An introduction to one of the basic elements of music.
When you have more than one pitch sounding at the same time in music, the result is harmony. Harmony is one of the basic elements of music, but it is not as basic as some other elements, such as rhythm and melody. You can have music that is just rhythms, with no pitches at all. You can also have music that is just a single melody, or just a melody with rhythm accompaniment.
But as soon as there is more than one pitch sounding at a time, you have harmony. Even if nobody is actually playing chords, or even if the notes are part of independent contrapuntal lines, you can hear the relationship of any notes that happen at the same time, and it is this relationship that makes the harmony.
Harmony is the most emphasized and most highly developed element in Western music, and can be the subject of an entire course on music theory. Many of the concepts underlying Western harmony are explained in greater detail elsewhere (see Triads and Beginning Harmonic Analysis, for example), but here are some basic terms and short definitions that you may find useful in discussions of harmony:
implied harmony - A melody all by itself (Monophony) can have an implied harmony, even if no other notes are sounding at the same time. In other words, the melody can be constructed so that it strongly suggests a harmony that could accompany it. For example, when you sing a melody by itself, you may be able to "hear" in your mind the chords that usually go with it. A Bach unaccompanied cello suite also has strongly implied harmonies; if someone really wanted to play an accompaniment, the appropriate chords could be found pretty easily. But some melodies don't imply any harmony; they are not meant to be played with harmony, and don't need it to be legitimate music. (Good examples of this include plainchant, some modern art music, and some Non-Western music, for example, Native American flute music.)
drones - The simplest way to add harmony to a melody is to play it with drones. A drone is a note that changes rarely or not at all. Drones can be most easily found in bagpipes music, Indian Classical music and other musics that use instruments that traditionally play drone notes. (See Harmony with Drones.)
parallel harmony - Parallel harmony occurs when different lines in the music go up or down together (usually following the melody). (See Parallel Harmonies for examples.)
homophony - Homophony is a texture of music in which there is one line that is obviously the melody. The rest of the notes are harmony and accompaniment. (See Homophonic.)
polyphony or counterpoint - Both of these terms refer to a texture of music in which there is more than one independent melodic line at the same time, and they are all fairly equal in importance. (See Polyphonic and Counterpoint.)
chords - In Western music, most harmony is based on chords. Chords are groups of notes built on major or minor triads. In traditional triadic harmony, there are always at least three notes in a chord (there can be more than three), but some of the notes may be left out and only "implied" by the harmony. The notes of the chord may be played at the same time (block chords), or may be played separately with some overlap, or may be played separately but in a quick enough succession that they will be "heard" as a chord or understood to imply a chord (arpeggiated chords or arpeggios).
chord progression - A series of chords played one after another is a chord progression. Musicians may describe a specific chord progression (for example, "two measures of G major, then a half measure of A minor and a half measure of D seventh", or just "G, A minor, D seventh") or speak more generally of classes of chord progressions (for example a "blues chord progression"). Please see Beginning Harmonic Analysis for more information.
functional harmony - Harmony can simply be more than one note sounding at a time, providing texture and interest to a piece; drones are one example of this non-functional type of harmony. One of the most important features of common practice music, however, is functional harmony. This is harmony in which each chord functions in a specific way in the key, and underpins the form of the piece of music. For an introduction to functional harmony, see Beginning Harmonic Analysis
harmonic rhythm - The harmonic rhythm of a piece refers to how often the chords change. Music in which the chords change rarely has a slow harmonic rhythm; music in which the chords change often has a fast harmonic rhythm. Harmonic rhythm can be completely separate from other rhythms and tempos. For example, a section of music with many short, quick notes but only one chord has fast rhythms but a slow harmonic rhythm.
cadence - A cadence is a point where the music feels as if it has come to a temporary or permanent stopping point. In most Western music, cadence is tied very strongly to the harmony. For example, most listeners will feel that the strongest, most satisfying ending to a piece of music involves a dominant chord followed by a tonic chord. In fact, a song that does not end on the tonic chord will sound quite unsettled and even unfinished to most listeners. (See Cadence.)
diatonic - Diatonic harmony stays in a particular major or minor key.
chromatic - Chromatic harmony includes many notes and chords that are not in the key and so contains many accidentals.
dissonance - A dissonance is a note, chord, or interval that does not fit into the triadic harmonies that we have learned to expect from music. A dissonance may sound surprising, jarring, even unpleasant.
accompaniment - All the parts of the music that are not melody are part of the accompaniment. This includes rhythmic parts, harmonies, the bass line, and chords.
melodic line - This is just another term for the string of notes that make up the melody.
bass line - The bass line is the string of notes that are the lowest notes being sung or played. Because of basic laws of physics, the bass line sets up the harmonics that all the other parts - including the melody - must fit into. This makes it a very important line both for tuning and for the harmony. The bass line also often outlines the chord progression, and it is often the most noticeable line of the accompaniment.
inner parts or inner voices - Accompaniment parts that fill in the music in between the melody (which is often the highest part) and the bass line.
descant - The melody is not always the highest line in the music. Attention is naturally drawn to high notes, so a part that is higher than the melody is sometimes given a special name such as "descant". This term is an old one going all the way back to when harmonies first began to be added to medieval chant. (See Counterpoint for more about descants.)
Suggestions for activities that introduce young students to harmony may be found in Harmony with Drones, Simple Chordal Harmony, Parallel Harmonies, and Independent Harmonies.