Cold Hard Science: physics of skating video

[AgnesNitt]

https://www.youtube.com/watch?v=qd4CVvItJlo

[jbruced]

That was interesting and well done.

[Isk8NYC]

I totally enjoyed that video! Thanks for sharing!

[Query]

Very clear.

But:

1. The picture shows the hockey players stopping with blade contact near the ball of the foot. I want to ask other hockey players about this. I think that something on Blademaster's web site, at least at one time, explained that the center length should have a long rocker length, so that they can balance better, glide faster and stop faster there. But if they aren't stopping near the center of their blade, then the stopping part of that argument makes no sense.

2. He says speed skaters use no hollow, and that the cross section of the blade is flat at the bottom. That isn't uniformly completely true. Many (most??) speed skaters, just as with figure skates, create a feel-able sharpening burr at each side, and bend them to point downwards into the ice - not a true hollow, but an "over-burr" at the sides, which acts in a somewhat similar manner to a hollow ground blade. Specifically, it probably increases the drag, but allows a stronger push, and helps the blade track more straight.

3. He says skates slide because of "Friction melting". There are many conflicting theories of the physics of ice skates, but I'm pretty sure friction melting is not the majority view.