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The Casimir Effect
HobbySpacer writes "A recent article in Physics World provides a lucid description of the the Casimir effect, which is an attractive force between two surfaces caused by electromagnetic fluctuations in the vacuum. The article discusses some practical application such as the nanotech machines mentioned here earlier."
In simplistic terms this works because photons of certain wavelengths are excluded from the space between the plates. This doesn't happen on the outer faces of the plates, and the difference in the vacuum energy inside versus outside leads to an "attracting" force.
It only works on uncharged plates.
PV = nRT
Er. Well, not quite. The ideal gas is exactly true only under a certain set of limiting conditions. These conditions include high temperature and low density, among others. For typical gases (oxygen, nitrogen, helium, carbon dioxide--you know, the stuff that comes to mind when we think 'gas') it's not a bad approximation at room temperature and one atmosphere of pressure. Allow a ~10% engineering fudge factor and you're pretty safe.
In the experiment you described, the particle density would become extremely high. A number unplesant (from a calculation standpoint) effects would make themselves known. For example, the volume occupied by gas molecules would have to be accounted for--something neglected by PV=nRT.
Depending on the gas used and the operating temperature used, you might also force a phase change (gas -> liquid or gas -> solid). Again, all bets are off when something weird like that happens.
Because the plates are attracted by the Casimir effect, and the casimir force grows quadratically as the plates draw nearer, eventually, even the pressure will be insignificant compared to the Casimir force. I think that's a pretty good conclusion using rough estimates.
Nope. There are other effects you might see, as well:
chemical interactions between the gas between the plates and the plate surface
physical deformation of the plates by the high-pressure material between them
limits on compression of the 'gas' because its constituent atoms are pretty close to incompressible
Of course, as you mentioned this experiment would be impractical in reality, because gas would escape around the edges of the parallel plates--it's a tough device to seal. (And it's hard to get around this by trying to move the plates together quickly. Gas molecules at room temperature typically move with speeds on the order of hundreds of meters per second--they don't stay in one place very long.)
Oh. Right. Casimir effect. It should go away when there's crud (gas or otherwise) between the states. Establishing standing waves between the plates requires empty space between them. A few gas molecules will weaken the effect--anything near one atmosphere (or worse) will kill it completely.
~Idarubicin
I dunno whether it was because the author of the article doesnt understand physics and such, or was talking for the layperson, but a vacuum has no energy, no matter, no vacuum fluctuations, etc.
Your opening sentence is incorrect, and that makes hash of the rest of your post. You seem to be discussing classical vacuum, and in fact seem to be stuck on classical physics in general. For instace, a complete absense of everything would not have a temperature of zero, it would have no temperature.
I'm not a big physicist myself, but you are criticizing things that you don't even have the faintest conception of. Vacuum fluctations result from virtual particles, which is a concept that some view of is necessary to rationalize certain other quantum effects that occur in particle interaction. You need to learn more.