Yes, Intervals are so important they need their own page.
The distance between two notes is called an Interval.
In music we use the first 7 letters of the alphabet.
The distance from the note A to the note B is 2. We call this the interval of a 2nd.
Likewise the distance from E to the note F is also a 2nd.
However, one of them is bigger than the other.
A-B is a Major 2nd
E-F is a minor 2nd
Major means Big
Minor means small
We have a few intervals that occur in nature. They are the Perfect 4th, the perfect 5th, and the Octave. They are not major or minor.
Here are the same intervals shown spread across strings in relation to the same starting point each time.
The guitar is tuned (from one string to the next) in intervals of 4ths.
E string to A string for example.
E - A = P4
Except for the 2nd string G - B it is tuned as a Major third. Precisely one fret lower than all the other strings are tuned to one another.
To keep the same interval the shape will be compensated up one fret.
Not understanding Compensating on this string is a huge source of confusion for many players.
Now go do some interval worksheets and think about what you have learned. The next time you are playing a G7 chord.. Maybe think about what that might be in terms of intervals. Look at the shapes. You will start noticing these intervals in everything that you do and it will make more sense out of why a scale, chord or arpeggio is called major(bigger) and why one is minor(smaller)
and what a 6 or 7 or 9 is.
They are all intervals.
Play an E chord then play an A chord
notice to keep the A chord Major you compensate one fret up on the second string.
The E and the A chord are intervalically the same, all major chords are intervalically the same.
Now play an A chord then a D chord.
See what happens?