I understand there are three octaves to the harmonica. What are they??? Where are they found?? Are they different for the key you are in??
The term "octave" is just a way of measuring how far apart two notes are.
The more notes an instrument can play, the wider its range, and octaves are one way of describing range.
Let me give some background and define the term "octave."
Notes are named after the first 7 letters of the alphabet: A B C D E F G
Sometimes sharps (#) and flats (b) are added to these names to alter them, but let's ignore that for now.
If one note vibrates faster than another note, that note is higher in pitch.
Let's say you start with the note A that's the blow note in Hole 1 (called Blow 1) in an A-harp.
That note vibrates 220 times a second. As you progress up the scale - A B C# D E F# G# (the notes with a # are sharped, but don't worry about that detail right now), each successive note vibrates faster.
When you get to G#, you've moved through seven notes. What do you call the note after that?
It's also A, but this A vibrates twice as fast as the previous one, at 440 vibrations per second.
When you count up from A220 to A440, you count up 8 notes in the scale (including your starting note), so that's called an octave (from the Latin "octus," for eight).
If you counted up from B to B, that would also be an octave. This is true for any pair of notes with the same name where you count up (or down) 8 letter names to get from one to the next.
Any time you count the distance between two notes in this manner, you're counting the interval between those notes. The octave is only one of several intervals.
When you hear that your harmonica has a range of three octaves, it means that if you count from the note in Hole 1 (usually the same note as the key of the harp, such as A on an A-harp or C on a C-harp), you'll count up three octaves before you reach the note in Hole 10. Because pitch doubles each octave, the note in Hole vibrates 8 times as fast as the note in Hole 1 (2 x 2 x 2).
Most people have a singing range of much less than three octaves, while most other wind instruments top out at around three octaves, so the harmonica has a pretty wide range.
Not exclusively. If you look at the note laout for a C harmonica, for instnace, you'll see that Blow 1 and Blow 4 are both the note C, but an octave apart. Blow 4 and BLow 7, also both Cs and an octave apart. And again for Blow 7 and Blow 10.
But you can also find octave relationships for most other notes. Any tome you look at the diagram on a diatonic harmonica and see two notes with the same name and they are eitehr 4 or 5 holes apart, those notes are an octave apart from each other.