The video below, taken (incidentally nearby here in Southern Ontario) at Sea World (though not by me, no), is incredible in every sense of the word.

[youtube http://www.youtube.com/watch?v=TMCf7SNUb-Q]

Aside from the dolphins themselves, and the implications to the intelligence of what they are doing, there is a certain beauty for the ring bubble itself; for they seem to be no ordinary bubbles. Vorticies (confined, circular fluid flow) such as these form when two masses of fluids interact with sufficiently different velocities. That is, one fluid moves quickly through a mass of a relatively stationary second fluid (i.e., air moving through water, as depicted in the video); but can also occur if the “two” fluids are actually the same substance moving differentially with respect to itself.

Imagine an isolated bubble of air moving steadily through the water. As the water streams past, the outer most surface of the bubble is peeled away with the direction of motion. Once the surface tension of the bubble is overcome by this current, the spherical shape punctures into the doughnut shape seen. The larger surface area of the outer edge experiences greater stress than along the inner edge, causing the entire ring to rotate rapidly: the outer edge moving with the direction of motion, wrapping behind the ring, and up through it’s center against the direction of motion; stabilizing itself against further rupture.

Thus, in spite of the seeming complexity of its form, the nature of… well, nature… is that the ring bubble is precisely what one should expect to have formed; the no ordinary bubble, is in fact ordinary afterall, and spectacular for being so ; )

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