Domain: Natural Science — Chemistry
Target concept: Physical Properties of Benzene

Video generation prompt: At room temperature, a beaker contains an appropriate amount of liquid benzene. The beaker is cooled with ice until its temperature approaches 0 degrees Celsius.

Evaluation guide:
(i) Target concept: Supercooled liquid benzene undergoing heterogeneous nucleation-induced solidification upon thermal contact with ice.
Minimum mechanism: Benzene must be pure and quiescent to remain metastable below its melting point; ice provides nucleation sites; solidification must be complete, homogeneous, and morphologically consistent with polycrystalline benzene (opaque, white, non-translucent, flat-front propagation).
(ii)Storyline: [Phase 1: Baseline] Colorless, still, transparent liquid fills beaker with concave meniscus; no ice present. [Phase 2: Initiation] Ice placed adjacent to beaker wall, no immediate change. [Phase 3: Transition] Over time, opaque white solid emerges from beaker wall interface and advances uniformly inward/upward until full volume is solid. [Phase 4: Completion] Solid occupies original liquid volume with flat, matte upper surface; no residual liquid visible; ice remains externally fixed. Perspective: Fixed frontal close-up, no camera movement, full beaker in frame, unobstructed view of liquid/solid interface and ice-beaker contact zone.

Manual:
Experimental Procedure
1. Place a clean, transparent glass beaker on a stable surface.
2. Pour colorless liquid benzene into the beaker until it reaches ~half its height.
3. Place ice cubes directly against the outer wall of the beaker.
Observation of Experimental Phenomena
The initially clear, colorless liquid benzene gradually transforms into a uniform, opaque white solid that fills the lower portion of the beaker, maintaining a flat upper surface aligned with the original meniscus.
Summary of Experimental Principles
Benzene has a melting point of 5.5°C. When cooled toward 0°C without adequate nucleation sites, pure, undisturbed benzene can remain a metastable supercooled liquid below its melting point rather than freezing immediately. Contact with ice — which provides ready crystal nucleation sites — triggers rapid, complete solidification into opaque white crystalline benzene, whose milky appearance comes from light scattering at grain boundaries.

Prompt Grounding rubric:
level_1: No beaker is shown; no colorless liquid benzene appears; no ice or other cooling method is shown; there's no indication the scene starts at room temperature and then cools.
level_2: A beaker with a transparent liquid appears, but the liquid doesn't read as benzene (it's tinted, or clearly labeled as something else); or ice appears but never touches or sits next to the beaker; or there's no way to tell that cooling is happening over time (no before/after difference).
level_3: A clear beaker holding a transparent, colorless liquid is shown at the start; ice is placed against or right next to the outside of the beaker; the shot is continuous with a fixed camera; the sequence implies the beaker is being cooled (ice appears and stays in place while the liquid is initially unchanged).
level_4: Everything required for score 3 holds, and in addition the beaker looks like ordinary lab glassware, the liquid fills roughly a third to two-thirds of it, the ice stays fully visible and doesn't move away from the beaker, no object enters or leaves frame, and neither the beaker nor the liquid is swapped out mid-clip.
level_5: Everything required for score 4 holds, and in addition the beaker sits centered and facing the camera the whole time, the liquid surface starts flat and still, the ice (whether one piece or several) stays fully in view without being blocked, and there's no flicker, cut, or zoom that interrupts the sense of one continuous cooling setup.

Scientific and Causal Correctness rubric:
level_1: The liquid turns solid but looks wrong for benzene (dendritic ice-like crystals, bubbling as it freezes), or it never changes state at all, or it solidifies without any ice present nearby, or the benzene appears colored or cloudy at some point before solidifying.
level_2: The liquid stays liquid the whole time; or it solidifies only at the edges while the center is still visibly liquid with no real transition; or the solid looks granular, slushy, or half-clear rather than a solid opaque mass; or a solid appears even though the ice has been removed or was never shown.
level_3: The liquid starts out transparent and colorless; once the ice has been placed and enough time has passed, a uniform, opaque white solid appears, covering the whole liquid surface and filling the beaker bottom evenly; no liquid layer is visible beneath the solid; the solid's surface looks matte rather than glossy.
level_4: Everything required for score 3 holds, and in addition the solid only starts forming once the ice is fully in place and doesn't melt back into liquid afterward; the top of the solid forms a clean, flat boundary roughly where the original liquid's surface was; there's no yellowing, browning, or patchy transparency in the solid.
level_5: Everything required for score 4 holds, and in addition the solid fills essentially the same volume the liquid originally occupied (no visible shrinkage gaps or overflow, no distorted meniscus line), the solid's top surface stays flat and still, there's no frost or condensation forming on the outside of the beaker that would suggest a much colder environment than an ice bath, and nothing in the shot looks like leftover liquid is still present.

Spatiotemporal Consistency rubric:
level_1: The beaker disappears and reappears, the liquid's surface height changes abruptly with no visible cause, the ice suddenly jumps position or spins, the lighting shifts dramatically between one frame and the next, the beaker changes shape mid-video, or the clip cuts between multiple unrelated camera angles.
level_2: The beaker stays on screen but shifts noticeably away from its starting spot; the liquid surface keeps rippling without ever settling; ice pieces visibly split apart or merge together in a way that doesn't track normal melting; the shadows change direction; the brightness flickers across several frames in a row; or background objects stretch or shrink inconsistently.
level_3: The beaker stays in the same spot in the frame; the liquid surface is calm for most of the clip; the ice keeps the same touching/adjacent relationship to the beaker the whole time; the beaker's shadow keeps a steady direction and softness; nothing blocks the view of the beaker for more than a moment.
level_4: Everything required for score 3 holds, and in addition the beaker shows no perceptible shake or drift in its position, the liquid surface stays flat and undisturbed even as the ice is set down, the ice doesn't visibly shrink or give off vapor in a way that looks like it's melting unnaturally fast, and the background stays put with no drifting or scale change.
level_5: Everything required for score 4 holds, and in addition the beaker's rim and base look perfectly still with no visible shift for the entire clip, the liquid/solid surface's height and shape don't waver once settled, the ice keeps the same outline and edge sharpness throughout, and the overall brightness and color of the scene stay constant from frame to frame.