One result can fit different explanations. Look for plausible alternatives and a test where they predict different observations. These invented case data practise reasoning; no experiment is claimed. Safety: Paper analysis only. Any later practical repeat needs separate adult approval and a low setup. Stop: End at a proposed repeat. Do not perform an unapproved test or write an imagined result as an observation.

Materials: Paper; Pencil; Two colouring pencils 1. Copy this illustrative case: A paper bridge fell when a pencil was placed on it. The observer did not measure the book gap or check whether a paper end slipped off. Draw the two books, bridge and pencil. 2. Write explanation A: the unsupported paper bent too much. Write explanation B: a paper end slipped off a support. Circle the observation that both explanations must fit: the bridge fell. 3. Under each explanation draw what you would look for during a repeat: A, paper bends in the middle while both ends stay supported; B, an end moves off its book before the fall. Mark both as predictions, not results. 4. Plan one safe repeat using stable books on the floor, a measured gap and a marked overlap line on each end. State that an adult would watch the ends and middle. No repeat is required today. 5. Now use this new illustrative clue: Both paper ends stayed on the books while the centre bent down. Choose which explanation this supports better. Say what remains uncertain, such as paper thickness or damage. Done: Two alternatives, their different predicted clues and a reasoned choice from the supplied new clue are recorded. Proof: Keep the annotated sketch and repeat-test plan. Note adult suggestions of alternatives; label all case data illustrative. Stop: End at a proposed repeat. Do not perform an unapproved test or write an imagined result as an observation.