## COLD HARD SCIENCE.The Physics of Skating on Ice (With SlowMo) – Smarter Every Day 110

Hey it’s me Destin. Welcome back to Smarter Every Day. So in the olympics the most athletic team always wins right? No. It’s actually more complicated than that because there’s physical objects in the olympics. Now the team that is able to manipulate these physical objects better than the other team usually wins. For example, curling. This curling stone is very heavy, and if you can figure out how to manipulate it across the ice better than the other team you will win. So physics is a huge deal and a knowledge of physics is very important. So today on Smarter Every Day we’re gonna start a three part series on equipment used in the olympics and how it interacts with the world around it. Today we’re gonna focus on ice skates. There are three major types of ice skates used in the olympics. The figure skate, the hockey skate and the speed skate. This is my new friend Glenn. He’s a figure skating coach. It’s really awesome. [laugh] So everyone already knows that angular momentum trick right? So large moment of intertia, bringing it in. Small moment of intertia. That’s pretty awesome. So show me your skates. What makes you be able to do that? Cause I mean, I would mess up because of the toe pick, so where are you actually rotating?
(Glenn) I’m actually spinning backwards. My blade is spinning backwards, and I’m spinning on a small area we call the ball of the foot. Also my bottom toe pick is touching the ice. So it’s allowing me to put forward pressure down without sliding forward like I would on a hockey skate.
(Destin) So that’s how you’re able to keep from falling backwards?
– Right.
– Yeah I’m not really getting it. He’s saying he’s rotating about this point but he’s dragging that toe pick. Clearly this is a good excuse to break out the Phantom. Alright. OK now this is making sense. You see I used to think that they pivoted on one spot under the ball of the foot. Looks like I was wrong. They’re actually skating backwards and he’s dragging that toe pick to maintain his balance. That’s pretty cool. Alright, it’s time to move onto jumps. OK Glenn’s gonna show us three of the main jumps in figure skating. Here’s the waltz jump, the salchow, and the flip. There’s a gouge where you left the ice, – I pushed off my toe pick.
– Pushed off the toe pick, and then there’s another gouge..
– And I landed on my toe pick. But then I go down to my blade. So I’m pushing off the ice, and I’m landing on the ice, with my toe hitting first and then my blade.
– OK Glenn’s gonna do a jump and he’s gonna land with his toe pick, which is how they always land. It adds stability. It’s in the landing of these jumps where the design of the figure skates really start to show. You can spike yourself down into the ice with the toe pick and then you slowly rock the blade down. In fact the curvature of the bottom of the blade is called the rocker. After it’s planted firmly on the ground you’ll notice it doesn’t immediately move away. The skater imparts the momentum from his opposite leg back into his lower foot and then he moves. So it’s a three step process. Spike, plant, move. Interesting. But a question I have is that, if the bottom is rounded, how do you sharpen a round blade? So this seems like a good opportunity to move from the figure skate to the hockey skate. So let’s meet my friend Nick who’s the director of hockey operations at UAH. [hockey sticks fall over] So you want to show me.. I’m sorry.
– Second time.
– [laughs] Sorry dude, show me the blade, how’s this work.
– So the blades here, if you look, it’s two separate edges so I’ll draw it up here for you.
– So this is a cross-section.
– Looks like that.
– No way! – A lot of people think it looks like that but it’s actually, there’s a hollow in here.
– Really. – Yep.
– Can we see the sharpener? I like the name [wrestling announcer style] Blademaster! – This is the wheel, which actually sharpens the skate. – How do you hold the blade up there? Is this a sled or something?
– Jig, slider, everybody’s got their own little nickname for it. – OK and so then if the wheel were turning, you would bring that in there let me focus. OK I can see that curvature that you’re talking about, can you go closer if you would to the wheel?
– So that’s the radius of the skate, 3/8ths, half, 5/8ths.
– I’m not sure I understand. You’re saying this hollow right here..
– Yeah some of them will look like that, some of them will look like that, some of them will look like that.
