Here is the question I have: When you blow across the opening of a bottle, how will the sound vary with taller and shorter bottles? With fatter and thinner bottles? How will the shape of the bottle opening affect the sound? Ok, now I am not totally clueless on this subject matter, let me tell you what I have. The flow of air in the tall bottles has to travel further, producing a larger air column, which causes the air to vibrate slower and thun produce a lower pitch. The opposite happens with a short bottle. For fatter and thinner bottles, would it be the same relation (fatter = slower vibrations)? Thanks.