system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: How do wind instruments amplify the sound that their instrumentalist creates without breaking the laws of physics?

The sound a tuba player makes with their mouth without the instrument sounds much lower than the sound that comes out of the tuba.

How can the sound feel so much louder without any energy being added?
gpt
The other people aren't really answering where the energy comes from. Basically, the instrument turns moving air that the musician is blowing out of their mouth, into vibrating air that we perceive as sound. And really, sound doesn't involve much energy. Like, an instrument might put out just 0.001 W of power in the form of sound. That's tiny, much less energy than the kinetic energy of the moving air you blow out of your mouth. So, by converting just some of the energy of the moving air into sound energy, you can make a loud sound.