Our Second Paper Crumpling Experiment

We had guessed that the bigger sounds made by crumpling paper came from bigger areas jumping in and out, involving longer creases. Our first experiment to test this idea seemed to disagree with our guess.

We wanted a better proof that big sounds didn't come from the big areas and long creases. (Mostly, we didn't like it that our guess was wrong!) So, we cleverly put in our own creases!

We folded our paper into triangles as shown in the picture. We made some sheets with large triangles, and some sheets with small triangles. We then crumpled them gently, without making new creases. The sounds from the sheets with big triangles were about the same as the sounds from the sheets with small triangles!

Our hypothesis (our scientific guess) was wrong. We learned that the loudness of the crackles is not due to their size. Long creases don't make louder crackles than short creases.

Why are some crackles so much louder than others?

For the crackles made when crumpling paper, we don't really know yet. We believe the reason has something to do with the fact that paper is very thin. We know more about crackling noise in magnets.