Domain: Healthcare — Nutrition and Food Hygiene
Target concept: Aluminum Detection

Video generation prompt: Ten milliliters of noodle extract containing alum were placed in a test tube, followed by the addition of barium chloride solution and hydrochloric acid. The mixture was thoroughly shaken and allowed to stand.

Evaluation guide:
(i) Target concept: Visual confirmation of sulfate-derived aluminum contamination via BaSO₄ precipitation under acidic conditions.
Minimum mechanism: Presence of soluble sulfate (from alum) + Ba²⁺ source + H⁺ (to suppress interference from CO₃²⁻/PO₄³⁻) → immediate formation of insoluble, white, non-colloidal BaSO₄ that settles under gravity.
(ii)Storyline: [Frame 0–2] Static shot: upright test tube containing ~10 mL pale/transparent noodle extract. [Frame 3–4] First addition: clear liquid (barium chloride) dispensed into tube; meniscus rises, no immediate change. [Frame 5–6] Second addition: clear liquid (HCl) dispensed; meniscus rises again, no reaction. [Frame 7–8] Vigorous shaking: tube oscillates, liquid sloshes with coherent surface deformation. [Frame 9–10] Immediate cessation → tube held still → white granular precipitate emerges at bottom over ~1 second and remains fully settled; supernatant stays optically clear. Perspective: fixed frontal view, centered on tube, full tube height visible; no occlusion; lighting uniform and front-diffused to ensure precipitate visibility.

Manual:
Experimental Procedure
1. Place 10 mL noodle extract (alum-containing) into a clear test tube.
2. Add barium chloride solution dropwise.
3. Add dilute hydrochloric acid dropwise.
4. Shake tube thoroughly.
5. Stand tube upright and observe.
Observation of Experimental Phenomena
A dense white precipitate forms and settles at the bottom of the tube after standing; supernatant remains colorless and transparent.
Summary of Experimental Principles
Alum (KAl(SO₄)₂·12H₂O) provides sulfate ions; barium chloride provides Ba²⁺; in acidic medium (HCl), Ba²⁺ reacts with SO₄²⁻ to form insoluble white barium sulfate (BaSO₄) precipitate — confirming aluminum-associated sulfate presence.

Prompt Grounding rubric:
level_1: No test tube is visible; no noodle extract liquid is shown in it; no barium chloride solution or hydrochloric acid appears at any point; no shaking motion occurs; no standing/settling phase occurs; none of the objects or actions called for in the prompt appear on screen.
level_2: At least one required item appears (for example the test tube, or some liquid inside it), but three or more of the following are missing: the noodle extract, the barium chloride solution, the hydrochloric acid, a visible addition of either reagent, a shaking action, or a standing/settling phase; the order in which any of these appear is unrecognizable or reversed from addition-addition-shake-stand.
level_3: The test tube holds the noodle extract; both the barium chloride solution and the hydrochloric acid are shown being added as two separate liquid additions; a shaking action follows the additions; a standing phase follows the shaking; all four steps (add barium chloride, add HCl, shake, stand) occur in that order, but at least one of the two added reagents is not visually distinguishable from the extract or from each other (e.g., both look like plain colorless water with no separate dispensing visible).
level_4: The test tube contains the pale, transparent noodle extract, and the barium chloride solution and hydrochloric acid are each shown as their own separate, visually distinct addition (no sudden color shift on adding either one); shaking is clearly shown by liquid motion inside the tube; the standing phase is clearly shown by the tube going still; the four-step order is correct throughout; no object teleports or duplicates on screen.
level_5: Everything described above holds, and in addition the two reagents are dispensed from two visibly different tools (e.g., separate droppers or pipettes, not the same one reused); shaking begins only after both additions are complete, with no premature shaking; the standing phase shows the tube sitting undisturbed for at least a second and a half with no visible tube movement, hand movement, or repositioning; the tube stays in the same spot and orientation for the entire sequence.

Scientific and Causal Correctness rubric:
level_1: No precipitate ever forms; the liquid stays fully transparent through every step, with no cloudiness and no color change, so nothing matching the expected barium-sulfate reaction is shown.
level_2: A precipitate appears, but of the wrong kind: for example it is colored (blue, green, or yellow), it floats as foam, or it dissolves right back into the liquid; or a precipitate appears before the barium chloride has been added; or it appears only right after shaking with no standing phase shown at all.
level_3: A white precipitate appears only after shaking and only during or after the standing phase; it does not redissolve and settles toward the bottom of the tube; the liquid above it stays colorless; the causal chain holds (barium chloride reacting with the sulfate carried by the alum in the extract yields insoluble barium sulfate), though the precipitate may appear a little before the standing phase fully finishes, or a small amount stays suspended longer than expected.
level_4: The white precipitate appears only after shaking and becomes clearly visible only during the standing phase, as described above; in addition, it looks dense and granular and fully settles to the bottom; the liquid above it stays colorless and clear; no false phenomena appear (no bubbles, no oily layer, no cloudiness unrelated to the barium sulfate); the causal chain is intact from both reagents being present, through mixing by shaking, to the precipitate becoming visible on standing.
level_5: The precipitate behaves as described above, and in addition it collects mainly in the bottom third of the tube rather than spreading through the middle or floating near the top; no suspended particles remain in the liquid above it by the final standing frames; the precipitate looks uniformly fine-grained, without clumps, crystal facets, or fibrous strands; neither the liquid nor the precipitate takes on any yellow or brown discoloration at any point.

Spatiotemporal Consistency rubric:
level_1: The test tube holding the noodle-extract mixture vanishes from view and reappears later in the clip; the liquid inside jumps from one level or position to another with no visible pour or shake causing it; the lighting switches abruptly mid-sequence with no reason shown; the tube rotates more than about 30 degrees with no hand or tool ever touching it; the background changes abruptly; the sequence cuts repeatedly in ways that break the sense of continuous time.
level_2: One clear spatiotemporal flaw appears: the tube's position changes between the addition step and the shaking step with no hand visibly moving it; the liquid level changes with no addition or shaking to explain it; the shadow the tube casts swings to point a different way with no cause; the lighting flickers across several consecutive frames; or the camera zooms in or out abruptly with no smooth transition.
level_3: The test tube neither disappears nor breaks apart on screen; it stays continuously visible and in the same general spot; the liquid inside moves the way a real liquid would during shaking (no rigid sloshing, no impossible bounce-back); the tube's cast shadow keeps roughly the same direction and softness across the sequence; every action (adding, shaking, standing) flows as one continuous take or a clean cut, and any jitter in the tube's position is faint enough to go unnoticed on casual viewing.
level_4: The scene holds together as described above, and in addition the shaking shows natural liquid sloshing rather than a rigid, undamped swing back and forth; during the standing phase the tube appears visibly stationary at its base, with no drift across the several final frames; there is no ghosting, warping, or perspective shift anywhere during the motion.
level_5: The scene holds together as described above, and in addition the tube remains visibly upright throughout, without ever appearing to lean or tip to one side; the liquid's surface stays visibly steady and unchanging in shape during the standing phase, with no shimmer, rippling, or apparent evaporation; the lighting stays steady in brightness throughout, with no visible flicker.