Nothing but a shitty gravity here, but look at how the smoke plumes at the downstem, anyone have an explanation for this? pretty cool none the less [ame=http://www.youtube.com/watch?v=AVq_YiSxc74&feature=related]YouTube - smoke plume grav[/ame]
The shape of the bottle. It is rounded at the top. When the smoke hits the water, it goes outward and up the rounded sides of the bottle. Then the Low Pressure from the smoke exiting the down stem pulls the upper smoke back down into the center, creating donuts of smoke. The Bubbling smoke after that is the smoke rising as it gathers together with thickening smoke. Then falling as it cools... I think