How Yo-Yos Work

I guess you could call it. It's a painful sensation. I get up against the wall sometimes and do the blue the bear. That'll do sometimes too, But it's weird, like I only have backaches in about the same place, and that would be on my left shoulder blade on the western side of it, depending on which direction I'm facing. Curiously, this is going to be the most interesting this show. That is not a treat Chuck Man, So, Chuck, this

is going to be a great one. I have a feeling that's gonna be one of those ones where it's like, wow, that turned out to be really good. It's physics heavy, out the Yeah, everyone loves that. But the fact is, when we finished this, you're gonna know how yo yo works. This is probably the most truly titled, truest titled episode well we've ever done. Do you think yep? I don't know. All right, well we'll find out. I think it should be called physics through the eye of a yo yo.

So listen, have you ever seen the movie Harlem Nights? Uh parts dude? That is go back and watch it again. Oh you're crazy. It's one of the best movies ever. Eddie Murphy, Red Fox, Richard Pryor, and like everybody else in it too. I think Bernie Max in there terrible script. I don't think the script is terro. I thought it was great. Um. There's one thing about that movie that

bugged me to know it. It's setting like the twenties, right, and throughout the movie Eddie Murphy uses the word yo yo was obviously a modern term, and it just sticks out like a sore thumb every time he does. It drives me crazy, Like it drives me crazy that he did it drives me crazy that the director wasn't like, you can't say yo. This is like nineteen twenties New York. Yo wasn't around. I don't know that they were going for a historical accuracy in that one. They were wearing spats,

so um Jerry like that one. So I went back to the little digging Chuck and it turns out that yo was in fact around in the nineteen twenties. But Eddie Murphy was still wrong for using it in that capacity. Okay, so um yo goes back at least to like the fifteenth century, as like a hunting cry, right when somebody was like somebody else might go yo and you go chase fox. Um. That was kind of the first wave of yo um. As far back as eighteen fifty nine.

We know that there were sailors that were using yet yo ho Yo ho ho or also um. It was a response for roll call like yo, like somebody called your name, you would say yo. It wasn't until after World War two, though, that the modern incarnation comes and it came out of the Italian quarters of Philadelphia. So that's where they think yo came from after World War two. Hence Eddie Murphy was wrong in using yo, especially frequently

in the movie Harlem Nights. So I did all that research, or I could have just looked into Google Translate from English too, uh Filipino or vice versa, and find that it just means come. Yeah, but I don't think that's what it means here, does it? It does now, So the word yo yo as it stands, it means come, come or come back. Yeah, that makes sense. Did you know that? I did? You want to talk a little

bit about the history of yo yos? Did you know before reading this fantastic article that yo yo's originated as we understand them now, originated in the Philippines in the nineteen twenties. I didn't know that. I did know that it was around for a long time before that though, And you know other forms, well, pretty much the same form. They were like two forms of yo yo's in history, and one came out of the new one came out of the Philippines. The other one that's pretty old, well

ancient Chinese or at least ancient Greeks years ago. But they think the Chinese had something similar to that. Yeah, I'm starting to strongly suspect that the Chinese or the origin of human civilization. Yeah, they came up with beer. Well, they came up with beer, you have it. They went right there. Uh, and it is the oldest toy on

the planet except the doll. The dolly. I thought that was pretty interesting too, Yeah, yeah, of course, although I wonder if they're kind of diminishing any kind of ancient rituals or rights by saying like, look at that's cute doll, when really it's you know, some sort of fetish m hmm. I don't know. You never know. So it's been around long time. They've designed it in different ways over the years. Uh. The original design was had the string tied tight to

the little access there. We'll call it the Greek design, the Greek design. Now we'll call it the Chinese design or the European design. Well, not designed, but it was popular in Europe. And that obviously if if you ever used an old yo yo like that or redesign yours to where it's tied around the axle, it'll pop up, you know, as soon as you throw it down, it'll pop back up because it's tied to the axle. Um,

