If you’ve ever wanted to “take the 5th,” wondered if the 4th was really “with you,” or perhaps thought that the difference between a minor 3rd and a major 3rd is age (with the minor being younger), then it may be time to have a talk about intervals. Intervals in music refer to the distance between any two notes in chords and scales. Take the C major scale, for example (Ex. 1): The notes in this scale are C, D, E, F, G, A, B, and C. In order to find the interval designation between C (the root) and any of the other notes in the scale, you simply count the letters, starting with the C being “one” and continuing until you reach your destination letter: C to D is a 2nd (Ex. 2); C to E is a 3rd (Ex. 3) ; C to F is a 4th (Ex. 4) ; C to G is a 5th (Ex. 5); C to A is a 6th (Ex. 6); C to B is a 7th (Ex. 7) ; and C to C is an 8th or octave (Ex. 8) . Note that in these examples, the diamond shape is the root, the solid dot is the interval, and the broken circles are the other notes of the scale.      Now for the really useful stuff. The bass is a symmetrical instrument, which means all of the intervals can be reached with the same fingering pattern. If you put your middle finger on the 3rd fret of the A string, which is the note C, then you can reach the major 3rd, the E, by pressing your index finger onto the 2nd fret of the D string. This move from the middle finger on the root to index finger on the 3rd can be duplicated anywhere on the fingerboard. In fact, the simplest way to deal with interval terminology is to play a major scale and count the note names as numbers: C=1, D=2, E=3, F=4, G=5, A=6 , B=7, C=8 (or octave). Take a look at Ex. 9 for the notation, tablature, and fingering for the C major scale (while at it, I included the same for all the other major scales, as well). You can transfer this pattern to any key by starting it with the middle finger on the root and making sure you have three strings and four frets to fit it all in.  Now to the finer points of the terminology. The intervals in their “natural state” are based on the major scale and are as follows: C to D = major 2nd; C to E = major 3rd; C to F = perfect 4th; Cto G = perfect 5th; C to A = major 6th; C to B = major 7th; C to C = perfect eighth or octave. As you can see, all of the intervals in the major scale are either “major” or “perfect.” So, what happened to the minor, diminished, and augmented you’ve been hearing about? Thought you’d never ask. I don’t want to geek you out with all the terms that are possible for different intervals. Instead, I’ll stick to the terms you actually use in real life, because in real life nobody wants to hear about a double-augmented 4th, only to find out it’s really a perfect 5th.   Speaking mathematically, the distance between C and D is two half-steps (two frets) and is called a major 2nd. By shortening the distance by one half-step (one fret), you get a minor 2nd, from C to Db.