I love when art and physics demonstrations collide!

When I was in Paris recently, I stayed very close to the Pompidou and was fortunate enough to see this “kinetic sculpture” titled “Flux” by Zilvinas Kempinas.  Basically, by pointing a fan down at table, he is able to suspend a loop of magnetic tape pretty much indefinitely.

I’d love to break down in greater detail how this works someday. I have a feeling it’s sort of the opposite of the more recognizable, equally cool phenomenon of suspending a ping pong ball with a vertical air jet.  In that case, Bernoulli’s principle explains that when air is flowing around the ping pong ball, if the ball shifts slightly outside the center of the air stream, the faster moving air in the center of the jet “sucks” the ball back in to the middle.

The tape is remarkable in that is suspended and relatively stable (it doesn’t drift off).  As the air deflects back up and away from the table, it pushes the tape up against gravity just as is the case with the ping pong ball. But I believe what keeps the magnetic tape centered has less to do with Bernoulli and more to do with drag.  As the jet spreads out away from the centerline, its speed decay.  In this way, when a segment of the tape gets “too far” from the centerline, the push it’s getting from the jet decreases.  When it gets too close to the center, the velocity is greater, so the drag is greater, pushing the tape more towards the periphery.

I dug around YouTube a bit for more Kempinas and found other cool magnetic tape fun:

And another!

I’d love to come up with something this cool someday; I love when science is art is science. My particular aspiration would involve fun with fountains!