Seymour Duncan pickups can make your guitar look and sound as cool as this one.

What is a key? We have all heard that term before, as in ‘What key is this song in?’ When we first start out playing guitar this all seems so complicated, but in the end it isn’t. The last Breaking Down the Barriers blog focused on the musical alphabet, and how it relates to guitar playing. This article with actually focus on how to use this alphabet in a musical way.
Referring back to a piano, if we look at the white keys, we get just the normal letters:
A B C D E F G
Now, let’s start this on the letter C:
C D E F G A B
Remember last article when I talked about all of the notes of our musical scale, and how they are each ½ step from one another?
A  A#/Bb  B  C  C#/Db  D  D#/Eb  E  F  F#/Gb  G  G#/Ab
Now, the distance between C & D is a whole step. The distance between D & E is also a whole step. The distance between E & F, however, is a half step. And so on.
So if we think about C D E F G A B in terms of half steps (1/2) and whole steps (1) we have:
1  1  ½  1  1  1  ½ .
On guitar, the distance between, lets say the 3^rd fret and the 4^th fret is a ½ step. The distance between the 3^rd fret and 5^th fret is a whole step. So to use this formula starting on the 3^rd fret of the second biggest string, we get:

Now, playing this up one string is kind of inefficient. And unlike piano, the same notes occur in different places on the guitar. This makes things easier, as we do not have to slide our fingers up one string.

We just played what is called a C major scale! In fact, if you start this formula on any letter, you get a major scale.
Now, lets start on F:
F G A Bb C D E
How does this relate to a key? Well, a key is just a collection of notes and chords that sound good together (and are mathematically related, but that isn’t as important right now).
Now, we know the tradition of playing scales is a boring one. After all, when we think about it, we can picture someone sitting at a piano practicing while a stern instructor glares on. This isn’t the fun part!
What is fun? Well a scale really comes alive when we play it over top of chords. How do we know which chords to use? That is easy: since chords are just 3 or more notes played together, the notes we choose are in the scale. Here is that F scale again, with numbers assigned to the notes:
F  G  A Bb C  D  E
1  2   3   4   5  6   7
This is what we call an F major scale, and it contains all of the information we need to figure out the chords in this key, the key of F.
The first chord is an F, the name of the key, that is easy. It contains 3 notes (like all the chords will in this key). What notes? Well it certainly contains an F. And western harmony is mostly built on stacking every other note in the scale. So, our first chord contains an F, an A & a C- every other note starting from F, and ending after 3 notes. Three note chords are called triads and are the basis of all chords. What about power chords you say? Those have 2 notes! Something is wrong wrong wrong! Yes, that is true. Power chords contain the 1 and the 5, or F & C. However, by classical harmony standards, you need 3 notes to be called a chord. I am a guitarist, like you, probably- so let’s be rebels and break the rules.
F, C, & A played together is called an F major chord, or what most musicians call an F.  You can double or triple or quadruple any of the notes in the chord, in any order, and it is still an F major- as long as it has only and F, C & A in it. If you add any other notes, you have to re-name the chord!
Playing an F major scale over an F major chord sounds sweet:

By the way, examples here are played with a Custom 5 bridge pickup. It is a crunchy bridge pickup with a defined low end.
We have derived our scale as well as the first chord of our key. Stay tuned for the next Breaking Down the Barriers when we get the rest of the triads and start making music!