By Kawser Abdulahi
With the Winter Olympics kicking off in PyeonChang last week the world’s eye turned to the Korean Peninsula. Although we’re all familiar with the big sports like bobsleigh, figure skating and the skeleton, curling is possibly one of the most (if not the most) puzzling sport at the Winter Olympics.
Originating from Scotland in the mid-16th Century, where misshapen stones from riverbeds were used to slide them across frozen waters. From a game once only played in Scotland alone, Curling made its debut as an Olympic sport during the Chamonix Winter Games in 1924 held in France. However, it wasn’t until 1998, 82 years later, when the sport was added to the official Olympic programme.
Curling is a team sport whereby two teams made up of four players slide stones on a rectangular sheet of ice towards a target area or house at either end which is segmented into four circular rings.
Nicknamed ‘The roaring game’ because of the rumbling sound the 44-pound granite stones make as they travel across the ice, curling played indoors has the artificially created ice is sprinkled with water droplets onto surface which then freeze into tiny bumps on the ice surface.
This ‘pebbled ice’ helps the stone’s grip and results in more consistent curling. Curling players also use brooms to help the stone glide further. There are two types of broom, the most common one is a brush known as ‘push broom’ and the Canadian/straw/corn broom with long bristles which looks more like a normal broom than equipment for an Olympic sport.
The curling rock or stone is made from a dense, rare type of granite quarried from the country of the sports origin in Scotland’s Ailsa Craig and is polished weighing 19.1kg. Players also wear special curling shoes which grip the ice well. Extremely slippery surfaces such as Teflon are used on the sliding foot whilst shooting which are built into some shoes and strapped on.
Aside from the player’s attire the sport which has been often termed as ‘chess on ice’ has increasingly become more high tech and reliant upon the science behind friction as well as the interactions between the stone and ice that determine the outcome of the match.
With dominating teams of the sport originating from Scandinavia, Scotland and North America, it’s unsurprising that research into the science behind curling has emerged from scientists from these regions.
Researchers in Sweden, where the Women’s Team has won gold at the Winter Games in Turin(2006) and Vancouver(2010), after being approached by the Swedish Curling Federation were part of a team looking at how ‘The asymmetrical friction mechanism that puts the curl in the curling stone’.
Nyberg and his colleagues used the same approach to work out stone curls as their more typical work on wear and friction in industrial and technical processes. They looked at the surface in a high resolution to observe the specific machinations and found that the curved path taken by the curling stone is due to the microscopic texture and roughness of the polished stone which created microscopic scratches in the ice.
As the stone glides across the ice it leaves scratches that cause it to turn as the rear of the stone passes over the initial scratches leading to a change in the stones path, changing its direction. This ‘scratch guiding’ is what generates the force needed for the curl.
John Bradley and his team, approached by the Scottish Institute of Sport(SIS), have also looked at another aspect of curling, the broom and the role of the sweeper, using a sweeperogometer. The
sweeperogometer is a normal curling broom with attachments to measure the movement of the strokes on ice.
Bardley and his team found that sweeping harder is more effective at certain points with faster sweeps at others to gain the best results. They also noted that sweeping hard and fast is physically taxing but is very effective at impacting the stone’s path which is essential in a sport where mere fractions and centimetres are the difference between taking home the Gold or Silver.