In music a key is a group of seven specific notes which have been derived from the chromatic scale, which are then used to build seven chords. The seven notes and seven chords of a key can be used to produce the melodies and harmonies of a piece of music. There are 12 major keys and each one has its own very specific group of seven notes. Some of these keys contain a combination of natural notes and sharp notes. These are known as sharp keys, and some contain natural notes and flat modes. These are known as flat keys, there is only one key that has only natural modes.

And for this reason, it's called a neutral key. We're going to look at this neutral key as well as an example of a shock key and the flat key. The key of C is our neutral key. It's seven notes, our C, D, E, F, G, A and B. Notice that these are all the natural notes from the chromatic scale, but they're just arranged so that they start from C instead of a Using these seven notes we can build seven chords. Now the notes of the key of C are collectively called the C major scale.

The first note of a major scale in this case C is said to be the tonic note. We can write the C major scale on the stage like this. Notice that when we end the C major scale with the tonic note an octave above our starting node, it gives a nice sense of completion. Here we have a few chords from the key of C making up a chord progression. Next, we will take the key of G as an example of a sharp key, the seventh note of the key of G, R, G, A, B, C, D, E and F sharp, you can see that it has six natural notes and one sharp note. These seven notes are used to build the seven chords of the key of G. The seven notes of the key of G are collectively called the G major scale, and it looks like this on the stave.

Now, looking at this example, you may think you've spotted a mistake because we said that we wanted an F sharp mode and not an F natural because we're dealing with the key of G that has an F sharp mode and not an F natural. We write a shop symbol on the line that represents F on the stave right at the beginning of A piece of music just after the treble clef. This is called the key signature. It lets us know that we were in the key of G, and we're using the G major scale for all the melodies and chords on the stave. Writing the key signature at the beginning of a piece of music means that we don't need to write a shop sign in front of any of the F sharp nodes. Since we can assume that every note that falls on the line or space that represents the note F, will be an F sharp note instead of an F natural.

This holds true for wherever you can find F on the stave, whether it be on the top line, or the bottom space, or the third ledger line below the stave, or the space above the third ledger line above the state will take a practical example so that you can see how this key signature affects a piece of music. Firstly, notice the key signature F sharp, which lets us know that we're using the notes of the key of G for our melodies and harmonies. The first note is on the top line of the stave, which of course we know is an F sharp because of the key signature. The second note is G natural, then we're back to the same F sharp note again. After that we have an E natural followed by D natural. When we come to a harmony made up of the notes D, A, D, and F sharp.

This is your regular D major chord. Notice how the key signature effects the modes within harmonies to. Then we finish up with a harmony made up of the notes G, B, D, G, B, and G, which is your stock standard G major chord. Let's take a listen to how this would sound. Now let's look at an example of a flat key, the key of F, seven loads to the key of F, F, G, A, B flat, C, D, and D. You can see that there are six natural notes and one flat mode. We can use the seven notes to build the seven chords of the key of F. These seven notes are collectively called the F major scale, which can be written on the stage like this.

The key signature for the key of F is B flat, which you can see as indicated by a flat sign on the line that represents B just after the treble clef. Of course, this tells us that we're in the key of F and using the F major scale for the melodies and harmonies on the stave. Whenever we see a note on a line or space representing the B, we should play a B flat instead of a b natural. This holds true regardless of which B you're looking at, whether it be the second space above The state, or the third line of the state, or the space below middle C. Now, these are just three examples of keys, but each of the 12 keys has its own key signature by which it can be identified. The notes chords and key signatures for the other keys have been laid out for you in the section of the course too, for future reference.

Next, we're going to practice writing the C major scale, the G major scale and the F major scale with their respective key signatures on the stave.