From the major scale to the harmonized scale (Pt.1 triads)

In this video I’ll show you how to build the harmonized scale, which is vital to find out what chord belong to a specific key. In the example I am building the Harmonized scale in the key of C major. In one of the successive videos of this series you’ll see that you can use these chords to build a very simple songs in a single key.
The process is fairy simple: I stack on top of every note of the scale two consecutive diatonic 3rds. Let’s say, for example if I start from C, the two notes will be E and G. If I start from D the notes will be F and A…is this easy enough?

In the example below every note of a major scale identifies a ‘grade’ of the scale. In the example I have used C major, but this is valid for every other major scale.

If I stack on every grade two more notes a third apart (basically every other one) I end up with different kinds of triads (triad=group of three notes). These triads are shown in the example below. If we analyze the intervals between notes:

On the guitar, like in the video:

You will have the same series of chords in all the other keys Eg: F major: F, Gm, Am, Bb, C, Dm, Em.

This again is valid for all the 12 keys. This concept is vital to understand how songs are built and how to pick the correct scale for a solo.