Minor confusion...

For the first part, you might be confusing 'harmonization' (building chords using only scale tones) with chord construction. Any scale can be harmonized, but chords are only built from the major scale of the root.

The reason we use the major scale for chord construction is that other scales have more than one variation... if you build a Cm6 chord on a major scale, you have:

1-b3-5-6 = C-Eb-G-A

If you looked at the minor scale, and say "well, that's just 1-3-5-6 on the minor" you'd get the same notes.... unless you're in the melodic minor scale. Then you'd need the formula 1-3-5-b6 (since the 6th is raised in the melodic minor, you'd need to lower it to get the same Cm6 sound as other scales). To avoid this confusion, all chord formulas come from majors.

When you harmonize a minor scale, the chords you get depend on the type of scale you're using. If you're talking about the natural minor, you get the same chords as the major scale, just in different places. Since there are several minor scales, you end up with different chords if you use the harmonic or melodic minor.

You mentioned the IV and V being the same...

C major = C (I) F (IV) G (V)
A natural has C (III) F (VI) G (VII)

but

A harmonic minor has C+ (III+) F (VI) G#dim (viiº)
and A melodic minor has C+ (III+) F#dim (viº) and G#dim (viiº)

Now the second part: for all scales, the pattern between notes changes depending on your starting note. A major scale is WWHWWWH (or TTSTTTS if you prefer that notation); the natural minor is WHWWHWW.

The major pentatonic starting on C is C-D-E-G-A, or 1-2-3-5-6. The minor pentatonic starting on A is A-C-D-E-G, or 1-3-4-5-7. Same notes, different starting point - so you get different intervals between the notes.

Thanks for your help.

I get the first answer. It's derived from the major scale. I suspected this but just wanted to be sure.

The second answer: I understand that scales have intervals which decide which notes are part of the scale. I just want to clarify.

-Pentatonic scales are derived from the Major scale.
-The major pentatonic scale uses 1-2-3-5-6 from the major scale.
-The minor pentatonic scale uses 1-3-4-5-7 from the major scale.

As a result of this Pentatonic scales will always have the same intervals:
Pentatonic Major: W, W, WH, W, WH.
Pentatonic Minor: WH, W, W, WH, W.

I don't really know what your talking about with 'harmonization' do you have a link to a good tutorial?

-Pentatonic scales are derived from the Major scale.
-The major pentatonic scale uses 1-2-3-5-6 from the major scale.

Yes.

Since C major is C_D_EF_G_A_BC,
the C major pentatonic is C_D_E__G_A__C,
-The minor pentatonic scale uses 1-3-4-5-7 from the major scale.

Ummm, no.

The minor pentatonic uses 1-3-4-5-7 from the minor scale (specifically the natural minor).

These happen to be the same notes as for the relative major. i.e. C major and A minor share the same notes.

Thus the C minor pentatonic is C_Eb_F_G_Bb_C,

but A minor pentatonic is A__C_D_E__G_A, the same notes as C major penta above.

Here are the notes from the different major scales and their various relative minors:
Key Minor Signature 1 2 3 4 5 6 7
C major A minor C D E F G A B
G major E minor # G A B C D E F#
D major B minor ## D E F# G A B C#
A major F# minor ### A B C# D E F# G#
E major C# minor #### E F# G# A B C# D#
B major G# minor ##### B C# D# E F# G# A#
F# major D# minor ###### F# G# A# B C# D# E#
F major D minor b F G A Bb C D E
Bb major G minor bb Bb C D Eb F G A
Eb major C minor bbb Eb F G Ab Bb C D
Ab major F minor bbbb Ab Bb C Db Eb F G
Db major Bb minor bbbbb Db Eb F Gb Ab Bb C
Gb major Eb minor bbbbbb Gb Ab Bb Cb Db Eb F

and here is how you build chords from the major scale by picking every other note:

This is known as Harmonising the Major Scale in Thirds:

1 2 3 4 5 6 7 8 C D E F G A B C Chord no. Chord name.
-------------------------------------------------------------------------
1 3 5 C E G I C major
2 4 6 D F A ii D minor
3 5 7 E G B iii E minor
4 6 8 F A C IV F major
5 7 9 G B D V G major
6 8 10 A C E vi A minor
7 9 11 B D F vii° B diminished


You can also harmonise the scale in 4 note chords, building 7ths of each chord, like so:

Note_degrees Note_names_in C Chord_no Chord_name
-------------------------------------------------------------------------
1 3 5 7 C E G B Imaj7 Cmaj7
2 4 6 8 D F A C iim7 Dm7
3 5 7 9 E G B D iiim7 Em7
4 6 8 10 F A C E IVmaj7 Fmaj7
5 7 9 11 G B D F V7 G7
6 8 10 12 A C E G vim7 Am7
7 9 11 13 B D F A viim7b5 Bm7b5

Often only the V chord is played as a 7th.

In your first table you show Key followed by minor. Whilst I understand that A minor is equal to C major (other than the starting note) is this information useful? Or are you just demonstrating they are the same?

In your first table you show Key followed by minor. Whilst I understand that A minor is equal to C major (other than the starting note) is this information useful? Or are you just demonstrating they are the same?

Well, C major and A natural minor share the same notes and chords.

A minor is the relative minor of C major.

C minor is the parallel minor of C major.

In the key of A minor, one would frequently sharpen the G and thus use an E or E7 chord instead of the Em. Sometimes the F would be sharpened as well (melodic minor).

I was wondering why those particular notes are taken out to form the pentatonic?

Well, they're not really 'taken out' - they weren't there to begin with :)

Pentatonic scales probably developed Asia, and spread from there. They're certainly among the oldest scales used in music - almost every culture on earth has melodies composed using a pentatonic scale.

Major scales most likely developed from the music of the minstrels and troubadors in Europe, probably in the 1400s. Diatonic scales have been around a lot longer, since Greek times - but the pitch arrangement that leads to the major scale is pretty modern.

Since we're brought up with Western music, though, the major scale is the one most familiar to us - and consequently the one we relate everything else to when we try to incorporate other musical material.