The Major Scale
The root of music theory can be seen by playing the Major scale in the Key of C on the Piano (only the white keys from C to C)
C to D is one whole step or tone due to the black key in between them. E to F is one half step or semitone there are no keys between them. The Major Scale can be thought of as - whole step - whole step - half step - whole step - whole step - whole step - half step.
The Major Scale pattern WWHWWWH
Another way to think of the major scale notes is as numbers - the first note C=1 and the second note D=2 and the third note in the scale E=3 and so on.
Please have a look at Diatnic Harmony to see how the numbers way is the best in the end.
By Michael Pelletier