Domain: Natural Science — Earth Science
Target concept: Melting wax poured onto a cold stone surface formed a flowing crust.

Video generation prompt: Molten candle wax is poured from a small metal spoon onto a flat, cold stone surface, where it flows outward along the surface.

Evaluation guide:
(i) Target concept: Thermal quenching-induced crust formation governing non-Newtonian spreading of molten wax on a high-conductivity, low-temperature substrate.
Minimum mechanism: Wax must be initially molten (T > 60°C), stone must be significantly colder (T < 20°C) and thermally massive, and interfacial heat flux must exceed wax solidification rate to initiate crust nucleation before bulk flow arrest.
(ii)Storyline: [Phase 1] Spoon held stationary above stone → [Phase 2] Wax stream initiates and travels unbroken to surface → [Phase 3] Impact triggers immediate crust nucleation at contact point → [Phase 4] Fluid interior pushes crust outward radially while simultaneously thickening it → [Phase 5] Crust stiffens progressively until flow ceases completely; all phases must occur within single fixed viewpoint, with stone surface fully visible and unoccluded, and spoon remaining in frame until wax release completes.

Manual:
1. Experimental Procedure: Hold a small metal spoon containing molten candle wax (amber-yellow, translucent, fluid) 10–15 cm above a flat, cold stone surface. Tip spoon to pour wax vertically onto center of stone. Observe immediate contact and outward flow.
2. Observation of Experimental Phenomena: Wax contacts stone and spreads radially outward as a continuous fluid sheet; leading edge rapidly thickens and dulls into a solidifying crust; inner region remains glossy and fluid longer; flow halts as crust fully immobilizes the mass.
3. Summary of Experimental Principles: Rapid conductive heat transfer from molten wax to cold stone causes localized solidification at the interface, forming a viscoelastic crust that governs outward flow dynamics—demonstrating thermal quenching and non-Newtonian spreading under thermal gradient.

Prompt Grounding rubric:
level_1: No metal spoon present; no cold stone surface visible; no wax pouring action shown; no flowing outward motion observed; scene depicts unrelated objects or actions.
level_2: Metal spoon is present but empty or holds non-wax substance; stone surface is present but not clearly flat/cold (e.g., appears warm, textured like wood/metal); pouring action occurs but wax does not contact surface; no outward flow along surface observed.
level_3: Metal spoon containing molten wax is shown pouring downward; cold flat stone surface is visible and in frame; wax makes contact with stone surface; outward flow along surface begins and is visually discernible for at least one continuous segment.
level_4: All 3-point conditions satisfied AND spoon is held steadily above stone before pouring; wax stream is continuous from spoon tip to stone contact point; flow spreads radially outward from single impact point without splitting into disconnected lobes or vanishing mid-spread.
level_5: All 4-point conditions satisfied AND spoon is small and metallic (shiny, rigid, non-transparent); stone surface is uniformly gray/buff, matte, and visibly dense (no pores, gloss, or grain inconsistent with cold igneous/metamorphic rock); wax is amber-yellow, translucent when molten, and forms a single cohesive crust that flows continuously and symmetrically outward from impact point without splattering, rebounding, or freezing prematurely.

Scientific and Causal Correctness rubric:
level_1: Wax appears solid before contact; no state change observed; flow direction contradicts gravity (e.g., flows upward); wax color remains opaque white throughout; no crust formation visible.
level_2: Wax is liquid before contact but solidifies *before* contacting stone; flow stops immediately upon contact with no spreading; crust forms only at edges while center remains molten puddle; color changes inconsistently (e.g., blue-to-green).
level_3: Molten wax (translucent amber-yellow) contacts cold stone and undergoes rapid localized solidification at interface; outward flow occurs *while* leading edge cools and thickens; crust forms progressively from contact point outward; flow ceases when crust fully immobilizes the mass.
level_4: All 3-point conditions satisfied AND crust is visibly thicker at outer edge than at center; inner region remains fluid longer than outer region; no re-melting or secondary flow after initial spread; no bubbling, steaming, or discoloration inconsistent with wax-on-stone thermal quenching.
level_5: All 4-point conditions satisfied AND crust exhibits fine radial cracking *only after* flow halts; inner fluid region maintains smooth convex meniscus until final solidification; temperature gradient is visually implied by sharp transition between glossy fluid center and matte crust; no anomalous phase behavior (e.g., crystallization, phase separation, charring).

Spatiotemporal Consistency rubric:
level_1: Spoon teleports from off-screen to over stone; stone surface geometry changes abruptly mid-video; wax appears/disappears between frames; lighting shifts drastically (e.g., daylight to night) without cause.
level_2: Spoon moves jerkily with visible frame skips; wax stream breaks into disconnected droplets mid-air with no continuity; stone surface flickers or warps; flow path shows discontinuous motion (e.g., jumps sideways without intermediate positions).
level_3: Spoon position remains stable relative to stone across entire video; wax stream is unbroken from spoon tip to stone; flow spreads continuously outward without teleportation, reversal, or sudden speed change; stone surface maintains fixed orientation and consistent texture.
level_4: All 3-point conditions satisfied AND no inter-frame object distortion (e.g., spoon handle stretching/shrinking); no abrupt shadow displacement on stone; no temporal aliasing (e.g., strobing, ghosting) in moving wax; no parallax shift indicating camera movement or zoom.
level_5: All 4-point conditions satisfied AND spoon-to-stone spatial relationship remains invariant (same relative size, alignment, perspective); wax flow exhibits natural deceleration as crust thickens (visible via progressive narrowing of fluid front); stone surface reflects ambient light consistently without specular anomalies; zero frame duplication or omission detectable in motion sequence.