And you said it was popular in Europe. There were other words for other names for the yo yo before it was a yo yo, that's right. There was the lemigret, the Bendalora. The Bendalora was British, I believe the quiz. Yeah, I didn't. I didn't get a country of origin for that, but it was very popular in Europe. There's a painting

of I think Louis is he the boy King? I don't know whichever Louis was the boy king of him holding like a yoyo, like a royal painting of him with a yoyo or the what was a little hoop on and a stick? I think that's what it's called. That was an awesome game hoop on a stick? Who uh? And then um, I don't think you can compare the yo yo to the hoop on a stick. No, I'm not comparing. I'm just saying I just never got that

to Oh okay, well here's another one for you. Napoleon was well known for carrying and using a yo yo, apparently for stress relief. Oh yeah, it didn't work too well. Here's a stressed out dude. He needed the yo yo. But as as you said that, that's the the European favored or Chinese design, where like the strings tied really tight to the axel and it just basically goes up

and down right. So the Filipino design led to the modern yo yo as we understand it now, and the huge distinction is that the the string is just looped around the axle kind of loosely, which has the added benefit of allowing the yo yo itself to spin once it reaches the end of the string. Sleep. That's what the that's why people yo yo I think. Yeah, it's all about the tricks. I mean, it's sort of fun for a minute just to go up and down, but it's really all about the tricks. It's just a stress

reliever if it just goes up and down. Did you yo yo when you were a kid? Uh? Yeah, here there. But even as a kid like I could sense that, like these these new modern ones that we'll talk about with like ball bearings and clutches, they just seem like cheating. I agree, let's not even talk about them. It's not even a real yo yo. So, Chuck, you want to talk about a little bit about physics, Well, let's finish the history for shall we. Okay, Well, I have plenty

of that. Uh. It was originally in the Philippines. They think it was a hunting weapon for like four years, so, but not like a little tiny yo yo. They were really big and it was basically a big spindle attached to a rope with like spikes coming off of it. They were like the size of a ugo. Yeah, and I guess the just the benefit there is you could get it back after you threw it at somebody. Right. The stream was almost just useless though, Well you can

just throw it and run after it. Oh really okay, it was actually heavy rope in the US for hunting too, right. Well, at some point down the line, well, yeah, you would think anything used in hunting, you know, does double duty and more exactly anything you're trying to kill. Yeah. Um. The At some point though, they became smaller and became

toys and uh. In the twenties, a Filipino immigrant to the US named Pedro Floris Um started a company, the first modern yoyo company in the United States, and did pretty well for himself, uh, and then sold out to a man named Duncan. Right, Donald Duncan, Yes, Donald Ducan and Duncan Duncan and uh, you know Florest's and Santa Barbara and like you said, was selling these things like hotcakes enough that Duncan said, hey, let me buy that I'm gonna keep the name yo yo because it's catchy.

I'm gonna trade market and now I own it. And uh. Through the years he had competitors that made similar devices with different names, and they were like, dude, everyone's calling the sing of yo yo. We want to be able to call it a yo yo two. And he said, no, no, I own it. Then the federal courts in the nineteen six five says, you know what, that's generic enough now where you don't own it any longer. They're all yo yo's.

Well what these legal challenges to their trademark? The name yo yo um was one of the things that bled the company dry. It eventually went bankrupt. Duncan, the Duncan Company went bankrupt in the same year they ruled yeah against them. They were like, well, that's it for us, But they also had other money troubles. They were they were actually victims of their own success, the Duncan Company was.

