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pelle
Apr 8, 2007, 11:20 AM
Is it possible for a flat steel plate to float in water? (Theoractical ans ok)

Capuchin
Apr 8, 2007, 11:23 AM
Depends how big a plate... and what your definition of float is... if the plate is small and thin enough, then it will be held by the surface tension. It wouldn't float though (ie, if you put it under the water, it would sink, not rise to the top). This is because steel is more dense than water.

asterisk_man
Apr 8, 2007, 04:49 PM
An object floats if the volume of the object which is submerged below the water line has a weight which is less than or equal to the weight of water of the same volume. A steel ship can float because the interior is mostly air, therefore the "average density" is lower than water but for a flat steel plate the "average density" will always be equal to the density of steel which is always greater than the density of water so it will always sink.

pelle
Apr 9, 2007, 06:23 PM
OK What about a steel plate placed into a container slightly larger that displaces a drop of water so at the atomic level the plate is on the water molecues and not touching the container. Is this floation or surface tension. Granted this is near impossible but theorectically which would it be.

ballengerb1
Apr 9, 2007, 06:29 PM
Capuchin told you in his first post that his example that it's surface tension. The plate appears to float but not by asterisk's definition. It isn't near impossible. You can "float" a needle or an old time double edge razor blade. They stay up but only with surface tension.

pelle
Apr 10, 2007, 05:52 PM
In regards to my last post:
OK What about a steel plate placed into a container slightly larger that displaces a drop of water so at the atomic level the plate is on the water molecues and not touching the container

Asterisk says "An object floats if the volume of the object which is submerged below the water line has a weight which is less than or equal to the weight of water of the same volume."

SO does my example fall under surface tension or floating by definition?

asterisk_man
Apr 10, 2007, 07:33 PM
I don't really understand your example pelle.

If the steel plate displaces a drop of water then its volume must be equal to one drop.

I'm interested in your example but you will need to offer more information so I can comment properly.

Are you saying that there is a super thin layer of water under the steel?

I'll be back when you expand on your example.

pelle
Apr 11, 2007, 02:26 PM
asterisk_man

I am referring to the theory that I read once of a battleship floating in a gal of water and the agruments that went along with it.
This isn't the same thing do to shape of hull etc.. But it made me think could a plate say 12"X12" by 1/4" steel float on water.. So yes there is a superthin layer of water under the steel actually down to the molecular level but the plate is sperated from the container by water. Is the plate floating.

If you are interested in the battleship theorys I could post the links here.

ebaines
Apr 12, 2007, 08:12 AM
I think I see what pelle is getting at. A different example might help. Imagine that you are wearing shoes with incredibly smooth soles, and you step into a puddle of water on incredibly smooth ground (any imperfections in both sole of your shoe and the ground suface are smaller than the size of a water molecule). Imagine also that your shoe has a microscopic lip around the perimeter that is smaller than the diameter of a water molecule. Your shoe will displace most of the water to the side, but one last layer of water molecules would remain trapped under your foot. In this case your weight is being held up by that one layer of water molecules. So, does that mean you are "floating" on the water? Personally, I think not - in this case the fact that the water molecules are supporting your weight has nothing to do with principles of displacement. It's also not surface tension. Rather, the water molecules are holding you up due to simple compression. Same principle as how a piston works.

Capuchin
Apr 12, 2007, 08:47 AM
That isn't floating, and it probably isn't surface tension either, that's more to do with electrostatic repulsion.

asterisk_man
Apr 12, 2007, 09:41 AM
100% agree with capuchin.

It is neither floating nor surface tension. It is the same as if the water were replaced by ball bearings. Electrostatic repulsion is the winner.

pelle
Apr 12, 2007, 01:43 PM
Thank you!
As for you ballengerb1 asterisk_man asked for some more explantaion which I gave him.