On 02/22/2010 08:38 PM, Jones Beene wrote: > > *From:* Jed Rothwell > > Ø That's a splendid little video, and an elegant demonstration of spin > conservation. I urge people to see it. > > … if it is authentic, it is splendid indeed. >
It looks authentic enough -- but it's *NOT* smoke rings. It's dye in water. It doesn't move like smoke in air; it moves like dye in water. It seems obvious that's liquid, not gas, we're seeing in these videos. The YouTube post doesn't say what it's in; it's only the low res copy which was asserted to be "smoke" rings, but that assertion obviously didn't come from the original author of the video. > Ø The air particles and spin both rotate 90 degrees as a result of the > collision. Fascinating! > > … that is the part that “almost” looks too contrived to me – to be > accepted as true without a thorough investigation (at least to my > thinking). There simply does not seem to be enough momentum in the > initial colliding tori to carry forward and retain the spin structure > for that kind of orthogonal change and transfer. > > It would be relatively easy to fake with computer graphics, if someone > were so inclined … but I hate to even mention that possibility, since > there is absolutely no apparent reason to believe that deception was > involved – other than there are plenty of geeks who would delight in > the challenge. > > Jones >
