Every voice, note, and slammed door pushes air molecules together and pulls them apart, hundreds of times a second. Wavelength turns that pressure wave into something you can actually watch move.
Visualizes sound from your mic instead of the tone generator. Nothing is recorded or sent anywhere — it stays in your browser.
Sound doesn't move air from one place to another — it moves a disturbance through it. A speaker cone (or your vocal cords) shoves nearby molecules forward, they bump the next ones over, and a ripple of squeeze-and-release travels outward. This is a longitudinal wave: the molecules vibrate back and forth along the same direction the sound is heading, not up and down like a wave on water.
Where molecules bunch up, air pressure rises for an instant — that's compression. Where they spread out, pressure drops — that's rarefaction. Your eardrum is just a membrane thin enough to feel that alternating push and pull, which your brain decodes as pitch and loudness.
The particle field above is a real simulation of this: each dot is displaced horizontally by A·sin(kx − ωt), the same equation that describes a real longitudinal wave. Brighter, denser clusters mark compression; the gaps mark rarefaction.