What am I doing?

[Mankito]

I am fiddling around then I start playing the open A string as a pedal note, then I play notes from the A Major scale on the 4th and 2nd strings down the neck, starting on the 9th fret,only the notes from this scale. It sounds nice as I end playing the E chord on the 1st position then finish the sequence with an open A chord. I realize I've been playing the diatonich chord sequence of that scale without actively thinking about it.
Then you can do the same with the open D string...and I suppose with the E string...
Then I just played the same A pedal note but this time playing only natural notes on any of the three first strings and I realized I ended up playing the C natural minor scale because the tonal note was A, isn't it?

I am not sure what I am asking here but I presume is the way the guitar is designed allows you to achieve this progressions, right?

[albertbert]

I think you are actually playing the A minor scale. A minor is the relative minor to C major. Both contain only natural notes.
C major:
C D E F G A B C
A minor:
A B C D E F G A

[Mankito]

Yes, exactly. What amazes me is how easy is to play "nice" little things using the open strings and then choosing the notes of that scale in the area, then moving up the neck or down and adding open strings that belong to that scale.

[Aelfa]

That's one of the nice things about the guitar: even simple things can sound very good!

[JonR]

Originally Posted by Mankito

Yes, exactly. What amazes me is how easy is to play "nice" little things using the open strings and then choosing the notes of that scale in the area, then moving up the neck or down and adding open strings that belong to that scale.

In certain keys, yes the guitar lends itself to this kind of thing.
Of course, you have to choose a key where one of the open strings is a keynote!

The guitar is designed (tuned) to make as many keys as possible relatively easy, but it's not possible to make ALL keys equally easy (on any instrument!).
So the easy keys on guitar are G, D, A, C, Em, Am.
Slightly less easy (but still popular) are E, F, Dm, Bm, Gm.
You should be spotting by now that these keys all feature most of the open strings in their scales (often as chord roots), as well as many of the well-known "cowboy chords" that everyone starts off learning.

The remaining keys (mostly the flat ones) are harder, because of lack of open strings, especially as roots.

It's possible to tune the guitar differently to make one or two keys VERY easy (eg various open tunings), but that makes all the other keys that much harder. (People who like open tunings use capos to get round this.)
So the EADGBE standard is a kind of compromise.

Another reason for that tuning - giving 3 notes of a scale on most strings - is that you can easily play scales across the strings without having to stretch your fingers too far, or move your hand up and down the neck.
The 4ths between each string (plus one 3rd) also make most common harmonies and chord forms fairly easy.

[Mankito]

Thanks JonR, I am trying to explore all these keys, it also helps on learning the notes on the fretboard.