I mentioned the octave in the explanation of the chromatic scale. Now I will explain how the eight notes of the major scale are chosen. The major scale can start with any note on the chromatic scale. This note is known as the root note. In order to determine which notes are included in the scale we follow this pattern: W-W-H-W-W-W-H (W - Whole Step, H - Half Step). This gives you an eight-note scale of Root -2-3-4-5-6-7-Octave, where the octave is a higher pitch of the same note.
For example, in the “C” scale, we would choose the following notes from the chromatic scale: