Domain: Healthcare — Nutrition and Food Hygiene
Target concept: Toxicity Detection of Abrus precatorius

Video generation prompt: Ten milliliters of legume extract containing abrin were placed in a test tube, followed by the addition of tannic acid solution. The mixture was thoroughly mixed and allowed to stand.

Evaluation guide:
(i) Target concept: Visual detection of abrin via tannic acid-mediated precipitation.
Minimum mechanism: Abrin must be present in legume extract; tannic acid must be added and mixed to enable molecular binding; standing enables gravitational settling of the resulting insoluble abrin-tannic acid complex.
(ii)Storyline: [Phase 1: Setup] Static shot of empty test tube → [Phase 2: Extraction] Legume extract poured into tube (10 mL volume implied by fill level) → [Phase 3: Reagent Addition] Tannic acid solution added (distinct stream/layer pre-mix) → [Phase 4: Mixing] Tube inverted/swirled causing homogeneous turbidity → [Phase 5: Standing] Motion stops; liquid clears slightly at top while white precipitate forms and settles downward under gravity; all observed from fixed frontal view with consistent lighting and no occlusion.

Manual:
Experimental Procedure
1. Place 10 mL legume extract containing abrin into a clear test tube.
2. Add tannic acid solution to the same test tube.
3. Mix thoroughly by gentle inversion or swirling.
4. Allow mixture to stand undisturbed.
Observation of Experimental Phenomena
A cloudy white precipitate forms and gradually settles to the bottom of the test tube during standing.
Summary of Experimental Principles
Tannic acid binds abrin (a toxic lectin from Abrus precatorius), forming an insoluble complex detectable as visible precipitate — a classic qualitative test for abrin presence in food hygiene and toxicology screening.

Prompt Grounding rubric:
level_1: No test tube appears; no legume extract is visible; no tannic acid solution is visible; no mixing is shown; no standing/settling phase is shown; none of the prompt's core elements (test tube, legume extract, tannic acid solution, mixing, standing) appear in the clip.
level_2: At least one of the core objects is present (the test tube, or the legume extract, or the tannic acid solution), but none of the actions (adding the extract, adding the tannic acid, mixing, letting it stand) are shown; the order is missing or reversed; at least three of the five core elements are absent.
level_3: The test tube holds liquid; the legume extract is shown going into the test tube; the tannic acid solution is added to that same tube; the tube is visibly agitated (mixing); the liquid is then left undisturbed for a stretch of time (standing); all five steps from the prompt appear in that order.
level_4: All conditions for score 3 are met, and the test tube stays upright and in place throughout; the legume extract and the tannic acid solution look visibly different from each other before they're mixed (different color or clarity); the mixing motion stays inside the tube's boundaries; once standing begins, the liquid surface stops moving.
level_5: All conditions for score 4 are met, and the legume extract clearly goes into the tube first, the tannic acid solution clearly goes in second, the mixing clearly starts right after the tannic acid is added, and the standing phase clearly starts right after the mixing stops, with none of these four steps shown out of order, skipped, or visibly overlapping each other.

Scientific and Causal Correctness rubric:
level_1: No visible reaction occurs at all: no change in cloudiness or color, and the liquid stays clear the whole time; or a precipitate appears even though no tannic acid was ever added; or a precipitate appears before the mixing step happens.
level_2: A precipitate does appear, but not tied to the mixing-then-standing sequence: for example it shows up before the tannic acid is added, or while the tube is still being actively mixed rather than during standing, or it looks the same color and clarity as the surrounding liquid with no visible contrast.
level_3: After the mixing stops and the standing phase begins, a visible precipitate appears as distinct solid particles or a cloudy suspension that stands out from the surrounding liquid; the precipitate stays inside the tube and does not dissolve or scatter back into the liquid during standing.
level_4: All conditions for score 3 are met, and the precipitate only appears once mixing has stopped and standing has begun, not during the mixing itself; it looks noticeably denser or more opaque than the liquid around it; it visibly moves downward over time as it settles.
level_5: All conditions for score 4 are met, and the precipitate only ever forms once both the legume extract and the tannic acid solution have been combined (it never appears if either one is shown missing from the tube), and it has the granular, cloudy look of a settling solid rather than a smooth color change or a crystal-clear liquid.

Spatiotemporal Consistency rubric:
level_1: The test tube suddenly appears in a different position or vanishes and reappears; the liquid's level jumps without any pouring or spilling to explain it; the lighting or shadows swing wildly for no reason; the tube looks like it cracks and then is whole again; the mixing motion suddenly reverses direction with no visible cause.
level_2: The test tube tips or spins more than about 30° off its upright position; the liquid's surface curves the wrong way (bulging upward oddly) during the standing phase; the mixing motion appears to come from outside the tube and pass through its wall; the standing liquid trembles or ripples on its own with nothing touching it.
level_3: The test tube stays upright and in the same place in the frame; the amount of liquid inside stays constant, with no evaporation or spilling; the mixing motion stays confined to the inside of the tube and looks continuous; once standing begins, the only motion visible is the precipitate slowly settling; there are no sudden light or shadow changes and the tube never appears to warp.
level_4: All conditions for score 3 are met, and the camera view never pans, tilts, or zooms; the test tube keeps the same orientation and position across the whole clip; the liquid's surface stays curved the normal way (slightly concave) once standing begins; the precipitate moves downward smoothly and in one direction only.
level_5: All conditions for score 4 are met, and the transition from mixing to standing looks physically natural (the swirling motion slows down and stops before the tube goes still), and the precipitate first appears somewhere in the liquid and then sinks downward, with no repeated or frozen-looking frames anywhere in the clip.