B Perfect Floating Ball Illusion (inspired by Jeff Koons' Art)

Wrichik Basu

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Recently I chanced upon a video from the Royal Institution. The host has tried to replicate a piece of art by Jeff Koons (snapshot from video):

Annotation 2019-08-02 221728.png


At Ri, they have tried to produce the same thing by balancing the ball filled with water, in a tank containing saturated saline water at the bottom, and tap water on top:

Annotation 2019-08-02 221516.png


However, as you can see from the above picture, there is a clear difference in refractive indices between tap water and saline water. But this is not present in the original version.

Any other ideas to create this kind of "floating ball illusion"?
 

phinds

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Any other ideas to create this kind of "floating ball illusion"?
I assume Koons created a fluid mix that is (1) as clear as water and (2) is more dense than water and (3) has the same refractive index as water. I don't even know if you CAN make such a thing but that's what seems most likely.
 

Andy Resnick

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Recently I chanced upon a video from the Royal Institution. The host has tried to replicate a piece of art by Jeff Koons (snapshot from video):

Any other ideas to create this kind of "floating ball illusion"?
Koons dissolved salt (sodium chloride) in water to achieve the desired density, but you could also use glycerol to tune the density.
 

Wrichik Basu

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Koons dissolved salt (sodium chloride) in water to achieve the desired density, but you could also use glycerol to tune the density
Actually, we don't know what Koons used. The host in the video used salt in water. Glycerol can be used as well, but there will again be a marked difference in refractive indices, which is what I want to eliminate.
 

A.T.

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However, as you can see from the above picture, there is a clear difference in refractive indices between tap water and saline water. But this is not present in the original version.
Maybe it is just a matter degree. At some point the difference in refractive index might become not perceivable, but requires a better balanced ball.
 

sophiecentaur

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As this was an illusion, the 'football' may not have been a football but a very thin skinned sphere (balloon), made of a material with a density very near to the mean between fresh and low concentration salt water.
Add to that, the different background in the original image, the distortion could be better hidden.
Illusions make us assume certain things about the situation and that's where the showman sneaks things past our critical faculties. Is there a link to the actual video?
 

Wrichik Basu

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Is there a link to the actual video?
I have put a link in post #1. In that video, you can see the illusion. Other than that, I don't have a link to any other video on the original illusion.
 

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