The major scale is the foundation of Western music. Happy, bright, and resolved - it's the sound of "Do Re Mi Fa Sol La Ti Do". If music theory had a default pantry, this would be it. Every other scale is essentially described in terms of how it differs from the major.
The formula: T-T-S-T-T-T-S
The major scale is built from a specific pattern of tones (T) and semitones (S). This pattern is the same in every key - same recipe, different starting ingredient.
Building C major step by step
C major scale - all white keys from C to C
C major is special because it uses only white keys. That's why C is the default starting point for learning theory - no sharps or flats to think about.
Same pattern, any root
The power of the formula is that it works from any starting note. G major uses the same T-T-S-T-T-T-S pattern.
G major: G A B C D E F#
G major scale - notice the F# (one black key needed)
G major needs one sharp (F#) to maintain the T-T-S-T-T-T-S pattern. Every major scale that doesn't start on C needs at least one sharp or flat.
The major scale as intervals
Another way to define the major scale: the semitone distances from the root. This connects directly to the intervals topic.
The numbers 0, 2, 4, 5, 7, 9, 11 define the major scale. This is exactly how scales are stored in produc.ing's code.
Hear both keys
Same pattern, different starting note. Notice how both sound equally "major" - bright and resolved - just at different pitches.
Key takeaway
The major scale uses the pattern T-T-S-T-T-T-S (semitones: 0, 2, 4, 5, 7, 9, 11). It works from any root note. C major uses only white keys. Other keys need sharps or flats to maintain the pattern. The major 3rd (degree 3) is what makes it sound bright.
Next: the major scale's darker sibling - the natural minor scale.
Generate in any major key
Pick a root note and select "Major" in Starts. The generated melody will use exactly this scale.