– This is completely eye opening to me. I had no idea that ice skates had two different working edges. So why would a player prefer a deeper hollow vs a shallower one? Well think about it. If you have a shallow hollow you’re able to sit on top of the ice and glide very easily so this is very good for speed. But if you have a deep hollow, your points are gonna cut down into the ice and plow so you’ll go a lot slower however you’ll get much better grip. And if there’s one thing a hockey player needs it’s good grip. Have you ever seen them stop and change directions? So I’ve asked a couple of hockey players to show me how this double edge is used to stop on ice. Behold, the awesomeness of physics! [laugh] Isn’t that crazy? Look at what he’s doing. He’s controlling that edge and scratching the top layer of ice off, but he’s doing it in such a way that it’s converting that shear energy into power which he’s using to decelerate. Some people want to believe that hockey players are just dumb brutes but I’m not buying it. I told this player I wanted him to stop on a very specific spot on the ice. so I could zoom in with the phantom and catch the ice spray, and he did it on the very first try. Can you imagine the math that’s going on in his brain in order to automate this feedback loop? He’s constantly sensing his deceleration and somehow his brain’s converting that information to signals to control the angle of his skates and feather the exact amount of ice that he’s shearing off. To complicate matters, he’s got ice in between him and his target and he has to anticipate the total amount of impulse left in that ice so he can stop exactly where he wants to. Let’s ask him to see if he can explain exactly what he’s doing because I’m pretty sure hockey players are physics geniuses. You don’t gotta take your glove off man Ben, thank you very much. Do you have any, like if you had to say anything about that hockey stop, how exactly do you do it? – Well you’re just trying to find a balance, because you have two, there’s two edges on the skate blade, so you wanna find that inside edge, you know if you get over the top of your outside edge you go over. (Destin) So you’re trying to find that edge on the ice and just shave a fine mist.
– Just the inside one. – So like a noob, somebody that’s just learning how to do that, would they just chatter across the ice? – Yeah. When I started playing I was like three years old so, maybe by the time I was like six I could stop.
– Yeah. – So a couple of years, but like..
– Did you just hit that puck without looking? – Yeah.
– He just hit a puck and you hit it without looking. – I mean I saw it.
– Yep I’m right, they’re geniuses. So if we want grip for a hockey blade we don’t want it for a speed skate right? Which might explain why speed skaters are always falling. This was counterintuitive to me, but the bottom of a speed skate isn’t pointy. It’s actually a flat sharp 90 degree angle. To see speed skaters in action let’s go to the Pettit National Ice Center in Milwaukee and check out the US junior long track championships. OK look at how the skater starts off the line. You see that open stance? They do this because ice skate friction is asymmetrical. They glide easily going forward but they dig in on the sides. So to propel themselves skaters have to push off the sides of the blade. The larger this angle alpha is, the harder they can push. That’s why they line up with their foot at almost a 90 degree angle to the direction of skating. Speed skates are flat which means each individual stride has to be perfectly level when the foot hits the ice. This can be a problem because when you extend your ankle the blade tries to come up off the ice. The solution to this is called a clap skate. Clap skates allow a long track skater to keep their blade on the ice longer into the stride. I’ll let Adam explain. – The clap starts to come out, like this, and once they pick their skate up it just kinda just flies back like that. And so that extra push that makes the clap, gives you a lot more contact on the ice. And so you can get a lot more power.
– All this talk about ice skating and we didn’t even explain why it’s slippery in the first place. So there’s this thing called friction melting. If you’re moving something along ice it creates this really thin layer of water, think like nanometers thick. That is why you can slip on ice so easily. The coefficient of friction can be defined by this equation. It’s very interesting. OK a couple more things you might be interested in. Number one, we’ve been making infographics of all these winter sports. You can go download those and share them with whoever you like. Also I’d like to thank the sponsor that lets me do crazy things like try to explain sports I don’t really understand. So that’s audible.com. You can support Smarter Every Day by going to audible.com/smarter you get a free audio book, whatever you want, they’ve got thousands of titles. I used audible before they asked to be a sponsor for Smarter Every Day so I’m more than happy to suggest that to you. audible.com/smarter Smarter Every Day will get credit, and that’ll help us move forward, do more crazy stuff like this. Speaking of more crazy stuff like this, if you would like to see more videos on winter olympic sports, the next couple of videos, I’m gonna try to get them out pretty quick, are things like curling, and other stuff like that. It’s pretty cool. Anyway, support our sponsor, audible.com/smarter, and if you think we’ve earned your subscription consider that please. I’m Destin, you’re getting Smarter Every Day, thanks for listening to me I appreciate that. Have a good one. Why are you putting your hands out all the time? Why do I always see figure skaters do that?
– Because my coach told me to, over and over. It helps with my balance. Using my arms to rotate, turn myself. And to be a little more dramatic.
(Destin) [laughs] You gotta have a little finesse to it right? That’s awesome. [ Captions by Andrew Jackson ]
captionsbyandrew.wordpress.com Captioning in different languages welcome.

