What We Learned by Crumpling Paper

While we were doing our experiments, we tried to guess why some of the crackles were so much louder than others. This kind of scientific guessing is called making hypotheses.

Big Sounds from Little Areas

One of our hypotheses was that big crackles would need to involve big areas of the paper jumping in and out. Here's a picture of a flattened piece of crumpled paper. Notice the creases: some are long, some short. It seemed a good guess that big noises would happen when long creases were made, or when big areas between long creases would jump!

We tested this in two ways. First, we tried seeing if the sounds were louder when we first started crumpling.

Get a fresh sheet of paper, and try crumpling it just a little. About how long are the creases? Then really crumple it into a small ball. Are the creases shorter?

Our hypothesis was that the crackles would be quieter at the end of each crumpling, when the creases got shorter. When we tested this, we hardly could tell the difference!