Domain: Natural Science — Physics
Target concept: Shine a flashlight on a transparent glass cup and a ceramic cup to verify that the transparent cup allows all light to pass through, while the ceramic cup casts a dark shadow on the wall.

Video generation prompt: Place a transparent glass cup and an opaque ceramic cup upright against a wall. Hold a flashlight at the same distance and orientation, and direct the beam of light through each cup toward the wall in succession. Clearly demonstrate the switching between the two cups and the path of the flashlight beam.

Evaluation guide:
(i) Target concept: Light transmission through transparent media versus light obstruction by opaque media.
Minimum mechanism: Incident light must travel in straight-line path; wall must serve as uniform projection surface; cups must be static and non-emissive; ambient lighting must be low enough to isolate beam effect.
(ii)Storyline: [0–3s] Two upright cups placed side-by-side against wall; flashlight enters frame, held steady. [3–6s] Beam directed through glass cup → bright spot appears on wall, aligned with cup opening. [6–10s] Glass cup removed; ceramic cup placed in identical position; same beam directed → dark shadow appears on wall, matching cup silhouette. Perspective: Fixed frontal view; wall fills lower 2/3 of frame; cups centered horizontally; flashlight visible in upper third, partially occluded by hand; no camera motion or zoom.

Manual:
Experimental Procedure
1. Place transparent glass cup and opaque ceramic cup upright, adjacent to each other, against a plain wall.
2. Hold flashlight at fixed distance and orientation; direct beam through glass cup onto wall → observe result.
3. Remove glass cup; replace with ceramic cup in same position; direct same beam onto wall → observe result.
Observation of Experimental Phenomena
- With glass cup: bright, well-defined illuminated area appears on wall.
- With ceramic cup: solid dark shadow appears on wall, sharply bounded.
Summary of Experimental Principles
Transparent materials allow light to pass through; opaque materials block light, casting shadows — demonstrating light transmission vs. absorption.

Prompt Grounding rubric:
level_1: No upright cups visible; no flashlight present; no wall background; no sequential illumination of two distinct cups; no side-by-side or adjacent placement shown.
level_2: At least one cup and flashlight appear, but cups are not both upright against a wall; or only one cup is shown; or flashlight beam is not directed toward the wall; or cups are not clearly differentiated by material (e.g., both look identical or both translucent/opaque).
level_3: Two upright cups placed adjacent to each other against a wall; flashlight held at consistent orientation and distance; beam visibly directed toward wall in sequence; two distinct cup types (one transparent, one opaque) are present and spatially separated in frame.
level_4: All conditions for score 3 satisfied, AND the switching between cups is visually unambiguous (i.e., one cup fully occludes beam path before removal and replacement with other cup: no simultaneous dual-cup illumination; no overlap or stacking); flashlight remains stationary in position/orientation across both trials.
level_5: All conditions for score 4 satisfied, AND the two cups are shown in fixed side-by-side spatial relationship throughout entire video; flashlight never moves its base position or tilt angle; beam originates from same point and maintains identical divergence/convergence appearance across both trials; no cut, jump, or repositioning between cup trials.

Scientific and Causal Correctness rubric:
level_1: No light transmission or shadow formation observed; both cups produce identical wall effects (e.g., both cast dark shadows or both show bright spots); or wall shows no change when cups are illuminated.
level_2: One cup produces a bright spot on wall, the other produces a dim or diffuse spot, but no clear dark shadow; or shadow appears under transparent cup; or brightness difference is inconsistent with material properties (e.g., ceramic cup shows high transmission).
level_3: Transparent cup allows light to pass: bright, well-defined illuminated area appears on wall; ceramic cup blocks light: distinct dark shadow with sharp boundary appears on wall; both phenomena occur sequentially and are visually separable.
level_4: All conditions for score 3 satisfied, AND the illuminated area behind transparent cup is continuous and uniformly bright (no internal distortion or unexpected dark regions); the shadow behind ceramic cup is solid black or near-black with no light leakage or penumbra blurring that contradicts opacity.
level_5: All conditions for score 4 satisfied, AND the illuminated area behind transparent cup matches expected shape/size of cup opening (e.g., circular if circular cup mouth); the shadow behind ceramic cup matches exact outer silhouette of cup (no scaling, warping, or misalignment); no ambient light contamination (e.g., no secondary illumination on shadow region or wall outside beam path).

Spatiotemporal Consistency rubric:
level_1: Cups teleport between frames; flashlight disappears/reappears; wall geometry distorts; cup orientation flips abruptly; light beam discontinuously jumps or flickers on/off without motion cause.
level_2: Cup or flashlight exhibits unnatural stretching/compression; beam appears/disappears without hand motion; shadow shifts independently of cup movement; wall surface texture changes mid-sequence; lighting environment fluctuates (e.g., room lights turn on/off).
level_3: Cups remain upright and stable in position; flashlight is held steadily; beam travels continuously from source to wall; shadow forms only when ceramic cup is in place and vanishes when removed; illuminated spot appears only when transparent cup is in place and vanishes when removed.
level_4: All conditions for score 3 satisfied, AND spatial relationships are preserved: cups stay adjacent and upright; flashlight maintains fixed relative position to both cups; beam origin stays anchored to flashlight head; shadow and illuminated spot appear exclusively on wall surface (not floating or detached).
level_5: All conditions for score 4 satisfied, AND motion is physically plausible: hand holding flashlight shows natural micro-stillness (no jitter or float); cup placement/removal occurs via smooth linear translation (no sliding, floating, or rotation during transfer); beam propagation shows continuous luminance gradient from source to wall; no inter-frame object clipping or occlusion inconsistency.