Speaking of physics, I had taken a series of oscilloscope FFT readings of various whistles a while back. Assuming they post in the same order as I'm uploading them..
1) Closed end cylinder whistle, approx 1 inch effective length.
2) Two tone marine flat whistle. AKA "lifejacket" whistle.
3) Harmonica with the cover removed. Note the large number of harmonics produced by a free reed vs a fipple.
4) Storm Whistle with a light blow. Not enough to get the pea moving. The fundamental I'd a close match to the advertised 3150 hz frequency.
5) Storm Whistle note the drop in frequency once the pea gets moving. My WAG is the air being dragged around by the pea is damping the oscillations.