Fun with physics (and flutes)

I love science.  Physics and biology are my preferred fields and my favourite classes in school were always the music and science ones.  So, it's no real surprise that I've done a fair amount of research about the physics of music.  Fascinating stuff.  It's good to know how your instrument works on the mechanical level.  When you have a basic idea how it works, you can do some simple diagnostics to pinpoint where the problem is if something is wrong, and you can play the instrument better. 

In fact, instrument shape has a huge impact on how it sounds (with the exception of electric instruments.  Shape plays no part in how an electric guitar will sound.  All that matters there is the electronics.)  So, speaking of instrument shape (I'm really going on an unintended tangent here, BTW): trumpets and cornets sound different because of their shapes and bores (the bore is the shape/size of the inside of the tube).  Both horns play the same music, in the same key, and with the same fingerings.  But cornets, because they have more bends in their shape, in comparison with the more sharply curved trumpet, have a mellow sound.  The tighter angles of the trumpet give it its piercing quality.  Shape is also part of the reason why a saxophone sounds like a saxophone and not a like a bassoon.

The purpose of this post, though, is this:  go find a flute and perform a simple experiment.  Use just the head joint (the part that the player blows over) and blow a note.  If you aren't sure how to make a sound on the flute (which is a whole new physical concept altogether) it can be loosely equated to the blowing-across-the-soda/beer-bottle trick.  The experiment is this:  blow a note on the head joint.  Then, cover the open end with the palm of your hand and blow the note again.  If you are careful not to over blow, the resulting pitch is roughly an octave below the first pitch (the flute I tried this with was a half-step away from a full octave).  This is because the sound wave is forced to make a return trip from your palm back to the open lip plate that you are blowing over.  The longer sound wave produces a lower pitch.  In other words, you've demonstrated how short sound waves make high pitches and long sound waves make low pitches. 

Incidentally,  this is also why most basses need special amplifiers.  Bass sound waves are very big and will not "fit" into the smaller speakers used by guitars. 

Now, I expect you to totally nerd out at the next concert you attend.