Before all these newfangled toys arrived on the scene—like the 3D printer for kids, or the droid you remotely control with your wristband—there were simpler toys, toys that involved boxing robots, cups and balls, and maybe even some whittling. But not every old-school toy is as simple as it seems. Exhibit A: the yo-yo, which has spinning innards (spinnards?) that move as quickly as those inside the engine of a Formula 1 race car.
In the above clip from the Science Channel show Machines: How Do They Work, we find out exactly how high-end yo-yos function, and it turns out that there is a lot more going in the guts of the ubiquitous plaything than you might think. And it’s all thanks the mightiest of modest mechanical marvels, the ball bearing!
In the video (as well as the above GIF), we see a moving cross section of the ball bearing inside of a yo-yo, and the display shows us exactly how the “rolling element” allows for minimal friction, and maximal inertia. As outlined in the video, the ball bearing is able to provide such incredible spin times (up to 10 minutes of spin after a single throw) thanks to the fact that the inner and outer rings of the bearing house a series of small metal balls, which act as rotating interfaces between the rings. And because the balls roll, they incur much less friction relative to something that doesn’t. This means that after you throw a yo-yo, the string tightens its grip around the outer ring, slowing it down and/or stopping it, while the inner ring—which rotates the axle—continues to spin rapidly.
The video also notes the fact that in many high-end yo-yos, extra weight is added to the disks on both sides of the axle because making them heavier will increase spin time—heavier disks will yank harder than lighter disks on the axle after the yo-yo has been thrown. But that bearing is the real star of the show, along with the yo-yo-pros, of course.
Now that you know all this, are you ready to look at these old-school toys in a whole new way, or are you still a no-go on the yo-yo? Let us yo-know in the comments below-yo!
Images: Science Channel