You can get different kinds of 2nds, 3rds, 4ths, 5ths, 6ths, 7ths and 8ves.
In any major scale, with the key note as the bottom note of an interval, all the intervals are called major or perfect intervals. See the picture below of a C major scale with all the intervals within it, using C as the lower note. In brackets you can see how many semitones* make up each interval.
If you change the top note of the interval so that it is no longer one of the notes within the major scale, e.g. by sharpening or flattening it, you get an interval that is not major or perfect.
For example, if you take the major 3rd - C to E, and change the E to E flat, you get a minor 3rd. So, C to E flat is a minor 3rd. By changing the E to E flat, you have made the interval a semitone smaller. (The major 3rd is 4 semitones, the minor 3rd is 3 semitones.)
Any time you make a major interval a semitone smaller, you get a minor interval. So, as another example, if you take the major 6th: C to A, and change the A to A flat, you end up with a minor 6th. So, C to A flat is a minor 6th.
If you make a perfect interval (or a minor interval) a semitone smaller, you get a diminished interval. Eg. C to G is a perfect 5th. If you change the G to G flat, you get a diminished 5th. So, C to G flat is a diminished 5th.
If you make either a major or perfect interval a semitone bigger, you get an augmented interval. Eg. C to F is a perfect 4th. If you change the F to F sharp you get an augmented 4th. So, C to F sharp is an augmented 4th.
Notice how F sharp is the same key on the piano as G flat - the two notes are enharmonic equivalents, i.e. the same pitch but with different names. So, even though the interval of C to F sharp looks exactly the same as the interval of C to G flat on the piano, we call them something different depending on which letter name they use. An augmented 4th has the same number of semitones as a diminished 5th, but the choice of letter names will determine whether we call it a 4th or 5th. C to F is always a kind of 4th no matter what kind of C or F (i.e. it doesn’t matter whether the C or F is sharpened or flattened), because you count 4 letter names - C D E F. C to G is always a kind of 5th because you count 5 letter names - C D E F G.
Here is a picture of more intervals using C as the lower note:
Intervals Worksheet and Model Answers
PDF download of intervals worksheet with explanation of how to work out the intervals, and a separate PDF with the model answers.
Flash Cards - Musical Word Spelling Game
PDF download. Fun note naming theory game for children to improve their music reading.
Flash Cards for Adults and Children - Note Naming
PDF download. Learn to read music, or improve your music reading skills with these flash cards for practising note naming.
Major and Minor Key Signatures Worksheet and Model Answers
PDF download. Worksheet - name the key and rewrite with key signatures instead of accidentals. Model answers sheet also included.
Flash Cards - Piano Keyboard Intervals
PDF download of flashcards for naming intervals on the piano keyboard.
Music Manuscript Staff Paper Template - Free
Free PDF download of music manuscript staff paper, two different types - portrait and landscape.
Flash Cards and Chord Chart - Roman Numeral Chords - Primary Triads in Every Major Key
Keyboard Note Naming Flash Cards - Free
Free PDF download of piano keyboard note naming flash cards.