J
josephkk
- Jan 1, 1970
- 0
Strictly speaking, that's neutral buoyancy. A floating object must
displace an amount of water that weighs more than it does.
Mark L. Fergerson
Did you mean a forcibly submerged object?
?-)
Strictly speaking, that's neutral buoyancy. A floating object must
displace an amount of water that weighs more than it does.
Mark L. Fergerson
Polyethelene and polypropylene are the only ones that come to mind.
Strictly speaking, that's neutral buoyancy. A floating object must
displace an amount of water that weighs more than it does.
Did the paisons miss the adjective "gradient" ?>:-}
...Jim Thompson
You've obviously never heard of "floating through space".
It will still float if the material is less dense than water, which may
well be the case although I'm not sure either way (wish I had a ping-pong
ball I could test that with). Some common plastics *are* less dense than
water.
Strictly speaking, that's neutral buoyancy. A floating object must
displace an amount of water that weighs more than it does.
Phil said:Also, as water gets deeper, its density does not change due to increasing
pressure but only temp variations.
water is compressible too,
using 4000 bar the density is doubled.
Who was it that proved the compressibility of liquids?"Uwe Hercksen"
** Even at the deepest ocean depth, density increases by only 1.8%.
** Nonsense.
http://en.wikipedia.org/wiki/Properties_of_water#Compressibility
.... Phil
Hello,
water is compressible too, using 4000 bar the density is doubled.
Bye
Hello,Phil said:
I've never seen a solid ping-pong ball.
You mean polyethelene but not high density polyethelene. The stuff milk
bottles are made of does not float until they are made into plastic
kayaks and filled with paddlers.
HDPE has a specific gravity a bit less than water, so it should float
(especially if it has a few bubbles attached).
http://www.ineos.com/Global/Olefins...on/Typical Engineering Properties of HDPE.pdf
There isn't really that much difference in density between HDPE and
LDPE (maybe 5%).
The bulk modulus for sea water is apx 2.38E9 Pa.
You can expect a 1% change in volume for every 238 bars.
4000 bar pressure will give about 17% change in volume or density.
qrk
Uwe Hercksen
Thing is, it's not linear, thus the bulk modulus is not a constant- it
increases with pressure.
Water has about 11% volume change at 4000 bar:
http://image.thefabricator.com/a/articles/photos/1333/fig1.jpg
"Spehro Pefhany"
** Correct, 4000 bar corresponds with 60,000 psi.
Water is extraordinarily incompressible, less so than steel.
Diamond and few modern materials are less compressible than water.
.... Phil- Hide quoted text -
- Show quoted text -
Strictly speaking, that's neutral buoyancy. A floating object must
displace an amount of water that weighs more than it does.
Hello,
no, that is wrong. A swimming ship sinks so deep in water that it
displaces an amount of water that weighs the same than the ship does.
The ship sinks if it is not able to displace so much weight of water
that the ship weighs.
Neutral bouyancy has a submarine when it is completely under the water
and stays in every depth without sinking or rising. No propulsion active
of course.