Naked Science Forum
General Science => General Science => Topic started by: neilep on 20/06/2006 23:55:05
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Say you have a football...A regular good old fashioned football...pressurised to the correct amount (what ever that is)...but (for arguments sake)...the ball is made from an indestructible material..it will not bend under pressure at all.
Is there a depth in the ocean that would preclude it from floating up ?
The reason I ask is that I understand there is a depth of a few hundred meters (I think) where the human body will not float back to the surface...is this true ?
Would the same apply to this football ?...and what about bubbles on the ocean floor from vents and fishes bottoms ? [:D]...do they float up ?.....
Men are the same as women, just inside out !
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Hello sailor
A body is only buoyant if it contains air or gases through decomposition.
And one cant rise from deep down due to the pressure of the water squeezing the body together so much that their are no air gaps so any gases or air trapped within is it are squeezed out through one of its holes
Michael
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Aye Aye Captain,
Ahh...but I said the ball is indestructible.....what I also meant is that no gas can escape.
Men are the same as women, just inside out !
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A normal football like the air in a human body would be compresses and at some point the ball would no longer float to the surface. A rigid ball of the same weight would always float to the surface. Ok any material would eventually fail and be crushed under extreme pressure but a spherical object will resist a very great deal of pressure before it fails
Learn, create, test and tell
evolution rules in all things
God says so!
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quote:
Originally posted by ukmicky
A body is only buoyant if it contains air or gases through decomposition.
And one cant rise from deep down due to the pressure of the water squeezing the body together so much that their are no air gaps so any gases or air trapped within is it are squeezed out through one of its holes
The conclusion is probably right, but I'm not sure about the logic.
There is no greater reason for gasses to escape from the body when under high pressure than when under low pressure, since the same pressure would be applied to the orifices as to the outer body mass, and indeed, the orifices would be even less able to resist the pressure (i.e. you'd lose the gasses quicker in a high vacuum than at high pressure).
What is true is that buoyancy is not a matter of what gasses, or otherwise, you contain, but upon your average density (i.e. since your mass will essentially remain constant, thus what matters is how much volume you take up). Once you start being crushed, unless there is adequate build-up of pressure in some way within your body (e.g. from the build-up of decomposition gasses), your body will collapse, and thus take up a smaller volume, and thus will be less buoyant than it otherwise might be.
George