5l Dewar with liquid nitrogen over it. The whole room was full of mist, but to my surprise the rag hardly got colder. ;-)
However, I would not try this with liquid helium.
Firemarshal Bill (Score:2)
Fuck that. (Score:2)
"who hasn't yet dumped a bucket of icy water over his or her head for charity?"
Me. Because fuck you if you think you can publicly shame me into giving money to a cause when I could name a hundred other equally worthy causes. Also, I don't brag about my charitable donations.
Dust (Score:2)
Here in California we are in a drought, so we dump a bucket of dust over our heads to conserve water.
Re:People who did High School Chemistry know this. (Score:5, Funny)
I was educated in the inner city, you insensitive clod. We didn't get any liquid nitrogen at my school because we might make drugs out of it.
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Exactly what I came here to post. We had the demonstration of what happens when you immerse something in liquid nitrogen vs what happens when you pour it over the top. Even if you didn't get to play with liquid nitrogen in school, there are lots of videos of this.
Although I was under the impression that the Leidenfrost effect only worked well on bare skin, so I'm surprised he didn't get frost burns to his scalp and clothed parts.
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I certainly wouldn't try it with my only head.
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I figured there was a very specific safety reason why they only used a small quantity.
Perhaps to reduce the impact, in case they screw up.
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The nitrogen will still form a blanket of gas independent of the quantity or flow rate and this is what keeps you safe. The problem occurs if the liquid nitrogen pools or is otherwise forced into direct contact (like you could do with a suitably high enough pressure stream or immersion). That is when people get hurt.
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I just went through high-school education (in Portugal) and I didn't know this. Although, to be fair, I didn't have chemistry the last year (but did have it during the 10th and 11th grades, plus whatever they teach before that).
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We covered this when I was about 15, which is Grade 10 in Australia. We also watched our teacher set fire to his hand after dipping it in methylated spirits. This was, depressingly, 20 years ago now so maybe things have changed.
The Nitrogen on the hand was only done by the teacher. We dropped water droplets on a hot plate to create the same effect.
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Ultimate Ice Buckey Challenge (Score:5, Funny)
Hal Finney -an ALS sufferer- did the ultimate Ice Bucket challenge with liquid nitrogen last week (Aug 28, 2014) when he was cryopreserved after passing away from ALS:
http://en.wikipedia.org/wiki/H... [wikipedia.org]
Re:Translation for kids... (Score:5, Insightful)
My first reaction when I read this: I think we found the winner of 2014's Darwin Award. No, not that guy. But some copycat who has, unlike him, no clue about Physics and insists in topping the performance.
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There's a point where you are intelligent enough to play with the dangerous stuff, but not intelligent enough not to.
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It's like when a rain drop hits a hot exhaust manifold...
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Well, imagine you're driving on a really hot day. The road is really hot. So your tyres start to melt and you lose traction. It's a bit like that, because the liquid loses traction on the solid surface.
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