This will be a short post.
Review: Western music is built around half steps and whole steps. The organization of these steps defines which kind of scale we use (major, minor, or others).
The word “scale” is derived from the Latin scala, meaning “ladder” or “staircase”.
A scale is a series of half and whole steps between the octave. In a major scale, there will always be 2 whole steps, followed by a half step, followed by 3 whole steps, and finally another half step. This exact order of pitches – W W h W W W h – is the order that makes a major scale. Looking at the keyboard, and starting on C, you will notice that this sequence of steps corresponds to just the white keys.
Let’s start on a different pitch: A. If we just use the white keys again, you will see 1 whole step, one half step, 2 whole steps, another half step, then 2 more whole steps: W h W W h W W. This happens to be the order of the minor scale.
Starting a white-key scale on the other white keys, you can see that there are 5 other ways to use this series, but still keeping the sequence intact:
- Starting on D – W h W W W h W: Dorian scale
- Starting on E – h W W W h W W: Phrygian scale
- Starting on F – W W W h W W h: Lydian scale
- Starting on G – W W h W W h W: Mixolydian scale
- Starting on B – h W W H W W W: Locrian scale
- A scale is the series of pitches between one pitch and its higher (or lower) octave.
- The keys on the piano are arranged by whole step and half step.
- These steps are arranged in groups of 2 whole steps, followed by a half step, followed by 3 more whole steps, followed by another half step.
- You can create 7 different kinds of scales, depending on which pitch you start on.
For listening examples of these scales, you can visit here: http://www.classicfm.com/discover-music/latest/guide-to-musical-modes/
 These scale names were given by the ancient Greeks and were associated with different regions of Greece. As to the reason why they thought the Dorian scale reminded the Greeks is not a topic I want to get into. For more about this ethnicity, go to https://en.wikipedia.org/wiki/Dorians.