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

Video generation prompt: A 10 mL solution containing solanine from sprouted potato extract was placed in a test tube, to which sulfuric acid-potassium dichromate solution was added. The mixture was well shaken and boiled for 5 minutes.

Evaluation guide:
(i) Target concept: Oxidative colorimetric detection of solanine via acidified dichromate.
Minimum mechanism: Solanine must be present in extract; dichromate must be in acidic medium (H2SO4); oxidation requires thermal activation (boiling); product must be chromogenic (dark green-brown to brown-black) and stable post-reaction.
(ii)Storyline: [Frame 0–2s] Test tube centered, 10 mL pale yellow extract poured in → [2–4s] Orange-yellow reagent added → [4–6s] Tube shaken manually (liquid turbulently mixed) → [6–10s] Tube placed on heat source, bubbling begins, steam rises, then persistent dark green-brown to brown-black color emerges uniformly in liquid phase by final frame. All events occur from fixed frontal viewpoint; tube remains fully visible; no cuts or perspective shifts; lighting consistent; coloration must appear *only* after bubbling commences and intensifies.

Manual:
Experimental Procedure
1. Place 10 mL sprouted potato extract into a clean test tube.
2. Add sulfuric acid–potassium dichromate solution to the tube.
3. Shake tube vigorously to mix.
4. Boil mixture for 5 minutes.
Observation of Experimental Phenomena
As boiling proceeds, the mixture darkens from the reagent's original orange-yellow into a dark green-brown to brown-black tone, which persists once boiling ends.
Summary of Experimental Principles
Acidic potassium dichromate is a strong oxidant (Cr6+, orange) that oxidizes solanine while itself being reduced toward Cr3+ (green); the resulting dark green-brown to brown-black coloration, rather than one fixed brown/black hue, is the qualitative indicator of glycoalkaloid presence in food samples.

Prompt Grounding rubric:
level_1: No test tube, no potato-extract liquid, no sulfuric acid–potassium dichromate reagent, and no boiling/heating step are shown; none of the four required elements or the pour-add-shake-boil actions ever appear.
level_2: Some elements appear (for instance the test tube or the reagent bottle), but none of the four actions ever plays out: the extract is never poured into the tube, the reagent is never added, and neither shaking nor boiling occurs.
level_3: The extract is poured into the test tube, the sulfuric acid–potassium dichromate reagent is added afterward, the tube is shaken, and the mixture is then heated/boiled, but the order or timing is off in at least one respect: for example the reagent appears to go in before the extract, or the shaking is shown happening after the boiling starts.
level_4: The same four actions (pour extract, add reagent, shake, then boil) occur in exactly that order within one continuous shot, the test tube stays in view the entire time rather than cutting away and coming back changed, and no step (such as boiling) is shown out of sequence relative to the others.
level_5: That correct, continuous sequence holds, and in addition the liquid looks like a single homogeneous solution before boiling starts (no undissolved chunks), the reagent's container is visually distinguishable from the extract's container, the shaking reads as an active hand-driven swirl or back-and-forth motion rather than a static cut, the boiling shows sustained bubbling or a rising steam column, and no unrelated props (gloves, timers, extra labels) enter the frame.

Scientific and Causal Correctness rubric:
level_1: The liquid's color never changes across the whole video: it looks the same after boiling as it did when the extract and reagent were first combined, with no reaction phenomenon of any kind visible.
level_2: The liquid does change color, but to a hue unrelated to this acidic-dichromate reaction with solanine (for example a persistent blue or violet that never darkens toward green-brown or brown-black), or the color shift happens only during shaking and has faded again before boiling starts.
level_3: The liquid darkens toward a green-brown or brown-black tone only after boiling begins, but the darkening either fades back toward the original color before the video ends, appears before boiling starts, or shows up without any preceding shaking step, breaking the pour-add-shake-boil-then-darken causal chain.
level_4: That darkening appears only once boiling is underway and, unlike the case above, holds steady through to the end of the clip rather than fading, with no unrelated effects (like sudden fizzing or a separated layer) contradicting this acidic dichromate reaction with solanine.
level_5: That stable darkening holds, and further the dark green-brown/brown-black color is even throughout the liquid rather than showing floating flecks unrelated to the reaction, it visibly deepens as boiling continues, no ring of unreacted orange-yellow dichromate color remains visible at the liquid's surface or tube wall, and the tube's glass stays clear rather than clouding in an unrelated way.

Spatiotemporal Consistency rubric:
level_1: The test tube instantly relocates between shots with no travel path, the liquid level jumps up or down between frames with no pouring or spilling action to explain it, the framing swings from bright to dim lighting mid-action for no reason, the tube visibly warps or cracks and then looks intact again, or steam and bubbling appear with no heat source under the tube.
level_2: The shaking looks like a jerky stop-motion sequence rather than continuous motion, steam appears all at once with no gradual buildup, the reagent seems to pour in from off-screen with no hand or dispenser ever visible, the boiling bubbles freeze mid-frame or skip ahead, or the tube spins or tilts with no hand or force shown causing it.
level_3: One brief spatiotemporal slip occurs (for instance a short flicker as the video cuts from shaking to boiling, or the shaking hand briefly blocks the liquid surface from view), but the tube never teleports, warps, or breaks apart.
level_4: None of those problems occur: the tube stays whole and in place except for hand-driven motion, the liquid sloshes naturally during shaking and the steam rises continuously once boiling starts, the camera holds a fixed angle or pans smoothly, and the shadow the test tube casts on the bench keeps pointing in the same direction and keeps the same length from the moment the extract is poured until the tube is set onto the heat source, with no unexplained jump to a different apparent light angle.
level_5: All of that continues to hold, and further the liquid's meniscus keeps a natural curve during shaking rather than flattening or flipping unnaturally, the steam column drifts straight upward the way convection would carry it rather than veering sideways, the changing liquid color is never smeared into a trailing blur that hides the tube behind it, and the tube's glass keeps a constant, believable transparency rather than warping like a lens as the reaction proceeds.