Hand vs. Liquid Nitrogen and the Leidenfrost Effect
tags:
Stumble This"I stick my hand (momentarily) directly into liquid nitrogen but don't suffer any injuries due to the Leidenfrost effect.
The Leidenfrost effect is the formation of a gas barrier between a hot surface and a boiling liquid if the temperature difference is great enough. This gas barrier greatly slows the heat transfer between the two and allows the liquid to last longer and consequently the hot surface to remain hot longer. This effect can be seen in a frying pan as it's being heated. At first the water quickly boils as it's dropped in but at a hot enough temperature the Leidenfrost effect takes over and makes the water skate around the surface lasting a very long time.
Liquid nitrogen vs. a room temperature object will also exhibit the effect preventing it from instantly freezing the object... such as my hand."
The Leidenfrost effect is the formation of a gas barrier between a hot surface and a boiling liquid if the temperature difference is great enough. This gas barrier greatly slows the heat transfer between the two and allows the liquid to last longer and consequently the hot surface to remain hot longer. This effect can be seen in a frying pan as it's being heated. At first the water quickly boils as it's dropped in but at a hot enough temperature the Leidenfrost effect takes over and makes the water skate around the surface lasting a very long time.
Liquid nitrogen vs. a room temperature object will also exhibit the effect preventing it from instantly freezing the object... such as my hand."
what's with the hostage-taker's voice? Does he have Leidenfrost bound and gagged in his trunk? And proving it with these experiments?
If it soaks into the glove, you are pretty boned.
I can understand scientific phenomena as well as the next guy, but testing them on myself is another matter altogether.
Kudos on the sheer testicular prowess required to stick your hand in that...
I can understand scientific phenomena as well as the next guy, but testing them on myself is another matter altogether.
That is the power of science!, you trust it every time you step on a plane or willingly let others perform surgery on vital parts of your body. This is what separates it from meaningless mantras like "faith" or "other ways of knowing": It is something you can reliably believe in, and it provides a true "way of knowing", not because scientists are smarter or more reliable than priests, but because they know that they aren't, so they put their own ideas to the test, and they are happy if people can prove them wrong. Because our intuition is often so very wrong, we need science to look deeper into it. And it works.
what a .... sillly person.
Very interesting... Buuuut. Why is his voice altered? Is he in witness protection or something?
It looks like the video is sped up. He probably lowered his voice to counter the "chipmunk" effect.
>> ^demon_ix:
Kudos on the sheer testicular prowess required to stick your hand in that...
I can understand scientific phenomena as well as the next guy, but testing them on myself is another matter altogether.
That is the power of science!, you trust it every time you step on a plane or willingly let others perform surgery on vital parts of your body. This is what separates it from meaningless mantras like "faith" or "other ways of knowing": It is something you can reliably believe in, and it provides a true "way of knowing", not because scientists are smarter or more reliable than priests, but because they know that they aren't, so they put their own ideas to the test, and they are happy if people can prove them wrong. Because our intuition is often so very wrong, we need science to look deeper into it. And it works.
*wipes a tear away*
HAIL SCIENCE
God damn, is there a "well said" channel?
>> ^furrycloud:
You gotta admit, Leidenfrost or no Leidenfrost, this would take some big brass balls to try for the first time.
Wait... I thought we were talking about balls here
You gotta admit, Leidenfrost or no Leidenfrost, this would take some big brass balls to try for the first time.
I have tried this! So thanks for the compliment by implication.
Hot (pun intended) tip: Remove all rings from your fingers before trying this, or you will jump around in pain trying to remove a ridiculously cold metal object from your skin.
You gotta admit, Leidenfrost or no Leidenfrost, this would take some big brass balls to try for the first time.
Somehow I bet the first person to try this didn't do it intentionally. But he must have been pretty damn relieved when he found his hand wasn't all frost bitten and dead.
That is the power of science!, you trust it every time you step on a plane or willingly let others perform surgery on vital parts of your body. This is what separates it from meaningless mantras like "faith" or "other ways of knowing": It is something you can reliably believe in, and it provides a true "way of knowing", not because scientists are smarter or more reliable than priests, but because they know that they aren't, so they put their own ideas to the test, and they are happy if people can prove them wrong. Because our intuition is often so very wrong, we need science to look deeper into it. And it works.
But the scary thing isn't the science, it's the implementation details.
I can tell you that water has a very low electrical conductivity, but you wouldn't want to get into a bathtub with a toaster -- and rightly so, because it turns out that the dissolved minerals in tap water raise its conductivity several orders of magnitude.
Once you encounter engineered systems of moderate complexity, you can't trust the simple scientific principles too much. And there's no more complex, engineered system than the human body.
So what I'm saying is, you're justified to be scared stepping into a commercial airliner. You're three times more likely to die on that plane trip than you are on your average car trip. If you're a safe, defensive driver, then a plane trip is ten times as dangerous.*
5 to 6 out of a million otherwise healthy people who go under general anesthesia will die. That number was 20 times higher in the '50s, but it's still scary.
