[1][2] The word "scale" originates from the Latin scala, which literally means "ladder".
[1][2] Often, especially in the context of the common practice period, most or all of the melody and harmony of a musical work is built using the notes of a single scale, which can be conveniently represented on a staff with a standard key signature.
Based on their interval patterns, scales are put into categories including pentatonic, diatonic, chromatic, major, minor, and others.
A specific scale is defined by its characteristic interval pattern and by a special note, known as its first degree (or tonic).
[5] Many music theorists concur that the constituent intervals of a scale have a large role in the cognitive perception of its sonority, or tonal character.
"[6] "The pitch distances or intervals among the notes of a scale tell us more about the sound of the music than does the mere number of tones.
Scales in traditional Western music generally consist of seven notes and repeat at the octave.
Notes in the commonly used scales (see just below) are separated by whole and half step intervals of tones and semitones.
Western music in the Medieval and Renaissance periods (1100–1600) tends to use the white-note diatonic scale C–D–E–F–G–A–B.
The music of this period introduces modulation, which involves systematic changes from one scale to another.
In Western tonal music, simple songs or pieces typically start and end on the tonic note.
Also commonly used is the (movable do) solfège naming convention in which each scale degree is denoted by a syllable.
In the major scale, the solfège syllables are: do, re, mi, fa, so (or sol), la, ti (or si), do (or ut).
Again, this implies that the notes are drawn from a chromatic scale tuned with 12-tone equal temperament.
For some fretted string instruments, such as the guitar and the bass guitar, scales can be notated in tabulature, an approach which indicates the fret number and string upon which each scale degree is played.
This process is called "scalar transposition" or "shifting to a new key" and can often be found in musical sequences and patterns.
Since the steps of a scale can have various sizes, this process introduces subtle melodic and harmonic variation into the music.
The blue note is an interval that is technically neither major nor minor but "in the middle", giving it a characteristic flavour.
In Western music, scale notes are often separated by equally tempered tones or semitones, creating 12 intervals per octave.
Each interval separates two tones; the higher tone has an oscillation frequency of a fixed ratio (by a factor equal to the twelfth root of two, or approximately 1.059463) higher than the frequency of the lower one.
[13] Many musical scales in the world are based on this system, except most of the musical scales from Indonesia and the Indochina Peninsulae, which are based on inharmonic resonance of the dominant metalophone and xylophone instruments.
For example, in the Chinese culture, the pentatonic scale is usually used for folk music and consists of C, D, E, G and A, commonly known as gong, shang, jue, chi and yu.