Phonon noise

Okay kiddo, let me tell you a story about something called phonon noise. So, every object in the world is made up of tiny things called atoms. These atoms are always moving and shaking, even when we can't see it. Sometimes, when they move, they create something called sound waves.

Now, imagine you're sitting in a quiet room. Even though it might seem totally silent, there are still tiny sound waves floating around. These sound waves are so small that we can't hear them, but they're there.

Now, back to those atoms. Sometimes, when they move, they create sound waves that are really small - even smaller than the ones we can't hear in that quiet room. We call these sound waves "phonons".

Phonon noise is when those tiny sound waves from the atoms are loud enough that we can hear them. It's kind of like someone whispering in your ear - it might be a really quiet noise, but you can still hear it.

Scientists study phonon noise because it can tell us a lot about how materials work. It can help us figure out how materials conduct heat, for example. And even though it might seem like a small thing, understanding phonon noise can help us make all kinds of cool stuff - like better computer chips, or more efficient solar panels.

So there you have it, kiddo - an ELI5 explanation of phonon noise. Stay curious!