system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: I know resonance is when you vibrate something at its natural frequency and so it vibrates more, but what is a natural frequency and why do different things have different natural frequencies?
gpt
Clap. Now smack your chest. Now slap your butt.

All different sounds, right? That's bc they are built differently. Your hands have little muscle, and many bones, the sound will be high pitched (high resonance frecuency), your chest will sound more like a deep bass. It has bigger bones than your hands and a huge empty space bc of the lungs. And your butt will be a midground, bc it's mostly muscle and fat.

The frecuency (sound) a material or objet has and resonates at depends on a lot of factors. Tension, material, hardness, mass, thickness, weight.

The best way to picture this is simply grabbing a guitar. Thin cords are high pitched, thick cords are low pitched. And you can modify the pitch by adding tension.