Minor Scales

There are three kinds of minor scales in music: Natural Minor, Harmonic Minor and Melodic Minor

Natural Minor

The Natural Minor scale has the following pattern: W-H-W-W-H-W-W 

H (Half) W (Whole)

This is a C Natural Minor scale: C-D-Eb-F-G-Ab-Bb-C

A natural minor scale has no alternations. It only has the key signature that is designated to it. C Natural Minor only has three accidentals in its key signature: Bb, Eb and Ab. The 6 and 7th notes are not altered.

Harmonic Minor

The Harmonic Minor is an altered scale.The seventh note is raised by a half-step as you go up and down the scale. Here is the pattern for the following scale: W-H-W-W-H-A2-H

Here is a Harmonic Minor scale starting on C: C-D-Eb-F-G-Ab-B-C

Melodic Minor

The Melodic Minor scale is different because when the scale ascends up, we use one pattern. As the scale descends, we use another pattern.

Here are the ascending and descending patterns for the Melodic Minor scale starting on F:

Here is an example of a C Melodic Minor scale: 

Melodic C Minor Scale = C - D - Eb - F - G - A - B - C (Ascending)
Natural C Minor Scale = C - D - Eb - F - G - Ab - Bb - C (Descending)

The scales goes back to a Natural C Minor scale when the notes go back down the scale.

Relative vs Parallel Keys

Here is a tip on how you can remember the difference between a relative key vs a parallel key of a Major or minor keys.

Formulas:

Relative keys = same key signatures/different tonic. 
Parallel keys = same tonic/different key signatures

Relative key is a key that shares or has the same amount of sharps or flats (key signature) but has a different tonic than the key it shares.

For example, lets say we are working with c minor key. c minor has three flats in its key signature. So, what is c minor's relative key? c minor's relative key is Eb Major because Eb Major also has three flats in its key signature.

A parallel key shares the same tonic with another key , but has different key signatures. When working with parallel keys, one will be minor and one major key.

For example, c minor is parallel to C major because they have the same tonic. However, C major has no sharps or flats in its key signature. c minor has three flats.

You can also use the "Circle of Fifths" to help you understand relative and parallel keys better.