Different musical instruments work because they play the note you want to hear. This seems obvious, but it’s no small thing to make something play exactly the right note, and leave out all of the other noise. How do they do this?

Instruments are made from lots of different stuffs and geometries. Some things, like violins and guitars, use tight strings to create their notes. Tuning forks and the reeds of a harmonica use vibrations of solid materials with specific lengths. Other instruments, such as organs and clarinets, produce the notes in a tube of air. That’s the kind of instrument I’m playing with here, except my tube is a simple piece of pipe.

You might not have a tuning fork to create this phenomenon, but is there something else you could do to make a tube sing? What other instruments could you create? What do you think the sound waves in the tube look like?