What Puts the Curl in a Curling Stone?

[pokerfan]

Dr. Mark Shegelski is a social curler, a curious curler, and an Associate Professor of Physics at the University of Northern British Columbia in Prince George. He and his co-workers, fascinated by the whys of curling, have published four scientific papers on the physics of the curl in curling. He was recently interviewed by the Discovery Channel and the CBC's "Quirks and Quarks".

Any curler knows that a curling rock, rotating counter-clockwise (when viewed from above and behind) curls to the left. But to a scientist new to the game, it is surprising. Why so?

Consider an overturned drinking glass sliding over a smooth surface and rotating counter-clockwise: the glass will curl to the left? No, it curls to the right! This may be surprising to the curler (ed. note: an empty overturned glass may be even more surprising) but it is fairly easy for the scientist to explain.

Read the rest here: http://www.icing.org/game/science/shegelsk.htm

Shegelski was also interviewed by Scientific American and you can download the podcast here:
http://www.scientificamerican.com/podcast/podcast.mp3

[blue sky at night]

1. I am in love with Curling......

it is so different from other sports, and the women are beautiful...especially the danes! I am of Danish Decent, thinking I should ask for Immigration back to the motherland!

[amerikat]

2. Me too. The ice is not flat......how they make the ice for curling.

Curling Ice

There is no question that is ever asked a curler more often about curling ice than, "Do you use a Zamboni on it?" The short answer to that question is "no." And if you read on you will learn all about how curling ice is made and how it is different than hockey ice and skating ice.
The Ice Bed

There is an old joke about an ice fisherman hearing voices from above telling him that there are no fish underneath the surface in which he is boring holes. After moving a few times he continues to hear the voice and finally asks, "Are you God?" To which the voice responds, "No, I'm the arena announcer, now get off the ice." If you were to bore a hole through the curling ice, what would you find? Besides one extremely agitate ice maker, you would find one of two things: either a big pile of sand or a slab of concrete. Some clubs are fortunate enough to have a concrete floor that is cooled much in the same way a refrigerator is cooled allowing for very even ice temperatures and very quick ice making due to an extremely level floor and unexposed pipes. Other clubs use a sand base that contains a series of pipes through which a cooling agent is passed. With sand beds the cooling pipes are exposed and the sand can shift and displace the cooling pipes make the bed not quite so level.
The Ice Itself

Curling ice does not have to be tremendously thick. It need only be about 1/2 to 3/4 of an inch thick above the highest part of the ice field. So, generally speaking, the ice will be thicker in a sand field than on a concrete floor. Creating curling ice can be a time consuming process. If you simply filled the ice bed and let it freeze you would like have ice that was not very level and not very good to play on. Instead, a series of "floods" are done. A very thin layer of water is set down in the bed and allowed to freeze. Once it has frozen solid, another thin layer of water is set down. So on and so forth until the ice is built up enough to survive an entire season of play. After a few floods, but before the final floods, the ice is painted. Those circles that you see on the ice are in fact painted by hand to look as nice as they do. At the same time lengths of ribbon, yarn or string are run along the surface to mark the boundaries of play. Immediately after being painted or having a placed on it, that section of ice is sprayed with a fine mist of water to help seal in the color of the paint or the line placed down.
The Ice Surface

Our bed is made. We've laid some floods on it, done our painting and laid some more floods down. We are ready to play right? Well, not quite. Curling ice is not flat ice, so running a Zamboni over it would not be helpful for us at all. Instead little droplets of water are sprayed on the ice (using a backpack with a hose and sprinkler head assembly or any of a number of other methods) and allowed to freeze. This is called "pebbling" the ice and the little water droplets are called "pebble." This pebble allows curling stones to travel easily over the ice and more importantly to make the stones curl. Pebble also makes the people who sweep the ice effective by changing the path of the moving stone. By sweeping the ice they are in fact melting the pebble and reducing the friction between the stone and the pebble, allowing the stone to travel further and straighter.
Care Of The Ice

Caring for curling ice is tremendously important. Pebble will accumulate over time and every once in a while it needs to be removed entirely and replaced. This is akin to cleaning all the shuffleboard wax off a shuffleboard table and starting anew. We do this by using a tool called a scraper, in effect a large metal blade attached to an electric motor. Scraping the ice in this manner not only removes the old broken down pebble but also scrapes off any frost that has accumulated as a result of moisture in the air.

There are also small things that curlers can do to help maintain the ice as well. Keeping shoes and brooms clean keeps dirt from getting ground into the ice. Not to mention, keeping our hands and arms off the ice, since our own body heat can make flat spots on the ice by melting it.
Want More Information?

Do you want more information about the creation and care of curling ice? Ice makers are notorious for their abilities to go on and on and on about curling ice. Simply stop your local icemaker and he or she will be glad to explain to you about dew point and humidity and scraping patterns and nippers and everything else about curling ice! Don't have an ice maker handy? Drop us a line at [e-mail] and we'll be glad to help you out!

[PoiBoy]

3. Thanks for the links..!!

here's a link to an interesting article about the curling stone...

http://sports.yahoo.com/olympics/vancouver/curling/news?slug=dw-curling021810&prov=yhoo&type=lgns

<snip>
Jutting its rounded self from the waters off the west coast of Scotland is Ailsa Craig, an uninhabited 104-acre island that’s home to the only known supply of the granite needed to make a proper curling stone.
<end>

it's an interesting story, IMO, of the blue hone granite, a world class sport, and puffins...

<snip>
In the 1960s, native birds, most notably the puffin that for centuries used the island as a prime breeding ground, disappeared. The British government later decreed it a Site of Special Scientific Interest and concluded that rats, which miners had brought to the island, were eating the bird eggs. In the 1990s, the government stopped all commercial activity and grew poisonous wheat to cull the rats. Birds began returning, including a couple dozen breeding pairs of puffin. Today the island is managed as a bird reserve by the Royal Society for the Protection of the Birds.
<end>

I'm really impressed by the level of environmental protection afforded the island by the government.

<snip>
Kays of Scotland had to work out a special one-day permit in 2001 that allowed it to pull blue hone granite off the island. It wasn’t allowed to quarry or blast the island’s high rock walls. It was merely allowed to scoop as much already displaced blue hone – rocks already lying around – as possible. The company says it gathered 1,500 tons onto a ship that day.
<end>

At current levels, the 1500 tons of blue hone granite that they harvested 9 years ago represent a 10-20 year supply.


Like I said.., a very interesting story, IMO..!!!



:hi:

[pokerfan]

4. Don't take the granite for granted!

They will run out someday.



Note the the scalloped sides where they've excavated rock to make stones. :)

[laconicsax]

5. God did it.

:P