What is a Minor Scale?

How does Minor Scales comes about? I posed the question to my Piano Teacher yesterday. And the answer (after some personal analysis) I got is:-

There are many different types of scales. The most basic kind of scale is the Major Scales, which we all know. But to add more colour to the tone of the music, additional scales are came out with. For classical music, minor scales are created with the intention of adding colours to the music. For jazz music, other forms of scales are created. There are also the chromatic scales and apreggios. All with the intention of allowing the pianist to practice so that it will help the pianists to be able to relate what they have learnt in their scales and the pieces that they play.

Some teachers will say "Minor Scales" for usually used for composing of sad music. Melodic Minor is usually used for composing the melody part of piece, which is the actual tune of the music (to put it loosely, for right hand). And Harmonic Minor is usually used for harmony or as an acompany to the music (to put it loosely, for left hand).

However, it is normal for music to transit from one type of scale to another type of scale. It is common to see pieces which are composed with no key signature to use C major for some parts of the piece and A minor with the accidentals in other parts of the same piece. Some pieces even changes their modulation from C major to G major (for example), where it all depends on how the composer wish to create the mood and the tone of the piece. Although, over the years, there are a set of "rules" which is what has been deduced and pen down, but music in itself is about creativity. So, it is still possible to compose music outside of these "rules" so long as it does not sound weird.

Practising and playing scales help pianists to learn proper fingerings, train techniques, build up finger muscles, which keys belongs to a scale (family) and also to ensure that foundations are strong so that future learning of more demanding pieces are not as difficult.