At this time of year, when the weather gets colder and the ground is covered with snow and ice, there are many activities that people take part in that physics plays a crucial role in. These festivities include skiing, sledding, and skating as well as even simpler things like driving on icy roads and cutting down your Christmas tree. So in spirit of the holidays, I thought I would explore the physics behind some of these activities in a series of winter blog posts. In my first post, I will be exploring the physics behind skating.
Figure skating, ice hockey, and even just leisure skating are fun to watch and participate in because of the low level of friction between the ice and the blades of skates that allows one to go so fast. With such little friction, in order to start moving forward, a skater must apply a force perpendicular to the blade of the skate. You can see this concept demonstrated in the image below.
While watching a hockey game the other day, someone asked how the players are able to skate backwards. This seems to come very easily to those who play hockey or figure skate regularly. But for the rest of us, we can use physics to help us understand how to skate backwards. It is actually quite similar to skating forwards, but instead of turning your skate outward, you turn it inward. However, a skaters blades usually never leave the ice when they are skating backwards and they instead glide in a type of "S" pattern. It is pretty cool to see someone skate backwards at fast speeds because it is harder to push off against the ice
Another part of skating that we talk a lot about in physics has to do with figure skaters spinning. When a figure skater enters a spin, they start off slow with their arms outstretched, but as they bring their arms in tight they are able to increase their speed. If you look at the equation for angular momentum, L = Iw it can help you make sense of this change. When they pull their arms in close to their body, they are essentially decreasing their radius and thus reducing their moment of inertia. Then, due to the law of conservation of momentum, their rotational velocity increases. Here is a short old video that demonstrates this.
Speed skaters also take advantage of physics to increase their speed in numerous ways. They reduce their air resistance by crouching which decreases their frontal area and allows them to accelerate and maintain a greater speed. Speed skaters also take advantage of slip streams, which I talked about in more depth in one of my recent blog posts.
Many different elements pertaining to physics can be manipulated to create faster, more efficient athletes in the world of skating. With the winter Olympics approaching, it will be interesting to see what new things the athletes can accomplish and examine the physics behind it. But its also pretty amusing to examine what happens when non-professional athletes put on skates. Thanks for reading and enjoy this video!