Goal: keep a raw trial record and label an interrupted run without silently treating it as a valid stop. Proposed codes: AC9SFI02, AC9SFI03, AC9SFI05. Prepare: M's fifth entry, four-run sheet, optional adult-pretested apparatus, Card 93.
- Safety gate · 3 min. Adult verifies tray, lip, carton, supervision and quiet access, or selects M only. Children may observe or use description without touching.
- Read · 4 min. Read M fifth entry: carton tipped and touched the rim. Say it is invented and marked INTERRUPTED.
- Model · 5 min. Teacher preserves the raw entry but excludes it from valid-stop comparison; model a cautious reason, not “it would have reached STOP.”
- Child try · 7 min. Card 93 routes classify VALID versus INTERRUPTED from a labelled paper entry; if genuine safe rehearsal occurs, record date, apparatus and what actually happened separately.
- Check · 4 min. Offer “Cross out the tipped run so our record looks neat.” Child keeps it, labels it, and asks whether a safe repeat is possible.
- Exit · 2 min. Save raw/unrevised record; a rehearsal alone is not a four-run comparison.