Domain: Natural Science — Atmospheric Science
Target concept: Frost crystals growing on a supercooled glass plate in moist air

Video generation prompt: A glass plate cooled below the freezing point is placed in a transparent chamber, with moist air flowing steadily over its surface.

Evaluation guide:
(i) Target concept: Deposition of water vapor into frost crystals on a supercooled substrate under controlled humid airflow.
Minimum mechanism: Surface temperature < 0°C + water vapor supersaturation with respect to ice + absence of liquid water reservoir (i.e., no dew formation first) + nucleation sites enabling direct vapor-to-ice transition.
(ii)Storyline: [Phase 1: Setup] Glass plate is stationary inside transparent chamber. [Phase 2: Initiation] Moist air begins flowing horizontally across plate surface: vapor becomes visibly present and moves unidirectionally. [Phase 3: Nucleation] Within first 2–3 seconds, discrete white crystalline clusters appear at multiple locations on the plate surface (edges, corners, and/or center are all physically plausible nucleation sites). [Phase 4: Growth] Crystals expand outward in branching, feathery patterns: density increases progressively without coalescing into solid sheet. [Phase 5: Steady State] Growth continues progressively across the exposed surface while vapor flow persists; no reversal, melting, or condensation interference. Perspective: Fixed frontal view, full plate face visible, no occlusion, chamber walls fully transparent and static.

Manual:
Experimental Procedure
1. Place a clean, smooth glass plate into a transparent, enclosed chamber.
2. Cool the plate to below 0°C (not shown, but implied by subsequent frost formation).
3. Introduce moist air steadily flowing horizontally across the plate surface.
Observation of Experimental Phenomena
White, opaque, feathery/dendritic frost crystals nucleate randomly on the plate surface and grow outward continuously while moist air flows—no liquid droplets, no melting, no frost on chamber walls.
Summary of Experimental Principles
Frost forms when water vapor in moist air deposits directly as ice onto a surface colder than freezing (deposition), bypassing the liquid phase—characteristic of supercooled surfaces in unsaturated or marginally saturated air.

Prompt Grounding rubric:
level_1: No glass plate visible; no transparent chamber present; no airflow indication (e.g., no vapor motion, no inlet/outlet markers); no moist air representation (e.g., no visible humidity, fog, or condensation source); demonstration goal completely unrepresented.
level_2: Glass plate appears but is not visibly cooled (no frost-relevant surface state); chamber is present but sealed/static (no airflow cues); moist air absent (no visible water vapor, mist, or droplet suspension); at least one object type matches (e.g., plate or chamber), but zero correct action–object–environment alignment.
level_3: Glass plate is present and placed inside a transparent chamber; moist air is represented as visible suspended vapor or fine mist flowing steadily across the scene; plate is stationary and centered; sequence shows placement → exposure → observation (no reversal or omission of placement step); all required objects exist and are co-located in same scene with fixed viewpoint.
level_4: All elements of 3-score are present AND airflow direction is unambiguously indicated (e.g., vapor stream moving horizontally across the plate from one side to the other); chamber walls are fully transparent (no opaque framing, tinting, or occlusion); the plate occupies the central foreground with an unobstructed full-face view throughout; no extraneous objects (e.g., hands, tools, labels) enter the frame.
level_5: All elements of 4-score are present AND the plate is shown being placed into the chamber *before* airflow begins (two distinct sequential actions: placement then airflow onset); vapor flow is continuous, laminar, and maintains consistent density and trajectory across the entire duration; the chamber has visible inlet/outlet ports aligned with the vapor flow direction; no camera motion, zoom, or cut: single fixed shot with stable framing.

Scientific and Causal Correctness rubric:
level_1: Frost crystals do not appear at all; plate remains visually unchanged (no surface texture change, no white/icy appearance); any ice-like formation is incorrect in morphology (e.g., smooth glaze, dripping liquid, or snow-like powder not adhering to surface); no causal link between moist air and surface change is visually supported.
level_2: Frost appears but violates the state-change order or morphology: it is visible *before* the moist air begins flowing across the plate; OR it appears as a single uniform sheet covering the whole plate instantly rather than as scattered crystal clusters that spread over time; OR its morphology is liquid droplets/dew instead of crystalline ice; OR its color is translucent blue or glossy rather than opaque white/milky.
level_3: Frost crystals appear *only after* moist air contacts the cold plate surface; crystals initiate at multiple nucleation sites (which may include edges, corners, or the plate center) and spread outward; texture is granular, feathery, or dendritic (not smooth, pooled, or amorphous); color is uniformly opaque white or off-white (not transparent, colored, or iridescent); crystal growth is confined to the plate surface (no growth on chamber walls or in the air).
level_4: All elements of 3-score are present AND crystal growth progresses continuously (no sudden full coverage, visible incremental expansion over time); no melting, dripping, or phase reversal during the video; crystals remain dry and non-reflective (no liquid sheen or wetness); no coexistence of liquid water and frost on the same surface region.
level_5: All elements of 4-score are present AND crystal morphology is distinctly branched/dendritic (not isotropic or circular); multiple nucleation sites appear within a short window of each other (not one appearing long after the rest) and then spread across the plate without long unexplained stalls; density increases steadily without stalling or regressing; no visual ambiguity between frost and unrelated particulates (e.g., dust, scratches, or lens flare).

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal violation: the glass plate teleports to a different position; the chamber's walls distort or change shape mid-video; frost patches appear or vanish instantly with no growth or melting shown; the whole scene abruptly flips from bright to dark (or dark to bright) with no apparent cause, or the reflected glare on the chamber glass switches sides or disappears with no apparent cause; the vapor stream reverses direction or cuts on/off without any transition.
level_2: Multiple discontinuities: the plate rotates or tilts with no visible support for the motion; frost spreads via visible jump cuts (a patch is suddenly larger with no in-between frames); the vapor stream fragments or disappears then reappears; the shadow cast by the plate or chamber frame jumps to a new position without the light source moving; the chamber walls flicker between transparent and opaque.
level_3: The plate stays stationary and upright, the chamber walls stay rigid and aligned, and the vapor drifts in one steady direction with visible continuous motion; frost grows gradually with no teleporting or clipping of the ice patches; the reflection/highlight visible on the plate's glass surface and chamber wall keeps the same position and brightness throughout, with no highlight suddenly jumping or the scene unexpectedly brightening or dimming.
level_4: All elements of 3-score are present AND there is no geometric warping of the plate or chamber outline (no bulging or pinching of straight edges); no inter-frame jitter or shake of the plate/chamber; no stutter or frozen-looking motion in the vapor stream; the vapor particles keep a consistent relative drift speed; the advancing edge of the frost patches grows smoothly rather than jumping in uneven bursts.
level_5: All elements of 4-score are present AND every element sits at a consistent depth relative to the others (the plate, frost, vapor, and chamber walls never appear to float free of or sink into their surroundings); motion blur on the drifting vapor matches its visible speed while the more static frost shows no blur; no lens flare, color fringing, or vignetting inconsistent with a plain lab-chamber shot; the shadow cast under the plate and in the chamber corners stays consistent in shape and darkness throughout.