Now we have the minor pentatonic understood, the next step is to learn the blues scale. This cool new scale is the minor pentatonic with an additional note. It has a unique sound and is commonly used across all genres, not just blues!
The blues scale is essentially just the minor pentatonic scale with the addition of a flattened 5th note. This extra note is considered a passing note, which means that it is not wise to hang about too long on this note. Try to consider the function of this extra note as a bit of tension that resolves to the notes either side (the 4th or 5th). This tension gives the scale a bluesy feel, hence the name of the scale! This scale is used across all genres, not just blues as the name suggests. The formula for the blues scale is , as shown below:
To help you put this into practice, here is a common shape for the blues scale in the key of C minor (as per the example above). Notice the notes on the neck as you go through it, trying to say the degrees of the scale (i.e. 1st, b3rd, 5th etc...).