How do you determine the interval of music by ear?
A common way to recognize intervals is to associate them with reference songs that you know well. For example, the song Amazing Grace begins with a perfect fourth. So when you hear an interval that sounds like the beginning of Amazing Grace, you can quickly conclude that it's a perfect fourth.
What is an interval in music theory?
Intervals are the building blocks of scales, chords (or harmonies), and melodies. Intervals are a measurement between two pitches, either vertically or horizontally. When measuring vertically, we refer to harmonic intervals because the two notes sound simultaneously.