That is quite interesting and I second on the explanation. Is it brought up again in part 3?
its because when given the note "C" all the chords that have "C" in the triad, are listen there,
example,
it says
Ab Major - the Major Third, is a C
C major - thats a given...... the first note is a C
F major - the Fifth degree, or the Dominant, is a C
F minor - same as f minor
A minor - the minor third is c,
and so on,

so if you were to take the note G
the chords would be,
Eb Major - G is the major third
C major - G is the fifth/dominant
G major - G is the first/Tonic
E minor - G is the minor third
c minor - g is the fifth/dominant
and so on.....

the reason why the C and the G both work major or minor, is because they are either the first or the fifth degree, which dont change in a chord whether the chord is Major or Minor,
like explained in the video, the third degree is the note that changes a chord from Major to Minor
lol thats funny i just watched the rest of the vid and he uses G as an example too perfect =)
Quote by N@TE!
its because when given the note "C" all the chords that have "C" in the triad, are listen there,
example,
it says
Ab Major - the Major Third, is a C
C major - thats a given...... the first note is a C
F major - the Fifth degree, or the Dominant, is a C
F minor - same as f minor
A minor - the minor third is c,
and so on,

so if you were to take the note G
the chords would be,
Eb Major - G is the major third
C major - G is the fifth/dominant
G major - G is the first/Tonic
E minor - G is the minor third
c minor - g is the fifth/dominant
and so on.....

the reason why the C and the G both work major or minor, is because they are either the first or the fifth degree, which dont change in a chord whether the chord is Major or Minor,
like explained in the video, the third degree is the note that changes a chord from Major to Minor

But couldn't the possibility of chords be endless?
of course, and thats the beauty of music, its not right or wrong, its your opinion of whether you like it or not,
but generally speaking, certain notes sound better than others, with certain chords....
like the example above, that note goes good with those chords, because the notes are in the triad of those chords, but if you want to play, say a e minor chord, with the note c, you would get a minor 6th... which can sound awesome, but they're talkin, what works best
hopefully that makes sense...
I am gonna give it a go then:

Using A as a central point, I get:

F minor
A major
D major
F major
A minor
D minor

Is that correct?

Also, I noticed you used dominant to describe the fifth (yes I know they mean the same thing) but what does dominant mean? Isn't the third the voicing of the chord?
Quote by Nitro89
I am gonna give it a go then:

Using A as a central point, I get:

F minor
A major
D major
F major
A minor
D minor

Is that correct?

Also, I noticed you used dominant to describe the fifth (yes I know they mean the same thing) but what does dominant mean? Isn't the third the voicing of the chord?

Not quite.

There are four positions that a note can be in a chord: Root, minor third, major third, and fifth.

When it is the root or fifth, the chord can be major or minor.

So for A we have:

Root- A major and A minor

Minor Third- F# minor

Major third- F major

Fifth- D major and D minor

And dominant and fifth don't mean the same thing. "Dominant" refers to a scale degree, and fifth refers to an interval- so a chord has a fifth, and a scale has a dominant.

For example, in C major (key) we have G as the dominant and from that G we can make a G major chord, but it's still the dominant chord because it's in relation to the scale.

However, if we take a C major chord it's made of intervals (Root, third and fifth), not scale degrees (for this chord: tonic, mediant and dominant).

If we take the dominant chord of C major, G major we have G B and D. These notes are: root, third and fifth (for the G chord)- but in the key of C major they are: dominant, leading note, and supertonic.

There's a difference.