Songs in minor keys are very common as well as the use of minor scales. There are many different ways to play a minor scale and three common types will be discussed here.
A minor scale is any scale that has the third degree a minor third above the root note. However, the term is usually used to refer to the natural minor, harmonic minor, and melodic minor.
Natural minor has a minor third, a minor sixth, and a minor seventh. An easy way to remember them is to base them off their related major scale. The related major scale has the same key signature as it's minor and starts on a minor third above the root of the minor scale. So A minor has a related major scale of C major and both have no sharps or flats; C major is CDEFGABC and A minor is ABCDEFGA.
A lot of the time you will see the use of leading tones in minor scales by raising the the minor seventh degree back to it's major interval. In A minor this would be
A B C D E F G# A. This type of minor scale is called a harmonic minor and sounds very exotic.
Sometimes you will see both the minor seventh and minor sixth reverted back to major intervals. In A minor this would be A B C D E F# G# A. This minor scale is called melodic minor and sounds mysterious.
Here are the three types of minor scales in C minor:
You may want to go back and review
or if you want to continue on your quest to learn scales, proceed to the
or for basic theory, go on to
Circle of Fifths