Domain: Natural Science — Atmospheric Science
Target concept: Rotating trajectory in the form of a vertical column under the influence of a rotating airflow

Video generation prompt: White background, a cylindrical transparent glass chamber, with a small rotating fan placed at the bottom, and a small opening at the center of the top to release incense smoke. After turning on the fan, the smoke trajectory is recorded.

Evaluation guide:
(i) Target concept: A vertically aligned, rotationally stable smoke column generated solely by a bottom-mounted fan inducing a vortex within a confined cylindrical volume.
Minimum mechanism: The fan's spinning blades directly impart azimuthal (swirling) momentum to the air they push upward (this direct aerodynamic torque from the rotating blades, not friction against the glass walls, is the primary driver of rotation), producing a forced vortex with axial updraft and circumferential flow; sealed lateral boundaries (glass walls) contain the swirl, the open top allows buoyant smoke egress, and central symmetry keeps the vortex aligned with the chamber axis.
(ii)Storyline: [Frame 0–2] Static setup: white background, intact cylindrical chamber, fan at bottom, central top opening, incense smoke beginning to rise linearly. [Frame 3–5] Fan activation: visible blade motion begins → airflow disturbance appears near fan → smoke flow transitions from linear rise to gentle curvature. [Frame 6–10] Vortex establishment: smoke coalesces into continuous vertical column, rotation initiates at base and propagates upward, column locks to chamber centerline with symmetric spin, all observed from fixed frontal view with full chamber in frame and no occlusion.

Manual:
Experimental Procedure
1. Place small rotating fan at bottom center of cylindrical transparent glass chamber on white background.
2. Open small circular aperture at exact center of chamber top lid.
3. Light incense stick and hold tip just below aperture to release steady smoke upward through opening.
4. Turn on fan; record smoke trajectory as it rises.
Observation of Experimental Phenomena
Smoke forms a continuous, vertically oriented, rotating column centered inside the chamber — rotating around its own axis due to induced vortex from fan-driven airflow.
Summary of Experimental Principles
Rotating trajectory in the form of a vertical column under the influence of a rotating airflow — a demonstration of vortex formation in atmospheric science, where the fan blades' own rotational torque drives the airflow that generates a stable, upright columnar vortex (e.g., analogous to dust devils or tornado genesis).

Prompt Grounding rubric:
level_1: The video shows no white background, no cylindrical glass chamber, no fan, no central top opening, and no incense smoke; the described chamber setup is entirely absent or unrecognizable.
level_2: A white background and some kind of chamber are present, but fewer than three of the five core elements (white background, cylindrical glass chamber, fan mounted at the bottom, central top opening, incense smoke) are correctly shown together: for example the fan is missing or mounted on the chamber's side/top instead of its bottom, or no smoke is visible at all.
level_3: The white background, a cylindrical transparent glass chamber, a small fan mounted at the chamber's bottom, and a small circular opening centered on the top are all clearly visible and correctly positioned, and incense smoke is visibly emerging from that top opening, but the fan is not yet visibly rotating (no spinning blades or blurred rotor disc, no airflow disturbance near it).
level_4: All elements from the 3-point level are present, and the fan is now visibly rotating (spinning blades or a blurred rotor disc is discernible) at the same time smoke continues to emerge from the top opening; the chamber, fan, and opening all remain inside the frame and unobstructed.
level_5: All elements from the 4-point level are present, and the fan's rotation and the emerging incense smoke are both continuously visible for the entire recorded duration, with the chamber, fan, and top opening never leaving the frame or becoming occluded; no second fan, chamber, or smoke source appears, and the fan and opening never swap positions.

Scientific and Causal Correctness rubric:
level_1: Smoke exits the top opening but drifts sideways, spreads outward in a widening cone, or sinks back down instead of following a defined upward path, and its motion shows no rotation about a vertical axis at any point, regardless of whether the fan is spinning.
level_2: Smoke rises from the opening but never visibly rotates about a central axis; or it rotates but the resulting strand tilts noticeably off the chamber's centerline, breaks into disconnected puffs instead of a continuous strand, or its swirl direction reverses at random without any corresponding change in the fan's spin direction.
level_3: Smoke rises from the central opening and visibly swirls around a vertical axis near the chamber's centerline, but the swirl repeatedly pauses and restarts, or the strand bows or bulges to one side instead of staying straight and centered.
level_4: Smoke forms a single, unbroken, centered vertical strand that rotates steadily in one direction for the full stretch of video in which the fan is shown running, but the video never shows the fan starting up, so the link between the fan's spin and the smoke's rotation is never directly demonstrated.
level_5: Smoke forms a single, unbroken, vertically centered strand that begins swirling only once the fan's blades are shown spinning (never before), continues rotating steadily in one direction for as long as the fan runs, and, if the video shows the fan slowing or stopping, the swirl visibly winds down rather than continuing on its own.

Spatiotemporal Consistency rubric:
level_1: The fan or chamber jumps to a different position or size between frames, the chamber's cylindrical outline visibly warps into a different shape (e.g., bulging or flattening), the incense smoke cuts out completely in one frame and reappears in a later frame with no plume visibly dispersing or re-forming in between, or the lighting swings violently between frames (e.g., bright to dark with no visible cause) with shadows jumping to the wrong side or vanishing inconsistently.
level_2: The fan's rotation speed visibly stutters or jumps between frames, the chamber's rim flickers or warps momentarily, or the smoke strand jumps by more than roughly 10% of the chamber's height to a different position between consecutive frames with no connecting motion shown.
level_3: The chamber, fan, and top opening stay in the same place and size across the whole video; the fan spins continuously without vanishing or relocating; smoke keeps emerging from the same opening without gaps; a slight, continuous wobble in the smoke strand's axis is acceptable at this level.
level_4: All conditions of the 3-point level hold, and in addition the smoke strand's rotation and vertical alignment stay steady from frame to frame (no sudden jump in its tilt or position), the fan's spin rate does not stutter, and the chamber's transparency does not flicker on and off.
level_5: All conditions of the 4-point level hold, and in addition the fan blades and the rotating smoke strand move with smooth, continuous motion for the entire video with no frame where either appears frozen, duplicated, or skipped, and the light on the chamber and smoke does not change in a sudden burst at any point.