Step 4: For an F blues scale, we need one last tweak: a sharpened fourth degree. This means we take the fourth degree of the scale, raise it in pitch by one semitone and add this note to the scale.

The Blues scale is an adaptation of the minor pentatonic, identical except for the addition of one vital note, a sharpened fourth. With that one all-important additional ‘blue’ note, this scale is ...