Originally Posted by: CSchlegelThe sound of a major 3rd interval is the sound that happens when we play 2 notes that are 2 whole steps (or 4 frets) apart. The sound of of a minor 3rd is the sound that happens when we play 2 notes that are 1 1/2 steps (or 3 frets) apart.

You might be over-thinking it Axe... when Christopher explains stuff, he speaks in layman's terms, and makes every effort to remove room for misinterpretation. So what I quoted above, he means that literally. Any note on its own on the fretboard isn't a major 3rd or minor 3rd or really anything but the note it is. You need the root note (so the first note you'll play) in order to create an interval (the second note you play).

Read the above quote again, but this time with your guitar in hand. Play any note, that's the first note, then move up 2 whole steps, in other words, move up 4 frets on the guitar. That note, in relation to the first note you played is a major 3rd. Make sense? Play the same first note, then play the note 1 1/2 steps, which is 3 frets, apart, and that note is a minor 3rd from the first note.

Playing these notes separately like this is playing part of a scale. The different intervals between the root, 2nd, 3rd, 4th, 5th, 6th, 7th and 8th (the octave) will define what kind of scale you're playing, while the root note will define the key. When we play intervals together using multiple strings, we create chords. Hope that makes sense.

Its always good when you're working on this stuff to play the root, then the interval you're trying to hear. If you're trying to get the feel of a mode like Dorian for example, droning the root note while playing the scale really helps you hear what the scale sounds like.