Is the canvas exposed to the air on the bottom? If so, perhaps a disc freezes, then lifts off and rises to the top, to be replaced by another later on. Can you stay up all night, watch it and let us know what happens? Roger On 15 Aug 2010, at 7:31 AM, Marilyn wrote: > Thank you for the information. It's very interesting. > > Marilyn > ----- Original Message ----- > From: YGelmanPhoto > To: List for Photo/Imaging Educators - Professionals - Students > Sent: Saturday, August 14, 2010 9:47 PM > Subject: Re: PF gallery Aug 14, 2010 Ice Disks > > This may become too off-topic fro the forum, so please respond to me personally at ygelmanphoto@xxxxxxxxx and I'll try including interested discussants in my replies. > > But I'll just put this out generally. > > It was a good idea to look for reference articles -- I didn't even begin to think about it that way. But the wikipedia article refers to ice formed in moving water -- in which the circular shape is made by ice in eddies rubbing against rock or other ice. Also, the size of the discs in these articles are very large -- with photos of 10-25 foot disks and mention of one over 60 meters. > > One very interesting article from MIT in 1993 described theories of ice di Charles River that year, but also very large. > > Here are some specifics of the disks in my photo: > > 1. The water was contained in a depression, or well, of plastic canvas; > 2. Dimensions of the well were about 2 feet x 1.5 feet across and about 3 inches deep at the center; > 3. The well was located under a tree; > 4. The disks formed overnight; > 5. The largest disks were about 4 inches in diameter, opaque, with slight roughness on the upper surface; > 6. When first observed, the disks were surrounded by a layer of thin ice that was nearly clear; > 7. The clear ice contained many small opaque imperfections that may also have been disks; > > I can't believe that rotating water had anything to do with this. > There may have been something dropping into the well from the tree branches, say small p drops. > Or, there may have been insects(?) in the water that somehow caused initial crystallization that grew out from the center. > The trouble with crystallization growing out is that I've never heard of circular crystallization. > > That's all I can say for now. > -yoram > > > On Aug 14, 2010, at 10:05 AM, Palma Allen wrote: >> Yoram Gelman - Ice Disks >> I've never seen anything like that and I grew up by a river. Sorry, I cheated and looked it up. >> http://en.wikipedia.org/wiki/Ice_circle >> > > Roger Eichhorn Professor Emeritus University of Houston eichhorn@xxxxxx
