Domain: Natural Science — Atmospheric Science
Target concept: The cold plate inversion phenomenon on the desktop causes the incense smoke to remain in layered stagnation.

Video generation prompt: Place a flat metal plate cooled by ice packs on the desk; allow the smoke from the incense to flow over the surface of the metal plate.

Evaluation guide:
(i) Target concept: Surface-based thermal inversion causing density-stratified smoke confinement.
Minimum mechanism: Plate must be significantly colder than ambient air to generate a stable, dense, near-surface air layer; smoke particles must be buoyant enough to rise *unless* impeded by that denser layer; ambient air must be quiescent to prevent turbulent disruption of the interface.
(ii)Storyline: [Frame 1–2] Cold metal plate resting on desktop, incense burning adjacent → [Frame 3–4] Smoke begins flowing horizontally toward plate surface → [Frame 5–6] Smoke contacts plate and halts forward motion → [Frame 7–8] Lower smoke layer thickens and stabilizes into motionless horizontal stratum directly above plate → [Frame 9–10] Upper smoke layer continues rising vertically, forming sharp, persistent interface; all events occur from fixed frontal viewpoint showing plate surface, incense base, and full smoke path; no occlusion of plate surface or smoke-lower-layer region.

Manual:
Experimental Procedure
1. Pre-chill a flat, unmarked metal plate by keeping ice packs pressed against both of its broad faces for at least 20 minutes (or by placing it in a freezer) until its surface is noticeably colder than the surrounding room air.
2. Remove the ice packs and immediately place the chilled plate directly onto a wooden desktop, then begin filming right away so the plate's own thermal mass keeps its surface below room temperature for the entire shot.
3. Light an incense stick and place it adjacent to the plate, ensuring smoke flows horizontally toward the plate surface.
Observation of Experimental Phenomena
Smoke contacts the cold metal plate surface and forms a stable, motionless, horizontally stratified layer directly above it, while a second, thinner, rising smoke layer persists above — no vertical mixing between layers — and this stratification holds for the full duration of filming because the plate's pre-chilled thermal mass keeps it colder than the surrounding air throughout the brief recording window.
Summary of Experimental Principles
A metal plate that has been thoroughly pre-chilled keeps the air layer directly above it colder and denser than the surrounding room air for some time after it is placed on the desktop, since a plate with this much thermal mass warms back toward room temperature only gradually; this dense layer acts as a barrier that traps incense smoke in a stagnant, layered configuration for as long as the temperature difference is maintained — a visual demonstration of temperature inversion near a surface.

Prompt Grounding rubric:
level_1: No metal plate visible; no incense or smoke present; no desktop surface shown; none of the three required objects (cooled metal plate, incense, desktop) appear.
level_2: At least one required object appears (e.g., incense stick or smoke), but the cooled metal plate is absent or unidentifiable as a flat metal plate; desktop is missing or ambiguous; no evidence of plate placement or smoke interaction with plate surface.
level_3: All three required objects are present and identifiable: flat metal plate placed on desktop, lit incense emitting visible smoke, and smoke flowing toward/over the plate surface; however, the plate shows no visual cue of cooling (e.g., condensation, frost, or thermal haze) and/or smoke does not visibly interact with the plate surface (e.g., no stagnation, layering, or deflection).
level_4: All three required objects are present and correctly arranged: flat metal plate placed on desktop, lit incense positioned adjacent to plate, smoke visibly flowing over the plate surface; plate exhibits at least one cooling indicator (e.g., visible condensation, subtle thermal distortion near surface, or duller metallic sheen consistent with cold); smoke is seen contacting plate surface, but no layered stagnation is visually resolved.
level_5: All three required objects are present, correctly arranged, and functionally contextualized: flat metal plate placed centrally on desktop, lit incense positioned side-by-side (not above or behind), smoke continuously flowing from incense toward and directly over the plate surface; plate shows clear visual evidence of being cold (e.g., localized condensation or uniform matte/dull surface distinct from ambient metal); smoke contact with plate surface is unambiguous and immediately followed by visible horizontal layering and stagnation: no upward dispersion, no turbulent mixing, no penetration through layer.

Scientific and Causal Correctness rubric:
level_1: Smoke rises vertically without deviation; plate shows no thermal effect; no stagnation, layering, or horizontal confinement observed; smoke behavior is identical to ambient air; no inversion-related phenomenon present.
level_2: Smoke deviates slightly near plate (e.g., mild bending), but no horizontal confinement; no discernible layer formation; plate temperature state contradicts phenomenon (e.g., plate appears warm/hot or emits steam); causal chain (cold surface → denser air → smoke trapping) is visually unsupported.
level_3: Smoke contacts plate surface and exhibits initial horizontal spreading, but layer remains thin, discontinuous, or transient; no persistent separation between upper rising smoke and lower stagnant layer; vertical vs. horizontal contrast exists but lacks clear bimodal structure (i.e., no two visually distinct, parallel smoke strata).
level_4: Smoke forms two continuous, non-mixing horizontal layers: lower layer is dense, motionless, and confined strictly above plate surface; upper layer rises freely and is visibly less dense; boundary between layers is sharp and stable for ≥3 consecutive video frames; no vertical breakthrough or inter-layer diffusion observed, but lower layer thickness varies noticeably or edge definition is partially blurred.
level_5: Two fully separated, parallel, and continuous smoke layers are simultaneously visible: lower layer is uniformly dense, completely motionless (zero detectable drift or ripple), horizontally confined within fixed height above plate surface, and sharply bounded above; upper layer is consistently thinner, rising vertically with smooth laminar flow; interface is perfectly planar, stable across entire field of view, and persists without fluctuation or merging for full duration; no trace of turbulence, entrainment, or vertical continuity between layers.

Spatiotemporal Consistency rubric:
level_1: Objects teleport (e.g., plate appears mid-air then snaps to desk), smoke materializes/disappears abruptly, lighting shifts violently between frames, or structural integrity breaks (e.g., plate bends unrealistically, desktop surface fractures or warps).
level_2: Minor spatial discontinuities: plate position shifts without motion, incense changes orientation instantaneously, smoke flow direction flips without cause, or light/shadow cast by incense or plate jumps inconsistently across frames.
level_3: All objects maintain fixed relative positions: plate remains stationary on desktop, incense stays in fixed location adjacent to plate, smoke originates consistently from incense tip; lighting and shadow remain coherent and stable; no object flickers, vanishes, or morphs, but minor jitter in smoke edge or brief frame-level occlusion occurs.
level_4: Full spatiotemporal coherence: plate, incense, and desktop retain rigid alignment and scale throughout; smoke flows continuously with no frame drops, stutters, or reinitialization; shadows cast by incense and plate remain geometrically consistent with light source; no parallax violations, no floating elements, no inconsistent perspective, but one instance of minor motion blur that slightly softens smoke layer boundary.
level_5: Zero spatiotemporal artifacts: plate, incense, and desktop exhibit pixel-perfect positional stability; smoke moves with perfectly smooth, continuous, and physically plausible motion: no motion blur, no strobing, no interpolation ghosts; all shadows align precisely with object geometry and fixed light source; no depth inconsistency, no lens distortion, no temporal aliasing; every frame maintains identical spatial hierarchy and scale fidelity.