h a l f b a k e r yWarm and Fussy
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Take a ball of glass or polycarbonate, say 3 inches in
diameter with a void about an inch across in the centre,
and drill a fine, tapered hole into it so as to access the
void.
Then take the ball into space and leave it there for a few
months. Before bringing it back to Earth, put a tight-
fitting
tapered plug into the hole then return to Earth with
it.
Atmospheric pressure should push the plug into the hole
very tightly indeed, leaving a near-perfect vacuum inside
the ball.
Sell balls that contain nothing to wealthy collectors of such
curios.
Of course, if you were to take the plug out then the ball
would be empty, rather than containing nothing.
I thought this looked a bit familiar.
Space_20for_20sale
[2 fries shy of a happy meal, Oct 21 2011]
Yours is really out-of-this-world compared with Rare Earth
Rare_20Earth
[swimswim, Oct 21 2011]
Vacuum Dirigible Service Tech
Wanted_3a_20Vacuum_...le_20Service_20Tech
[sqeaketh the wheel, Oct 25 2011]
The same thing but not for sale
http://www.foxnews....pture-space-bottle/
You don't deserve extra points for tapered holes [mylodon, Oct 28 2011]
[link]
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Genuine space nothing! Don't accept inferior artificial vacuums manufactured at ground level! |
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You could probably sell small Balls of Nothing™
(made with an impermeable, soluble exterior shell)
as a fad diet aid. |
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Filled with empty calories, [hippo]? |
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Gottfried Leibniz ping pong balls. |
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You'd better fit a nothing filter in there, or it might get filled with space dust. |
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How much are you charging for that, [leopard]? |
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I'd buy some. I could use some more space in the living room. |
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An idea about balls full of vacuum
Made [bigsleep] mistakenly assume
That writing in verse
would not be
perverse
when really it's a foretaste of doom |
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//when really it's a foretaste of doom// |
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It could be disastrous if these became extremely
popular and they all "inhaled" a little bit of
atmosphere at roughly the same time... everyone on
Earth might asphyxiate. |
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[+] //and they all "inhaled" a little bit of
atmosphere// Much sooner than that. Think of all
the air that would have been removed from
the Earth in the course of manufacturing the things. |
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[infidel]'s blown their cover: clearly an
extraterrestrial engaged in atmosphere-smuggling. |
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False advertising: the ball of "nothing" contains lots of vacuum energy. |
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Is this part of some strange scheme to bring space to us, a bit at a time? |
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Smaller nations could buy these one by one and eventually merge them into one big piece of space and insert their satellite into it, saving the launch costs.....erm...hang on... |
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It won't be long before there's a Chinese copy: "Prove there's not a vacuum inside and we'll refund your money" |
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That's easily proven, if you can get the ball's density. |
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It's rather like the barometer/height-of-tower
problem. How many different ways could you
prove
no vacuum inside, without removing the cork.
Computerized tomography is obvious.
(Does it count as penetration? Bearing in mind
that natural
electromagnetic radiation is passing through the
glass constantly? Amend this one to "tomography
+ lawyers".)
Mechanically oscillate it, while measuring reactive
force, and demonstrate "sloshing" of internal gas,
or rotate it, decelerate sharply, and demonstrate
that gas inside continues rotating, transfering
angular momentum to the outer shell, which then
warms by friction?
Suborn an employee of the manufacturer? Drill a
hole through the cork? (Thereby evading the
"penetrate the glass" criterion.) Demand ISO
9000 certification? |
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Hit it with a finely-tuned (i.e. narrow) ultrasound scanner;
a vacuum
will show up as a 'blank spot'. If there's air inside, there
will be a return from the far interior wall. |
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How about a container design with convex dimples that will only turn concave if the capsule contains a hard vacuum. Then you'd only need certification of authenticity from a reputable manufacturer to guarantee the contents... or the nontents as it were. |
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// reputable manufacturer // |
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A company is only as reputable as their bottom line allows.
Independent testing is a necessity. |
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//How many different ways could you prove no vacuum inside, without removing the cork.//
If the container was clear glass you could use spectrophotometry. |
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I was just about to suggest that these glass balls be blown in space for a more permanant containment of nothing.... then I realized I'd sound like an idiot. |
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Apart from the 'blown' part, which I took in the figurative
sense anyway, you're actually on the mark; a vacuum
environment is an excellent place to form glass structures.
Theoretically, glass made in space could be as hard as
steel, or more so. |
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//you're actually on the mark// |
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Ah. I guess my brilliance has surpassed even me. |
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[2fries], your idea albiet the exact same product, doesn't have a see through container. If I spend a lot of money on nothing, I want to *see for my self* that something is not in there. |
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That's why I said 'space' the second time. As per usual, I
could have been more clear. |
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Sorry, but I won't be volunteering to blow your balls,
glass or otherwise, in space or anywhere else. |
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Pff, like I'd ask you to. T.G.F.J. has exclusive access as far
as ball-blowing is concerned. |
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Trans-Gender [FarmerJohn]??! |
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//I won't be volunteering to blow your balls, glass or otherwise, in space or anywhere else// |
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I will not blow your balls in zero-G
I will not blow them, don't you see?
