Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.
Target/codes: use A A B B to place and name one source change after event 2; AC9AMUFD01, AC9AMUFC01. Prepare:C switch board, Practice C, A/B key and wide boundary marker.
Welcome · 3 min. Keep pitch and four event places fixed; source choice is the changing element.
Model · 4 min. Lay A A B B, then place a large marker between 2 and 3. That marks the first B, not a higher pitch or louder instruction.
Try together · 5 min. Child uses word, shape and raised texture to locate the sole A→B source transition.
Child choice · 7 min. Child chooses a different switch point or keeps AABB for an invented game-room cue or plain score, explaining a musical reason. Optional AABB candidate (playback review held) needs prior review.
Notice · 4 min. Save source sequence and stated switch; separately note if a real listener perceived a contrast.
Close · 2 min. Tomorrow a source's sound depends on an action, not just its name.
