Both scales and keys refer to groups of tones and sometimes we can either say scale or key and mean the same thing. … It is true that the G Major Scale includes the same tones: G, A, B, C, D, E and F#. But a song in the key of G could at the same time include several scales.

What is the difference between a scale and a key?

A very simplistic way to look at it is this: A scale is a defined set of ordered pitches. A key is the use of a scale in actual music. To say that a piece is in the Key of A, would mean that usually most of the notes in the piece would follow the tonal rules of the A Major scale.

What is key signature and scale?

Key Signatures and Scales The melodies and chords used in most pieces are based on the notes of a specific major or minor scale and the key signature is used to specify those sharps and flats.