Domain: Natural Science — Physics
Target concept: Mixing ethanol and water, the temperature rise caused by exothermic reaction is displayed through thermochromism.

Video generation prompt: A transparent glass beaker coated with a thermochromic film (initially blue at room temperature) contains water; ethanol is added under constant pressure without external heating and the mixture is gently stirred.

Evaluation guide:
(i) Target concept: Exothermic mixing-induced temperature rise detected via thermochromism.
Minimum mechanism: Ethanol and water must form an intimate molecular mixture (not layered); heat must be generated *in situ* (no external source); thermochromic film must be in direct thermal contact with solution; color change must require heat transfer (thus delayed relative to mixing onset) and follow monotonic, reversible thermal response.
(ii)Storyline: Frame 1–2: Static shot: beaker with water, blue film intact, ethanol container adjacent, stirring tool beside beaker. Frame 3–4: Ethanol poured into beaker: film remains blue, liquid interface visible, no color shift. Frame 5–6: Stirring tool enters liquid and begins gentle motion; film remains blue during initial insertion. Frame 7–10: Continuous stirring: film begins at liquid level and progressively transitions blue → purple → red upward across full coating; no reversal, no skip, no spatial fragmentation; final frame shows fully red-coated beaker with tool still in motion.

Manual:
Experimental Procedure
1. Place transparent glass beaker containing water on surface.
2. Ensure beaker exterior is fully coated with thermochromic film (initially blue).
3. Pour ethanol into beaker.
4. Gently stir mixture with stirring tool.
Observation of Experimental Phenomena
Thermochromic film changes continuously from blue to red only after stirring begins — no change before or during pouring; transition spreads uniformly across entire coated surface.
Summary of Experimental Principles
Mixing ethanol and water is exothermic; released heat raises local temperature; thermochromic film responds to temperature rise by shifting color from blue (cool) to red (warm).

Prompt Grounding rubric:
level_1: No transparent beaker is shown, or the beaker is not coated with a visible color-changing film, or no separate ethanol container appears, or no stirring rod is shown, or neither the ethanol-pouring action nor the stirring action is depicted.
level_2: Beaker with water, coated film, ethanol container, and stirring rod are all visible, but only one of the two required actions (pouring ethanol into the beaker, stirring the mixture) is shown, not both; or the film shows no color at all (e.g., transparent/uncoated) so no baseline blue tint is established.
level_3: The beaker (holding water, coated with a blue film), ethanol container, and stirring rod are all present, and both the pouring and stirring actions occur; but their sequencing or the film's behavior only partially matches the prompt: e.g., the rod begins stirring before ethanol is visibly added, or the film shows a faint color hint prior to stirring.
level_4: All prompt elements are present and correctly ordered: the water-filled beaker is coated with a blue film, the ethanol container is present, ethanol is visibly poured into the beaker before the stirring rod is inserted, and the film stays blue during the pour and only begins to change after stirring starts; but one minor setup detail is off, e.g., the film coating is patchy or incomplete on part of the beaker, or the stirring rod is a different plausible utensil (e.g., a spoon instead of a glass rod), or a stray unrelated object appears in the background.
level_5: All prompt elements are present exactly as described and fully ordered: transparent beaker holds water and is uniformly coated with the blue film; ethanol container is present and ethanol is poured into the beaker; stirring rod is then inserted and used to stir gently; film remains blue throughout the pour and begins changing color only once stirring starts; no extraneous objects, no missing elements, no order violations.

Scientific and Causal Correctness rubric:
level_1: The film shows no color change at all, or changes to a color inconsistent with heat-driven thermochromism (e.g., green or black), or the color change begins before the ethanol is poured or before stirring starts, or the film is depicted as a static painted surface rather than a heat-responsive coating.
level_2: The film changes color, but the sequence contradicts thermochromic behavior: e.g., it jumps directly from blue to red with no intermediate purple hue and shows no timing relationship to when stirring starts, or it changes color before the ethanol has actually mixed into the water.
level_3: After the ethanol is poured in and stirring begins, the film's color visibly shifts away from blue; but the change is only partially consistent with the exothermic mixing mechanism: for example, only part of the coated surface changes while adjacent regions stay blue despite equal liquid contact, or the color reaches red directly within a single frame with no visible intermediate purple stage.
level_4: The film's color change begins only after stirring starts (not during the pour) and spreads continuously across the coated surface without gaps, passing visibly through an intermediate purple hue between blue and red; but one physically implausible detail remains, e.g., an isolated patch of pure red appears before the surrounding purple catches up, or the color briefly reverts from purple back to blue before continuing on to red.
level_5: The film stays uniformly blue until stirring begins, then transitions continuously through blue → purple → red across the entire coated surface with no reversal and no isolated patches; the change starts near the liquid level and spreads generally upward as the stirred mixture warms, without abrupt jumps or regions that lag or lead implausibly; the timing of the change tracks the stirring action rather than the pour.

Spatiotemporal Consistency rubric:
level_1: The beaker is visible, then briefly missing from the frame, then reappears in the same spot with no motion explaining the gap; the ethanol container disappears the instant after pouring; the stirring rod jumps to a different position between frames; the film's color flickers on and off rather than changing gradually; the room's brightness suddenly flashes or drops to darkness with no visible cause.
level_2: One clear continuity break occurs: the beaker rotates or shifts by more than about 30 degrees with no hand or support causing it, or the ethanol stream breaks contact with the container mid-pour, or the stirring rod passes through the beaker wall as if the glass weren't solid, or the blue film's colored boundary slides to a different position on the glass between frames.
level_3: The beaker, ethanol container, and stirring rod stay in the same relative arrangement throughout (beaker centered, container beside it, rod inserted only during stirring); but a small continuity slip is visible, such as the color boundary on the film momentarily jittering back and forth by a visible margin, or the water briefly appearing cloudy then instantly clear again, or the shadow the beaker casts on the table shifting position with no corresponding change in the light source.
level_4: No object disappears, teleports, or deforms; the liquid's surface moves in a smooth, gentle swirl consistent with gentle stirring rather than snapping into rigid rotation; the blue film stays fixed to the beaker's outer surface across all frames; but one small timing hiccup occurs, such as the stirring motion visibly freezing for a beat before resuming, or the color transition appearing to repeat or skip a step rather than progressing smoothly.
level_5: The beaker, film coating, water, ethanol container, and stirring rod keep consistent positions, sizes, and proportions relative to one another throughout; the stirring motion is smooth and continuous with no sudden jerks or freezes; the film's color change progresses frame to frame with no repeated or skipped stages and no flicker; the liquid surface swirls gently without splashing or sudden jumps; the shadow the beaker casts on the table keeps a consistent direction and softness, matching a single, unmoving light source throughout the clip.