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

Video generation prompt: Ten milliliters of tomato extract containing solanine were placed in a test tube, followed by the addition of ammonium vanadate-sulfuric acid solution. The mixture was thoroughly shaken and allowed to stand.

Evaluation guide:
(i) Target concept: Colorimetric detection of glycoalkaloid solanine via vanadate-mediated oxidation in acidic environment.
Minimum mechanism: Solanine must be present in tomato extract; ammonium vanadate-sulfuric acid must be added to provide V⁵⁺ oxidant and low-pH conditions; shaking ensures molecular contact; standing allows redox reaction completion and chromophore stabilization; pink-red complex must form *only after* equilibration, not during mixing or agitation.
(ii)Storyline: [Phase 1: Setup] Test tube stationary, filled with ~10 mL pale orange tomato extract. [Phase 2: Addition] Reagent solution dispensed from separate vessel into tube; two visually distinct (but miscible) liquid layers briefly visible, not yet mixed. [Phase 3: Mixing] Tube shaken laterally; interface collapses, liquid turbulently homogenizes. [Phase 4: Equilibration] Tube returns to rest; surface calms, liquid becomes still. [Phase 5: Detection] Pink-red hue emerges uniformly across liquid column, persisting through final frames. Perspective: Fixed frontal close-up, shallow depth of field emphasizing tube center; no occlusion; full tube height always in view; lighting front-diffused to maximize color discrimination.

Manual:
Experimental Procedure
1. Place 10 mL tomato extract into a clear test tube.
2. Add ammonium vanadate-sulfuric acid solution to the tube.
3. Shake tube thoroughly.
4. Allow tube to stand undisturbed.
Observation of Experimental Phenomena
After standing, the mixture develops a distinct pink-red color, indicating solanine presence.
Summary of Experimental Principles
Solanine reacts with ammonium vanadate in acidic medium to form a pink-red complex; color intensity correlates with solanine concentration.

Prompt Grounding rubric:
level_1: Fewer than two of the five setup elements appear: test tube, tomato extract, ammonium vanadate-sulfuric acid solution, a shaking action, and a standing/settling phase. For example, only an empty tube is shown, or only a pour with no tube visible, or nothing recognizable from this procedure appears at all.
level_2: Two to four of the five setup elements appear, or all five appear but in an order that reverses the procedure's logic: e.g., the tube is shaken before the reagent is ever poured in, or it is shown standing/settled before any shaking has occurred.
level_3: All five setup elements appear in roughly the right order (extract already in the tube, reagent poured in from a separate vessel, tube shaken, tube left standing), but with a placement or continuity flaw: e.g., the reagent solution appears to already be inside the tube before any pour is shown, the tube's size or position shifts noticeably between phases, or the shaking and standing phases blur together instead of being distinct.
level_4: All five setup elements appear, correctly ordered, and the test tube keeps the same size, position, and orientation across the extract-loaded, reagent-added, shaken, and standing phases; only cosmetic imperfections remain, such as an illegible tube label, an uneven pour stream, or brief camera jitter during the shake.
level_5: All five setup elements appear, correctly ordered, and the tube's framing stays essentially unchanged throughout; in addition, the reagent is clearly poured in from a distinct source vessel rather than appearing pre-mixed, the shaking reads unambiguously as repeated tube motion (not a single jolt), and a clear, sustained motionless standing period follows before the clip ends.

Scientific and Causal Correctness rubric:
level_1: No pink-red color ever develops, or the depicted phenomenon flatly contradicts this chemistry: e.g., an immediate solid precipitate forms, gas bubbles are released, or the liquid remains completely colorless/unchanged even after standing, none of which correspond to the vanadate-solanine oxidation reaction.
level_2: A color change occurs but undermines the detection logic: e.g., color appears immediately on contact or during shaking rather than developing while standing, the resulting hue is something other than pink-red (blue, green, yellow, brown, or purple), or a color that formed during shaking fades away instead of persisting through the standing phase.
level_3: The correct pink-red hue eventually appears after standing, but with a lesser flaw: e.g., it is already faintly visible during shaking and only deepens afterward, the tomato extract and reagent look identical before mixing so no two-liquid distinction is visible, or the final color is faint or patchy rather than clearly saturated.
level_4: Tomato extract and reagent solution are visibly distinct liquids before mixing; shaking visibly homogenizes them with no color change occurring during the shake itself; the pink-red color develops only once the tube is left standing, is unambiguous, and fills the liquid column evenly; no contradictory phenomena (layer separation, foaming, persistent cloudiness) occur.
level_5: All of level 4, and the full causal chain is unambiguous: the two liquids' distinct pre-mix appearance, their homogenization during shaking, the complete absence of any color during and right after shaking, and the emergence of a saturated, uniform pink-red exclusively during the standing phase are all clearly and consistently shown, with no doubt about timing or hue.

Spatiotemporal Consistency rubric:
level_1: The test tube or its liquid contents blink out of frame and back in with no pour, shake, or camera motion to account for the change; or the liquid's fill level changes abruptly between frames with no visible action causing it; or the shaking is broken into a couple of frames of blur followed by a five-frame-or-longer freeze, repeated several times; or the room's lighting abruptly shifts between bright and dark with no lamp, hand, or camera change to explain it; or the tube rotates more than about 30 degrees with no hand or mechanical cause visible; or the camera visibly cuts or re-angles mid-action.
level_2: Two or more of the following appear: the tube's position shifts by more than about a quarter of its own width, or its tilt jumps noticeably, between the pour, shake, and standing phases instead of changing gradually; the liquid keeps sloshing for several seconds after the tube has clearly stopped moving; the shaking stutters, alternating between blurred bursts and momentary stillness rather than a steady back-and-forth; or the shadow the tube casts shifts position with no light source movement to explain it.
level_3: The tube shifts by roughly an eighth of its own width or less in position or framing between phases rather than staying perfectly put, the liquid shows one brief extra ripple (well under a second) after shaking ends before settling, or the shaking has a momentary hesitation but still reads as one continuous back-and-forth motion; none of these break the sense of a single continuous take.
level_4: The tube's position and orientation stay the same across the pour, shake, and standing phases; the liquid level changes only in ways the action explains (rising when the reagent is poured in, sloshing while shaken, flat once still); the shaking is a smooth, evenly paced back-and-forth motion; once shaking stops, the liquid settles fully and shows no further movement.
level_5: All of level 4, plus: the hand or holder driving the shake moves continuously and plausibly throughout with no sudden jump in speed or position; the liquid's sloshing visibly and smoothly dies down into stillness right as shaking ends, rather than cutting straight from turbulent to calm; and the tube's size and placement within the frame stay effectively constant from the opening shot to the closing one.