So they moved in the forties to luck wiscon In, which very quickly became known as the yo yo capital of the world, and at their peak they were making thirty six d yoyos an hour, mostly out of would At first maple They're using a million board feet of maple wood every year. Yeah. And they actually, in addition to their legal challenges, like the money going to fight their legal battles, um, they were paying tons of money

in overtime to advertising. Um. And as a matter of fact, I think in nineteen sixty two, Chuck, they managed to sell forty five million yo yos and in that same year there were only forty million kids in the US. That's pretty astounding. A chicken in every pot and a yo yo and every exact other hand at sure, un, I guess some kids were yo yo with both hands. They're rich kids. Um. But like I said, they they the company ended up going bankrupt anyway, but yo yo

enthusiasts still look very fondly on the Duncan name. And um, I think June sixth, Yes, June sixth is National Yoyo Day, which happens to be the same day as Donald Duncan's birthday. Yeah. Well, and the Duncan name lives on. Obviously, you still see Duncan yoyo's. They sold out, They didn't just shut down, well, they went bankrupts and sold all right. Yeah, so who was the flam flam Bail plastics company. They said, we'll keep the name Duncan because it's synonymous with yoyos. It's

not generic yet. There's a little yoyo history for you. I got a little more. I'm going to stay to the end. I think you'll like. Okay, we didn't tease you with it that. Let's talk about physics. Well, I think this is very interesting. Good. So there's a two Okay. You mentioned with the string tied to the classic Chinese design yoyo, you have one kind of um energy going on, right, yes, and that is linear momentum, the ability of it to

go up and down or I should say down and up. Right, that's right with the Filipino design, the modern design and has two kinds of potential energy. It has that same linear momentum to go up and down, but it also has angular momentum. And angular momentum is um its ability to spin on an axle. Okay, so you've got two things going on. And like you said, when the yo yo hits the end of the line of its linear momentum, it can still it's built up since it's wound around

the school. It's built up a lot of angular momentum, so we can just sit there and spin or sleep as you called it. It actually increases as it goes down, which is the key to keeping it spinning right. It gets faster as it falls. There's another pretty cool trait to yoyo. Who knew they were so complex? I didn't? Did you? I did not? Okay? So um. They also

have gyroscopic stability, chuck, they do, okay. So if you if you have a yoyo that's sleeping and you witch down on top of it, like it goes down and then back up, that's because of its gyroscopic stability. That point that you push down on the yo yo is transferred from the front and spun around to the back. So that's even now, So the yo yo just keep spinning as long as it's spinning fast enough. Gyroscopic stability, yes, that means a spinning object object will resist change to

its axis of rotation. And have you ever thrown a football it's the same thing. Yeah, Or if you've ever thrown a football poorly, what do they call that? Wibbler turkey, wounded duck brick. That's why wounded duck doesn't go very far because it doesn't have that tight spin, so it falls off its axis and won't travel as far, the same as a prison And then the whole team's man. Basically, anything that spins frisbees, footballs, there's there's gotta be a baseball.

We could liken it to a baseball somehow. Let's say a curveball, knuckleball slider. Definitely not a knuckleball slider than spin. It all really like a shot put. No, the knuckleball. You the whole key is it doesn't move. It travels like this, and that's why it moves all around crazy. Um. So you've got your you've got your yoyo sleeping. You're you're totally aware of its gyroscopic stability um and you

understand that it's angular momentum is just awesome. It's far out right, it's far out but you want to wake it up. And that's when you bring it out of its sleep and rewind it back up the spool. Right, we'll tug on the old finger. Yeah, And the reason why it's because the loop, right, there's less friction with the loop around the axle. When you tug it, you increase that friction and you allow it to rewind. It just grabs ahold of its buddy and just let's go

back up to the palm. Yeah, it's pretty cool. Yeah. I like yoyo physics a lot. So we basically just talked about the two hardest parts, right, sleeping and waking. Yeah, And like I said, sleeping is the key to do any kind of trick like walking the dog, which I was pretty good. I used to. Could do a few

