Seven doors into the same notes
Seven notes. Seven homes. Seven moods.
The keys below never change — they are the white notes, the C major set. The only thing you can move is home: the note the music rests on. Move home and the same seven notes reorganise around it into a completely different mood. That is what a mode is — and “relative minor” is just one of the seven doors.
Tap any white key to make it home. Keep the drone on while you switch — the mood change is the lesson.
What to try
C, then A, drone on. Home on C is major; home on A is the natural minor — with not a single note changed. Relative major and minor are the same set read from two doors.
Walk the brightness ladder. Lydian (F) is the brightest door, then Ionian (C), Mixolydian (G), Dorian (D), Aeolian (A), Phrygian (E), Locrian (B) — each one semitone-flatter in character than the last. Try them in that order.