A vortex ring is the phenomenon where a quantity of fluid or gas in a toroid (donut) shape, travels through a medium of fluid or gas, while spinning like a thick circular bracelet that is being rolled off of a person’s arm. (Except the spin is in the opposite direction as when a bracelet is rolled off in this way.)
Are these videos real? Yes, we’re pretty sure they are. So how exactly is this done? A small burst of air is released into a toroidal or poloidal vortex, essentially a spinning donut of water.
Bubble rings are actually made of two different rings, one inside the other, spinning in the same direction. The outer ring is made of water, and the inner one is made of air…
From YouTube User Maxwel Hohn, How to make a horizontal bubble ring:
Just remember to always be safe when underwater. Please conduct all experiments with adult supervision.