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Toroidal bubbles

Donut (doughnut) bubble
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Conceived at the same time as "large bubbles".

The first part depends on the idea that a toroidal bubble is stable, and wouldn't collapse. Correct?
The second part is how to make them: my idea is by using an arrangement similar to one of those "air bazooka" set ups.

An air bazooka can be easily made from a plastic bucket: cut a hole in the bottom, about 5 inches diameter. Tape some thick plastic over the mouth of the bucket (I used floor lino). Make sure its really taped well, all around the brim. Then sharply hit the centre of the plastic with the heel of your hand. A 5 inch invisible "smoke" ring will shoot out the other end. It can ruffle hair at 10ft or so - very stable.

Now add soap solution (that's the part that I'm not sure about), and make a smoke ring bubble!
Ling, Dec 16 2004

Toroidal bubble http://www.tomnoddy.com/press.html
Look closely at the photo with Tom Noddy in it. [Ling, Dec 16 2004]

Dolphins can do it http://earthtrust.org/gif/lordrings3.gif
Isn't the least energy solution a spherical one? But obviously not in this case. [Ling, Dec 16 2004]

Dolphin vortex ring video http://www.youtube....watch?v=ig0ENGq7AZk
If you haven't seen this yet you really should. [2 fries shy of a happy meal, Jul 20 2011]

[link]






       //The first part depends on the idea that a toroidial bubble is stable, and wouldn't collapse// - really ? show us a sum.
neilp, Dec 16 2004
  

       This is the assault weapon I've been looking for to off the money cop behind the cash register at the warehouse grocery store.
mensmaximus, Dec 16 2004
  

       Well, your idea seems to depend on an assumption that isn't really correct. Even if toroidal bubbles are possible, as seems to be the case, nobody considers them even remotely stable.
5th Earth, Dec 16 2004
  

       The dolphin case probably has something to do with the greater density of the water compared with air. Perhaps the standard bubble is squashed until the centre colapses...   

       What is stability anway...? Show me a stable system and I will show you god.
madness, Dec 17 2004
  

       The dolphin bubbles are not "bubbles." They are pockets of air trapped in the center of an underwater ring-vortex. They can appear as circular chains of bubbles, or the chain can join together into a bubble filament. They're held in shape by the "tornado" of water surrounding them.
wbeaty, Dec 17 2004
  

       Actually, I was going to suggest using just the same mechanism to blow toroidal bubbles as that dolphin is evidently using. They are indeed comparable.   

       Toroidal bubbles are eminently unstable, but instability alone isn't enough to stop something existing. If you set up air eddies putting energy into the system, they could keep the doughnut hole open just the same way the dolphin does it with water.   

       I have a smoke gun that blows smoke rings. I wonder if the mechanism could be adapted to blow bubble rings.
DrCurry, Dec 18 2004
  

       So... yes it's possible. But I don't think this will do it. What's stopping you from trying and letting us know if it works?
sophocles, Dec 18 2004
  

       This will work. I don't know how I missed this idea when it was posted but I was searching before posting something and..., daaaaang nice one.   

       You would need to add a circular central flap to the exit hole of the vortex launcher with the soapy layer already held in a two dimensional torus shape, this flap may need to be inset or protruding from the exit point depending on... something, I'm not sure what. The flap may also need to be conically shaped towards the center of the membrane that receives the impact in order to work, And may or may not have to make a secondary inner 'normal' vortex ring through a hollow in the inverted apex of the cone shaped flap in order to work.   

       I think
...again, it might be the chili. (+)
  

       Could you have some toroids in the punchbowl?
bungston, Jul 20 2011
  

       The title should be "Toroidal soap bubbles", and no, I don't think they are possible. The problem is that the bubble film has surface tension, and is trying hard to make a sphere.   

       I used to make long cylindrical bubbles by holding a bubble maker (that pumped fluid up into a ring with holes in it) out to one side as I rode my recumbent bike. I could get continuous bubbles a block long, supposedly, but the back end was always necking down and pinching off bubbles.   

       A smoke ring might hold a bubble open for a second, but it's going to pinch itself down at some point, become an arc-shaped bubble, then contract into a sphere. A big wobbly sphere, true, but it won't stay as a toroid.
baconbrain, Jul 21 2011
  

       You can use one of those giant-bubble toys to make a contiguous loop (at least my cousin could when we were kids; I couldn't get the hang of it), but it's irregular, short- lives, and could hardly be described as toroidal. Nor could it be shot out of a cannon, for that matter.
Alterother, Jul 21 2011
  
      
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