Domain: Engineering — Food and Bioprocess Engineering
Target concept: Carotenoid Analysis (Simplified Paper Chromatography)

Video generation prompt: Carrot extract was spotted near the bottom edge of the chromatography paper, kept above where the solvent will sit, and the paper was then placed into a developing solvent composed of petroleum ether and acetone. After chromatographic separation for 5 minutes, the paper was observed.

Evaluation guide:
(i) Target concept: Capillary-driven chromatographic separation of plant pigments based on differential solubility and adsorption affinity.
Minimum mechanism: Solvent must contact paper bottom → wick upward → dissolve spot → carry components at different rates → form spatially resolved bands; band order must reflect polarity gradient (nonpolar fastest).
(ii)Storyline: Frame 1–2: Static shot of dry paper with spot at bottom edge. Frame 3–4: Paper inserted downward into solvent container; spot remains dry but bottom edge touches liquid. Frame 5–6: Solvent front advances steadily upward; spot begins to dissolve. Frame 7–8: Two discrete bands emerge and separate as the solvent rises: the less-polar orange-red β-carotene band moves fastest and pulls ahead toward the solvent front, while the more-polar yellow xanthophyll band lags behind, staying closer to the origin. Frame 9–10: Bands stabilized; solvent front clearly visible as sharp horizontal boundary; no further change. Viewpoint: Fixed frontal, eye-level, orthogonal to paper plane; no occlusion; full paper and solvent container in frame throughout.

Manual:
Experimental Procedure
1. A strip of chromatography paper is held vertically.
2. A small spot of carrot extract is applied near the bottom edge.
3. The paper is placed upright into a container with petroleum ether–acetone solvent so the spot is just above the solvent level.
Observation of Experimental Phenomena
After development, distinct upward-migrating bands appear: an orange-red band farthest from the origin, nearest the solvent front, and a yellow band below it, closer to the origin; solvent front is visible as a clear horizontal line.
Summary of Experimental Principles
Carotenoids in carrot extract separate by polarity via capillary action in the solvent system; less polar β-carotene migrates farther (orange-red), more polar xanthophylls lag (yellow).

Prompt Grounding rubric:
level_1: No chromatography paper is visible; no carrot-extract spot appears near its bottom edge; no container of petroleum ether/acetone solvent is shown; the paper is never placed into the solvent.
level_2: The paper is shown standing upright, but the carrot-extract spot is missing or sits more than about 5 mm from the bottom edge; the solvent container is present but holds the wrong liquid (water, a colored dye, or a single solvent rather than the petroleum-ether/acetone mixture); the paper is never lowered into the solvent.
level_3: The paper stands upright with a visible dark orange-brown spot near its bottom edge; a see-through container holds solvent whose level sits below the spot; the paper is lowered in so that the spot stays above the liquid surface while the paper's very bottom edge touches the solvent; all these pieces appear together in correct relative position.
level_4: Everything required at the 3-point level is present, and in addition the paper stops moving once inserted; the solvent's liquid line is level all the way across the container; the spot itself does not shift position while the scene is observed; no unrelated tools, hands, gloves, or labels appear in the shot.
level_5: Everything required at the 4-point level is present, and in addition the paper's top edge stays fully in view and vertical; the spot sits right at the very bottom edge rather than being smeared upward before the paper touches solvent; the solvent's surface is calm and flat; the paper never bends, tilts, or floats free in any frame; the camera holds a fixed, straight-on view of the paper for the whole clip.

Scientific and Causal Correctness rubric:
level_1: No pigment separation happens at all: the paper stays uniformly white or uniformly stained one color, with no bands forming and no directional movement of pigment away from the spot.
level_2: Pigment moves but only as a single smeared streak with no distinct bands; the color present is wrong for carotenoids (e.g., green, blue, or purple, or only yellow with no orange-red at all); or the smear moves sideways or downward instead of rising with the solvent.
level_3: An orange-red band and a paler yellow band both appear and rise above the original spot as separate, non-overlapping bands running parallel to the solvent front; neither band rises past the upper half of the visible paper; the orange-red band sits farther from the origin, nearer the rising solvent front, than the yellow band.
level_4: Everything required at the 3-point level is present, and in addition both bands keep sharp, straight leading edges with no merging, bleeding, or fading; the solvent front is visible as a distinct line above the original spot; the orange-red band is the more intense of the two and continues to lead the yellow band toward the solvent front.
level_5: Everything required at the 4-point level is present, and in addition the orange-red band is the uppermost band, closest to the solvent front and clearly the most intense; the yellow band trails below it, closer to the origin, with a clean gap between the two; no third (e.g., green) band appears; neither band's position drifts or widens once formed.

Spatiotemporal Consistency rubric:
level_1: Severe continuity breaks: the paper's position jumps between shots; the solvent's liquid level changes suddenly with no pouring shown; the carrot-extract spot blinks out of existence and back mid-clip; the light on the scene swaps brightness or direction with no camera change; the paper spins more than about 10 degrees with no blur to show the motion; or the background or the paper/container edges flicker or tear between frames.
level_2: Less extreme but still visible problems: the paper flexes or buckles unnaturally as it is lowered in; the spot smears upward before the solvent ever reaches it; the solvent's surface ripples inconsistently; the paper shifts sideways or tilts by more than about 5 degrees after being placed, with no hand or cause shown; the shadow the paper casts points a different way than the light source would allow.
level_3: The paper is lowered in smoothly and then holds still; the spot stays intact at its starting point until the solvent reaches and begins to dissolve it; the solvent front rises steadily and evenly; the paper, container, and bands stay the same size and shape and keep their positions relative to each other; nothing in the shot blinks out of view or appears out of nowhere.
level_4: Everything required at the 3-point level is present, and in addition the paper is completely still after insertion, with no residual sway; the solvent front climbs at a steady, unchanging pace; the bands only begin forming once the solvent has actually reached the spot; the paper and the container edges behind it never drift relative to one another as the camera holds its framing.
level_5: Everything required at the 4-point level is present, and in addition the paper stays perfectly flat with no curling; the solvent's surface stays level and unbroken across the whole clip; both bands' leading edges rise together evenly across the paper's full width; the paper and container never show a mismatched frame-to-frame jump in scale or angle; the brightness and direction of the light on the scene stay the same for the entire clip.