How is this done?

[ron101]

Originally Posted by lastlight

if you placed a mostly full pop bottle of water into the sink upsidedown quickly, the water would stay in the bottle. Could you not then have an air pump with the input inside the bottle drawing from that air cavity at the top? Blow this air into the bottom of the bottle so it just goes right back where it came from?

Yes but I would be concerned about eventual oxygen depletion from recycling the air. Although there may be enough gas exchange from the 'open' areas of the tank.

[moldrik]

Depends on how the tank is setup, it wouldn't be a big mess.

If you fill up the bottom tank, setup the vertical part, and vacuum the vertical part, you basically guarantee that if it fails, all the water would be sitting in the bottom tank. The water probably wouldn't splash either because of the vacuum that has been setup at the top.

If the vacuum is stable, it technically will hold, since the only way that water will get out of there is by new air coming in. And basically as the new air comes in, the same, small volume of water water would be pushed out.
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CD175