Major and Minor Scales Explained | Music Theory Intervals

In Western music theory, semitones (half-steps) are the smallest interval between adjacent notes on a piano keyboard, while tones (whole steps) consist of two semitones; these intervals serve as the fundamental building blocks for all Western musical compositions, regardless of genre or instrument.

In music theory, a semitone (or half tone) is the smallest distance between two adjacent piano keys, such as from C to C-sharp, while two semitones together equal one tone (or whole tone); these units serve as the fundamental measuring tool for determining the distance between any two pitches, and they form the basis for understanding intervals, chords, and scales in Western music.

An interval is a musical distance between two notes. Basic intervals include: half step/semitone (smallest distance), whole step/whole tone (two semitones), octave (12 semitones higher), tritone (three whole tones), and unison (identical notes). All intervals are measured by letter classes (A-G), where different notes can share the same letter class (e.g., G#, Gb, G natural). The terms 'major' and 'minor' in music theory mean 'big' and 'small' respectively. When moving through letter classes, seconds can be whole steps (major second) or half steps (minor second), establishing the foundational principle that interval quality relates to size.

The smallest units of movement in music are called steps, specifically whole steps and half steps. A whole step (whole tone) is the distance between two adjacent white keys on a piano keyboard, such as C to D or D to E. A half step (semitone) is the distance between a white key and an adjacent black key, such as C to C# or B to C. The formula for the major scale is: whole, whole, half, whole, whole, whole, half.

Western music theory is built upon two fundamental interval types: half steps (semitones) and whole steps (whole tones). A half step moves to an adjacent note (e.g., C to C#), while a whole step skips one note (e.g., C to D). These intervals form the basis for all scales. The natural minor scale follows the pattern: whole, half, whole, whole, half, whole, whole. The major scale follows: whole, whole, half, whole, whole, whole, half. The major scale uniquely uses only white keys on the piano. Understanding these interval patterns enables musicians to construct scales in any key and understand the mathematical foundations of Western harmony.

The 12 notes do not cover all audible frequencies for human ears, so they must be repeated across multiple registers. A register (registro) contains the same 12 notes, but at different frequencies. Higher registers produce more acute sounds, while lower registers produce more grave sounds. An octave is the distance between a note and the same note repeated in another register. Learning to move within one octave allows you to move across all other octaves, with only the perceived pitch changing.

An octave is the interval between a note and the same note in a higher or lower register. The seven notes (Do, Re, Mi, Fa, Sol, La, Si) repeat in different registers or octaves. On a piano, the middle register is the central area, with higher registers to the right (higher pitches) and lower registers to the left (lower pitches). The seven white keys from Do to Si represent one complete octave.

This comprehensive lesson explains how octave registers solve the problem of multiple notes sharing the same letter name in musical notation. A register indicates pitch level or height, with lower numbers representing lower pitches. An octave spans eight notes, causing the musical alphabet (A-G) to repeat. The numbering system uses C as the reference point where numbers change—every time a new C is reached while ascending, the octave number increases. Notes between consecutive Cs belong to the same register. For example, C3 to C4 forms register III, and C4 to C5 forms register IV. Middle C (C4) sits precisely at the center of the grand staff, serving as the central reference point. This systematic approach allows musicians to precisely identify which specific note (e.g., which C) they are referring to, eliminating ambiguity in notation.

Octaves are ranges where higher notes have the same letter names as lower notes but at different pitches. The first octave starts from the bottom line (Do) and ends at the top line (Si). The second octave starts from the space above the top line (Do) and ends at the space above that (Si). The third octave starts from the line above that (Do) and continues upward. The same note letter (like Mi) can appear at different octaves, each with a different pitch. Playing a note from a different octave than written changes the song's octave, even though the note name remains the same. Understanding octaves is essential for proper musical interpretation.

An octave is the interval between a note and its higher repetition. When you play Do (D) and then reach the next Do (D) an octave higher, you have completed one octave. The lower Do is thicker and lower in pitch, while the higher Do is thinner and higher. The seven notes repeat in this pattern: Do, Re, Mi, Fa, Sol, La, Si, then back to Do (an octave higher).

The piano keyboard provides the easiest visual representation of musical notes among all instruments. The white keys represent the natural notes: C (dó), C# (dó sustenido), D (ré), D# (ré sustenido), E (mi), F (fá), F# (fá sustenido), G (sol), G# (sol sustenido), A (lá), A# (lá sustenido), and B (si). The black keys represent the sharps and flats. This layout makes it simple to visualize all notes and the intervals between them, particularly semitones (intervalos de semitons), which are the smallest intervals between adjacent keys.

This comprehensive section covers the foundational elements of music notation. It begins with creating a paper piano keyboard to visualize the layout, where black keys are arranged in groups of two and three. The white notes are named C, D, E, F, G, A, B in sequence, with D resembling a dog in a kennel. An octave spans eight notes, with the sequence restarting at A. The bottom note of a full piano is A, and the top is C. Middle C is always to the left of two black notes. Semitones are the smallest distance between adjacent notes, with sharps raising notes by one semitone and flats lowering them. The section then introduces clefs: the treble clef (G clef) for notes above middle C starting on the G line, and the bass clef (F clef) for notes below middle C starting on the F line. Ledger lines extend the staff beyond the five main lines, with middle C written on a ledger line in both clefs.

Once you know which note a staff position represents, you can locate it on the piano keyboard. For example, the first F space on the treble clef is located just above middle C. Moving a note down one position on the staff moves it down one key on the keyboard. Notes outside the standard staff range require ledger lines, which extend the staff above or below to accommodate additional notes.

This lesson covers the complete method for calculating distances between musical notes on a piano keyboard. Students learn to memorize the keyboard layout, convert whole tones to semitones by multiplying by 2, and count semitones starting from 0 (the starting note is never counted). Positive intervals (moving right) use sharp symbols when landing on black keys, while negative intervals (moving left) use flat symbols. The method applies to any starting note, including those beyond the visible keyboard range, requiring students to mentally continue the pattern.

Piano music notation uses a grand staff system consisting of two superimposed staves: the Treble Clef (top) for high notes played with the right hand, and the Bass Clef (bottom) for low notes played with the left hand. Each staff has 5 horizontal lines where notes are placed either on lines or between lines. The same staff position represents different notes depending on the clef—for example, a position might be 'Do' in Treble Clef but 'Mi' in Bass Clef. Ledger lines extend the staff for very high or very low notes. The grand staff is connected by a brace and represents the complete keyboard range of 88 keys.