True “neutral buoyancy” is impossible to obtain. Consequently, an object at rest will rise to the surface or sink to the bottom. Still true?
In practical terms, I can see that it might be unattainable, but in theoretical terms, it ought to be possible, or at least I don’t see why not.
Cite?
Archimedes (287? - 212 B.C.)
Do you mean he wasn’t neutrally buoyant before or after he was dead?
In a body of water, the deeper water should be denser due to gravity, so an object with the correct density should float at a certain depth in the water, neither sinking nor rising.
Same idea as a hot air balloon.
No it shouldn’t. It will be under greater pressure but it won’t become denser. Liquids, like solids, do not compress under pressure. The density of water is always 1g/ml.
What about a submarine?
Even under no forward propulsion, the ballast could be adjusted to any depth.
And borchevsky water (unlike air) is not compressible and so water has a constant density despite the presure to which it is subjected. (I imagine there could be a negligible increase at higher pressures but this is inconsequentail for this discussion.)
Darned !
ReallyNotThatBright types faster than I do.
Sorry for repeating the same information.
That isn’t true; liquids don’t compress very much, to the extent that for many applications, they can be considered incompressible, but they are compressible nonetheless, as are solids.
(if this were not so, sound waves would not be able to travel under water)
And SettingSun
How abount a website link for neutral buoyancy being unattainable?
This is the best site I found on the Internet, but not really comprehensive to the OP … Archimedes Law
I’m trying to work out what the objection would be; my best guess is that factors like convection currents and maybe even Brownian motion might make it a practical impossibility.
But in theory, all you should need is a body whose displacement exactly equals its own mass.
Actually, it might be quite difficult to go from the position of sunk or floating to a position of static neutral buoyancy, as slowing your ascent or descent would actually involve adjusting the buoyancy to the other side of neutral and in an ideal model, you would only end up oscillating about a fixed point by ever-smaller amounts, never actually achieving rest.
maybe that’s what the OP means.
No, the “law” is an object at rest will either float to the surface or sink to the bottom …
Pardon me, but that sounds like a contradiction; could you explain a little more?
If you hold an object perfectly still at some depth in water and release it, it will either float to the surface or sink to the bottom.
What’s the argument about? They use it in cosmonaut training. Are they breaking the law? :rolleyes:
OK, why?
What will happen if the object precisely of the same overall density as water - i.e. the water it displaces when fully immersed weighs exactly the same as the object?