What-If 0050: "Extreme Boating"

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ijuin
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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Sat Jun 22, 2013 3:09 am UTC

socom wrote:Forget fire; even a coin-sized chunk of sodium thrown into water will explode, and larger chunks will explode spectacularly. The biggest "sodium party" I've ever heard of involved a four-kilogram block which exploded with the force of a depth charge (you can read about it on Theodore Gray's WPT website; not sure what the forum policy is for posting links but it's easy to google).

With a boat-sized chunk of sodium an explosion would be inevitable, and it would be massive. I wouldn't expect the cruise to last more than a few seconds - expect an earth-shaking explosion throwing chunks of the boat every which way. These would then trigger more explosions as they splashed down hundreds of meters from the original blast site. Bottom line is, you *really* wouldn't want to be in (or for that matter, anywhere near) the boat. :mrgreen:


When my high school chemistry teacher demonstrated this, a one-gram piece of sodium SHATTERED the entire beaker into coin-sized fragments.

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Re: What-If 0050: "Extreme Boating"

Postby Pfhorrest » Sat Jun 22, 2013 5:32 am UTC

PhysProf wrote:Superfluids really are that weird - check out Wikipedia's section on liquid helium (I can't post the link, since I'm a noob).

Superfluids are a single quantum state of all the atoms, and their collective energy, linear momentum, and angular momentum are likewise quantized. This means that when you put a little paddlewheel in superfluid LHe and spin it, it spins without any resistance at all - it can't start a collective motion of the fluid. Similarly, trying to whack it with a paddle won't do any good, for the paddle can't start a collective motion. This means the LHe really doesn't interact with the paddle at all, as non-classical as that sounds.

Is this just because the paddle can't apply enough force to move the entire lake? I mean, if you have a bowl of a superfluid, and you move the bowl, the fluid moves with it right? It does interact with its container, at least to the point of being contained at least; a superfluid isn't just going to fall through the bowl and the floor and the whole Earth like it's not there, right?

So if you pour a tiny amount of a superfluid into a tiny pit on a paddle and move the paddle, that will move the superfluid, yeah?

If a tiny amount of the superfluid was in a big bowl and you pushed at the droplet with the paddle, could that move it?

But a paddle in a lake of it wouldn't even know it was there? Would a boat even float in that case or would it just fall right through?

At what point and for what reason does the paddle stop moving the fluid?
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Re: What-If 0050: "Extreme Boating"

Postby teelo » Sat Jun 22, 2013 7:22 am UTC

What about liquid Mymadeupmetalsten?

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Re: What-If 0050: "Extreme Boating"

Postby KarenRei » Sat Jun 22, 2013 2:55 pm UTC

socom wrote:Forget fire; even a coin-sized chunk of sodium thrown into water will explode, and larger chunks will explode spectacularly. The biggest "sodium party" I've ever heard of involved a four-kilogram block which exploded with the force of a depth charge (you can read about it on Theodore Gray's WPT website; not sure what the forum policy is for posting links but it's easy to google).


I've seen video of sizeable chunks of sodium persisting on water for many seconds, even minutes, without explosion (or with delayed explosion), simply outgassing. It's all about when the hydrogen ignites, which can depend on a number of factors. And note that if we're talking about an arbitrary planet here, there may not even be oxygen to ignite it (the explosion is a hydrogen explosion, the sodium takes the oxygen from the water)

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Re: What-If 0050: "Extreme Boating"

Postby rmsgrey » Sat Jun 22, 2013 3:23 pm UTC

teelo wrote:What about liquid Mymadeupmetalsten?


Could you provide us with its relevant properties?

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Re: What-If 0050: "Extreme Boating"

Postby Klear » Sat Jun 22, 2013 3:38 pm UTC

rmsgrey wrote:
teelo wrote:What about liquid Mymadeupmetalsten?


Could you provide us with its relevant properties?


I'm pretty sure most of its properties are given in imaginary numbers.

