Make:

if you had small clear fins spinning at a very hight rate of speed in the bottom, the distortion of the glass and water would prevent them from being obvious to casual observation. A close look at all the pictures that were provided showed some heavy distortion. I think to be sure you would almost need a shot from the bottom of the tank looking up into it, and even then I doubt it would be evident.

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I notice that it doesn't say "water" but "fluid". There are fluids with the same, or similar index of refraction as glass. There is a fairly common "science" magic trick involvine glass rods changing to glass chains using the liquid. Same sorta "trick", you would never see the blades unless they were spinning fast enough for cavitation. Maybe something similar (this is consistant with previous post). Or does the chamber spin? (unable to see video on work computer.)

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It looks like a blown-up version of a magnetic stirrer of the sort found in most any biological or chemical laboratory. A small magnet is not very visible once it's spinning.

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I agree with michael. A giant magnetic stirrer.

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I believe the vortex is created by something much less complex than magnets or "invisible" fins: The container simply rotates. Granted the artist achieved an amazing level of precision in the rotation of the vial, but once that's in motion, the water in it will produce a nice vortex. It wouldn't even need to spin all that quickly.

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Wrique, your guess is a much more difficult solution, and to transfer the motion to the liquid would require a non-circular interior which would likely be much more visible than a small spinning magnet at the bottom.

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Hey AP; thanks for the feed back, but I disagree, there's plenty of friction between the water & the vial. Once the vial is in motion, it would get the water up to speed in very little time.

The most complex part of this piece, would be achieving a perfectly symmetrical vial and to set it up perfectly on its axis so that its spin is imperceivable.

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After a little digging, my theory appears to be incorrect. Sorry about that.

Here is a picture of a similar sculpture by the same artist where he used a cubic vessel. On the bottom of this one, there is clearly a hole. I presume the turbine is just below that, & it stirs the water in the vessel.

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If the whole container rotates uniformly, it will transfer its momentum to the water, but that will equilibrate to a parabolic surface, not a vortex.

Another way to get this effect would be to make a classic "bathtub" vortex, with just a hole at the bottom to let the fluid drain out. The trick would then be to pump the liquid back up to the top invisibly, which could be done with a double-walled vessel, where the two walls are transparent and the fluid is pumped up between them.

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Again, on the topic of the "bathtup" method:

In this picture of a water vortex (by Artist-in-Residence Doug Hollis) from the Exploratorium, you can (barely) see the pipe bringing water back up to the top. There are some pictures and a movie of that sculpture here.

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Originally I was going to say that it was a magnet, it seems to be the obvious solution. Just a small magnet sitting in the bottom of the container, and a slightly larger one below it attached to a motor. It would be incredibly cheep, and effective.

All tough I do like the method proposed by Windell_Oskay, something I personally would never have thought of, but very simple in design. Either method would probably work, and they both would be pretty easy (in the latter case a small pump and clear hose would do the trick).

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I think gunterhausfrau is on the right track. The only problem I see with it is that such liquids are rather thick oils--which wouldn't form that nice of a vortex, would they?

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Why speculate, it says
electric turbine

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