Domain: Healthcare — Digestive Physiology
Target concept: Downloaded table in

Video generation prompt: Two test tubes containing equal volumes of casein solution were placed side by side on the table. An appropriate amount of trypsin solution was added to the left tube, while an equal volume of water was added to the right tube. Both tubes were incubated at 37°C for 60 minutes. The solution states of both tubes were continuously recorded via video for several hours.

Evaluation guide:
(i) Target concept: Enzymatic proteolysis specificity demonstrated via differential turbidity change in identical substrates under controlled conditions.
Minimum mechanism: Casein must be suspended colloidally (not dissolved), trypsin must be active at 37°C, hydrolysis products must be molecularly small enough to eliminate light scattering, and water must lack proteolytic activity.
(ii)Storyline: Frame 0–1: Two side-by-side tubes filled with identical milky-white casein solution. Frame 2–3: Pipette delivers clear liquid to left tube; identical pipette delivers clear liquid to right tube, both additions visually matched in volume and kinetics. Frame 4–9: Left tube progressively loses opacity (transitioning white → translucent → clear) while right tube retains uniform milky-white appearance with no fading, settling, or separation. Viewpoint is fixed frontal close-up, ensuring full visibility of both tubes, menisci, and whichever left/right identification cue (label or color-coding) marks which tube received trypsin; no occlusion, no cutaways, no external interference.

Manual:
Experimental Procedure
1. Place two identical transparent test tubes side-by-side on a lab bench.
2. Fill both with equal volumes of white opaque casein solution.
3. Add trypsin solution to left tube; add equal volume of water to right tube.
4. Incubate both at 37°C for 60 min.
Observation of Experimental Phenomena
Left tube gradually clarifies (increased transparency); right tube remains stably opaque/milky-white with no change.
Summary of Experimental Principles
Trypsin hydrolyzes casein protein into soluble peptides, reducing turbidity; water causes no enzymatic breakdown — control remains turbid.

Prompt Grounding rubric:
level_1: Neither test tube appears, or the casein solution is missing from both containers, or no liquid is added to either tube, or the two tubes are not standing next to each other on the bench; none of the described setup (two adjacent tubes with casein, one dosed with trypsin, one with water) is depicted.
level_2: Two containers appear but are mismatched in shape or size, so they do not read as a matched pair of test tubes; or the casein solution fills only one container while the other is empty or holds something else; or a liquid is added to both tubes in the same way (or to neither); or the tubes are stacked, overlapping, or spaced far apart rather than standing beside each other, with nothing distinguishing a left tube from a right tube.
level_3: Two matching transparent test tubes stand upright side by side, each filled with an equal amount of opaque white casein suspension; a colorless liquid is added to the left tube from a dropper/pipette, and a separate colorless liquid (water) is added to the right tube from a similar dropper/pipette; both additions are clearly shown entering their tube, but nothing on screen (color, marking, or a stated left/right convention) tells the viewer which tube got trypsin and which got water.
level_4: All elements of score 3 present AND: the left tube is visually identified as the trypsin tube and the right tube as the water tube, through a legible label, a distinct color on the cap/tape/pipette, or a clear and consistent left/right placement a viewer can follow, so the two tubes are never confusable; both pipette deliveries look matched in volume and drop count; the tubes stay in the same spot on the bench for the whole shot; no extra props (spare tubes, hands, timers) enter the frame.
level_5: All elements of score 4 present AND: the trypsin/water identity of the two tubes stays visually unambiguous for the entire shot, whether through consistent color-coding, a persistent on-screen marker, or an unwavering left/right convention; there is no moment where the two tubes could be swapped in the viewer's mind; both tubes show matching meniscus height and wall clarity before and after their additions; the camera keeps both tubes and their liquid levels fully in frame with no blur or cropping at any point.

Scientific and Causal Correctness rubric:
level_1: No difference in turbidity develops between the two tubes over the course of the video, for example, both stay equally opaque, both clear at the same rate, or the left (trypsin) tube stays opaque while the right (water) tube is the one that clears, reversing the expected outcome; or either tube changes to a non-physiological color (e.g., blue, green, or purple) instead of the expected white-to-clear change.
level_2: A difference appears but violates the expected trypsin/water logic: the right (water) tube loses its opacity while the left (trypsin) tube does not; or both tubes lose opacity together at the same pace; or the left tube starts clearing before the trypsin has even been added; or the turbidity change is accompanied by a color shift rather than a plain white-to-clear transition.
level_3: The left (trypsin) tube visibly and steadily loses its milky-white opacity over the recording, becoming progressively more see-through, while the right (water) tube stays opaque and white with no comparable loss of turbidity; the left tube's change runs in one direction only (it never becomes cloudier again), and neither tube develops any new color.
level_4: All elements of score 3 present AND: at every point after the additions, the left tube looks clearer than the right tube, and that gap keeps widening rather than narrowing or flickering back and forth; the right tube's opacity stays essentially unchanged: no fading, no settling into layers, no bubbling; the left tube's clearing is smooth and even, with no separate curd-like clump forming.
level_5: All elements of score 4 present AND: by the end of the recording the left tube looks about as clear as plain water, showing the casein has broken down enough to stop scattering light, while the right tube's milky-white appearance looks essentially the same as it did in the very first frame; the left tube's liquid stays evenly clear with no floating haze or film, and the right tube stays evenly cloudy with no casein settling toward the bottom or clearing near the top.

Spatiotemporal Consistency rubric:
level_1: Between one shot and the next, a test tube snaps to a different spot on the bench or changes size with no camera motion to account for it; the picture cuts straight from bright to dark (or the reverse) with no fade or pan bridging it; the liquid meniscus in a tube blinks out of view for an instant and then is visible again although nothing was poured at that moment; the left and right tubes swap places on the bench; or a tube's glass wall visibly bends, melts, or warps out of its normal straight shape.
level_2: One tube flickers in and out of the shot briefly; the shadow cast by a tube or by the pipette swings to a noticeably different direction with no corresponding change in the room's light source; the frame crops or zooms suddenly, cutting off part of a tube; the pipette appears to be dispensing liquid before it has entered the frame; a tube slides sideways on the bench with nothing (no hand, no bump) causing the movement.
level_3: A single, minor inconsistency appears without derailing the rest of the shot: the tubes show a small, noticeable wobble rather than sitting perfectly still, or the room's brightness flickers up or down once and then settles; the pipette's motion blurs slightly while dispensing but the tubes themselves do not shift position; neither tube is blocked from view, and neither the tube walls nor the tabletop show any bending or warping during the shot.
level_4: All elements of score 3 present AND: the camera holds a single fixed framing with no pan, tilt, or zoom for the whole shot; the two tubes keep the same size, tilt, and spacing relative to one another in every frame; the shadow each tube casts on the bench points the same way as the shadow cast by the pipette, and that relationship holds steady for the whole recording; the pipette moves in and dispenses fully before withdrawing, with no overlap between the two additions.
level_5: All elements of score 4 present AND: the motion throughout is smooth, with no stutter, doubling, or strobing between frames; when each liquid is added, the meniscus in that tube rises by a small, natural amount matching the volume delivered; there is no stray glare, flare, or color fringing on the glass at any point; the tubes, the pipette, and the bench all look optically consistent from the first frame to the last.