1. #### DiSCo

as a hocky player lol jkkk

2. #### incurser

This explains so much!! I tried ice skating once, and a friend showed me how. He just said, angle your blades, but never explained why so I didn't quite get it. And with stopping, I figured out that putting a blade perpendicular to your direction of travel would stop you, but I kept on falling over. That's because I kept my centre of mass was always pretty much directly over where the blade was, so when I was decelerating, my centre of mass slowed down slower than my feet did and caused me to tip. And learning that hockey players decelerate fast by tilting the blade so that one point sheers through the ice plays into that as they tilt their body to add more pressure to the blade, making it difficult a little deeper as well as preventing them from falling over or losing balance at all. This is super interesting, wow!!

3. #### janiheikkonen

7:52 torilla tavataan

4. #### Roderick Lee

you should do a 100,000 frames per second on a curling stone going down the ice

That hockey stuff is muscle memory too my man

6. #### Bhop

I my self ever had hockey practice…. About the "mathematic thing " no not really its honestly just guessing

7. #### Drew Ching

I didn’t know hockey stop was hard to others but I play hockey and it’s just muscle memory I learned when I was 3

8. #### Einezweioctopi

This goes straight into just how unbelievably complex The Lord made our brains. To be able to calculate such things with such accuracy is no mere feat. I see this every time I dabble with physics, especially when working with the Calculus.

9. #### MICROMORON

What about INLINE speed skating? There's a lot more variables at play. Humidity, wheel compound, wheel dimensions, wheel crowning, amount of flexibility in the frame, track material (wood w/ polyurethane, vinal, concrete, or tarmac), wheel firmness, number of wheels (usually 3 (120-125 mm) or 4 (100-110 mm)), wheel heat, wheel wear, wheel hub streingth, wheel hub material,and the number of mounting points on the frames even. That's what we have to deal with when choosing parts for inline speed skates.

10. #### stillpending79

as a hockey goalie, i really love it when figure skaters destroy my crease with their toe picks :))))

11. #### Flappy Dunker

7:02 me trying any one of the skates

12. #### Finna Yeet

We don’t think about stopping and how much math goes into it we just do it

13. #### Evan Wall Media

Let's go Havoc lol

14. #### Danish Ara

WHERE MY SUPERSUIT

15. #### Xavier Silva

I cannot watch this videolike at all , it makes me cringe , the blade against the ice 😣

16. #### sonnyjs15

The heel mechanism on the speedskates reminds me of an atlatle. I'm sure I'm spelling it wrong but check it out. Extended spearthrowing tool invented by early man. Genius.

Go Bulls

18. #### Alex Yelland

I love that Destin always looks like hes about to just completely explode with excitement XD

19. #### Furbloke

"Did you just hit that puck without looking?" 'Yeah' – Like so casually about it, as if to say "Whats wrong with that? Its not hard". Brilliant

20. #### Frosty.

i still hate that the "ball" of the foot isn't the round ball shape part ><

21. #### Max

There are 2 types of hockey skates. Player skates and goalie skates

22. #### Miami Sports

1:58 is it just me or we’re all those the same

6.9M subs

24. #### Life with Laura

no wait, wait… there is different types of skates

25. #### Just Looking

'Sow Cow' must have been invented by a beefpig farmer.

Thanks

27. #### Krischan Turk

@smartereveryday I got to the Petit ice center every once and a while so this is cool to see you were in town!