I will not blow them on a shuttle.
Not one single crystal bubble!
I will not blow your balls in space.
I will not blow them any place!
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// Trans-Gender [FarmerJohn]??! // |
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No, sorry. The Good Fairy Jenny, who is [The Alterother]'s
wife, at least until the hallucinogens wear off and she
realizes what she's married to. |
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Thanks [21]. I'm about to amend all of my limericks. |
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Such a vacuum packaging procedure may be useful for the professional Vacuum Dirigible Service Tech. {link} |
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Down in my office, on top of my desk,
Is a small crystal ball that is empty, or less,
See, the ball's been to space, and filled with the
same,
So the contents inside are a stuff with no name,
For anything inside was surely leaked out,
When the ball was opened in space and the air got
sucked out.
Before the ball was resealed and stowed in a box,
Then delivered to Earth with some little green
men and some rocks.
Now it sits on my desk and mocks me at night,
For the only thing in it is the ghost of starlight. |
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I wouldn't be so sure of that [21 Quest]. I was aiming
for Theodore Geisel, I must admit. |
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Um, a glass vessel full of vacuum is a very dangerous thing to break. Old TV picture tubes used to be disposal hazards. The air pressure sends all the glass thudding inward, and it bounces back out. |
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Which brings up a test for vacuum: Buy two, break one. |
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//"Prove there's not a vacuum inside and we'll refund your money"// |
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Wouldn't a glass-ball containing a vaccum simply weigh less than a glass-ball containing some air? |
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Looking at it from another angle, shouldn't a full compressed-air cannister weigh more than the same compressed-air cannister once it's empty? |
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Yes [ZT] but you would have to empty the vacuum out of the ball , and then re-weigh it when it was empty. |
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You could buy two balls, break one, and then measure the weight of them both. If they weigh the same, then the remaining one is faulty. |
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That just proves that there are manufacturing tolerances. |
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Yes, my point exactly. You have to test the same ball twice, once before and once after breaking it. |
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But that's not going to prove it to the imaginary Chinese
company. You are going to show them a broken ball and
say it doesn't have a vacuum in it...or if you do it (your
destructive test) in front of them, they can deny the
results to any third party. |
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The test needs to be repeatable (non destructive) and
portable. |
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Test it by using the fresh-egg test. Give the thing a spin, stop it for a moment, and see if it tries to start back up again. |
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You'd need to make the test more sensitive, of course, as there would only be air inside a fake. A simple motorized testing rig should be portable, if expensive. |
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[Later: Whoopsy. [mouseposture] suggested that up there a ways.] |
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Surely some sort of chromotography or spectromographic test would suffice? |
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If I may reiterate: ultrasound! My dad has a very nice
scanner that should do the trick, and a slightly less fancy
one that is indeed portable. It's in my workshop right now;
he brought it over to use as a stud-finder the other day.
That's what made me think of it in the first place. |
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That was inevitable. At least it was over with quickly. |
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//ultrasound!// That will work, but not in the way
you describe (if I understand you correctly). If the
sphere's filled with gas, you'll see an image of the
central, gas-filled void. If it's vacuum-filled you'll
see no image at all, since the sound waves won't
be transmitted through the center (hence not
reflected off the far wall). |
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Actually, sound waves'll presumably be
transmitted through the glass around the
circumference, and set up complicated
interference patterns -- hard to say what it would
look like, but presumably nothing like an image of
the central void. |
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On the third hand, maybe that effect will
dominate even if the sphere's gas-filled (if the
glass transmits ultrasound much better than
the air. In which case, ultrasound wouldn't work
as a
way of disproving vacuum. |
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// If it's vacuum-filled you'll see no image at all, since the
sound waves won't be transmitted through the center
(hence not reflected off the far wall). // |
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That's exactly how I was trying to describe it when I wrote: |
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// Hit it with a finely-tuned (i.e. narrow) ultrasound
scanner; a vacuum will show up as a 'blank spot'. If there's
air inside, there will be a return from the far interior wall.
// |
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I was
thinking about throwing on some PPE and experimenting
with some old vacuum-tubes I have, but I didn't know if
they'd blow up or otherwise pose a risk of damaging my
dad's equipment. |
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It is easier to ask forgiveness than permission. But
don't tell him I said that. |
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(Maybe you could get a goat, or something, to
swallow a vacuum tube?) |
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But then we're risking damage to the goat as well. I have
no idea what would happen if you passed an ultrasound
scanner over a vacuum tube, but I can envision plenty of
bad things that _might_ happen. |
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