Smarter Every Day did a YouTube video on this (<a href="https://www.youtube.com/watch?v=7CUojMQgDpM" rel="nofollow">https://www.youtube.com/watch?v=7CUojMQgDpM</a>) where he talks about the phenomenon and also talks to the exact same guys featured in this New Yorker article. I think he does a much better job than the New Yorker article, too.<p>Destin also notes that, countries that study curling tend to win olympic medals. He said that in 2014, and it's interesting to note that both Sweden and Canada won medals in curling in both 2014 and 2018. [Edit: Though I believe he did say it <i>after</i> the 2014 games.]
Curling Canada has a video online (<a href="https://www.youtube.com/watch?v=50cSDUIDMuM" rel="nofollow">https://www.youtube.com/watch?v=50cSDUIDMuM</a>) detailing the steps that a rink needs to go through in order to prepare their ice for a championship game. It's kindof amazing how many steps are involved, and I wonder if that has anything to do with it.
This paper came out and changed the game a few years ago. It's called scratch theory and the front edge of the stone scratches tracks for the back edge to run along.<p>There was a sweeping summit this summer to discuss brooms and how to make them scratch the ice less because it caused players to have extremely high stats for tournaments.<p>Brad Gushue video showing the effect: <a href="https://www.youtube.com/watch?v=haEuz42YCdM" rel="nofollow">https://www.youtube.com/watch?v=haEuz42YCdM</a>
These brooms have been made illegal in tournament play.<p>Some Scotties players describing the effect: <a href="https://www.youtube.com/watch?v=147vRw0kmAY" rel="nofollow">https://www.youtube.com/watch?v=147vRw0kmAY</a><p>The scratch theory paper:
<a href="https://www.thesalmons.org/lynn/curling/A5.pdf" rel="nofollow">https://www.thesalmons.org/lynn/curling/A5.pdf</a>
Investigating a complex physical phenomena that isn't tied to either fundamental research or immediate application = little chance of funding. The article is all "oh gosh, curling is so complex" but the real thing here is the limitations of our knowledge, and the ability to apply knowledge across abstraction boundaries.
One of the professors at the university I went to recently released some research on curling.<p><a href="https://www.unbc.ca/newsroom/unbc-stories/researchers-discover-why-curling-rocks-curl" rel="nofollow">https://www.unbc.ca/newsroom/unbc-stories/researchers-discov...</a>
For those of us who don't curl,<p>"It’s like golf: it’s easy to watch a guy hit a golf ball, and you think, ‘This isn’t very athletic.’ And then you get out there yourself and find that it’s incredibly difficult."<p>Anyone know how much force is applied to the golf ball on a professional's drive?
I suspect why the stone curls in the direction of rotation is that the edge on that side is moving more slowly relatively to the ice. It melts the ice less, generating less of a film of water and so experiences more friction.<p>If an axle with wheels rolls such that the left wheel is on pavement and the right hits grass, it will turn right.<p>A glass on a bar table top doesn't melt the surface to create a film; more motion means more friction not less. So, opposite.<p>It probably doesn't matter which edge (front versus back) has more weight on it, but rather which side of that edge (left or right) experiences more friction. I suspect even if you slide the glass up an inclined bar table top so that the weight is on the rear, it will still curl opposite.
THE SOLUTION IS SIMPLE<p>I suspect that the reason curling stones curl the way that they do is primarily due to one side of the stone being subjected to “static” friction while the other side experiences “kinetic” friction. This would also explain why the curling doesn’t start to happen until the stone’s linear velocity has sufficiently decreased.<p>If a stone is moving down the ice, away from the observer, and spinning to the left (that is, counter-clockwise when looking down on it), the right-side edge of the stone is moving in the same direction that the stone travels while the left-side edge of the stone is moving in the OPPOSITE direction that the stone travels. This means that the right edge of the stone is moving faster across the ice than the stone’s linear velocity. And the left edge of the stone is moving slower across the ice than the stone’s linear velocity.<p>As the stone’s linear velocity decreases, there will come a point when the left edge of the stone is no longer moving relative to the ice, while the right edge of the stone is still moving at 2 times the stone’s linear velocity relative to the ice. This means the left side of the stone is now being subjected to static friction while the right side is only being subjected to kinetic friction. The force opposing the left side of the stone is greater than the force opposing the right side of the stone, causing the stone to pivot around the left edge of the stone, “curling” to the left, until the stone's linear velocity reaches zero.
Feynman on "why is ice slippery?"<p><a href="https://www.youtube.com/watch?v=MO0r930Sn_8" rel="nofollow">https://www.youtube.com/watch?v=MO0r930Sn_8</a>
>>Archery, too, is fringe and unexciting<p>Lost me there. Archery is infinitely more exciting than many Olympic "sports", curling included.