How dolphins generate the silver rings:
They are "air-core vortex rings". Invisible, spinning, vortices in the water that are generated from the tip of a dolphin's dorsal fin when it is moving rapidly and turning. When dolphins break the line, the ends are drawn together into a closed ring. The higher velocity fluid around the core of the vortex is at a lower pressure than the fluid circulating farther away.
Air is injected into the rings via bubbles released from the dolphin's blowhole. The energy of the water vortex is enough to keep the bubbles from rising allowing the dolphins play time.
[ame="http://www.youtube.com/watch?v=TMCf7SNUb-Q"]YouTube - Dolphin play bubble rings[/ame]
They are "air-core vortex rings". Invisible, spinning, vortices in the water that are generated from the tip of a dolphin's dorsal fin when it is moving rapidly and turning. When dolphins break the line, the ends are drawn together into a closed ring. The higher velocity fluid around the core of the vortex is at a lower pressure than the fluid circulating farther away.
Air is injected into the rings via bubbles released from the dolphin's blowhole. The energy of the water vortex is enough to keep the bubbles from rising allowing the dolphins play time.
[ame="http://www.youtube.com/watch?v=TMCf7SNUb-Q"]YouTube - Dolphin play bubble rings[/ame]
