An interval is the distance (in scale steps) between two pitches. A melodic interval occurs when two notes are played in sequence, one after the other. Intervals can also be harmonic, meaning that the two notes are played together at the same time. For example, taking C as the tonic (the "1" or the first degree of the scale), then the third degree of the C major scale is E, so the interval between C and E is called a major third. If we the second tone in a major interval is lowered by one half step, the interval becomes minor. The example below shows a major third and a minor third, each starting on C.
Intervals provide the basic framework for almost everything in music. Small intervals such as half steps and whole steps combine to form scales. Larger intervals combine to make chords. The ability to identify intervals by ear is one of the major goals of ear training. Intervals are fundamental to working out melodies by ear. They are also used to help identify the quality of chords, in determining for example whether a chord is major, minor, augmented or diminished. Use the Interval Demo application below to compare the sounds of different melodic intervals. First select a bottom tone, then press the buttons to hear how various melodic intervals sound when played from that tone. Also be sure to check out the difference between ascending and descending intervals.
Melodic Drops will help you quickly recognize the most commonly used intervals. It starts with a small set of the most basic intervals and progresses gradually through the complete set, played with a variety of instruments.