Yeo tricks. Yeah, I could walk the dog, and I could do uh, I could do the deal where you you make a triangle and then TikTok through the triangle something like a cradle or probably the cats and the cradle, let's call a cat's cradle, and then I could I could do the around the world. Wow, around the world. Yeah, I couldn't do any of those. I'm gonna this inspired

me to get a new yo yo. By the way, I like the vintage Duncan ones, specifically the yellow ones with the butterfly, like the gold the gold butterfly, the inverted ones, because they had those that were that looked like a butterfly that were inverted, and I think that actually plays apart and the uh increasing the moment of inertia section. Yeah, I think that's why they flipped it out to put more weight on the outside. Yeah, okay, what you want to talk about that? So do you

remember when we did the Um Murphy's Law podcast? I could, I forget remember one of the books that he wrote was for Your Moments of Inertia. Yeah. Yeah. I didn't realize it was a terrible, terrible engineering pun until I read this article Paul staff a little bit. We love that guy, so, Chuck. A moment of inertia is basically a way of describing as spinning objects resistance two changes in that rotation, basically um being slowed down right, Um.

And what what smarter people than us have figured out is that if you increased the mass and distribute it slightly further away from the axis, you're going to increase its moment of inertia and that increases the amount of time is just sleeping right. Yeah. And like I said, I don't know this, but I just remember when I was a kid, they had those inverted yo yos, and I bet you anything that's why they did that. It's got to be because were wider at the outside and

then curved in, which had to be less mass. Yeah, it was less stuff. That's would So I'm gonna go on record as saying that's why they did that. But I think you want more mass further away to increase its moment of in nurture. Right. Yeah, so it was there was more mass on the outside further away from the axis. Yeah, so that allows things to sleep a lot longer. And um, that was a I guess you could say one of the breakthroughs in yoyo design. I think in the sixties they started adding mass to the

outside and um, extending the axle a little bit. Bam, yoyo has been improved. Think about this, right, maybe even longer than that. Years ago, somebody invented the yo yo does not change until the Philippines in the early twentieth century. Well I thought it said it did change, We just don't know. Said there were changes in designs over the years. No, not that I took. I took it like there was one way and then there was the Filipino way and

that was it. We got a correction to make them and then the twenty century hits and then there's all these great improvements on these designs. Indeed, one of the improvements Chuck was adding bald bearings. Right, yeah, well you and I don't think these are improvements, or at least I don't. Okay, that's absolutely true. That's a good caveat. I think that the Filipinos perfected the yo yo. Let's just call them modifications for sorry kids who don't know

how to yo yo rich kids. Yeah, that makes it easier, I think. Didn't that the whole point of both of these things. Yeah, I guess makes it easier to sleep. And yeah, and I guess they're like, well, if you're just enjoying sleeping and waking your yo yo, then why make it tough if you want to have fun with your toy. I can't believe they made it easier for kids to have fun. So the bald bearing design I

think is kind of clever. Um. Basically, the this modified asition takes the axle and splits it into into two races, which are basically little courses for ball bearings to spin around. Right now, does that split the axle? These are just around the axle. So one is connected to the axle that's the inter race, one is connected to the string that's the outer race, and then in between the two are ball bearings. They're not connected in any way, um

except maybe via the context with the ball bearings. So when you when you release your yo yo towards the ground and it's linear and angular momentum really build up. When it hits the inter race can tilt a little bit and um connect with the outer race via the ball bearings. So they're they're spinning, right, and then as they straighten out the um they they're they're not connected anymore, so that the string no longer has any effect on whether the yo yo spins or not, because it's just

the interrace connected to the axle that's spinning. So your yo yo can sleep far, far longer. Yeah, the outer race spens the interrace, which spens the axle. Right, it's like a transfer of angular momentum exactly, and then the strings just like you just let me know when you're done, and we'll wind back up. Well, it'll get a little tuggle. Do the same thing with that style, right, or you can just completely take yourself out of the equation altogether

except for a snap of the risk. The initial release is all you need to do with what's called the yo yo with the brain. These are really fake yoyo's. I want to get one though. It's kind of cool, like you could be in a vegetative state and do this yo yo. Yeah, this was in the nineties. Company called Yomega release these and they called it the yo Yo with the brain, when in fact they should have called it the yo Yo with the clutch. And Uh.

