Domain: Natural Science — Physics
Target concept: The expansion of the liquid in a glass thermometer placed in warm water and cold water

Video generation prompt: A glass thermometer is first placed into a cup of warm water, then moved to a cup of cold water containing ice, and finally returned to the warm water.

Evaluation guide:
(i) Target concept: Thermal expansion and contraction of liquids in response to temperature change, mediated by molecular kinetic energy.
Minimum mechanism: Glass thermometer contains a thermally responsive liquid (e.g., alcohol or mercury) sealed in a narrow capillary tube; glass envelope conducts heat to liquid; liquid volume changes cause meniscus displacement along calibrated scale.
(ii)Storyline: Frame 1–3: Thermometer fully visible outside cups. Frame 4–6: Thermometer descending into warm water cup → liquid column begins rising continuously. Frame 7–9: Thermometer lifted and moving laterally → column holds position mid-rise. Frame 10–12: Thermometer descending into cold water cup → column falls continuously. Frame 13–15: Thermometer lifted and moving laterally → column holds mid-fall. Frame 16–18: Thermometer descending into warm water cup again → column rises continuously, returning toward the same peak level reached during the first warm-water placement (a thermometer reads only the current water temperature and has no memory of prior readings, so it should not settle higher than before). All transitions require full visibility of thermometer bulb and liquid column; fixed frontal camera angle; no occlusion; cups must remain side-by-side in same plane throughout.

Manual:
Experimental Procedure
1. Place glass thermometer vertically into warm water cup.
2. Remove thermometer and immediately place it vertically into cold water cup containing visible ice.
3. Remove thermometer and immediately return it vertically into warm water cup.
Observation of Experimental Phenomena
- Liquid column rises in warm water (first placement).
- Liquid column falls in cold water (second placement).
- Liquid column rises again in warm water (third placement), returning to approximately the same level reached after the first placement, since the warm water is at the same temperature both times and the thermometer has no memory of its prior reading.
Summary of Experimental Principles
Thermal expansion: liquid in the thermometer expands when heated (rises in warm water) and contracts when cooled (falls in cold water); the final reading depends only on the current water temperature and equilibration time, not on the thermometer's history, so repeated immersion in the same-temperature water yields the same reading each time.

Prompt Grounding rubric:
level_1: No glass thermometer is visible anywhere, or no cup of warm water and no cup of ice water are shown, or the thermometer is never placed into any cup.
level_2: A cup and a thermometer-like object both appear, but the thermometer is never actually placed into any liquid; or only one of the two required cups (warm or ice) appears; or the cold cup contains no visible ice; or the sequence of placements is missing or too unclear to identify.
level_3: The glass thermometer, a cup of warm water, and a cup of cold water with visible ice cubes are all shown; the thermometer is placed into the warm water first, then moved to the ice water, then returned to the warm water, with all three placements occurring in that order and none skipped or shown out of sequence.
level_4: Everything required for score 3 holds, and additionally: the thermometer stays fully visible (not blocked by a hand or the cup rim) during all three placements; both cups stay in the same spot relative to each other the whole time; the thermometer is held vertically the same way at each placement; no unrelated objects (extra tools, a second thermometer, etc.) appear in the shot.
level_5: Everything required for score 4 holds, and additionally: the thermometer's bulb is fully underwater each time it is placed in a cup, never left partly above the surface; the ice in the cold cup is still visibly present and not fully melted by the time the thermometer leaves it; the warm water cup shows no steam or fogging suggesting near-boiling water rather than merely warm water; the thermometer and cups appear only once each, with no duplicated or mirrored copies anywhere in frame.

Scientific and Causal Correctness rubric:
level_1: The liquid column shows no visible movement at all across every immersion, or it rises when the thermometer enters the ice water and falls when it enters the warm water (directions reversed), or no liquid column is visible in the capillary at any point.
level_2: The liquid column changes in only one of the three immersions (e.g., only during the first warm-water dip) while staying flat during the others; or it moves the wrong way during at least one immersion (e.g., dropping when placed in warm water); or the column vanishes and reappears at a different height rather than moving there continuously; or its color is implausible for a lab thermometer (e.g., bright blue liquid with a mercury-silver bulb) with no visual explanation.
level_3: The liquid column rises when the thermometer is dipped into the warm water (first and third placements) and falls when it is dipped into the ice water (second placement); the liquid keeps the same recognizable color (e.g., red-dyed alcohol or silvery mercury) across all three placements; the direction of movement never reverses out of sequence with the placements.
level_4: Everything required for score 3 holds, and additionally: the column's rise on first entering the warm water and its fall on entering the ice water are both large, visibly proportional to the sizeable temperature gap being crossed; the column's movement during each of the three immersions is continuous, without jumping ahead or freezing partway.
level_5: Everything required for score 4 holds, and additionally: once each immersion is held long enough to stabilize, the liquid column settles at essentially the same height after the third (final) warm-water placement as it did after the first warm-water placement, rather than settling higher or lower, since the reading tracks only the current water temperature; the column shows no overshoot or bounce past its settled height during any of the three stabilization phases; the meniscus stays aligned with visible scale markings throughout.

Spatiotemporal Consistency rubric:
level_1: The thermometer or a cup vanishes and reappears between shots with no hand or motion carrying it there; a cup's position jumps by more than half its width between one moment and the next with no visible movement; the room lighting swings from bright to dark and back with no apparent cause; the thermometer or a cup bends or fractures in a way glass cannot.
level_2: The thermometer reappears displaced by more than about 1 cm from where it just was, with no visible path getting it there; a cup rotates or tilts by more than about 15 degrees between placements without any hand moving it; the shadows cast by the cups or thermometer point a different way after a cut than before, with nothing in the scene to explain the change; the background flickers or warps briefly during a transition.
level_3: The thermometer travels along a continuous, visible path each time it moves between the warm cup and the cold cup; both cups stay in the same spot and orientation throughout; the shadows the thermometer and cups cast keep pointing the same direction and keep roughly the same darkness across the whole sequence; nothing about the thermometer, cups, or liquid inside them stretches, clips, or warps.
level_4: Everything required for score 3 holds, and additionally: the thermometer moves straight from one cup toward the next without doubling back or hesitating partway; the distance between the two cups stays visually the same throughout; there is no visible repeating or stuttering of the view during any transition; the camera stays put with no pan, tilt, or zoom.
level_5: Everything required for score 4 holds, and additionally: the thermometer's speed as it moves between cups looks like a natural hand movement (no sudden bursts of speed or long frozen holds); the reflections and highlights on the glass thermometer and cups shift in a way consistent with a fixed light source and viewpoint rather than sliding independently; the thermometer's scale markings and the liquid meniscus stay clearly legible without warping or streaking as the thermometer moves.