A scale is a series of notes going either up or down in pitch. we can use them as a way of organising notes together according to pitch.
Musical notes are named after letters of the alphabet from A to G. When we reach G we start again from A. This means if we go up or down from one letter we will eventually reach that letter again.
To play a C Major scale we would play each note from C to the next C.
There are Several different types of scale the most common being Major and Harmonic Minor. Other types of scales include:
Whole Tone Scales