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Re: What-If 0050: "Extreme Boating"

Postby gladiolas » Sat Jun 22, 2013 4:23 pm UTC

It might be interesting to have a lake of technetium-99, which decays in 91 days into ruthenium-99, which is stable, Other isotopes have even shorter half-lives. They decay into either ruthenium or molybdenum.

Remember to wear a full-body suit.

Technetium's density is 11 g/cc,

Ruthenium's density near room temperature is 12.45 g/cc, at melting point is 10.65 g/cc.

Technetium:
Melting point 2430 K, 2157 °C, 3915 °F
Boiling point 4538 K, 4265 °C, 7709 °F

Ruthenium:
Melting point 2607 K, 2334 °C, 4233 °F
Boiling point 4423 K, 4150 °C, 7502 °F

Fluorine snowing onto a cesium lake might be interesting to watch...from a safe distance.

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Re: What-If 0050: "Extreme Boating"

Postby hamjudo » Sun Jun 23, 2013 12:34 am UTC

If you put too much power through an electrical superconductor, it will stop superconducting. Likewise, superfluid helium3 will stop being a superfluid if you exceed its limits. Oars at moderate speeds will experience no friction. Move the oars fast enough, and they won't be in a superfluid anymore. Then you just have to deal with all of the other issues with being in a liquid helium lake at 2.3 degrees K.

I doubt there would much of a problem rowing a smooth flat bottomed boat across a see of mercury, other than the mercury poisoning you, and ruining any exposed aluminum and gold. f-ma, and mercury has a lot of "m". So your oars would not have to push in very deep to have a lot of mass to push against.

I remember reading an article in National Geographic 4 or more decades ago. It was about workers in a mercury mine. It had pictures of workers floating on a pool of mercury gathering the crud that floated to the surface. The workers had no trouble moving around on the mercury pool. I doubt it gets harder if you use a boat.

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Re: What-If 0050: "Extreme Boating"

Postby Rachie » Sun Jun 23, 2013 5:03 am UTC

I'm surprised no one else noticed the glaring error: "Tungsten has the highest melting point of any element." Granted carbon sublimes instead of melts at human safe pressures, but it's still solid to 3627 °C at standard pressure. At higher pressure, it melts around 4300 °C. Both are well above wolfram's 3422 °C melting point.
Last edited by Rachie on Mon Jun 24, 2013 6:29 am UTC, edited 1 time in total.

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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Sun Jun 23, 2013 5:03 pm UTC

Well, tungsten has the highest melting point of any elment that does not combust in sea level air at below its melting point. If you tried to use a carbon container to hold something with the temperature of molten tungsten, the carbon would start to burn.

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Re: What-If 0050: "Extreme Boating"

Postby Rachie » Sun Jun 23, 2013 6:32 pm UTC

So do it above the lake of liquid helium. Not much combustion will be going on there. There's still the slight problem of tungsten carbide formation, but at least it won't burn.

How about a two layer crucible? Start with solid carbon, and fill it with iridium. Heat until the iridium melts, then add tungsten. The density of the liquid iridium is greater than tungsten, allowing it to float without touching the carbon. Iridium's low reactivity prevents the carbon from combining with it.

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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Mon Jun 24, 2013 4:48 am UTC

Hmm good point--you could hypothetically float just about any material in iridium. Now if only iridium weren't forty times rarer than gold. . .

http://en.wikipedia.org/wiki/Iridium

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Re: What-If 0050: "Extreme Boating"

Postby Rachie » Mon Jun 24, 2013 6:28 am UTC

It may be forty times rarer than gold, but it's currently about 75% of the price. With the right grants, an experimenter should have no trouble buying enough to fill a small crucible. Quite a bit cheaper than a lake of liquid helium, anyway.

