Domain: Natural Science — Chemistry
Target concept: Oxidation of Benzene

Video generation prompt: At room temperature, a beaker contains an appropriate amount of potassium permanganate solution. An appropriate amount of liquid benzene is added to the beaker.

Evaluation guide:
(i) Target concept: Chemical inertness of benzene toward cold aqueous KMnO4 oxidation.
Minimum mechanism: Benzene must remain physically immiscible and chemically unreactive, requiring preservation of two optically distinct, non-diffusing, non-interacting liquid phases with no energy release or absorption signatures.
(ii)Storyline: [Frame 0–2] Static shot of empty beaker → [Frame 3–4] Purple KMnO4 solution poured and settled → [Frame 5–6] Colorless benzene added smoothly onto surface → [Frame 7–10] Immediate formation and sustained maintenance of sharp horizontal interface; no motion except gravity-driven settling; viewpoint fixed frontal; lighting uniform; all events visible without occlusion or cut.

Manual:
Experimental Procedure
1. Place a clean, transparent beaker on a neutral background.
2. Pour purple aqueous potassium permanganate solution into the beaker until ~2/3 full.
3. Carefully add colorless liquid benzene on top — no stirring or shaking.
Observation of Experimental Phenomena
- Purple KMnO4 solution remains unchanged in color and clarity.
- Colorless benzene forms a distinct, sharp, horizontal upper layer.
- No mixing, no color change, no gas, no temperature change — two immiscible liquid phases persist.
Summary of Experimental Principles
Benzene is resistant to oxidation by cold, dilute potassium permanganate due to its stable aromatic ring; no reaction occurs at room temperature — hence no decolorization or byproduct formation.

Prompt Grounding rubric:
level_1: No beaker appears; no purple potassium permanganate solution is shown; no liquid benzene is added; none of the three needed objects (beaker, KMnO4 solution, benzene) appear together.
level_2: At least the beaker appears, but the KMnO4 solution is missing or the wrong color (not purple, e.g. clear or a different hue); or benzene is missing or shown as something other than a clear liquid (a solid, a gas, or a differently colored liquid); or benzene is never shown being added to the KMnO4 solution.
level_3: The beaker holds a purple liquid consistent with aqueous KMnO4; benzene is added and forms a separate layer; the two liquids are visually distinguishable and share the same beaker; but either the benzene isn't clearly shown sitting on top, or the boundary between the two layers looks blurred or artificially stirred rather than a clean, undisturbed interface.
level_4: The beaker holds purple KMnO4 solution; clear benzene is added and clearly forms a distinct layer above it; there's no stirring or agitation shown; the benzene layer sits above the KMnO4 layer; all three elements are correctly identified by color, form, and position; the only flaws present are minor and non-essential (a touch of camera shake, a brief partial occlusion, a small lighting variation).
level_5: The beaker is centered with a steady camera angle; the purple KMnO4 solution fills roughly the lower two-thirds of the beaker; the clear benzene settles smoothly into a single, sharp, continuous horizontal layer above it; there's no motion blur, no blurring of the interface, no color bleeding between layers, and no moment where the two-layer arrangement looks inconsistent: both phases keep their correct color, amount, and stacking order for the whole clip.

Scientific and Causal Correctness rubric:
level_1: Something happens that contradicts the chemistry: the KMnO4 solution loses its purple color, the two layers mix on their own, the benzene sinks instead of floating, or bubbles/fumes appear, none of which should happen when benzene meets cold KMnO4 solution at room temperature.
level_2: At least one detail is scientifically off: the benzene shows some color instead of being clear, the KMnO4 solution isn't purple, or the boundary between the layers visibly blurs or diffuses over time; or benzene's addition is immediately followed by fading or cloudiness in the KMnO4 layer, implying a reaction that shouldn't occur.
level_3: The KMnO4 solution stays purple and the benzene stays clear and colorless; the two layers stay visually separate with no sign of a reaction: no fading, no precipitate, no haze, no gas; but the boundary between them looks wavy, broken up, or hard to make out, or the benzene layer looks noticeably thinner or thicker than the amount added would suggest.
level_4: The KMnO4 solution keeps a uniform purple color with no fading; the benzene stays uniformly clear; a straight, continuous, horizontal boundary between the two layers holds from the moment benzene is added to the end of the clip; there's no sign of one liquid dissolving into the other or the interface becoming unstable; everything shown matches benzene simply being inert toward cold KMnO4; only very minor issues remain, like a brief glare that partly obscures the interface for a moment.
level_5: Nothing deviates from the expected chemistry at all: the KMnO4 solution stays a uniform, deep purple with no fading or dulling anywhere; the benzene stays completely clear; the boundary between the two stays flat, unbroken, and steady for the full duration, with no visible haze, cloudiness, or blending suggesting the liquids are mixing; the whole sequence reads cleanly as: benzene added → immediate layering → the layers simply sit there unchanged.

Spatiotemporal Consistency rubric:
level_1: The beaker disappears and reappears, the two layers jump to different heights between frames, the shot cuts abruptly to something unrelated, the lighting swings dramatically from one frame to the next (e.g., bright to dark), or the boundary between the layers suddenly relocates or tilts with no visible cause.
level_2: The beaker rotates or slides sideways by more than about 10% of the frame width; the height of one or both layers fluctuates for no reason; the boundary between the layers flickers in and out; the shadow the beaker casts changes direction partway through; or the lighting pulses noticeably brighter and dimmer.
level_3: The beaker shows only slight jitter (less than about 5% of the frame width); the boundary between the layers has a little bit of unevenness but stays roughly horizontal and unbroken; the lighting stays consistent aside from a faint drift in where a highlight sits on the glass; the beaker and both layers stay visible and don't blink out of view at any point.
level_4: The beaker stays fixed in place and orientation; the only movement in the layer boundary comes from natural settling (smooth and one-directional, not jittery back-and-forth); the lighting and shadows hold steady in direction and brightness; nothing about the beaker's shape looks distorted or torn between frames; at most one small flaw appears, like a brief instant of motion blur while the benzene is being poured, without ever hiding the layering as it forms.
level_5: The beaker's position, size, and angle in frame never waver; the boundary between the two liquids forms right away and stays essentially perfectly flat, horizontal, and unbroken with no perceptible drift for the whole clip; the lighting, shadow, and reflections on the glass look identical from the first frame to the last; there's no warping, no odd depth cues, and nothing about the scene looks stitched together from mismatched shots.