Major and Minor Scales
The diatonic scale patterns underlying Western tonality: the arrangement of whole and half steps that defines major and minor keys.
A scale is an ordered sequence of pitches spanning an octave from which melodies and harmonies are built. The major and minor scales — the diatonic scales — are the foundation of Western tonal music. What makes a scale major or minor is not the notes themselves but the pattern of intervals between them. The major scale uses the step pattern whole–whole–half–whole–whole–whole–half (W-W-H-W-W-W-H): starting on C gives C D E F G A B C, the white keys of the piano.
The natural minor scale uses W-H-W-W-H-W-W: starting on A gives A B C D E F G A — the same white keys, but with a different tonic, which is why A minor is the relative minor of C major. Two further minor forms exist for harmonic purposes: the harmonic minor raises the seventh degree (creating the characteristic leading tone, with an augmented second between the sixth and seventh steps), and the melodic minor raises the sixth and seventh ascending, restoring the natural form descending. Composers choose among them to shape melody and harmony.
Each degree of the scale has a function. The first degree (tonic) is home; the fifth (dominant) creates tension that pulls back to the tonic; the seventh (leading tone) leans upward to the tonic. The intervals a scale defines also generate its chords: stacking thirds on each degree produces the diatonic triads, the raw material of harmonic progressions. A piece in a major key feels bright and stable; minor keys are associated with darker, more expressive character — an association that is cultural as much as acoustic, since the intervals are identical in structure.
The circle of fifths organizes the twelve major and minor keys, each with its own key signature; every major key has a relative minor a minor third below it, sharing the same notes. Musicians practice scales as the vocabulary of tonality — the circle of fifths shows why keys with adjacent signatures are harmonically close, and modulation between keys in a piece is understood as movement along that circle. Scale structure, in turn, defines the time-signature-independent pitch dimension of music: rhythm organizes time, scales organize pitch.
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intervals keys music theory scales
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