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Re: What-If 0050: "Extreme Boating"

Postby gladiolas » Mon Jun 24, 2013 1:54 pm UTC

Okay, technetium isn't the best choice. (And I'm thinking in terms of transhumans doing amazing stuff with their advanced techniques and abilities, just for the heck of it, and writing stories about this.)

From wikipedia:

isotope half-life
minutes density g/cc melting point degrees C
carbon-11 20.334 2-3
nobelium-259 58 827
hours
fluorine-18 1.8295 -219

mendelevium-257 5.52 827
erbium-165 10.36 room temp. 9, when liquid near melting point it's 8.9 1529
fermium-252 25.39 1527
erbium-160 28.58
days
fermium-253 3
manganese-52 5.591 7-9 1246
thulium-167 9.25 9 1545

sulfer-35 turns into chlorine-35, which is stable. S-35's half-life is 87 days. density 1.8, melting point 215C.

These don't seem like very good choices either. Fluorine, sulfer or mendelevium?

I realize that rowing a boat through a radioactive sulfer lake while it's turning into chlorine might be interesting for transhumans, not at all fun for the rest of us.

I just thought it would be interesting to row a boat through a liquid while the liquid is slowly turning into something else. But maybe not.

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Re: What-If 0050: "Extreme Boating"

Postby socom » Mon Jun 24, 2013 2:39 pm UTC

ijuin wrote:Well, tungsten has the highest melting point of any elment that does not combust in sea level air at below its melting point. If you tried to use a carbon container to hold something with the temperature of molten tungsten, the carbon would start to burn.


Tungsten will actually oxidize (i.e. "combust") well below its melting point - at around 400C, which is why those old-fashioned lightbulbs are filled with argon. In an open-air environment few metals will survive 1000C, with ~1400C being the absolute limit (some FeCr superalloys can survive that, though not for long - google Kanthal for an example...)

An inert atmosphere is, of course, another story... :)

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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Mon Jun 24, 2013 6:01 pm UTC

Rachie wrote:It may be forty times rarer than gold, but it's currently about 75% of the price. With the right grants, an experimenter should have no trouble buying enough to fill a small crucible. Quite a bit cheaper than a lake of liquid helium, anyway.


I'd be less concerned with price than with sheer availability--being so rare, there are only so many kilograms of it in stock to begin with. You could probably fit the entire world's current reserves of refined iridium in a single standard 40 foot freight container (or an average-sized swimming pool). We won't be rowing on any iridium lakes any time soon.

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Re: What-If 0050: "Extreme Boating"

Postby Copper Bezel » Mon Jun 24, 2013 6:30 pm UTC

I had to look it up - 2010 production was unusually high, and would have apparently filled 3 1/3 of them. = ) That doesn't contradict that that's a crazy-small amount, natch.

But no one was talking about lakes, and apparently filling a crucible costs just ~$1000 USD. = /
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: What-If 0050: "Extreme Boating"

Postby Whizbang » Mon Jun 24, 2013 7:06 pm UTC

Ah, but buying up all that iridium will drive the price up, right? Sounds like a nice money making venture ...

Step 1, buy up all the iridium
Step 31, profit!

1Step two is intentionally left out of this process, for obvious reasons2.
2Which is that step two is obvious... and also because that's the joke.

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Re: What-If 0050: "Extreme Boating"

Postby jeanrenaud » Tue Jun 25, 2013 2:17 am UTC

The "Superfluid" reminds me a scene of the movie "The Matrix". At the beginning of the film, after Neo swallow The Misogyny Kool-Aid, he touches a mirror that seems liquid. Some liquid stay on his finger, then the liquid starts to climb on him, defying gravity...

"The superfluid climbs on its container"

Neo then says "It's cold... it's cold !"... Liquid Helium :)

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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Tue Jun 25, 2013 4:21 am UTC

Copper Bezel wrote:I had to look it up - 2010 production was unusually high, and would have apparently filled 3 1/3 of them. = ) That doesn't contradict that that's a crazy-small amount, natch.

