The Grand Staff
The Grand Staff holds the middle C line as the center of the musical graph. Standardly, the middle C line is not visible, but understood.
In the diagram above, the middle C line is shown as a dotted line to help students see the staff as a graph of pitches and how those pitches relate to a piano or keyboard.
The space between the staves is often stretched apart to leave room for lyrics or dynamic markings. It seems that there are two middle C's, but they are the same note. The musical graph has been pulled apart at the middle line.
Notice how the pitches stepping up or down on the staff alternate line note to space note. This pattern helps pitches become recognizable.
C D E F G A B C D E F G A B C D E F G A B C D E F G A B C
The Graph to Staff Approach of this self-teaching piano method breaks the beginning stages of reading notes on the Grand Staff into easy progressive steps.