system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly produces the characteristic sounds you hear when two specific materials collide?

From what I understand, sound is just energy permeating space that causes your eardrums to vibrate (this is a very layman understanding, one that which I am still not confident in).  My question however stems from the fact that when two materials collide, i.e. a piece of aluminum and a marble counter top, the same sound is always produced.  What physical properties cause the characteristic sounds we hear, down to the molecular level?
gpt
First of all, sound is vibrations of air molecules, when they hit your ear drum your ear drum vibrates with it.

The characteristic noise each material makes comes from how it vibrates. If a one object vibrates at a higher rate than another, then it will sound higher pitched or have a higher frequency. However, it doesn't stop there. Objects can emit sound at different frequencies simultaneously. The combination of these waves produces timbre and makes objects sound differently in more ways than just pitch alone.