I happen to believe the curling phenomena will prove to be a seminal problem. I think it is as important to the future of physics as the motion of a canon ball was to classical mechanics in the 1600's.
Harry > The Sunday Times - Scotland > > http://www.timesonline.co.uk/article/0,,2090-1325839,00.html > > The Sunday Times October 24, 2004 > > Scientists in a spin over curling clues > by Camillo Fracassini > > > IT IS a conundrum that has perplexed scientists for almost a > century . why do curling stones appear to defy the laws of physics > by spinning to the right instead of the left? Now researchers from > the two countries most associated with the winter sport have > locked brushes in a bid to come up with the definitive answer. > Scotland and Canada have produced rival explanations for the > unique motion of the granite rocks as they glide over ice. > > The problem is why curling stones, which rotate clockwise, curl to > the right, unlike other objects, such as a glass spinning on a > table, which veer in the opposite direction. > > Mark Shegelski, professor of theoretical physics at the University > of Northern British Columbia, has produced a complicated > mathematical formula to prove his theory that the front edge of > the > curling stone is lubricated by a microscopic slurry of water and > ice caused by friction. The liquid layer means there is less friction > at the front of the rock than at the back, making it curl in the > direction in which it is spinning. > > However, a rival theory put forward by Dr Brett Marmo, a > glaciologist at Edinburgh University, claims that the secret lies > not in the front or back of a curling stone, but its sides. > > Marmo argues that the lubricating effect of the water under the > stone increases as its velocity increases. The velocity of the > right-hand side of a curling stone spinning clockwise is higher than its > left causing it to curve right, the path of least resistance. > > Shegelski is adamant that his "wet friction" theory, based on 10 > years of research, is correct, but Marmo describes his formula > as "really ugly" and his reasoning "over-complicated". > > In his paper, published in the Canadian Journal of Physics, > Shegelski also claims to have killed off another rival Scottish > theory, published several years ago, which suggested that the > motion of curling stones was affected by ice granules lodged in the > granite. > > "Our work makes a very convincing case that melting is > inextricably involved," said Shegelski. "To explain our experimental > results without invoking the existence of a thin-liquid film, well, I > would be shocked if somebody came up with a successful theory that > involved no melting." > > While Marmo accepts that melted ice is involved, he is dismissive > of the Canadian paper, The Motion of Curling Rocks: Experimental > Investigation and Semi-phenomenological Description. "I don't > believe this explanation," said Marmo, who received funding from > the Scottish Institute of Sport to carry out his research. > > "Have you tried to read it? Speaking as someone in the game, I > found it incredibly technical. I'm a glaciologist and have spent my life > looking at ice, snow and friction. Whereas these guys are pure > physicists. > > "My theory is quite simple compared to theirs, which doesn't > explain why there is much more water at the front than the back ? the > mechanism isn't explained properly." > > Marmo added that his theory which was given the best paper award > at the 5th Conference of the Engineering of Sport in California > last month also explains why curlers are able to make stones curve > less and slide further by sweeping the ice, creating more water and > reducing friction. > > Marmo and his boss, Dr Jane Blackford, of the university's centre > for materials science and engineering, have been working closely > with the Great Britain curling team. > > Blackford helped the team of women curlers led by Rhona Martin win > gold at the 2002 Winter Olympics by developing a device to help > perfect their sweeping technique. > > Martin said the curve of curling stones was crucial, but said she > was not convinced by the Canadian explanation. > > "If stones run straight, it makes a game of curling very boring > because there can't be the tactical play. We want stones that > swing," she said. > > "There are lots of different factors involved, such as the quality > of the stone and the ice at the rink. The players aren't aware of > all the science behind it. I don't think I'll be studying these > equations." > > David Smith, Scotland's leading curling historian, said academic > debate over the motion of curling stones dated back to at least > 1920, when one of the first studies was published in the > scientific journal Nature. > >end
