Lesson 6
Accidentals
Sharps raise, flats lower, naturals cancel.
The in-between notes
The musical alphabet is A through G, but the piano has black keys between most of them. Accidentals name those pitches. A sharp (♯) raises a note one semitone. A flat (♭) lowers it one semitone. A natural (♮) cancels a sharp or flat that would otherwise apply.
F♯ and G♭ are the same piano key (enharmonic spelling) but they are written differently because the letter still matters for keys and intervals.