The major scale should be one of the first
scales that you learn. Besides being a good warm up and
technique builder, the major scale will be the starting
point for all theory. This is a two octave
scale. Oct is the Greek prefix for eight, so the 2nd red
oval is eight notes above the 1st. Be sure to memorize where
the roots are within the scale form. In order to train and
your ear and your brain, try stopping on each root as you
play. You should do this with all scales. Play the scale
going up and down keeping as steady of a beat as possible.
The blues scale is the minor pentatonic with
an added note (in both octaves). The note that is added
is sometimes referred to as the "blue note". This scale
is used in blues, but it is also used in all styles of music.
There is not a "heavy metal scale" or a "country scale",
just a blues scale.
For the major pentatonic scale shift your
hand and play the notes on the 1st and 2nd strings with
your 1st and 3rd fingers. Usually it is a good idea to shift
your hand like this if there is more than one string where
you would not be using your first finger.