Why Blowing in Bottles Makes Sound and Helmholtz Resonance

An explanation of why blowing in a bottle makes a sound, basically explaining how Helmholtz resonance works and how to bottles are Helmholtz resonators. The same explanation works for what role the speaker plays in moving objects/bottles using sound, the acoustic propulsion in one of my other videos below. This also explains a bit about resonant frequency and compares the sound wave compression and decompression to an oscillating spring, a simple harmonic oscillator.