The deal here is you've got these two clutch arms, uh weighted ball on one side, and it's not attached on the other side, and they're spring loaded. The spindle is not attached to the axle, but the clutch arms are attached to the spindle. So when you throw this thing down, it's gonna spin slower at first than the and the clutch is engaged. As it gets faster, all of a sudden it's enough inertia to pop the clutch essentially against the edges, and it releases the spindle, which

makes the whole thing spin faster. On the axis right, the centrifugal force um pushes down the weight, which pushes down the arm under the spring, which releases the two which allows it to spin. And it only spends for a certain amount of time. It's not like the kind that you tug back up. It'll spin til it slows down and then the clutch locks back down and boom it shoots back up, right back up. I wanna, I wanna wish we had one of those. I want to

see what it's like. So basically, the big to the two modifications are based on separating the string from the axle by by creating two different kinds of I guess axles are mendles or whatever, which are really just sort of taking the Philippine Filipino design a step further because although it made contact with the axle, it wasn't quote connected to the axle. Yeah, I guess it was, but

it wasn't tight. And a guy named Michael Caffrey is the one who came up with the yo yo with the brain Andy Omega started telling him in n but he came up with in two years after a man named Tom cun created the no jive three and one yo yo that you could take a part and replace the axle and do all sorts of modifications with no really big big time for changes in yo yo design. So did he rip this dude off? Is that what

you're saying? Okay, No, I'm just saying, like the two these two big steps in umsign he said two years after it was sinister. Well, you're a very suspicious person I am when it comes to yo yo design. Um, chuck, that's pretty much the physics of yo yos. Did you know that we just explained how yo yo's work. You know, I looked online at videos and stuff to make it a little easier, because this is a very visual thing,

and they do have videos. But what I found out is that a lot of teachers, physics teachers, use yo yo's to describe these whatever four to six properties that we described. I have to tell you, I understand angular momentum far better now. I understand and although it went through the yo yos, through the football, I understand the moment of inertia. Okay, all wait is that moment of inertia? No, that's angular momentum, angular moments spinning on an axis. Yeah, oh,

you're talking about the gyroscopic stability. That's what it was. See, I get confused. I need to chuck. It's physics, man, don't feel bad. Um, you want to know a couple more pieces of yo yo trivia? Yeah. In one, Abby Hoffman of the Chicago seven was um indicted uh or no, charged with contempt of Congress when he um started doing the walk the dog. Uh and during a House on American Activities Committee session that was investigating him. So he

was like, I'm just so over this, I'm gonna yoyo. Well, apparently, the way I read it is that he was trying to entertain, lighting everything up. It's like, here, watch me yoyo, and he was walking the dog and the sid. So that's how yoyo's are connected to McCarthy is m if you want to take an S Y S K quiz and that comes up. Plus, yoyos were huge back then. That was like the heyday. I think it was the sixties. Yeah, um, Nixon,

have you seen Nixon try to yo yo? Man? If you don't like Nixon, this will just make you hate him even more. The night that they opened the Grand Old Opry and I think sometime in nineteen four, Um, what's the main guy, like the whole cast of hehaus behind Nixon and then the main roy acoff. He presents Nixon with a yoyo and like has to put it on Nixon's finger and Nixon looks like what's going on?

You know? And um, and then he tries to do it once and it just kind of like lops down and makes like a sad trombone noise, and he just has this sullen like look on his face, like I don't like yo Yo's He looks kind of like you did. At the beginning of this episode, me and Tricky did um. And then they took a yo yo in space Chuck, Yeah, I saw that and it still work. It did work. They found that like letting it drop did nothing because they were testing it in microgravity. But if um, it

will it will go slowly. You can, you can do it slowly, but it will still spin. Um. And it moves kind of um, just kind of gracefully along the string like in just mid air horizontally and um, but it will never sleep. Well, thank god NASA did that. Those are all the videos you see that. They do much more than that. That was back when NASA was like, we have so much money, we don't know what to do. Let's launch something and let's say the Toys and Space Project, right,

