I was also talking about solid plastics. The range of plastics with a density less than that of water may not be very wide - I don't know, I'm no expert on plastics - but products made from them are quite common.
I'll take your word on that.
Strictly speaking, that's neutral buoyancy. A floating object must displace an amount of water that weighs more than it does.
Mark L. Fergerson
I've never seen a solid ping-pong ball.
Maybe the "real" question is: "What kind of sound would they make underwater?"
Without gravity, there is no "floating".
Ask Mr. Moose.
You've obviously never heard of "floating through space".
Did you mean a forcibly submerged object?
?-)
Not when he's so fat that he has gravity of his own . :)
Did the paisons miss the adjective "gradient" ?>:-} ...Jim Thompson
--
| James E.Thompson | mens |
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| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
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.
-- Rick
If it displaced an amount of water that weighed more than the object, it not only would float, it would rise until the rule Jim stated was met. I think you mean if the object is totally submerged it would displace water of a greater weight than itself, but that would require you to hold it down. The rule is about the equilibrium condition.
One thing folks have not mentioned that is important. When that water is displaced, it is pushed into the body of water which causes the level of the surface of water to rise. This rise of the water level is what stores the energy of the object lowering in the gravitational field.
-- Rick
Never saw his post, but what exactly does he think one would "float on" in space?
Without a gravitational attractor, all one does is traverse through space, and one would punch through anything one encountered in the form of gasses. With liquids, The results of that impact would depend on several factors with one of the main ones being relative velocity. What liquids exist in space, and how does it stay glommed together? Lotta water ice there, but any glomming was likely while it was solid ice.
But no floating.
Oh yes, they float, they all float up there. and when you're up there YOU'LL FLOAT TOO!"
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
"Pimpom"
** A sometimes missed fact is that when an object IS more dense than water - it sinks all the way to the bottom.IOW, objects either sink or float.
Fish and submarines etc can maintain a given depth, but that takes engineering and the ability to adjust buoyancy continuously.
A sub that has negative buoyancy will sink until the hull is crushed and then drop like a stone.
Also, as water gets deeper, its density does not change due to increasing pressure but only temp variations.
... Phil
snipped-for-privacy@bid.nes schrieb:
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.
Bye
Phil Allison schrieb:
Hello,
water is compressible too, using 4000 bar the density is doubled.
Bye
"Uwe Hercksen"
** Even at the deepest ocean depth, density increases by only 1.8%. ** Nonsense..... Phil
Who was it that proved the compressibility of liquids?
Howard Hughes, at 35000 ft.
At 4000 bar the density increases by about 11%
The pressure at the deepest part of the Earth's oceans (the Marianas Trench) is around 1000 bar, for a ~5% increase in density.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Phil Allison schrieb:
Hello,
you should read more carefully what you cite.
"The low compressibility of non-gases, and of water in particular, leads to their often being assumed as incompressible. The low compressibility of water means that even in the deep oceans at 4 km depth, where pressures are 40 MPa, there is only a 1.8% decrease in volume."
I was writing about a pressure of 4000 bar or 400 MPa.
Bye
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