Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: varsigma on 15/11/2024 03:30:53
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That sounds like a fancy title for what happens when you partly fill a wineglass and rub the edge.
Well, it is. The acoustic waves in the glass see a response in the liquid in the glass--waves start forming.
The kinds of waves can depend to some extent on the kind of glass. With lead glass, it seems to be easier to get a standing radial pattern on the surface of the water.
My conjecture is that these waves are not because the bulk of the liquid is vibrating, the surface pattern can't be very deep. So it's likely entirely electrostatic--the glass is vibrating so is producing an electric field displacement, this is projected over the surface of the water.
But I bet that's not the only causative agency--plasma physics is complicated and, the dipole moment of water molecules means it does act somewhat like a plasma does, when subjected to an oscillating electric field. The difference between tension at the surface and tension below it is why the surface responds and the pattern isn't destroyed.
Or is this all off the wall?
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So it's likely entirely electrostatic
Try it in zero gravity.
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Try it in zero gravity.
Gravity is the reason the liquid stays where it is. It's part of the construction.
Without gravity, arranging a liquid so it presents a flat surface is difficult. But you can't help but notice how gravity simplifies the problem.
One other detail; if you don't apply a smooth rubbing motion to the edge of the glass, you get chaotic patterns on the surface of the, ah, electrostatic fluid, near the glass.