Goal: reason about two broad objects of recorded widths under one passage, without treating differing material/action as a controlled size comparison. Proposed codes: AC9SFU02, AC9SFI01, AC9SFI03. Prepare: Model Q, change-one, optional verified matched-material broad objects, Card 56.
- Source · 3 min. Read Q as FICTIONAL MODEL. For real work adult verifies actual material/widths, same flat surface/gap and gentle action; if not matched, note differences.
- Notice · 4 min. Read R 8 cm across, S 12 cm across and drawn 9 cm passage; no local objects have been measured by this card.
- Model · 5 min. Teacher predicts R's outline could lie between lines while S's crosses; labels this geometric model, not an observed slide.
- Child try · 7 min. Card 56 asks which object-width comparison is represented and what actual check would be safe. If approved, predict then adult moves each gently one at a time and records distinct actual results.
- Check · 4 min. Ask, “If R is fabric and S card, may I say width alone caused the result?” Child notes material and any other difference; record INCOMPARABLE for a single-factor claim.
- Exit · 2 min. Keep source/date beside each actual result or NOT TESTED beside Q.