The Basic Physics of Sound
A sound is a wave.
Every sound is created from vibrations in the air.
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It can be louder...
Increasing the height of the wave, or amplitude.
...or more quiet.
Decreasing the amplitude.
It can be lower in pitch...
Lower notes will get longer.
And higher notes will look more compressed.
There are infinitely many notes.
Not just the ones you know, like A through G, but everything in between. So how do we pick which notes to use?