How to Construct Major and Minor Pentatonic Scales
A pentatonic scale, as the name implies, has only five notes. It's build from either the major or natural minor scale. Pentatonic scales are great place to start for song writing and improvising.
Major Pentatonic Scale:
In this tutorial instead of using note names I'll refer to scale degree numbers 1 - 7 of the major and minor scales. This makes it easy to transpose the scale into different keys and will help give you a broader view of the concepts.
The major pentatonic scale is scale degrees 1, 2, 3, 5, 6 of the regular major scale. In other words, it's a major scale without degees 4 and 7. When you remove degrees 4 and 7 from the major scale there are no more half steps; for this reason pretty much any note in the major pentatonic scale sounds good over a major chord progression.
Since I'm a sucker for examples let's throw a few out there. In these written examples you can see the gaps where note degrees 4 & 7 are omitted for the major pentatonic scale.
C major pentatonic scale:
Notes: C - D - E - G - A
G major pentatonic scale:
Notes: G - A - B - D - E
Eb Major Pentatonic Scale
Notes: Eb - F - G - Bb - C
Minor Pentatonic Scale:
The minor pentatonic scale is 1, 3, 4, 5, 7 of the natural minor scale. That is, a natural minor scale without degrees 2 and 6. Sometimes it's easier to think of a major pentatonic scale that starts and ends on degree 6.
E minor pentatonic scale:
Notes: E - G- A - B - D
If you haven't already learned about relative keys now would be the time to check them out. Understanding them can really speed up your learning of scales. Since there are twelve major pentatonic scales and twelve minor pentatonic scales you might be a little overwhelmed with trying to learn them all separately. However, understanding relative keys will cut those 24 scales in half so that once you learn twelve you've learned them all.
Do yourself a favor and read about relative keys!