Domain: Natural Science — Atmospheric Science
Target concept: Convective smoke plume forms above a warm surface

Video generation prompt: Hold a burning incense stick above a metal plate that has a small heat-sensitive (thermochromic) indicator patch showing it is warm, in a quiet room, and capture the smoke rising above the plate during combustion.

Evaluation guide:
(i) Target concept: Buoyancy-driven laminar-to-turbulent convective plume rising from a warmed metal surface in still air, made visible by incense smoke.
Minimum mechanism: Incense supplies sustained heat and a particulate tracer; the metal plate carries a visible heat-sensitive indicator patch confirming it is warm (not red-hot, no steam/boiling); ambient air is still so buoyancy, not fan-driven or drafty air, dominates the smoke's motion.
(ii)Storyline: [Phase 1] Incense tip ignites and emits warm, particle-laden smoke; the plate's heat-indicator patch shows its warmed color. [Phase 2] Smoke rises vertically from the tip due to buoyancy; the plume near the tip is narrow and orderly. [Phase 3] As the plume climbs, it draws in cooler surrounding air, gradually widening and developing gentle wisping/undulation. [Phase 4] The plume stays attached to the tip, continuous, and roughly vertical: no detachment, sideways bending, or collapse. [Visibility constraints] Fixed frontal or slightly elevated viewpoint; incense tip, plate surface (including the heat-indicator patch), and the full plume must stay simultaneously visible; no occlusion by hands or frame edges; lighting reveals the plume's gradient and the plate's indicator color without glare.

Manual:
Experimental Procedure
1. Place a clean, flat metal plate — fitted with a small heat-sensitive (thermochromic) indicator patch — on a stable surface in a quiet, draft-free room.
2. Warm the plate until the indicator patch shows its warm-color change (not hot enough to glow or produce steam).
3. Light an incense stick and hold it vertically, stationary, with its burning tip positioned 2-5 cm directly above the center of the plate.
4. Observe smoke behavior for ~10 seconds without moving the incense or plate.
Observation of Experimental Phenomena
A coherent, vertically rising smoke plume forms immediately, originating at the incense tip and ascending continuously; the plume is gray, semi-transparent, and gradually widens upward while remaining attached to the tip; no lateral drift or downward movement occurs; the plate's indicator patch stays in its warm-color state throughout.
Summary of Experimental Principles
The rising smoke plume is a buoyancy-driven convective flow: hot combustion products (less dense than the surrounding air) rise from the incense tip, and the warmed plate beneath sustains a gentle upward drift of near-surface air that keeps entraining into the plume as it climbs — an example of thermal convection under unstable near-surface conditions, where warm air sits below cooler air above and so keeps rising.

Prompt Grounding rubric:
level_1: No incense stick is shown; no metal plate is shown; no smoke is visible; the scene has nothing to do with an incense-over-plate setup (e.g., outdoors, water, a bare flame, or an unrelated background).
level_2: Only some pieces appear: an incense stick, or a metal plate, or smoke-like haze, but they never appear together correctly; objects are wrong (e.g., a candle stands in for the incense), misplaced (incense lying on the floor, plate on edge), or the incense is not positioned above the plate.
level_3: An incense stick and a metal plate are both present, with the incense held above the plate; smoke is visibly present; the incense reads clearly as a thin cylindrical stick with a glowing tip, and the plate reads clearly as a flat metal surface, but the plate's heat-indicator patch is missing, illegible, or shows no warm-color change.
level_4: Everything in the 3-point description holds, and in addition the plate's heat-indicator patch is clearly visible and shows its warm-color state; the incense stick is held steady (no hand shake or repositioning while smoke is emitted); the plate stays fully visible and unmoving; smoke rises from the incense tip alone, directly above the plate, with nothing (fingers, stands, labels) blocking the tip-to-plate-to-smoke line.
level_5: Everything in the 4-point description holds, and in addition the incense tip is visibly glowing red/orange; the plate itself shows no glow, shimmer, or steam (confirming it is warm, not hot or boiling) while its heat-indicator patch clearly reads warm; the whole scene is shot from one fixed viewpoint with no cut, zoom, or pan; the smoke plume runs continuously from the tip to the point it fades, without breaking into disconnected puffs or obvious added particle effects.

