Key Signatures
The Key Signature is the arrangement of sharps or flats on specific lines and spaces of the musical staff. This arrangement indicates that those pitches will always be raised (by sharps) or lowered (by flats) unless otherwise altered later in the music.
The key signature is placed right after the clef symbol at the beginning of the first line of music.
Solfege
This app uses a system called movable do to learn pitches. In this system names are given to the scale degrees.
This means that "Do" is always the first note of a major scale. Do, Mi and So will always be strong pitches within the key.
The solfege syllables are listed below in relationship to the different keys used in this app.
* NOTE - Other systems can work as well. Other methods include using Fixed Do where Do is always on C and Re is always on D and so on. Another method is using numbers for the scale degrees when learning to sight sing. If a different system is working for you, there is nothing wrong with that!