By the time this is published, the 2014 Winter Olympics will only have a couple of days of competition left.
Every few years, the Olympics are a testimony to tenacity and triumph. They celebrate the limits of human capability. They demonstrate our ability to overcome the insurmountable.
There is always the question - did we do our best? Did we win enough metals? And, for most Canadians, did we win the Olympic gold medal in that ultimate team sport - curling?
(Hockey is important, too!)
Yes, men and women with brooms sweeping rocks down a sheet of pebbled ice is one sport that Canadians can claim to be world leaders. Hopefully, we will also be Olympic champions.
Curling wasn’t invented in Canada. Indeed, all of the granite for curling rocks apparently comes from a singular Scottish island that is up for sale. But it is perhaps not surprising that with the amount of snow and pebbled ice that we have, it is a sport that has found a home across the country.
With the possible exception of the lower mainland, Canadians spend much of the year experiencing the joys and hazards of trying to negotiate their way around our winter wonderland. Sometimes driving feels like a game of curling with cars doing a slow turn before knocking one another out of the house or slipping past to come to rest in the four foot.
Curling is where sports, science, and everyday life all mix. Olympic curlers from Scotland have inspired researchers to think about the way that cars grip icy roads.
Materials scientist Jane Blackford and her team at Edinburgh University were interested in helping the British Olympic curling team. In 2000, they developed a new scientific broom. This “sweep ergometer” is a high tech device designed to measure how the brush is moving and how hard it is pushing against the ice.
In essence, the scientists believed that sweeping helps to melt the ice in front of the rock providing a very thin surface of liquid water for the rock to travel across. As anyone who has ever walked on wet ice will attest, it is a very slippery surface. Indeed, just standing still on wet ice can be a challenge - let alone moving!
Optimizing the power of the brush to generate a sliding surface would, in theory, provide better results. And by using their “sweep ergometer”, the scientists were hoping to help the curlers perfect their sweeping.
However, if the results of the Olympics are anything to go by, the scientific approach to sweeping adopted by Blackford and coworkers can only be considered a moderate success. Over the past decade, much more progress has been made in ensuring that the ice created for games is much better.
The interest in “cryotribology” or the study of ice friction that the researchers explored to improve the curl has not been without its spin off effects.
To learn more about how ice melts under pressure and with friction, Blackford’s team designed and built an instrument to study the process in detail. It is fairly simple, consisting of a stylus that is dragged across a rotating disk of ice. Different substances can be used for the stylus - such as metal, granite or stone (like a curling rock), and even rubber - along with different conditions.
The path on the disk is then examined using a scanning electron microscope. Doing this gives a very detailed picture of how the different forces or pressures can affect the microscopic properties of ice along with the effects generated by different materials and temperatures. Amazingly, despite the fact that we have been dealing with ice for hundreds of thousands of years, there is still a lot that isn’t known about what exactly is happening at the surface.
Refining the experiment and upping the magnification using an atomic force microscopic - which is capable of “seeing” the surface at the atomic level - has ultimately answered some of these questions science has about ice. Is the surface of ice really a liquid? Is it the mobility of the surface layer that allows an object to slide? Is pressure really necessary to create a liquid layer?
There are all sorts of arguments and opinions in the research literature about ice and what is occurring at the surface. The best understanding is that it is a solid with a very mobile monolayer of water molecules adhering to the surface that act as if liquid. It is on these mobile molecules that ice slides.
Ultimately, a better scientific understanding of the science of ice allows all curlers to play a better game. Indeed, understanding ice will help all Canadian athletes do better at the next Winter Olympics.
In the meantime, we can all enjoy the spectacle that is the Winter Olympic Games.
