Domain: Natural Science — Chemistry
Target concept: Reaction of Ethanol with Acidic Potassium Dichromate Solution

Video generation prompt: A test tube containing orange acidic potassium dichromate solution is treated with ethanol solution and then shaken.

Evaluation guide:
(i) Target concept: Redox-driven color change from Cr(VI) to Cr(III) in acidic aqueous medium, triggered by ethanol addition and enabled by mechanical mixing.
Minimum mechanism: Ethanol must be introduced *into* the orange solution (not alongside), and molecular contact + agitation must occur to enable electron transfer; color change requires sufficient reaction time *during* agitation and manifests as homogeneous green hue replacement of orange: no intermediates, no reversibility, no side products visible.
(ii)Storyline: [Frame 0–2] Static shot: upright test tube filled 1/3–1/2 with uniform orange liquid; no motion. [Frame 3–4] Ethanol solution enters tube from above via clear delivery tool (e.g., dropper), fully within frame; liquid level rises visibly. [Frame 5–6] Delivery tool withdraws; the tube sits briefly undisturbed with the liquid still orange; no color change has started yet. [Frame 7–10] Tube undergoes rhythmic back-and-forth shaking; liquid sloshes continuously; orange hue progressively diminishes and green hue uniformly emerges and dominates by final frame. Perspective: fixed frontal view, centered on tube, no occlusion, consistent lighting.

Manual:
Experimental Procedure
1. Place a clean test tube containing orange acidic potassium dichromate solution on stand.
2. Add ethanol solution dropwise into the test tube.
3. Cap and shake the test tube vigorously for several seconds.
Observation of Experimental Phenomena
The orange solution gradually turns green during shaking; no gas evolution, precipitate, or temperature change is visible.
Summary of Experimental Principles
Acidic potassium dichromate (K₂Cr₂O₇/H⁺) oxidizes ethanol to acetaldehyde (and further to acetic acid), reducing orange Cr(VI) to green Cr(III) ions — a definitive redox colorimetric indicator.

Prompt Grounding rubric:
level_1: No test tube is shown; there's no orange liquid in view; no ethanol solution is added; and no shaking of a tube happens; none of these four required elements (tube, orange solution, ethanol, shaking) appear.
level_2: A test tube (or similar container) appears, but the liquid inside is the wrong color (yellow, red, brown, or colorless instead of orange), or no ethanol is ever visibly added (no dropper, no pipette, no pour), or the tube undergoes some other motion (stirring, pouring out, spinning) instead of the back-and-forth shaking the procedure calls for.
level_3: A clear test tube holding an orange liquid is shown; a second, colorless liquid (ethanol) is visibly added into the tube from a dropper, pipette, or by pouring; afterward, the tube is shaken: visible back-and-forth or circular motion of the tube with liquid inside.
level_4: Everything in score 3 holds, and additionally: the ethanol is added just once from a clearly separate source (a labeled dropper or a second vial, not the same container as the orange solution); the tube stays fully in view during shaking, with no hand blocking the liquid, and the liquid visibly sloshes in time with the tube's motion.
level_5: Everything in score 4 holds, and additionally: the ethanol is fully added before any shaking starts: the last drop lands and only then does the shaking begin, with no overlap between the two; there's no extra action (wiping the tube, repositioning it, adding anything else); the camera holds one fixed framing on the tube throughout, with no cut, zoom, or reframing.

Scientific and Causal Correctness rubric:
level_1: The liquid stays orange from start to finish; no color shift happens at all, and nothing on screen suggests the ethanol addition is doing anything to the solution.
level_2: The liquid does change color, but not the right way: it turns blue, purple, black, yellow, or colorless instead of green; or it turns green before the ethanol is added or while it's still being poured in, rather than afterward; or the change happens as an instant cut with no visible transition, so it's unclear what caused it.
level_3: The orange liquid turns green only after the ethanol has been added, with the shift happening during or after the shaking; the green appears and settles throughout the body of the liquid, not just as a thin layer at the surface or edges; no other implausible color (red, brown, violet) shows up along the way.
level_4: Everything in score 3 holds, and additionally: the green ends up even throughout the liquid rather than in patches or separate layers; the color goes orange to green exactly once, with no partial reversal back toward orange or a further shift to some other color; the color change stays confined to the liquid itself, with no tinting of the tube wall, the meniscus, or any vapor above the liquid.
level_5: Everything in score 4 holds, and additionally: once green, the color holds steady for the rest of the clip with no fading or washing out; the whole column of liquid, top to bottom and center to edge, reads as the same green; nothing in the lighting or reflections makes any part of the tube falsely look green before the reaction actually reaches it; the color only starts shifting once shaking begins and keeps progressing while shaking continues, with no change before shaking starts or after it stops.

Spatiotemporal Consistency rubric:
level_1: Between one frame and the next, the test tube's position, size, or angle suddenly changes with no motion connecting the two, as if it jumped there; the framing zooms in abruptly mid-shake with no transition; the lighting or shadows flip from one look to a completely different one between frames; the liquid surface stays frozen while the tube keeps moving, or the tube stays put while the liquid keeps sloshing on its own.
level_2: The tube rotates more than a quarter turn with no visible pivot behind it; the liquid surface looks static while the tube is clearly accelerating, or sloshes around with no matching tube motion; the screen suddenly goes from bright to dark (or the reverse) with nothing to explain it; the glass or liquid briefly looks broken, cracked, or oddly see-through in a way that doesn't hold together.
level_3: The tube moves as one solid object throughout; the liquid inside deforms and flows in step with the tube's motion; there's no impossible spins and the liquid never freezes while the tube keeps moving; the lighting and shadows look the same in direction and brightness from beginning to end; nothing looks like a rendering glitch (see-through patches, warped mesh, clipping).
level_4: Everything in score 3 holds, and additionally: the waves on the liquid surface rise and fall in time with each shake, each one a bit smaller than the last as the motion settles; the liquid never appears to pass through the tube wall; there's no blur so heavy that it hides what color the liquid actually is; the camera framing never pans, tilts, or drifts; the background behind the tube doesn't shift oddly relative to the tube.
level_5: Everything in score 4 holds, and additionally: after the shaking stops, the waves on the liquid surface die down smoothly rather than cutting off abruptly; the whole clip plays without stutters or repeated moments; the curve of the liquid's surface stays smooth and believable before, during, and after shaking; the tube keeps the same proportions and shape throughout, with no stretching or squashing that would distort how thick or tall it looks.