Domain: Humanities and Social Sciences — Geography
Target concept: A wind vane or lightweight arrow will rotate with the airflow generated by the fan, aligning its direction with the air current.

Video generation prompt: On the desk, suspend a lightweight arrow-shaped ribbon with a thin string in front of a desk fan; turn on the fan and then rotate it so that the wind blows in a new direction.

Evaluation guide:
(i) Target concept: Directional alignment of a freely suspended aerodynamic indicator with local airflow vector.
Minimum mechanism: Ribbon must be low-mass, low-friction, and torque-sensitive enough to rotate freely about its suspension point; airflow must exert sufficient differential pressure on asymmetric (arrow-shaped) surface to generate net rotational torque until drag and restoring torque balance at alignment.
(ii)Storyline: [Phase 1] Static setup: ribbon hanging motionless in front of stationary, off fan. [Phase 2] Fan activation: blades spin → visible airflow onset → ribbon begins rotating. [Phase 3] Alignment: ribbon decelerates and locks into stable orientation parallel to airflow. [Phase 4] Fan rotation: fan base turns horizontally while operating → airflow vector rotates → ribbon detaches from prior alignment. [Phase 5] Realignment: ribbon rotates continuously (no reversal or hesitation) and locks into new orientation matching updated airflow vector. All phases occur in fixed-viewpoint, single-shot framing with desk, fan, and ribbon fully visible and spatially coherent throughout.

Manual:
Experimental Procedure
1. Place a desk fan on a flat desk.
2. Suspend a lightweight arrow-shaped ribbon from a thin string so it hangs freely in front of the fan.
3. Turn on the fan and observe ribbon orientation.
4. Rotate the fan horizontally to a new facing direction while running.
5. Observe how the ribbon reorients to align with the new airflow direction.
Observation of Experimental Phenomena
The ribbon rotates smoothly and stabilizes into a fixed orientation pointing along the airflow axis; after fan rotation, it reorients continuously to a new stable direction matching the fan’s new facing direction.
Summary of Experimental Principles
A wind vane or lightweight arrow will rotate with the airflow generated by the fan, aligning its direction with the air current.

Prompt Grounding rubric:
level_1: No desk, no fan, no lightweight arrow-shaped ribbon, no thin string, or no suspension setup visible; none of the required objects appear in the scene.
level_2: At least one required object is present (e.g., a fan OR a ribbon), but critical components are missing: e.g., ribbon not suspended by thin string, or fan not placed on desk, or ribbon not arrow-shaped, or no visible suspension point above desk.
level_3: All required objects are present and correctly typed: desk surface visible, desk fan placed on desk, lightweight arrow-shaped ribbon suspended by thin string directly in front of fan; ribbon is visibly distinct from fan and desk; no extraneous dominant objects occluding the setup.
level_4: All conditions for score 3 met, AND the fan is shown rotating (changing orientation) while ribbon remains suspended: rotation motion of fan is clearly visible and occurs within the video, with fan base remaining fixed on desk during rotation.
level_5: All conditions for score 4 met, AND the ribbon visibly reorients its pointing direction after fan rotation completes: new alignment direction is stable and visually distinct from initial direction; both pre-rotation and post-rotation ribbon orientations are fully visible and unambiguous within the same continuous shot.

Scientific and Causal Correctness rubric:
level_1: Ribbon shows no directional response to airflow: remains static or rotates randomly regardless of fan state; fan is off or produces no visible airflow effect; ribbon does not align with wind direction at any point.
level_2: Ribbon moves (e.g., flutters, swings, or oscillates) but never settles into a stable orientation aligned with airflow; or alignment occurs only when fan is off; or ribbon points opposite to fan’s airflow direction.
level_3: Ribbon visibly rotates and stabilizes into a single, consistent orientation while fan is running; orientation matches the direction the fan is facing (i.e., ribbon points toward fan intake or exhaust axis depending on design, but consistently along airflow vector); fan is visibly operating (blades spinning or air distortion visible).
level_4: All conditions for score 3 met, AND after fan rotation, ribbon undergoes a clear, continuous reorientation motion (not abrupt jump or teleport) and settles into a new stable orientation that matches the new fan-facing direction; both initial and final alignments are correct relative to fan orientation.
level_5: All conditions for score 4 met, AND ribbon remains motionless (no flutter, no oscillation, no drift) during stable alignment phases; reorientation occurs only during fan rotation and ceases immediately after fan stops rotating; no misalignment persisting beyond airflow stabilization time (i.e., final orientation is fully locked and sustained until fan stops).

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal violations: ribbon teleports between positions; fan disappears/reappears; lighting changes abruptly mid-video; ribbon detaches and floats away without string; desk surface fractures or warps; multiple inconsistent viewpoints (e.g., cut from overhead to extreme close-up without transition).
level_2: Major continuity flaws: ribbon string visibly breaks then reattaches; fan rotates but base shifts laterally or lifts off desk; ribbon orientation flips discontinuously (180° jump with no intermediate frames); shadow direction reverses without light source change.
level_3: All objects maintain fixed spatial relationships: ribbon hangs from fixed suspension point above desk; fan stays fully on desk throughout; ribbon string remains taut and vertically continuous; no object flickers, vanishes, or deforms unnaturally; motion is physically plausible (e.g., ribbon sways before settling, not snapping instantly).
level_4: All conditions for score 3 met, AND motion trajectories are smooth and continuous: fan rotation is steady (no jerking or stuttering), ribbon reorientation follows a natural arc (no linear sliding or pivoting around wrong axis), suspension point remains stationary, and all shadows/motion parallax remain consistent with fixed camera viewpoint.
level_5: All conditions for score 4 met, AND zero frame-level artifacts: no inter-frame tearing, no motion blur that obscures orientation, no temporal aliasing (e.g., fan blades appearing stationary due to strobing), no depth inconsistency (e.g., ribbon appearing behind fan grille when it should be in front), and no perspective shift violating fixed viewpoint constraint.