Intervals (Diads)

Notes played on their own are tunes, notes played together are chords.
Any two notes played together will sound a chord, but usually it takes three or more to make a real chord.
You've got to learn about scales to appreciate chords, but its well worth it. Every scale has a set of 8 notes from the root note to the octave.
You play these notes for scale practice don't you? (don't you?) e.g. Scale of (or Key of G) is:

1	2	3	4	5	6	7	8
G	A	B	C	D	E	F#	G

Chords start with the lowest note, called the root. So a G something chord starts with a G note and adds some higher notes.
Two notes of a scale together is called an interval, the name of the interval being derived from how far apart the two notes are.

1st note (root)	2nd note	interval	comment
1	1	unison	two notes sound the same like the twin strings on a mandolin course
1	2	2nd
1	3	3rd	a very important interval! It determines whether chords are major or minor
1	4	4th
1	5	5th	An interval that's usually present in any chord
1	6	6th	A pleasant sounding interval
1	7	7th	This one is straining to go up one to become octave
1	8	octave	two notes sound the same but an octave apart

These so called 'diad' chords sound OK but lack a bit of body. Some forms are very effective though, such as the 5th (see Power Chords)
Proper chords use three or more notes.