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How does an open bottom fish tank work? Answered


Your link even details making a vacuum pump.

I spent a bit of time looking, you tend to come across the same video clip a lot...


But what about the air being pumped into the upper tank? Wouldn't that allow the water to drop as the air replaces the water?

Set up your tank.  THe bottom is open and the top is closed.  Put a tube up to the top of the tower and suck out the air with a shop vac. and water will fill the tower and stay there.

My first thought was "not very well" but then I went and found out what an open bottomed fish-tank is.
It works by the air pressure on the surface of the lower open tank preventing the water running out of the raised tank.  Atmospheric pressure will support a column of water up to around 32 feet.   As Steve says, try it on a small scale with a glass.

Just with atmospheric pressure. Try it in your bathroom sink. Fill the sink, fill  a glass with water, invert it under the water and then lift the glass ALMOST out of the water.