Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Oxidative Degradation of Photosensitive Drugs

Video generation prompt: Take 1 mL of riboflavin solution and place it into two transparent test tubes. The left test tube is exposed to strong light, while the right test tube is wrapped in black cloth to avoid light exposure. After 30 minutes of continuous light exposure, observe and compare the two test tubes.

Evaluation guide:
(i) Target concept: Photochemical oxidative degradation of riboflavin as a model photosensitive drug.
Minimum mechanism: Riboflavin in aqueous solution absorbs visible light → generates reactive oxygen species → cleaves conjugated isoalloxazine ring → loss of yellow color; absence of light prevents initiation of degradation cascade.
(ii)Storyline: Frame 1–2: Two identical transparent test tubes enter static side-by-side composition; both contain yellow liquid at equal fill level. Frame 3–4: Opaque black cloth is fully applied to right tube, covering entire surface; left tube remains fully exposed. Frame 5–10: Illumination activates on left tube only; yellow color progressively lightens uniformly across left tube volume; right tube yellow intensity remains constant and uniform; final frame shows stable contrast between lightened left and saturated yellow right tube — all under fixed viewpoint, no occlusion, no motion beyond natural settling.

Manual:
Experimental Procedure
1. Take 1 mL of yellow riboflavin solution and dispense equally into two identical transparent cylindrical test tubes.
2. Place tubes side-by-side in fixed view: left tube uncovered, right tube fully wrapped with opaque black cloth.
3. Illuminate left tube with strong light (e.g., direct sunlight or a bright lamp) for 30 minutes; ensure right tube receives zero direct or indirect light during this period.
Observation of Experimental Phenomena
After 30 minutes of continuous light exposure: left tube liquid becomes visibly lighter yellow; right tube liquid retains original intense yellow color.
Summary of Experimental Principles
Riboflavin undergoes oxidative degradation when exposed to light, causing loss of yellow chromophore; light exclusion prevents degradation, preserving color.

Prompt Grounding rubric:
level_1: Scene does not show two transparent test tubes of yellow riboflavin solution positioned side by side; the test tubes, the riboflavin solution, or the black cloth are missing entirely, or only a single tube appears with no left/right pair.
level_2: A yellow riboflavin solution appears in two test tubes, but the setup fails the described conditions in an unambiguous way: the tubes are placed one behind the other or stacked rather than side by side, or the black cloth is missing from both tubes, or the black cloth is wrapped around the left (light-exposed) tube instead of the right tube.
level_3: Two transparent test tubes filled with yellow riboflavin solution to matching levels sit side by side under a fixed camera view; the left tube is uncovered and visibly lit; the right tube is entirely wrapped in opaque black cloth from its base to its rim; no other containers, tools, or liquids appear in frame.
level_4: All conditions for score 3 are met, and additionally: the black cloth on the right tube shows no visible light leaking through its weave, the two test tubes match each other in diameter, height, and glass appearance, and neither tube is picked up, tilted, or moved from its initial position for the remainder of the video.
level_5: All conditions for score 4 are met, and additionally: the left tube remains completely uncovered in every frame with no shadow, hand, or object briefly obstructing it, the black cloth on the right tube stays fully closed with no gap opening at the neck or base at any point, and the two tubes keep the same left/right spacing and orientation from the first frame to the last.

Scientific and Causal Correctness rubric:
level_1: Neither tube's liquid changes color across the video (both stay the same saturated yellow throughout), or the liquid in either tube turns a hue that riboflavin photodegradation cannot plausibly produce (blue, green, or an opaque/cloudy white), regardless of which tube this happens in.
level_2: One tube's liquid visibly fades or shifts within a plausible yellow-to-brown/orange/near-colorless range, but the effect is scientifically backwards or non-informative: the cloth-wrapped right tube fades while the light-exposed left tube stays fully saturated, or both tubes fade or darken by a similar, indistinguishable amount.
level_3: The light-exposed left tube's liquid visibly lightens from strong yellow to a noticeably paler yellow, while the cloth-wrapped right tube's liquid keeps its original strong yellow with no perceptible fading; a stable color difference between the two tubes is visible by the end of the video.
level_4: All conditions for score 3 are met, and additionally: the left tube's lightening proceeds in one direction only (it never darkens back toward the original yellow or flips between shades), and neither tube's liquid shows an added hue, such as a greenish or brownish tint, beyond a simple yellow-to-pale-yellow fade.
level_5: All conditions for score 4 are met, and additionally: the left tube's liquid fades evenly across its whole volume rather than only near the surface or only near the light source, and the right tube's liquid shows no visible fading anywhere in its volume, keeping the same yellow intensity from first frame to last.

Spatiotemporal Consistency rubric:
level_1: Either test tube disappears, relocates, or is replaced by a different object between frames; the black cloth appears or vanishes abruptly instead of being present throughout; the liquid level in either tube jumps up or down between frames; the lighting flashes, strobes, or cuts to a sudden blackout with no cause; or the camera view cuts or jumps to a different angle mid-video.
level_2: Both tubes stay in frame but visibly warp, bend, or change shape at some point; the black cloth flickers on and off or partially disappears mid-video and then reappears; or the liquid surface shows unnatural motion such as sudden sloshing, splashing, or floating upward that is unrelated to the tubes simply sitting still.
level_3: Both test tubes stay visible and in the same side-by-side positions throughout the video; the black cloth stays fully wrapped around the right tube without loosening or slipping; the liquid surfaces in both tubes stay flat and at a constant height; overall scene brightness stays steady rather than flashing or suddenly dimming on one tube only.
level_4: All conditions for score 3 are met, and additionally: the edge of the black cloth stays aligned with the right tube's outline in every frame rather than floating apart from it or overlapping the tube inconsistently, and any shadow cast by the light source falls in a direction consistent with a single fixed light across both tubes, not appearing under one tube's base while absent under the other's.
level_5: All conditions for score 4 are met, and additionally: the visible meniscus (liquid surface line) in each tube stays at a constant height and shape across the full video with no sudden shift that makes it hard to tell where the liquid ends and air begins, and both tubes stay equally in focus throughout, with neither tube going soft or blurry while the other stays sharp.