What are cadences?

Within Western music, the chords composers use in their compositions help give different musical effects. Cadences are chords progressions, and each cadence creates a different musical sound. The most common cadence is the "perfect cadence" and this uses a V-I chord progression. For example, if a piece is in C Major, chord I would be C major itself, and chord V (or V7) would be G major (or G major 7). We know this because in a C Major scale, (C D E F G A B C), G is the fifth letter. Moving from chord V to chord I is therefore a perfect cadence, and it is called this because of the nature of the sound, usually used by composers to end a musical phrase, and quite commonly used at the end of a piece. It is "perfect" because it moves from the two strongest chords of the C Major scale, and resolves onto the strongest one of them all, the tonic, chord I.

A few other common cadences include: plagal cadances (IV - I. e.g. in C Major, chord IV = F major and chord I = C major. therefore, F-C. commonly used in religious hymns, and reffered to as the 'Amen' cadence because of the nature of the sound), imperfect cadences (this can be either I-V, II-V, IV-V or VI-V. chords that move to chord V often sound unfinished, or "imperfect") and interrupted cadences (V-VI, instead of moving to chord I after chord V like a perfect cadence would, an interrupted cadence instead moves to chord VI, though a listener may expect chord I instead. therefore there is an interrupted sound to the progression, hence the name).