The major scale goes: a whole step (2 frets), a whole step, a half step (1 fret), a whole step, a whole step, a whole step and a final half step. This relationship is the same for every major scale. In G major this is:

G A B C D E F# G.

Now let’s look at Fireball Mail. This tune is in the key of G major and mostly uses the notes from the above scale to make up the tune.

Just like a scale, the root (key note) major chord, or triad, in any key also has the same fixed relationships in every key: the root note - in this case G, the 3rd of the scale – B – and the 5th – D. You can work this out easily by writing down the notes in a scale, and counting along from the root to the 3rd and 5th notes. It’s called a triad because it has three notes.

Fireball Mail has a melody whose notes are not just from the scale of G major, they are mostly from the chord of G major. The most important notes in a melody - the ones that fall on the natural stresses, which we’ve put at the beginning of a measure – usually define what the chord underneath it should be.

If you can hum the melody to Fireball Mail, try doing that and playing a root chord all the way through. Because this is a very simple melody whose notes focus around the notes of the chord (G, B and D) this works perfectly well. You’ll notice, however, that it doesn’t seem to ‘go’ anywhere.

We like music to feel as if it is ‘going somewhere’ rather than standing still. So first we must establish our ‘home’, our root chord, also called the I chord, as its root is note 1 of our scale (see More about Chords below). Then we can go away from it and come back (*). So where do we go?

(* There are many examples of pieces of music that start with a different chord to the I, instantly creating tension, but we have to start this explanation somewhere!)

The second most important chord in our harmony is the V chord, so called because its root is note 5 in our scale. This always comprises the 5th, 7th and 2nd notes of the root major scale (not always in that order).

The seventh note of the scale is only a half step below the root, and sounds like it needs to ‘resolve’ up to the root – in other words, take us home.

Here’s the chord chart for Fireball Mail:

Putting the V chord in the appropriate places .......

Learning and understanding scales and their related chords helps us when we are trying to fit the chords underneath a melody when we don’t ‘know’ what they ‘are’. Learning to recognise these musical patterns makes it much faster to work out how to play new things we hear.

I	II	III	IV	V	VI	VII
G	A	B	C	D	E	F
A	B	C#	D	E	F#	G
C	D	E	F	G	A	Bb
Bb	C	D	Eb	F	G	Ab

This chart illustrates with a few examples how chord numbers relate to the notes in the scale in any key. If we need to change the key of a song, we can take any root note and having found the notes in the scale work out what the new set of chords would be.

For example, if the chords in our song are I, IV and V, and the original key is G, we know that they are G, C and D. If we need to change the key to Bb, we can see that they will be Bb, Eb and F........