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<DIV> Does anyone know about this? I received an amazing video which I will gladly forward to anyone who wants it-too big for the rain list.<BR>Deb Clark</DIV>
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<DIV>Here's the explanation that came with it:<BR><EM>> The attached video is of dolphins playing with silver colored rings<BR>> which they have the ability to make under water to play with. It <BR>> isn't<BR>> known how they learn this, or if it's an inbred ability.<BR>><BR>> As if by magic the dolphin does a quick flip of its head and a <BR>> silver ring<BR>> appears in front of its pointed beak. The ring is a solid, donut<BR>> shaped bubble about 2-ft across, yet it doesn't rise to the surface <BR>> of the<BR>> water! It stands upright in the water like a magic doorway to an <BR>> unseen<BR>> dimension. The dolphin then pulls a small silver donut from the <BR>> larger one.<BR>> Looking at the twisting ring for one last time a bite is taken from <BR>> it,<BR>> causing the small ring to collapse into a thousands of tiny bubbles <BR>>
which<BR>> head upward towards the water's surface. After a few moments the<BR>> dolphin creates another ring to play with. There also seems to be a<BR>> separate mechanism for producing small ring which a dolphin can <BR>> accomplish<BR>> by a quick flip of its head.<BR>><BR>> An explanation of how dolphins make these silver rings is that they<BR>> are 'air-core vortex rings'. Invisible, spinning vortices in the <BR>> water are<BR>> generated from the tip of a dolphin's dorsal fin when it is moving <BR>> rapidly<BR>> and turning. When dolphins break the line, the ends are drawn <BR>> together into<BR>> a closed ring. The higher velocity fluid around the core of the <BR>> vortex is<BR>> at a lower pressure than the fluid circulating farther away. Air is <BR>> injected<BR>> into the rings via bubbles released from the dolphin's blowhole.
The <BR>> energy<BR>> of the water vortex is enough to keep the bubbles from rising for a<BR>> reasonably few seconds of play time.<BR></EM></DIV></BLOCKQUOTE></DIV></FONT><BR><BR><BR>
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