Domain: Healthcare — Nutrition & Dietetics
Target concept: The activity of catalase in potatoes reacting with hydrogen peroxide (rate of bubble formation)

Video generation prompt: Place fresh potato cubes into two transparent glass containers; add hydrogen peroxide, with one container placed in a water bath at an elevated temperature and the other maintained at room temperature conditions.

Evaluation guide:
(i) Target concept: Temperature-dependent enzymatic reaction rate demonstrated via catalase-mediated H₂O₂ decomposition.
Minimum mechanism: Catalase must be present and active in potato tissue; H₂O₂ must be substrate; O₂ gas evolution must be the sole observable product; elevated temperature must increase kinetic energy of enzyme-substrate collisions without denaturing catalase (within safe range <50°C).
(ii)Storyline: Frame opens on static side-by-side view of two identical transparent containers on lab bench → fresh potato cubes placed simultaneously into both → colorless liquid poured into both → one container immediately placed into or already situated within visible water bath (with thermal indicators), the other remains unmodified → after liquid addition completes, bubbling initiates promptly and becomes visibly dense in the water-bath container, while the room-temperature container also shows bubble formation but at a markedly slower, sparser rate (not a complete absence, since potato catalase remains active near room temperature) → both containers continue reacting at their own distinct rates through the remainder of the recording → all actions occur from fixed frontal viewpoint with no occlusion of container interiors or potato surfaces.

Manual:
Experimental Procedure
1. Place identical fresh potato cubes into two identical transparent glass containers.
2. Add equal volumes of colorless hydrogen peroxide solution to both containers.
3. Place one container in a visible water bath (warm, ~40°C); leave the other at room temperature — both side-by-side.
Observation of Experimental Phenomena
Bubbles form rapidly and densely in the water-bath container; bubbles also form in the room-temperature container, but more slowly and sparsely, since potato catalase remains substantially active near room temperature.
Summary of Experimental Principles
Catalase enzyme in potato accelerates hydrogen peroxide decomposition into water and oxygen gas; reaction rate increases with temperature, so bubbling is fast and vigorous under warmed conditions and slower and sparser — but still clearly present — at room temperature, since potato catalase remains active across a broad range that includes normal room temperature.

Prompt Grounding rubric:
level_1: No potato cubes are visible, or no transparent glass containers are shown, or no hydrogen-peroxide liquid is ever added, or there is no water bath and room-temperature container pair present, or the two containers are never shown together in the same shot.
level_2: At least one transparent container is visible but potato cubes appear in only one of the two containers (or in neither), or the added liquid is missing or impossible to identify as being added to both containers, or there is no visual cue at all (warm water, steam, ice, or similar) distinguishing which container is meant to be warmer than the other.
level_3: Two visually similar transparent containers appear together in the same shot; fresh potato cubes are visible in both; a colorless liquid is added to both; one container is clearly associated with a warm water bath (visible warm water, steam, or comparable warmth cue) while the other has no such cue and reads as room temperature.
level_4: Everything required for score 3 holds, and in addition the warm-bath container's warmth cue stays visibly present and distinguishable from the room-temperature container throughout the recording, and both containers remain in frame and unobstructed the whole time, with neither cropped out, swapped, or briefly hidden.
level_5: Everything required for score 4 holds, and in addition the potato cubes in both containers look comparable in size and cut, the liquid fills both containers to a similar height, and the camera viewpoint and framing stay fixed and steady from start to finish with no repositioning of either container.

Scientific and Causal Correctness rubric:
level_1: No bubble formation is observed in either container, or bubbles appear at the same rate and density in both containers, or bubbles appear before the potato cubes are ever in contact with the liquid, or the room-temperature container visibly bubbles faster or denser than the warm-bath container.
level_2: The warm-bath container shows bubbling while the room-temperature container shows no bubbles at all for the entire observation period, or the two containers show bubbling that looks equally vigorous with no rate difference between them, or bubbling begins before the potato cubes are submerged.
level_3: Both containers show visible bubble formation once the potato cubes are submerged in the liquid, but the warm-bath container's bubbling is noticeably more frequent and dense than the room-temperature container's, which shows fewer, slower, or more sporadic bubbles rather than a comparably vigorous stream.
level_4: Everything required for score 3 holds, and in addition the contrast in bubbling rate between the two containers stays clearly visible across the whole observation window rather than only appearing briefly at the start, and in both containers the bubbles look physically plausible — roughly spherical and rising through the liquid rather than floating unnaturally or staying frozen in place.
level_5: Everything required for score 4 holds, and in addition the warm-bath container's bubbling starts more promptly after the liquid is added and stays visibly dense through the recording, the room-temperature container's bubbling stays visibly slower and sparser throughout without ever matching or exceeding the warm-bath container's rate, and in both containers bubbles form cleanly at the potato surface and detach without unnatural clumping, freezing, or foam buildup.

Spatiotemporal Consistency rubric:
level_1: A container or potato cube disappears from the shot and reappears, or the liquid level in a container jumps up or down with no pouring action shown to explain it, or the screen flashes or a shadow jumps abruptly, or the camera angle snaps or zooms suddenly between frames.
level_2: One of the containers shifts position between frames with nothing shown moving it, or a potato cube's orientation changes with no visible cause, or the reflections on a liquid surface look inconsistent from one frame to the next, or the whole scene shows persistent small shaking.
level_3: Both containers stay in the same place and orientation throughout; the potato cubes keep a consistent position and shape; each liquid surface looks like a real liquid (small natural ripples rather than a perfectly frozen or artificially flat surface); nothing clips through anything else, and no shadow looks out of place relative to the rest of the scene.
level_4: Everything required for score 3 holds, and in addition the liquid is added as one continuous pouring motion rather than appearing already poured, the potato cubes are placed into the containers as one uninterrupted action rather than appearing instantly, and the warm-bath cue (steam or shimmer) stays visible continuously rather than flickering on and off.
level_5: Everything required for score 4 holds, and in addition the poured liquid shows a believable flow and meniscus rather than looking like a static texture, the potato cubes settle into the liquid with a plausible small splash or settling motion rather than snapping into place, and neither container nor any cube shows warping, ghosting, or unnatural blur at any point in the recording.