Scientific and Causal Correctness rubric:
level_1: Smoke drifts downward, sideways, or spreads out in all directions with no clear upward path; the smoke looks blue-white (cold, non-combustion smoke) or thick black (as if from incomplete burning only); there is no plume structure at all: no narrow rising column, no widening, no sense of surrounding air being drawn in.
level_2: Smoke does rise, but not as a column: it puffs, balloons, or diffuses chaotically instead; the plume doesn't start at the incense tip or looks detached from it; its color doesn't read as ordinary incense smoke (e.g., pure white with no gray, or an odd green/purple tint); the plume shows no sign of interacting with the warmed plate (e.g., it bends away from the plate or balloons out immediately at its base).
level_3: Smoke rises as a single, coherent column starting at the incense tip; the column is narrower near the tip and gradually widens going up; a gray-to-faint gradient is visible along its length; it stays attached to the tip the whole time, with no sideways drift or dipping; the plate shows no glow or steam (staying below boiling), and its heat-indicator patch is visibly in its warm state.
level_4: Everything in the 3-point description holds, and in addition the plume's lower stretch looks smooth and well-defined while its upper stretch shows gentle wisping and slight waviness (an early sign of turbulence, not violent mixing); the column keeps widening steadily going up with no sudden branching, splitting, or droplet-like condensation; the incense tip keeps glowing steadily, without flaring up or going out, while the plume forms.
level_5: Everything in the 4-point description holds, and in addition the plume stays close to vertical along its whole visible length, without a sideways lean or curve exceeding roughly 5°; its lower stretch shows no flickering or pulsing; its upper stretch fades out gradually through natural-looking diffusion rather than vanishing uniformly or looking like a static fog bank; the smoke's opacity fades gradually from the tip upward with no sudden jump in transparency; nothing about the plume's texture or motion looks synthetic or added in post.

Spatiotemporal Consistency rubric:
level_1: The incense or plate appears/disappears/relocates abruptly between shots; the smoke plume appears already fully formed with no visible point of origin; the room lighting flips on or off or changes character instantly (e.g., a shadow disappears then snaps back); the plate's edge or the incense stick visibly glitches or breaks apart across frames.
level_2: The incense tip drifts sideways relative to the plate by more than its own width between frames; the smoke's point of origin wanders sideways over time; a highlight on the plate's surface jumps from one side to the other with no camera movement to explain it; the smoke plume vanishes for three or more frames in a row and then reappears.
level_3: The incense tip stays above the same spot on the plate throughout; the smoke's origin point stays anchored at the tip; the plate's highlight stays in the same place; neither the incense nor the plate warps, stretches, or shears; the direction and strength of the lighting on the scene stay the same from start to finish, with no flicker along the smoke's or objects' edges.
level_4: Everything in the 3-point description holds, and in addition the plume grows in length smoothly, without visible jumps from one length to a much greater one; its opacity doesn't suddenly change along its length; no new disconnected puff of smoke appears out of nowhere; the incense tip's glow brightens and dims smoothly rather than flicking on and off.
level_5: Everything in the 4-point description holds, and in addition there is no motion blur that looks wrong for how fast the smoke is actually moving (e.g., no heavy smearing in otherwise still air); the plate and incense show no visible drift in position from frame to frame; there are no repeated/duplicate frames or abrupt micro-cuts; the smoke's edges look neither unnaturally crisp nor oddly soft compared to the rest of the scene; the background stays completely still with no stray dust, drafts, or grain that would suggest the room is not actually quiet.