* yes, per mile a commercial airliner is safer, but that's a stupid statistic. Per mile being an astronaut is extraordinarily safe, but in actuality it's outrageously dangerous. Per hour, the average commercial airliner is four times as safe as the average car, BUT, I don't drive the average car (I'm very safe, never drink and drive, always pay attention) but I DO have to fly the average airliner, with no control over who is flying, whether we should wait out the thunderstorm, or how well the maintenance was carried out.
yes, per mile a commercial airliner is safer, but that's a stupid statistic. Per mile being an astronaut is extraordinarily safe, but in actuality it's outrageously dangerous.
Say you're traveling from NYC to LA. You can either drive there, or you can fly there in one trip. Which is safer? Flying would be safer, because you have to physically cover the distance from point A to point B, and you said flying is safer according to distance.
A space shuttle "travels" many miles with respect to earth as it stays in orbit. Comparing the distance a shuttle "travels" to distance covered intentionally between two terrestrial locations is a stupid point to make.
I can tell you that water has a very low electrical conductivity, but you wouldn't want to get into a bathtub with a toaster -- and rightly so, because it turns out that the dissolved minerals in tap water raise its conductivity several orders of magnitude.
Guess what also tells you that getting into a bathtub with a toaster is dangerous because water with ions in it conducts? Science.
I really don't get the point that you're trying to make. Are you trying to say that the implementation of science is scary because statistics can be manipulated to show that cars are safer than planes or vice versa; or that a toaster in bathwater is bad? Or are you saying that applied science is scary because it cannot eliminate risk, only greatly reduce it? For example, your risk of dying from not performing the procedure would be far greater than the risk of dying from the anesthetics.
From www.straightdope.com
As a classroom demo of the Leidenfrost effect, former Scientific American columnist Jearl Walker dips his bare hand in water and then plunges it momentarily into a vat of molten lead, 700 degrees Fahrenheit. Says Jearl, who's even done this on Johnny Carson, "there is no classroom demonstration so riveting as one in which the teacher may die."
See it here!
http://vids.myspace.com/index.cfm?fuseaction=vids.channel&channelID=358705179
I don't agree with the eia, if anything, we need a new channel like sia, or science in action, instead of just plain old science.
Yeah. the eia is definitely unjustified considering the necessary precautions were taken, and the stunt was performed in a controlled environment. If this is eia, you might as well call any video of daily work in a science lab handling toxic materials eia. It even has a warning against trying this at home.
>> ^rychan:
yes, per mile a commercial airliner is safer, but that's a stupid statistic. Per mile being an astronaut is extraordinarily safe, but in actuality it's outrageously dangerous.
Say you're traveling from NYC to LA. You can either drive there, or you can fly there in one trip. Which is safer? Flying would be safer, because you have to physically cover the distance from point A to point B, and you said flying is safer according to distance.
A space shuttle "travels" many miles with respect to earth as it stays in orbit. Comparing the distance a shuttle "travels" to distance covered intentionally between two terrestrial locations is a stupid point to make.
I can tell you that water has a very low electrical conductivity, but you wouldn't want to get into a bathtub with a toaster -- and rightly so, because it turns out that the dissolved minerals in tap water raise its conductivity several orders of magnitude.
Guess what also tells you that getting into a bathtub with a toaster is dangerous because water with ions in it conducts? Science.
I really don't get the point that you're trying to make. Are you trying to say that the implementation of science is scary because statistics can be manipulated to show that cars are safer than planes or vice versa; or that a toaster in bathwater is bad? Or are you saying that applied science is scary because it cannot eliminate risk, only greatly reduce it? For example, your risk of dying from not performing the procedure would be far greater than the risk of dying from the anesthetics.
People don't think about distances when they step on a plane. They think "am I going to step off this plane alive?". The fact that the planes are covering more distance is as inconsequential as the spacecraft covering more distance. The fact that it would be even more dangerous to spend two full days driving the distance is inconsequential. They're stepping into a situation an order of magnitude more dangerous than when they step into their average car trip, so they're right to be scared. Of course, that fear is more based on lack of control and discomfort than statistics, but I hate people who try and calm you with statistics, because they're not strongly on the side of airplanes.
I'm saying science is great and reproducible, our human interface with science is often unreliable, because the real world and the human body have thousands of variables that science can't account for. And for that reason I'd be hesitant to test something like the Leidenfrost effect by dipping my hand in liquid Nitrogen (if I hadn't seen someone else do it, or maybe even then). Who knows, maybe if you sweat a lot and your skin is salty, if you have on nail polish, if you have on rings, etc... then something goes terribly wrong.
Adding video to channels (Geek, Science) - requested by Ornthoron.
i'm leaning toward balls.
But considering how big his brains gotta be he probably walks around bow legged too.
I tend to share your disdain for the plane safety statistics crowd, but I do think deaths/mile is the way to go. Consider that the auto equivalent of a plane, a bus (group transport, professional driver) is actually safer considered deaths/mile than a plane. The car stats, when used to compare long trips, are skewed largely because daytime highway driving is much safer than driving in general, and so the "planes are safer" numbers are a lie even in that case.
