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space popgun

escape velocity water powered popgun
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Put a payload a few feet above the bottom of a very long, strong tube sealed at the bottom by a not-quite-so-strong cap.

Immerse vertically in a lake or sea of your choice and your payload should disappear with a pleasing celerity when the cap collapses.

Long enough tubes should allow the creation of lots of new space trash.

james_what, Apr 03 2008

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       Is the tube evacuated? Even if it is, this won't work. The water will only enter the tube at a certain rate (the speed of sound in water, or something like it), limiting max velocity.
GutPunchLullabies, Apr 03 2008
  

       Perhaps I should add on a wider chamber below the payload for a bit more hydraulic oomph.
james_what, Apr 03 2008
  

       Escape velocity is like 11 km/s. Is the column of water going to come out at 11 km/s? That would be some waterspout.
GutPunchLullabies, Apr 03 2008
  

       We essentially just did this idea.
DrCurry, Apr 03 2008
  

       From earlier experiments with drinking straws and bathwater I don't think the water spout should be too pronounced. Mostly air & payload, with the occasional fish.
james_what, Apr 03 2008
  

       Ah - I must apologise if I appear to have pinched another's modus poperandi. I am an occasional visitor, but thought this worthy of pier review. I have missed the earlier postulation and dialogue.
james_what, Apr 03 2008
  

       Perhaps it's a lake of Diet Coke and the tube is lined with Mentos...
hippo, Apr 03 2008
  

       Now that's an intriguing effect, but essentially gaseous in nature; not to mention restricted to the USA since the rest of us do not have Mentos.   

       I am however suggesting a much more massive, pressurised and freely available medium to apply the pop.
james_what, Apr 03 2008
  

       TANSTAAFL, Even if this could work (possibly by using the water column from a larger chamber to compress air below the payload) the energy required to lower and raise the tube would be more than the energy transferred to the payload. You would be better off directly compressing the air in a standing tube to get the same effect, and that's been discussed elsewhere on this site.
MechE, Apr 03 2008
  

       I didn't say it would be energy-efficient! $ = energy though, and with all those people wanting to get their burnt body parts into space it might still turn a profit even if we just dropped the pipe into the ocean. It's maybe more likely just to burn them some more though, as air resistance upon exit will be significant.
james_what, Apr 03 2008
  

       First I thought you meant the other end of the tube was gonna be in the vacuum of space (so the water shoots up a whole... 30'ish feet or so).   

       No clue if this would work at all, but you might improve its chances by having microholes line the inside of the tube and force air into it to reduce friction.   

       Let's see, the Marianas Trench is 7 miles down and you want a tube of bathyspherian thickness...   

       There's a bit of a problem here: sure you get pretty monstrous pressure for the first couple seconds, but after that, the pressure:   

       a) decreases because your payload is nearing sea level, and...   

       b) decreases *alot* because the "payload" now includes tonnes of water
FlyingToaster, Apr 04 2008
  

       This is one of those ideas that comes around about twice per lunation and always perishes in the 'it's a conspiracy, man!' phase.
lurch, Apr 04 2008
  

       [marked-for-tagline] you want a tube of bathyspherian thickness
Voice, Apr 04 2008
  

       With a suitably wide and deep chamber relative to the bore of the pipe I'd be looking for the water level to still be low down, and at high pressure, at the time the payload and pressurised air cushion are thundering out of the spout.   

       It'd be a lot of air a long way down. Impromptu expulsions might be a problem.
james_what, Apr 04 2008
  

       What say you suspend your payloaded pipe from a high altitude blimp, and drop it into the ocean?   

       Ah, blimps. Is there anything they can't improve?
BunsenHoneydew, Apr 04 2008
  

       A very expensive premeditated suicide method. The bullet would be bound to hit the blimp I fancy, and then there's that heavy new sea anchor.
james_what, Apr 06 2008
  
      
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