28. #### Lalafua

not Genius, but trained

29. #### wesley ward

Destin you should visit my friends in Houston at the urban movement . There's some cool science behind parkour bar balance and laches and different moves

30. #### Silas Turnbull

I'm a hockey player and it sucks when figure skaters are on the ice before us because they leave divots in the ice everywhere. ugh just talking about it makes me mad T_T. 2:44 just look at that

31. #### VeProducctions

I hate to be that guy but ice skates don't work off friction, if they did they would stop working around -40°

32. #### Haydon Greer

I'm going ice skating tomorrow at the centennial sportsplex for the first time and I watched this to hopefully help me, thanks!

34. #### Dawson Sturch

I love that sharpness diagram! I use it all of the time and I never knew you guys made it! Also, goalies tend to sharpen their skates to have more bite because we have to be technical in our movements in order to position ourselves to stop the puck. The skaters tend to have less bite because, well, they skate more. It helps them skate faster and they don't need to grip the ice as much as goalies do.

35. #### bluntman3180

I dare say having more brain power being more athletic.

36. #### Psychotic Core

Hockey is pretty easy if you been playing for a year or so you know how to stop quickly and when to start braking PS I play hockey

37. #### Zach

This is at least my second time watching this video, and I just noticed the awesome editing trick you did with the skate switch but your kid doesn't change. well, either cool editing trick, or AWESOME parenting!

38. #### Riley Leatherwood

Figure skating is for pussys

39. #### Riley Leatherwood

Lets go havoc

40. #### DJ Davis

This guy is like imagine all the math they how to consider to stop on that theoretical feedback loop

Hockey player: I leaned back a little and I stopped moving.

41. #### Remy’s Island life

Hey I am a hockey player and when your playing your not thinking about the angle of the skate and all that stuff it’s all muscle memory and just takes practice

42. #### Rikardo35

Swimmers are physics geniuses

43. #### W inski19

Pliis more skating things

44. #### Hector Yedra

This guy has raped a couple of people you can see it in his eyes

45. #### Reece Masters

you should do freestyle skiing

46. #### Genevieve Furlong

My home rink (for figure skating) is the Pettit! Also I recently got new blades for free style, and i can tell the hallow is bigger on them than my old blades

47. #### dill hockey

The edges of a skate also helps me and everyone who plays hockey turn and do crossovers. Also we don’t think about the math wen stoping, we just look where we wanna stop and stop there. It’s kinda like an instinct almost like swimming. Once u know how to skate and use your edges, u just have to think where, when, and lean your body back a few inches. It’s that simple

48. #### Chris Gaming

I just realized this was uploaded on my birthday! 😀

49. #### Aurel

Dude wtf they don’t think its easy to do it u don’t have to think!!😂

50. #### Elizabeth Ludden

Speedskater here. I think it's fun to turn and skate sidways on the flat of my skates. I can go about 30 feet like this. Sloth snow plow 😂

51. #### Achmad Zulfikar F. N. H.

Just a little bit syrup and Walla

52. #### Paul Bilobrowka

Funny thing is as a Canadian this is pretty much common knowledge.

53. #### MN Awesomeness

Yeah and those gouges from the figure skaters, they really mess up the ice bad for us hockey players. It gets really bad. That's the number one reason hockey players dont like figure skaters.

54. #### Anthony Hewitt

Who said hockey players are dumb brutes. Same people who say dumb jocks. Haters. Its basically just Baseball and football mixed on Ice. Alot of strategy positioning and team work. Best sport ever.

55. #### Marlin L'enchanteur

Great video!

Humans inherently have these capabilities, we don't need to understand the physics behind it in order to perform.
Understanding the underlying science is extremely cool though.

We just need to train, practice, repeat over and over again, that's how we get a feel about anything.
Just like how a good cook is a "master chemist", able to instinctively handle hundreds of simultaneous chemical reactions to produce an exquisite dish, without having to precisely know all the science behind it.

The brain is a marvelous object, the amount of unconscious processing it does every second is incredible.

56. #### HarunGama

Please do something like this for skiing man. It’d be a great compare.

