[Adam Murphy (OP)]

Listener Richard got in touch with this question:

"Will a can of soda dropped in the ocean sink until it implodes, or will it float once the density reaches equilibrium?"

Any thoughts? No pressure.

[CliffordK]

I would expect them to float near the surface, at least until they're punctured.

Salt water should be a little higher density than sodapop.  And,  I think most soda cans have a small air space at the top.

Try an experiment in the bathtub or kitchen sink.  They may float in fresh water.

[Halc]

Clifford is right in that the small amount of gas at the top probably is enough to float the can itself, in which case it becomes a matter of time for the salt to sufficiently corrode the can to leak the pressurized contents.
If the can displaces less water than its mass, it will sink. It's a nice symmetric shape, so it will retain that shape for a while even once the pressure outside exceeds the pressure inside.  The top of the can bulges out with the pressure, and that will begin to bulge inward instead.  Given enough pressure, it might actually dent somewhere allowing the two pressures to equalize and preventing further deformation. It won't ever implode like a submarine. There's just not enough gas inside a soda can.

[CliffordK]

Ok, so at the bottom of the Mariana Trench, the density of water is supposed to be about 4.96% higher than at the surface.

So, if you took a can that was completely full of water put it in a net, and drug it down to the bottom, the the contents of the can would have to shrink by about 5%.  How that shrinkage would occur is difficult to say.  @Halc may be correct that the top and bottom would be pushed in to take up much of the difference.

Say one made a thin lead sphere filled with water, it may slowly shrink the sphere somewhat like shrinking foam, unless a defect allowed it to partially collapse.

[CliffordK]

Hmmm...  Learn something every day.

All soda cans aren't created equal.


Ok, so due to different sugar contents, Diet coke has a density of about 1 g/ml, and regular coke about 1.03 g/ml.  In pure water at a density of about 1 g/ml, the can/water/gaseous CO₂ allows the diet coke to float and the regular coke to sink.

I'm seeing seawater density is about 1.02 to 1.03 g/ml. 

So the diet coke would still float, while the regular coke may or may not float. 

Drag the regular coke down say 100 meters, and all the CO₂ will be forced into solution, and the can + soda will be at higher density than the ocean, and it will sink further.

 I have no doubt the can will slowly crush with increased pressure (crushing to reduce any vapor space, as well as that 5% or so fluid compression as it drifts down to the bottom of the Mariana Trench).

[Zer0]

Hello Richard & Thanks for your Question.
🙏

I see you have obtained satisfactory answers, hence not much is left to say...

Except for, that the Oceans are Not a Trash Bin.

Soda cans mostly are Aluminium.
(Easily Recycled)
👍

Inner Plastic coating protects the Can from ' Metal Turbidity '.
(Good for the Beer, Bad for the Ocean)
👎
Printed Logos & Trademarks are Toxic too.


P.S. - When We shall Cut down the Last Tree, catch the Last Fish & Poison the Last River...
Then We shall Finally Learn that We cannot Eat,Drink or Breathe Money!
✌️

[Eternal Student]

Hi all.

What impressed me the most is that no one got it wrong about the fizzy drink but I'm suspicious that the original question may have arisen because they were worried about the drink being fizzy.

A carbonated drink should be denser than a non-carbonated drink but that's not obvious.  You've forced a low density gas into a higher density liquid and so you might expect to obtain a sort of medium density overall solution.  The salt water in the ocean does behave as you might expect:  Something that is naturally solid (salt at s.t.p.) was forced into the liquid and did produce an overall solution that had a higher density than the pure water.
   Fizzy water isn't lighter and more refreshing, it's just more expensive.

[nudephil]

Thanks all for a really great discussion. Here's our (accessible) version of the answer, with some bits of Halc's deformation analysis: https://www.thenakedscientists.com/podcasts/question-week/will-can-ocean-float-or-be-crushed