The Controversial Physics of Curling - COLD HARD SCIENCE - Smarter Every Day 111

Hey it's me Destin, welcome back to Smarter Every Day. So in the last episode I explained

that it's not always the most athletic team that wins in sport, sometimes it involves

the physical manipulation of objects, so sometimes it's the most intelligent team.

So today, on Smarter Every Day, let's take a look at the physics of curling.

[music]

OK before we watch some curlers we need to learn the basics of the sport.

This is the curling sheet and the circles are the house. The goal is to get your team's rock

closest to the button. There's four people on each team. The thrower,

the sweepers and the skip who's in charge. Each team has eight stones

to throw, so each person throws two. They alternate with the other team

so there's a total of 16 stones thrown. The very last one is called the hammer,

which is a major advantage. Do you have any idea how difficult it was to find a

curling stone in Alabama? It is really hard. Anyway, so I know what you're thinking. Curling's like

the caveman sport right? I'm gonna slide this rock on ice and I'm gonna hit another rock

and we're just gonna try to out-rock each other. But oh no, it's way more difficult than that.

In fact there's so many things I had never even considered until

I took a closer look at how this works. For example, the simplest question of them all.

What makes a curling stone curl? OK let's pretend for just a second

that this isn't my coffee table, it's actually a curling sheet.

So we know from watching TV that when a player is back here at the hack, which is where they start,

and he pushes it toward the house where you're at, which is the bullseye on the ice, as he

rotates it or spins it counter clockwise it'll curl in the direction

of that rotation, right? Now my assumption is that has something to do with this,

which is called the running band. You'll see the bottom of the curling stone is concave

but there's this circular frictional interface that interfaces with the ice.

So we should be able to model a circular frictional interface of a moving

sliding object on a rigid surface right? Which is this,

a glass. I'm gonna take this circular object, I'm gonna put it down on the

low friction surface, I'm gonna push it towards you and spin it, and expect

a curl in the direction of rotation. Let's give it a shot.

But I don't see that. Let's try this again. Set this down,