## You can spend hours playing with a yo-yo. But did you know that the yo-yo is an innovative and interesting tool to learn concepts in science?

A toy is a great way to learn some concepts of science. The yo-yo is one such. It is engaging and inexpensive. Mastering the yo-yo takes some practice and the summer holidays are the best time to do so.

A little history

The yo-yo is known to have originated in ancient Greece. There is an image of a woman playing with a yo-yo found on a Greek urn that was made around 450 B.C. One can find ancient yo-yos made of terra-cotta in The National Museum of Athens. In the 18 century, Napoleon’s soldiers played with yo-yos to relax. Women of high society in the 17 century carried a yo-yo to pass time.

A yo-yo consists of two equal-sized discs connected with an axle. The string is tied or looped around the axle with a ring at the end of the string.

Wrap the string around the axle and curl your index finger around the yo-yo. Release the finger and allow the yo-yo to fall. As it falls move your hand upwards without any jerks. When the yo-yo has reached the end of the string, bring your hand down smoothly and help the yo-yo climb back .

Observe the falling and climbing yo-yo as it has many lessons in energy and motion. You will note that it spins like a wheel. Once it is spinning in a certain plane it tends to continue spinning there. The hand holding the yo-yo has to be steady to enable it to remain in that plane. If your hand moves, the plane changes and the yo-yo falls.

When the yo-yo drops, its potential energy changes into kinetic energy. It displays both downward linear motion as well as circular motion. The spinning effect gives it a boost to climb back.

Explaining the physics of yo-yo play, experts say, this toy demonstrates the Law of Inertia — Newton’s first law of motion, i.e., the body continues to be in a state of rest or motion unless acted upon by an external force.

A falling yo-yo experiences the pull of gravity which gives it speed. This speed combined with the weight of the yo-yo gives it a momentum. It continues gaining momentum until stopped by the end of the string.

When it stops it attains a state of inertia, due to which it bounces back and starts climbing.

Experts try some tricks like the ‘sleep’ trick and ‘walk the dog’ trick with the yo-yo. In the latter, the toy rolls on the ground before climbing back.

Steady your hand and you can master the toy. Now you can hold a contest with your friends and crown the yo-yo champ!