BobClair wrote: > Try this at home and report back. Take a wine or beer bottle. Fill it 2/3 full > with water. (The change in pitch for a given change in area is bigger when the > volume is smaller - patially filling it with water makes the effect easier to > see (hear) but if you think this makes the results suspect leave the bottle > empty). Blow across the bottle, note the pitch. Now cover half the opening > with a > finger. Try it again (it may take a bit of practice to get the note). Did the > pitch go up or down?
Wow, man, far out, it works. Sorry: I meant to say "Eureka!" Period. I tried this experiment with, like, a whole bunch of bottles (but since I didn't have any empty ones, I started with ones and, like, emptied them, if you catch my drift). The pitch went down every time. At least, I think it did. After a while the *room* was moving up and down, so it was hard to tell. But you know how it is in experiments; you do what you can with the variables. Science is way cool. BTW, change in pitch seemed about the same whether a 12-ounce bottle was empty or half empty. Transverse flute players adjust pitch on the fly by rolling the mouthpiece in or out. Rolling in flattens the note. I just tried it playing one of my flutes in front of a mirror. It's hard to tell, but it appears that rolling in tucks the hole under the lower lip and thus decrease its area. But I'm also blowing more vertically into the hole and less horizontally across it. I wonder if this causes compression of the air column and thus slows the vibrations and lowers the pitch. HP
