This short lesson presents notes, scales, intervals and chords. Refer to any music book or website about note timing and timing symbols.

Scales and keys

The picture below shows the treble clef or G-clef, and the notes that the lines and spaces represent.
This staff does not show all of the notes in its range. It shows only the notes that make up the C major scale. There are other notes in between these notes. This picture of part of a keyboard shows all the notes between middle C and high E.


Each black key has two names. We will see in a minute when you would use the sharp names and when you would use the flat names.

On the staff, to show one of the black keys you would put a sharp symbol (#) or a flat symbol in front of the note: Below are the notes of the C major scale. C is the first note of the scale, also called the tonic note:
If you want to play in a key other than C major, some of the black keys are used all the time. But instead of using the sharp or flat symbol each time, you just show it in the key signature at the beginning. Below is the staff with key signature for G major, which uses one sharp (F sharp).
These are the notes of the G major scale. The seventh note of the scale is F sharp: The key of E major uses four sharps. This is the key signature for E major and its scale: The sharp keys are the keys that have one or more sharps in their key signature. The sharp keys are G, D, A, E and B. These are their key signatures: The flat keys are the keys that have one or more flats in their key signature. The flat keys are F, Bb, Eb, Ab, Db and Gb: The black keys on the piano have two names, as noted above. The note C#, for example, is the same as the note Db. We call it C# in the context of a sharp key. We would call it Db in the context of a flat key.

The relative minor key to C major is A minor, because it uses the same notes as C major. This is its scale:
Equivalently, the relative major to A minor is C major. As another example, B minor is the relative minor to D major.

Intervals

The interval between a note and the note right next to it on the keyboard is called a half step. Here we are considering all the keys, white and black. So one of those notes might be a black key. Two half steps is a whole step or whole tone.

Twelve half steps is an octave. Two notes an octave apart sound like the same note, qualitatively, and are given the same name. Here are three octave intervals:

Three half steps is a minor third. Two whole steps is a major third. Here are some minor thirds:
Here are some major thirds:
Here are some fourths:
Here are some fifths. Note that a fifth is seven half steps. The fifth is the most fundamental interval after the octave.
A minor sixth is a half step greater than a fifth. A major sixth is a whole step greater than a fifth.

A minor seventh is a whole step less than an octave. A major seventh is a half step less than an octave.

Triads and seventh chords

A major third and a fifth that have the same lower note (root note) together make up a major triad. Below are some major triads:
A minor third and a fifth having the same root note make up a minor triad. Below are some minor triads:
These triads have a harmonically pleasing sound, and are the basis of all harmony.

Another common chord has four notes and is called a seventh chord: it is a triad, with a minor seventh on the root added.

Notes an octave apart sound like the same note. This means any note in a chord can be displaced an octave either way and qualitatively, the chord will still sound like the same chord. If the root is moved up so that the third of the chord is on the bottom, the result is called the first inversion. It sounds less solid than root position, but the harmonic effect is very useful in certain chord progressions. The second inversion places the fifth of the chord as the low note. The second inversion 1 chord sounds a lot like the 5 chord, and is sometimes heard in ending phrases, usually followed by a 5 chord. Below we see a G chord in root position, first inversion and second inversion:
In a major key, the major triad based on the tonic note is called the 1 chord (or I chord, if you are using the Roman numeral notation). This is the 1 chord in G major:
If you form a triad of successive thirds from notes of the major scale based on note 2, it will be a minor triad, and is called the 2 or ii chord. (The lower case Roman numeral indicates that it is a minor chord).

Similarly, you can form all seven basic harmonies in this way, as we showed in the Tutorial. The 6 chord in G major is an E minor chord:
The 5 or V chord , which has note 5 as its root, is the most common harmony after 1, and is called the dominant chord or dominant harmony. A seventh chord built on note 5 is called a dominant seventh and is written as 5⁷ or V⁷. Dominant sevenths are very common, and lead strongly back to 1. Here are the dominant and dominant seventh chords in C major:
Here are the dominant and dominant seventh in the key of B flat:
The secondary dominant is the 5 chord of the 5 chord, and it strengthens the 5 harmony. In C major it is a D chord:
The 5 of 5 in first inversion flows more smoothly because the notes don't jump around as much: