If you are learning to play the harmonica playing scales is not enough. You have to learn about harmony. You have to familiarize yourself the chords in a key, you have to know where the imprtant notes of the key are and how they work together to create harmonic functions. In order to get you started on this road we will start by taking a look at the primary triads of the major scale.
The diatonic major scale can be split up into 3 very important triads: the tonic, the subdominant and the dominant triad. The tonic triad is the triad built upon the root of the scale, the subdominant triad is build upon the 4th note of the scale and the dominant triad is built upon the fith of the scale. Each of these triads is a major triad consisting of a major third on the bottom and a minor third on top.
example 1: the primary triads of the C major scale.
example 2: the primary triads of the C major scale arpeggiated.
As you can see these 3 triads together hold all the notes of the major scale.
Although these three triads are constucted in exactly the same way they interact with each other when they are played one after the other to create a very familiar harmonic motion.
If you play the following line you will probably be able to feel how the triads function within the key.
example 3: tonic, subdominant, dominant melody.
In traditional harmony these three chords are usually described as follows: The tonic chord is a place of rest, the subdominant leads away from the tonic and the dominant leads back to the tonic.
Play the triad arpeggios on the following chord changes (as in the melody above):
| C | F | G | C ||
Slowly expand the notes that you are using, but stay within each of the triads. So on the C chord you can play any of the blow notes but none of the draw notes, on the F chord you can play any F, A or C on the harmonica but no other notes and on the G chord you can play any G,B or D on the harmonica, but no other notes.
Try to work within these limitations and still produce a good sounding melody. You will find that you will discover much about the functions of chords when doing this and in time you will start to recognize these functions in a lot of music that you know.
Once you are familiar with the primary triads of the first position you can start doing the same excersise for the other 11 positions.