57. #### Tommy

actually friction is not why skates are slippery, watch the joe rogan video with neil tyson on skating and he explains the real reason why skates slide

58. #### Cormac mckenna

I hate having rly sharp skate

59. #### T Miernicki

well you don’t learn physics to skate, you just learn skating and there happen to be physics invokved

60. #### Mateus Heinen Feltrin

I loved the video

61. #### Troy Hennigan

This. is the Huntsville ice complex I go here every time.

62. #### Jaxon _TheScooterGod

We are not dumb brutes! There’s actually a lot more then people
Think to hockey 🏒

63. #### Lyy

I’ve played hockey all my life and I never thought about angles and such unless I’m dumping the puck :/

64. #### Aidan Boyer

I see what you did with Reepicheep on this one 😆

65. #### Ryan MB

5:20 this made me feel really smart

66. #### water flavored ice cream

so a hockey blade is like a snow plow in a way?

67. #### Clorox Bleach

I wish he did one on soccer bc we r way smarter than these guys

68. #### Scrope

3:43 the machine looks so cute lawl it has tounge nose n eyes

69. #### Jd Brunette

As a Canadian, thank you for this. warms the cochles of my northern heart

70. #### Jack Hughes

I think you might be giving the hockey players a little too much credit… the hockey players that I know can't even calculate the area of a square, much less multiply numbers larger than 15, but that's my experience

71. #### Dawson O'Keefe

Hey what about goalies we do a lot of stuff with our skates

4:41

73. #### Pierobon

I am a ski instructor… Can you come to Austria, and we do some video together?

74. #### 乛Ekin乛

In one month i can go ice skat again

75. #### hockeyboi78

6:35 it's just peripheral vision it's not that hard

76. #### Thomas Nicolas

Figure skates are hollow too

77. #### Not_Lucid _Rang

5:51 naw bro we just stop

78. #### Kr8andrei

what did he not do a loop?

79. #### defyinggravity

Yea we aren’t geniuses and we don’t think about the physics while playing obviously but am I the only hockey player who finds this really fascinating

80. #### BenXVariety

5:55 i beg to differ. i have a D in physics.

81. #### Dog 101

Speed Skaters can't walk at 60 because of the way they skate, their ankles shouldn't do that

82. #### Blossom24680

Please do a video with equestrians

83. #### bob smith

considering how egregiously figure skaters literally tear the ice up compared to hockey players means they should be playing on a separate rink…. The ice is only 1/4 inch think, I'm amazed they don't almost immediately start tearing it down to the concrete

84. #### Super Seal

As a hockey player, this is really cool

85. #### Glenn Ooms

I have the same skates as the hockeyplayer at 5:26. They are pretty awesome

86. #### Flax!

jebe ti? ved to je fico

87. #### Dave Stambaugh

As I remember in my day when they ground figure skates, the skate was held at ninety degrees to what is shown here. The radius is dressed on the wheel here and as I remember this was only for hockey skates and for figure skates it was the diameter of the wheel that formed the radius on the blade however the grind marks slowed you down.

88. #### Sally Lemon

Yeah I've been wondering too. Why we fall on slippery floor but slay gracefully on ice.

89. #### Kim L

i cant even walk without tripping

90. #### Alexus Giamona

Casey Carlisle did it first 🙄🙄

91. #### Jenn Hoff

The difference between most of the moves in figure skating is which edge you're on. One spin is forward on your inside edge, and another is backwards on your outside edge. Every jump has a specific edge you take off from and a specific edge you land on. It IS something that most people don't seem to realize!

92. #### William Wilson

I play hockey and you are wrong cause Im not dumb

93. #### A Fischer

You may think that there is a lot of math in hockey, and stopping on hockey skates. There is not, it comes down to a feeling. You are taught HOW to skate and HOW to stop… the rest is up to you and over hours of practice you just "magically" know how to do it.

94. #### Bignose Bunnybear

You forgot goalie skates

95. #### Gavin Arbogast

0:47 i played there last weekend

96. #### Thomas C

As a hockey player it is so painful to watch that guy’s picks hit the ice. There are always so many holes in the ice from figure skaters, and if you hit one of those holes. It’s really embarrassing.

97. #### Cutiiez

I'm a freestyle skater. I don't care