Credit: http://www.bubblerings.com
People do it
Dolphins do it
How you can do it
How it works
http://en.wikipedia.org/wiki/Bubble_ring / vortex bubble bubble ring toroidal bubble underwater vortex ring air bubble occupies core of the vortex forming a ring shape ring of air nearby water spins poloidally travels through water spin rotate fast faster bubble ring spins stable bubble ring smoke ring vortex ring physics active study fluid dynamics devices invented generate bubble vortex rings bubblering /
