Vibrating an air column generates sound
1.1 Free aerophones (41) 1.1.1 Displacement free aerophones (411) 1.1.2 Interruptive free aerophones (412) 1.1.3 Plosive aerophones (413) 1.2 Non-free aerophones (wind instruments proper) (42) 1.2.1 Edge-blown aerophones or flutes (421) 1.2.2 Reed aerophones (422) 1.2.3 Trumpets (423) 1.3 Unclassified aerophones (43)