YO-YO QUESTION

The string moves from one side of the disks to the other. Why?

It was rainy today — no walking in the rain for me. So I challenged myself with an old yo-yo. My goal was to drop it down to unwind, then catch it when it spins back up. I went 10 times with right hand, then 10 times with my left. I had more misses on my left — naturally. Then I started to watch more closely to see if concentration would help. It didn’t, but I noticed a striking pattern.

The string appears to move from one side of the disks to the other, starting from the front one time and from the back the next time. I think I haven’t moved my hand — so it can only be explained by translational, rotational kinetic energy. Or maybe by optical illusion? I tried it many times — still the same pattern of front to back to front, alternatively on and on and on. I need much more work before I even begin to understand this physical phenomenon.

The Yo-Yo dates from ancient Greece. Pedro Flores started the Flores Yo-Yo Manufacturing Company in Santa Barbara, California, in the 1920s. The Duncan Yo-Yo was inducted into the National Toy Hall of Fame in 1999. There is an international competition with eight divisions. The free-style is a routine of tricks, performed to music. Tomorrow, I’m trying music.