In the production of small musical instruments, paper cups play the role of sound transmission. The way to make the rubber band sound is as follows.

1. Punch a small hole in the center of the paper cup bottom with a toothpick, insert the rubber band into the small hole, and take out a part.

2. Divide the toothpick into two parts. Part of the rubber band is stretched through the rubber band, holding a paper cup in one hand, pulling the rubber band in the other hand and poking the rubber band in the other. It is found that rubber bands are different in length and make different sounds.