But no one was talking about lakes, and apparently filling a crucible costs just ~$1000 USD. = /


Given the density of iridium, a single troy ounce is only 1.5 milliliters, so any useful-sized crucible will probably need 5-6 ounces at minimum.

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Re: What-If 0050: "Extreme Boating"

Postby Copper Bezel » Tue Jun 25, 2013 5:57 am UTC

I got the density just fine. I was just looking at the wrong product page. = / But yeah, I was assuming a 10cc crucible, which would be more like $10k.
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: What-If 0050: "Extreme Boating"

Postby Guanopsychotic » Tue Jun 25, 2013 6:11 am UTC

You could melt tungsten for study purposes in microgravity, but it would defeat the purpose of boating.

Stop thinking in terms of systems at equilibrium. Take a thick disk of tungsten, cool the bottom and outer edge actively, and continuously supply heat to the top center with your favorite means of heating things to over 3422 C. You now have a pool of liquid tungsten. If you make the pool big enough, or the boat small enough, you can now go boating. Make the boat out of something thermally conductive and keep the bilge full of water. It will be like the classic experiment where you hold a paper cup of water over a flame.

The boat will tend to freeze out the nearby tungsten, giving you the world's strangest analog to barnacles. Perhaps it will remelt if you keep the boat moving.

It will be a potentially unpleasant boat ride, as you're steamed by your own boat while getting sunburn from the thermal radiation from the tungsten. But you would have a great story to tell at parties.

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Re: What-If 0050: "Extreme Boating"

Postby Guanopsychotic » Tue Jun 25, 2013 6:28 am UTC

The cesium sea would be scenic. The metal is a beautiful golden color, at least until it oxidizes. A layer of oil on top of the cesium would allow it to coexist with oxygen-breathing life forms.

It could be expected to strip the oxygen out of the aluminum oxide coating on your rowboat. The wood in your oar might have enough moisture content to cause a problem.

Splash fights would be a remarkably bad idea.

Check the weather forecast first and don't go boating on cesium on a rainy day.

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Re: What-If 0050: "Extreme Boating"

Postby bouer » Tue Jun 25, 2013 11:35 pm UTC

Guanopsychotic wrote:Stop thinking in terms of systems at equilibrium. Take a thick disk of tungsten, cool the bottom and outer edge actively, and continuously supply heat to the top center with your favorite means of heating things to over 3422 C. You now have a pool of liquid tungsten. If you make the pool big enough, or the boat small enough, you can now go boating. Make the boat out of something thermally conductive and keep the bilge full of water. It will be like the classic experiment where you hold a paper cup of water over a flame.

The boat will tend to freeze out the nearby tungsten, giving you the world's strangest analog to barnacles. Perhaps it will remelt if you keep the boat moving.


I would guess that at those absurd temperatures the water in contact with the boat would almost instantly flash into vapor which would prevent the boat from conducting heat away from itself. Soon after the boat would vaporize.
It will be a potentially unpleasant boat ride.

Indeed.

Also, at 3422 Celsius every common element with the exception of Boron and Zirconium would be a gas.

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Re: What-If 0050: "Extreme Boating"

Postby Guanopsychotic » Wed Jun 26, 2013 10:01 pm UTC

Now there's an interesting question: would you get a steam explosion?

The rate of heat flow would be limited by the thermal conductivity of tungsten.

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Re: What-If 0050: "Extreme Boating"

Postby Rachie » Thu Jun 27, 2013 1:19 am UTC

With the proper design, the Leidenfrost effect could be exploited for both cooling and propulsion. As long as the boat has a supply of liquid water to flash boil on the tungsten, the hull will be shielded from the intense temperature. The steam could then be partially ducted to provide horizontal thrust.

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Re: What-If 0050: "Extreme Boating"

Postby bouer » Thu Jun 27, 2013 6:48 pm UTC

As absurd as it sounds, it might be more feasible to flash boil metal. A steel or aluminium boat could survive in a pool of 907 degrees celsius zinc and the zinc would not boil nearly as fast as water.

