Question:
What would be the effect of subjecting a can of commodity soda pop,
like Coke for instance, to increased air pressure, up to 5 BAR (72
psi)?  This is the ambient pressure encountered 50 metres (164 feet)
below sea level.

Would the can deform? Leak? Explode? Be crushed? Would it matter if
the period of increased pressure was shorter (say 1 hour) or longer
(say 1 week)?

Background:
I am writing a novel where containerised consumables and goods are
transported by submarine vessels at ambient internal air pressure.  50
metres is a depth below the surface at which turbulence caused by even
severe wave action is minimal.  I want to know whether it would be
realistic to posit a scenario where supplies are shipped by submarine
container vessels at elevated (ambient) internal air pressures.

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Clarification of Question by submergency-ga on 15 Aug 2006 07:01 PDT

Thank you all very much for helping me understand.  Especially to
frozengeek-ga, who answered my question better than i hoped, through
actual experience, and really deserves credit for his answer.

Obviously, it depends what is inside a package, whether it is
compressible or not, as to whether it is going to survive being
transported at 5 BAR.  The plan is to maintain the pressure in the
transports at ambient pressure with nitrogen, adding it from high
pressure tanks as the vessel descends and venting as necessary on
ascent.  Non-permeable containers which aren't full of incompressible
stuff are going to get crushed.  Could get very messy.

If I really wanted to know exactly what would happen, I would do the
following. Go to a hardware store and buy a 3 inch pipe nipple (I just
measured a soda can and it will fit inside 3 inch pipe) 6 inches plus
long and two pipe caps. Then you could drill a hole and insert a
standard air valve. You could then pressure up the soda can to
whatever air pressure you want (up to shop air pressure) from a
service station air compressor. If you want, you could even fill the
pipe with salt water before you pressure it up. This test wouldn't be
very expensive to do and would answer your question.

submergency-ga.

(great name, by the way)

I'm not sure if the can survives or not...try standing with all your
weight on a can of Coke and see what happens.

But I suspect the pressure would do weird things to the dissolved gas
in the soda, possibly resulting in a super-spray release when someone
opens the can at the other end of its undersea journey.

Just a thought...


pafalafa-ga

Since the liquid cannot be compressed, only the bit of air/C02 in the
can will be reduced to a fifth (?) of its volume, which maybe the can
could survive.
Try Redhoss's idea, or call a friend with a yacht and ask him to experiment.

Hi There!
   I can tell you my experience.  
First.... a little about my background.  I am a research technician
currently working for the US Antarctic Program on the research vessel
Laurence M. Gould.

A few years ago, I lost a bet.  I bet a beer that an unopened can of
Diet Pepsi, sent to a depth of 3000 meters (about 300 bar) would have
the top popped in.

That turned out to not be the case.

Nothing happened.  Seems the pressure on the can was enough to deform
it enough to compress the small amount of free gas enough to roughly
equalize the pressure from the depth.

You can keep the $25.

Salt water attacks aluminum. Even if your cans made the trip, they
would probably not be fit to sell.

Redhoss,
Don't be disappointed; yours was a great, practical suggestion.
Submergency's sailors will drink the stuff.
Hey, maybe they would prefer Redbull.
Myoarin

My guess is frozengeek is correct, although I am surprised, there was
not evidence that the can had shrunk while under 300 atmospheres. The
carbon dioxide would be a liquid at 300 barr, but the fiss would
recover when returned to normal pressure. Some can corrosion would
occur after a few days, causing a leak after a few weeks. Some soda is
sold in steel cans which look almost the same as aluminum cans.
Most wet pack cans of food should do just as well as the liquid is
esentially incompressable and there is a small percentage of gas and
vapor.    Neil

Frozengeek here again...

Tried it again.  Same results.  No visible change to the can, the soda
still fizzy when you pop the top.  We're only talking 6 hours under
water, so corrosion may become a factor in time, but I would think it
would make it from port to an undersea habitat without any issues.

Another thing we do for kicks though is crush styrofoam cups.  If you
take a Sharpie permanent maker, write on the styrofoam coffee cup
(with colored Sharpies you can get pretty fancy), and send it down to
the bottom, you get back (somewhat deformed) art-deco styrofoam shot
glasses.

And you'd die laughing seeing what it does to a sytrofoam wig head.....