What Is Sound: Vibration & Air Pressure Waves
Sound = a vibrating object pushing air into alternating sparse and dense waves.
When you speak or sing, your vocal folds vibrate, opening and closing rapidly in your throat. Each closure gives the air a push, like dropping pebbles into a pond — ripples spread outward and finally hit your eardrum, and that is when you "hear" sound.
Experiment 1 · Vocal Folds Opening & Closing Create Waves
Drag the frequency slider and watch three things change in sync: how fast the vocal folds open and close, how the air molecules bunch and spread, and the waveform on the oscilloscope. They are three views of the same vibration.
Vibration → air waves → eardrum vibration → sound. Frequency is how many times this vibration opens and closes per second. Every analysis in the app starts from this stream of waves captured by the microphone.