Intervals:

What is an interval?: An interval is the distance between two notes. Different intervals interact with each other to create a certain sound. Intervals are a vital part of scales and the notes/chords that they are made up of.

There are two main ways of playing intervals. These are known as harmonic and melodic intervals. When notes are played simultaneously e.g. in a chord, they are known as a harmonic interval. When the notes are played as part of a sequence they are known as a melodic interval as intervals are an important part of melody writing.

Each interval has a name or degree according to the scale. In order to do this you start on the 1st note of the scale (also known as the tonic) and count up with each natural note (with or without accidental) representing a degree. For example if you start on C and count up four on the stave you end up on F which is the fourth degree of the C major scale.

Chords: The primary intervals used when writing chords are the first (or tonic), 3rd and 5th degrees of the scale. By shifting the 3rd degree by a semitone we can change how the chord sounds. For example an F major chord contains the notes F (1st), A (major 3rd) and C (5th) this make the chord sound bright and happy. By moving the 3rd down a semitone we end up with a A flat (or G sharp) and this makes it an F minor chord which sounds sadder.

Example:

Here is the first section of Somewhere Over the Rainbow. As you can see in the first bar the starting note C (the tonic) moves up an octave (8 degrees) to a C and then moves down to a B which is the 7th degree of the scale. Have a go at figuring out the rest of the intervals in the piece by starting on the bottom C and counting up each degree of the scale.

Why do we use intervals?:

Intervals are relevant to music as they are a way of identifying notes within a scale. Each note reacts with certain notes to create specific 'moods'. E.g. the tonic and a minor 3rd sound sad. However, I don't think that intervals are that important for a beginner as they are just a way of identifying the position of a note within a scale. A beginner will only really need to know the names of the notes in the scale (e,g, C, D, E... etc. for C major).