How does a yoyo work

But a real yoyo uses a special yoyo string that loops around the axle. That means when you throw the yoyo down spinning, it can go to the bottom and keep spinning inside the loop. It uses the energy of the spin from your downward throw to wind back up the string. A good yoyo player knows how to throw the yoyo with high efficiency and put a lot of energy and spin into the yoyo, so that it sleeps a long time and can do longer tricks.

When the string is wound up and you are holding the yoyo in your hand, you have potential energy. If you push on a point at the top of a spinning wheel, for example, that point moves around to the front of the wheel while it is still feeling the force you applied.

As the point of force keeps moving, it ends up applying force on opposite ends of the wheel -- the force balances itself out. This phenomenon keeps a yo-yo's axis perpendicular to the string, as long as the yo-yo is spinning fast enough. See How Gyroscopes Work to learn more.

If the string is attached securely to the axle, as in the original design, the spinning axle will grip the string and start rewinding it; the yo-yo will travel back up the string. The yo-yoist must give a slight tug on the string as the yo-yo rewinds, in order to compensate for the energy lost to friction.

In the modern yo-yo, there is less friction between the string and the axle, since the string is only looped around the axle. When the spool completely unwinds, it will not automatically grip the spring -- it will simply spin freely. To get the yo-yo to rewind , the yo-yoist jerks on the string a little bit. This tug briefly increases the friction between the string and the axle so that the axle starts rewinding the string.

Once it starts rewinding, this sort of yo-yo will return to the yo-yoist just like the older design. The ability to make the yo-yo spool spin on the end of its string, or " sleep ," made yo-yoing a much more interesting challenge. Yo-yoists try to keep the spool sleeping while making shapes with the string and swinging the yo-yo around them. Another trick is to " walk the dog " -- let the spinning spool roll along the ground before pulling it back in.

Over the years, manufacturers have come up with a number of mechanisms to make it easier to do these sorts of tricks. In the next section, we'll check out a few of the more popular variations found in modern yo-yos. The word "yo-yo" and the modern yo-yo design come from the Philippines. Unlike the original Chinese and Greek yo-yos, Philippine yo-yos the word means "come come" or "come back" in the native Tagalog language had the ability to "sleep.

In any case, it dates back at least a few hundred years in the region. In the s, a Philippine immigrant named Pedro Flores decided to bring this yo-yo design to the United States. He achieved some success right away, and in , he sold his company to a businessman named Donald Duncan. Duncan trademarked the name "yo-yo" and, over the next few decades, built his company up into the premiere yo-yo manufacturer.

Duncan's competitors released similar products, under several different names including "twirler" and "whirl-a-gig". But the public adopted the term "yo-yo," leading the rival companies to challenge Duncan's trademark. In , the Federal Court of Appeals ruled that the term had become generic, and so could be used by anyone. In the same year, the Duncan company went bankrupt, selling the Duncan name to the Flambeau Plastics Company , which still sells Duncan-brand yo-yos today.

For most people, the hardest part of yo-yoing is getting the spool to sleep long enough to pull off some tricks. To get an ordinary yo-yo to sleep for a while, you have to throw it with a lot of force so it builds up strong angular momentum. But when you throw a yo-yo fast, your hand tends to jerk, pulling the spool back in.

Beginning yo-yoists also have trouble "waking" a yo-yo pulling it out of a sleep. It takes a lot of practice to get the right balance to put the yo-yo to sleep successfully. Yo-yo manufacturers have tried a number of things to make it easier to keep a yo-yo sleeping, and to make it wake up again. One of the simplest improvements was to redistribute the weight in the yo-yo in order to alter its moment of inertia. I practiced until my parents made me go to bed.

By then, I was pretty confident I had, if not mastered, at least learned the few tricks I needed for the commercial. I had even memorized the few lines I had. By the time we got to the park the next day, I had already been replaced. So much for my acting career. Rumor aka my brothers has it that the girl they replaced me with was much taller than my classmate and they kept getting their yo-yos tangled. Not sure how true that is, but I never did see the commercial.

There is no clear consensus on where the yo-yo originated, but most accounts agree that a man by the name of Pedro Flores first brought the yo-yo from the Philippines to the United States in the s and opened the Yo-Yo Manufacturing Company in Santa Barbara, California.

Later that decade, Flores sold the company to Donald F. Duncan, who trademarked the yo-yo name and rebranded it as the Duncan Yo-Yo. Since then, the yo-yo has evolved to include versions that have ball bearings and internal clutches, making it easier to do tricks much more complex than the ones that stumped me.

Nowadays you can find expert yo-yoers doing a whirlwind of tricks in demonstrations and competitions. But yo-yos are more than just a toy. For teachers and science enthusiasts alike, the yo-yo offers a perfect way to study simple physics concepts.

Regardless of the type, all yo-yos demonstrate the conversion of potential stored energy into kinetic moving energy. Question How do yo-yos work? Why do they come back up after being thrown down?

Asked by: Anita Kolat Answer When you release a yo-yo, gravity acts on its center of mass to pull the yo-yo downward. Because the string of the yo-yo is wrapped around the yo-yo's axle, and because one end of the string is attached to your finger, the yo-yo is forced to rotate as it drops. If the yo-yo could not rotate, it would not drop. Just as any object falling in a gravitational field, the rate of drop increases with time and so, necessarily, does the rotation rate of the yo-yo.

The rate of drop and the rotation rate are greatest when the bottom is reached and the string is completely unwound. The spinning yo-yo contains angular momentum or rotational kinetic energy derived from the gravitataion potential energy through which the yo-yo has dropped.

Usually, the string is tied loosely around the axle so that the yo-yo can continue to spin at the bottom.