and they did. Now, this was just where yo yos. That was the only thing they did on that flight. Well, no, the Toys and Space Project in company or encompassed to sixty Shuttle missions one for each toy that they tested out. Jack's was one of the best ones, the Belo paddle. So that's uh, that's Yo yos. Frankly, I'm pretty happy with this one. I thought you were going to lead in with something on Yo yo Ma. No man, try to look up Yo Yo's in the news and not

at Yo yo Ma. Cheez, can't do it, stupid. I searched yo yo minus ma minus knee minus gabba to finally get some stuff out. Oh what was the other one here, Mama neo yo MTV raps that came up to did it? Yeah? I stopped searching before I minus MTV two. You know you could minus, I was, yeah, and it'll it'll route out all the search, all this, all the results that have that. Really, so you just put the minus sign minus and then the next letter.

No space, had no idea, and you can do a bunch of different ones, no commas, no nothing, just like minus gabba minus yo minus mom minus knee. You literally just improved my life. Oh good, or my research for like eight times to day. Yeah, all right, well that's it, all right, yo Yo's. I was in a jewelry store once and Neo came in it seemed nice. Who's Neo? He's this rapper. He's from Atlanta. I thought you're talking about the matrix. No, that's like Neo. This is Knee Yo.

Oh yeah, I part of him. Yeah. Well, if you want to learn more about Yo Yo's including some really top notch illustrations, this is one of those ones that you will see why we have staff illustrators here in color. No. Um, you want to type in Yo Yo at the in the handy search bar how stuff works dot Com, that will bring up that really cool article. Um And I said handy search bar. So now it's time for Chuck

to shine with another edition of Listener Mail. Uh, Josh, this is uh one of our oldest than not by age, but one of our most loyal fans and its spies. She has a band and they put together. Uh well, let me just read it. This is coming out shortly after Christmas, and she said it was still great to

read this. Hi, guys and Jerry. Since we're firmly in the festive, greedy little griff of the holiday season, I was wondering if you could give a shout out to a project I'm involved in or my band is at least.

It's a charity album to raise funds for the continued fallout from the Japanese earthquake and nuclear disaster and the light of everything that's happened since, and it's been put on the backbrunner of most people's charitable contributions, which is why we were thrilled and honored to our part to re raise awareness when the label releasing this compilation approached us to contribute a track. So you know, she's right. You hear about these tragedies appen, and then six months

later you kind of forget about it. It's the curse of the news cycle exactly. But luckily there's a lot of people that, uh, my friend Dave is one of them that's still working, like on the tsunami from five or six years ago, so continued help is always needed. Uh, there's a CD. It's gonna be out in mid December, so by this by the time this comes out, it'll

already be out. You can stream the entire album, which is thirty seven tracks by thirty seven artists on the website More Hope for Japan dot Com and her band New Century Classics wrote and recorded a brand new song just for this compilation and she's quite proud of it, and I haven't had a chance to listen to it yet, but I'm gonna. And she says there's a lot of far better known artists on there. Uh and anyone who likes instrumental music, post rock, ambient and basically pretty melodic

guitar based and should dig it. So check it out. That's Anna's uh Anna's band, New Century Classics, More Hope for Japan dot com. Very cool, Thanks a lot and appreciate that. Thanks for letting us know, thanks for doing what you do, and thanks for listening for like years, She's been around forever. Yeah. Yeah, I guess if you're working on something that you feel like everybody's forgotten and shouldn't have, let us know and we'll try to help

your re raise awareness too. Yeah. Send us a tweet to s y s K podcast or you can shoot us Facebook something uh Facebook dot com slash stuff you should know and as always, you can get really personal and send us an email a real live email to stuff podcast at how stuff works dot com for moral this and thousands of other topics. VI is it how stuff works dot com. To learn more about the podcast, click on the podcast icon in the upper right corner

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