Specific intervals are measured both on the staff and in half steps on the keyboard.
As you learned in the previous lesson, C to D and C to Db are both generic seconds. Specifically, however, C to D is one half step larger than C to Db.
Let's learn a few specific intervals.
A major second is made up of two half steps.
C to D is a major second since it is a generic second on the staff and two half steps on the keyboard.
E to F# would be another example of a major second.
A major third is made up of four half steps. C to E is a major third.
E to G# is also a major third.
A perfect fourth is made up of five half steps. C to F is a perfect fourth.
F to Bb is also a perfect fourth.
A perfect fifth is made up of seven half steps.C to G is a perfect fifth.
B to F# is also a perfect fifth.
A major sixth is made up of nine half steps. C to A is a major sixth.
Eb to C is also a major sixth.
A major seventh is made up of eleven half steps. C to B is a major seventh.
D to C# is also a major seventh.
Finally, a perfect eighth (or perfect octave) is made up of twelve half steps. C to C is a perfect eighth.
In addition to major and perfect; minor, augmented, and diminished intervals exist.
A diminished interval has one less half step than a perfect interval.
Since C to G is a perfect fifth (7 half steps), C to Gb would be a diminished fifth (6 half steps).
B to F is also a diminished fifth (since B to F# is a perfect fifth).
An augmented interval has one more half step than a perfect interval. Since C to F is a perfect fourth (5 half steps), C to F# would be an augmented fourth (6 half steps).
F to B is also an augmented fourth (since F to Bb is a perfect fourth).
Major intervals can be augmented by adding a half step. For example, since C to A is a major sixth (9 half steps), C to A# is an augmented sixth (10 half steps).
Db to B is also an augmented 6th (Since Db to Bb is a major sixth).
Subtracting a half step from a major interval does not make it diminished; instead, it becomes minor. For example, since C to B is a major seventh (11 half steps), C to Bb is a minor seventh (10 half steps).
Only after subtracting another half step does it become diminished. Thus, C to Bbb would be our diminished seventh (9 half steps).
The above chart shows the number of half steps that each specific interval contains.