Major and minor scales form the backbone of Western music. They're like the DNA of melodies, each with its own unique pattern of whole and half steps. Understanding these scales is crucial for composing, improvising, and analyzing music.

Key signatures are the shorthand for scales, telling us which notes are sharp or flat. The circle of fifths is a handy tool for figuring out key signatures, showing how scales are related. It's like a roadmap for navigating different keys.

Major vs Minor Scales

Construction of Major and Minor Scales

• Major scales are constructed using a specific pattern of whole steps (W) and half steps (H): W-W-H-W-W-W-H
  • This pattern remains consistent regardless of the starting note
  • To construct a major scale, start on the tonic note and follow the pattern of whole steps and half steps until the octave is reached
• Natural minor scales are constructed using a different pattern of whole steps and half steps: W-H-W-W-H-W-W
  • This pattern also remains consistent regardless of the starting note
  • To construct a natural minor scale, start on the tonic note and follow the pattern of whole steps and half steps until the octave is reached

Key Signatures and the Circle of Fifths

• The key signature of a scale indicates which notes are sharp or flat throughout the scale
  • The key signature remains consistent throughout the scale
  • The circle of fifths can be used to determine the key signature of any major or minor scale
    • Each successive key in the circle of fifths adds one sharp or removes one flat from the key signature
    • The order of sharps in key signatures is always F#, C#, G#, D#, A#, E#, B#
    • The order of flats is always B♭, E♭, A♭, D♭, G♭, C♭, F♭

Key Signatures for Scales

Writing Key Signatures

• Key signatures are written at the beginning of a staff
  • They indicate which notes are consistently sharp or flat throughout a piece
  • The key of C major and A minor have no sharps or flats in their key signatures
• Relative minor scales have the same key signature as their relative major scales
  • Relative major scales start a minor third (three half steps) above the tonic of the minor scale
  • For example, C major and A minor have the same key signature, as do G major and E minor

Determining Key Signatures

• The circle of fifths can be used to determine the key signature of any major or minor scale
  • Moving clockwise around the circle adds one sharp to the key signature (C, G, D, A, E, B, F#)
  • Moving counterclockwise around the circle adds one flat to the key signature (C, F, B♭, E♭, A♭, D♭, G♭)
• The order of sharps in key signatures is always F#, C#, G#, D#, A#, E#, B#
• The order of flats is always B♭, E♭, A♭, D♭, G♭, C♭, F♭

Intervallic Structure of Scales

Intervals in Major and Minor Scales

• Intervals are the distances between notes, measured in half steps and whole steps
• Major scales are composed of the following intervals from the tonic:
  • Major 2nd, major 3rd, perfect 4th, perfect 5th, major 6th, and major 7th
  • The intervallic structure of a major scale is always W-W-H-W-W-W-H
• Natural minor scales are composed of the following intervals from the tonic:
  • Major 2nd, minor 3rd, perfect 4th, perfect 5th, minor 6th, and minor 7th
  • The intervallic structure of a natural minor scale is always W-H-W-W-H-W-W

Emotional Quality of Scales

• The intervallic structure of a scale determines its overall sound and emotional quality
  • Major scales often sound happy or bright due to their major 3rd, 6th, and 7th scale degrees
  • Minor scales often sound sad or dark due to their minor 3rd, 6th, and 7th scale degrees
• The specific intervals in a scale contribute to its unique character and mood
  • For example, the major 7th in a major scale creates a sense of tension and resolution, while the minor 6th in a minor scale contributes to its melancholic sound

Natural, Harmonic, and Melodic Minor Scales

Natural Minor Scales

• Natural minor scales follow the pattern W-H-W-W-H-W-W
  • They have a minor 3rd, minor 6th, and minor 7th scale degree
  • The intervallic structure of a natural minor scale is always W-H-W-W-H-W-W
• Natural minor scales are the most basic form of the minor scale
  • They are used in a variety of musical contexts, from classical to contemporary genres

Harmonic Minor Scales

• Harmonic minor scales raise the 7th scale degree by a half step
  • This creates an augmented 2nd interval between the 6th and 7th scale degrees
  • The raised 7th degree is used to create a stronger resolution to the tonic in harmonic contexts
• Harmonic minor scales are commonly used in classical and romantic period compositions
  • They provide a sense of tension and resolution in harmonic progressions
  • The raised 7th degree is often used in cadences to create a stronger sense of finality

Melodic Minor Scales

• Melodic minor scales raise the 6th and 7th scale degrees by a half step when ascending
  • When descending, they revert to the natural minor scale
  • This creates a more fluid melodic line and avoids the augmented 2nd interval found in the harmonic minor scale
• The raised 6th and 7th scale degrees in the melodic minor scale create additional intervals not found in the natural minor scale
  • These include the major 6th and major 7th
• Melodic minor scales are often used in jazz and other improvisational contexts
  • They provide a wider range of melodic possibilities and create interesting tensions and resolutions in melodic lines