That being said, I think that risk/benefit is a good way to asses risk in general, and in this guys case I think the benefit (presumably being called manly by anonymous denizens of the web) is so low that the risk is hard to justify.
He has ladyfingers ._.
Heh, maybe he's gay.
But even it were a flaming hot supermodel chick doing that experiment, she's still got bigger balls than me for sticking her hand in there and trusting science to give it back in one piece.
You're three times more likely to die on that plane trip than you are on your average car trip.
[for safe drivers] a plane trip is ten times as dangerous.
per mile, a commercial airliner is safer
Per hour, the average commercial airliner is four times as safe as the average car
The fact that it would be even more dangerous to spend two full days driving the distance [compared to flying]
They're stepping into a situation an order of magnitude more dangerous than when they step into their average car trip
LOL.. Here we have the example of someone pulling statistics out of their ass. Per mile and per hour a plane is safer... but also the same person says planes are three / ten / or order of magnitude more dangerous (as in deadly?).
Trust me, getting in a car is a lot more dangerous. Fatal may be a different matter, as most car crashes are not fatal, while most plane crashes are. (of course leaving out blood clots from flying)
From 1997 Newsweek, cars have .94 deaths per 100 million miles traveled, while trains have .04 deaths and planes and buses each came out the same with .01 deaths per 100 million miles traveled.
Even if you play some number games with hours spent on the road or in the air.. Planes are most dangerous take off or landing. So to compare to hours instead of miles, just rough ballpark assume a car averages 30 mph and planes average 300mph. Factor of 10 maybe. So deaths goes to cars. I would also say injuries go to car travel as well as financial risk.
And you seem to THINK you have more control because of how you drive, but you don't.
>> ^demon_ix:
Kudos on the sheer testicular prowess required to stick your hand in that...
I can understand scientific phenomena as well as the next guy, but testing them on myself is another matter altogether.
That is the power of science!, you trust it every time you step on a plane or willingly let others perform surgery on vital parts of your body. This is what separates it from meaningless mantras like "faith" or "other ways of knowing": It is something you can reliably believe in, and it provides a true "way of knowing", not because scientists are smarter or more reliable than priests, but because they know that they aren't, so they put their own ideas to the test, and they are happy if people can prove them wrong. Because our intuition is often so very wrong, we need science to look deeper into it. And it works.
Excellently put. Now for the too long; didn't read version:
Science. It works, bitches!
You can't do much with HOW you drive, but WHERE and WHEN make a massive difference.
Daytime, on highways, where most long distance travel takes place, is MUCH safer than driving in general. That is the primary reason that buses are just as safe as planes.
LOL.. Here we have the example of someone pulling statistics out of their ass. Per mile and per hour a plane is safer... but also the same person says planes are three / ten / or order of magnitude more dangerous (as in deadly?).
Trust me, getting in a car is a lot more dangerous.
Um, no, I'll trust the correct statistics that I just quoted above.
Fatal may be a different matter, as most car crashes are not fatal, while most plane crashes are. (of course leaving out blood clots from flying)
From 1997 Newsweek, cars have .94 deaths per 100 million miles traveled, while trains have .04 deaths and planes and buses each came out the same with .01 deaths per 100 million miles traveled.
As I already said, I don't accept risk per mile as a valid statistic, unless you want to admit to me that walking is extremely dangerous and being an astronaut is very safe. No! These modes of transport are for inherently different spatial scales, and the fact that my plane is covering a lot of distance doesn't make me feel safe about it.
Even if you play some number games with hours spent on the road or in the air.. Planes are most dangerous take off or landing. So to compare to hours instead of miles, just rough ballpark assume a car averages 30 mph and planes average 300mph. Factor of 10 maybe. So deaths goes to cars. I would also say injuries go to car travel as well as financial risk.
I don't need your rough ballpark numbers, I already quoted the correct numbers. The AVERAGE car is 4 times more likely to be in a fatal accident, per hour, compared to the average commercial airliner. But I'm not average. 69% of road fatalities relate to drinking and speeding. I do neither. A huge amount of road fatalities are from rural, non-highway roads which I never travel on. I wear my seatbelt.
Here, maybe this will convince you:
http://books.google.com/books?id=OyuGJJ6rKQ0C&pg=PA362&lpg=PA362&dq=taxi+fatalities+per+mile&source=bl&ots=zqhhjfksFG&sig=U1LhoIUSpsUrji7RA25kyBaYjVA&hl=en&ei=-DZfStbgFo7cNvOKgMAC&sa=X&oi=book_result&ct=result&resnum=6
To summarize, if you don't look at averages but take the demographics of people who actually fly, say a safe 40 year old, they are more likely to die on a 600 mile plane trip than if they had driven the same distance.
So yes, for very long flights the plane still comes out ahead. There are plenty of other situations where the car comes out ahead. And if you put a professional driver in the car, as in a bus (not like they're even that well trained) they'll beat the plane by any metric.
And you seem to THINK you have more control because of how you drive, but you don't.
Numerous experts on defensive driving would disagree with you. So would I. So would the analysis that I just quoted saying that the average, somewhat safe driver beats airplanes for trips of 600 miles.