Trick or treat? See for yourself

It's been a little quiet around here for a variety of reasons. So let's shake off some dust for ... Halloween? Why not?

Four drops of food coloring are added to the center of a half-filled "skinny fish tank" (a.k.a., Arbor Scientific Laser Viewing Tank) resting on a low-friction turntable (Pasco's Rotating Chair platform).

The tank is then given a spin. And, well..?

It made me say those magic words all people in science prize: "That's funny!" I didn't know what to expect, so in some ways, this wasn't overwhelmingly surprising. Still though...



I get the parabolic surface. But what's going on in the dye? I'm sure there's a lovely, simple explanation that I should know. But I don't.

If you do, kindly leave it in a comment. I am your student.