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Re: What-If 0050: "Extreme Boating"

Postby gladiolas » Tue Jul 16, 2013 1:40 am UTC

I can see why you guys aren't enthralled by my idea of sailing in a hot, toxic radioactive sea, but I thought of just one more variation.

Scientists have managed to produce compounds of rare gases.

Helium hydride is the strongest acid, and can't exist in a condensed phase, according to Wikipedia.
http://en.wikipedia.org/wiki/Helium_hydride

So a lake full of that would be out. But an atmosphere...

A few hundred noble gas compounds have been formed.

http://en.wikipedia.org/wiki/Noble_gas_compound

Argon fluorohydride is stable only below 17 K (−256 °C), or it decomposes into argon and hydrogen fluoride.

Would a fullerene sea be of interest? Somebody made a boron fullerene.

Okay, maybe we've covered everything by now.

http://en.wikipedia.org/wiki/Fullerene

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Re: What-If 0050: "Extreme Boating"

Postby bmonk » Mon Jul 22, 2013 4:48 pm UTC

indemoveritas wrote:I join your forum to comment on a topic I know well.
Please treat me kindly.

tups, you are correct. The fog above an open surface of liquid nitrogen is condensed water vapor.

Liquid nitrogen will kill you by asphyxiation, freezing, or physical explosion when contained, but not by direct chemical reaction.
Liquid oxygen will kill you by freezing or physical explosion, and also by supporting combustion.
The concentration of oxygen in liquid oxygen is about 5000 times that of air.
Demonstrating the reactivity of liquid oxygen is nerve wracking.
The order of addition of fuel, heat and LOx is critical; in that order, combustion. Rapid, unquenchable combustion.
Add fuel, LOx and then heat, and get deflagration or explosion.
Spilling LOx on oneself is a potential example of the second case, with the heat provided by the friction of frantically shedding a lab jacket.

Not for the squeamish, or those disturbed by cognitive dissonance,
a USN training video about handling liquid oxygen, Man from LOX on youtube.

There are also videos on using LOX to light a charcoal fire in the minimum time (a few seconds)
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Re: What-If 0050: "Extreme Boating"

Postby gladiolas » Wed Aug 14, 2013 1:00 am UTC

Red giants and dwarfs, and brown dwarfs are the coolest stars known. (They're even more cool if they have names which aren't just catalog numbers... 8-) ).

Betelgeuse, 3200 K.
Alpha Herculis 2800 K.

An M9V dwarf would be about 2300 K.

A brown dwarf might be less than 200 K.
http://www.skyandtelescope.com/news/118538359.html

We've found plenty of hot Jupters, and some of them are likely to get swallowed up.

So there might be planets orbiting inside a red giant star, or a red dwarf star... there's more room inside a red giant like VY Canis Majoris, a red hypergiant, 13.2 astronomical unites in diameter, about 1.227 billion miles.

A hot Jupiter which wanders into its atmosphere might retain its heavier metals for a while, with molten seas. Its temperature is around 3490 K. How long would its seas last?

Long enough for a few hours of extreme trying to impress your girlfriends (or boyfriends, as the case may be...) :)

COROT 7b is a planet where it can rain rocks, its temperature is about 2500 K.


EDIT: I should have mentioned, according to Wikipedia...

VY Canis Majoris has an average density of around 0.000005 kg/m3, a thousand times less dense than our atmosphere at sea level. How does that affect our efforts at sailing on the seas of a planet inside its atmosphere? The planet would have started out with an atmosphere way denser...

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Re: What-If 0050: "Extreme Boating"

Postby ijuin » Thu Aug 15, 2013 4:05 am UTC

A planet orbiting inside a star like that would experience enough drag to spiral inward on a scale of hundreds of thousands of years, so you'd better act quickly while supplies last!


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