Domain: Natural Science — Chemistry
Target concept: Catalase decomposes hydrogen peroxide, and reduces it in the presence of an inhibitor.

Video generation prompt: Two adjacent transparent test tubes, one colorless and the other colored, contain catalase; hydrogen peroxide is added to both simultaneously, with the colored tube containing an inhibitor, and the camera remains stationary.

Evaluation guide:
(i) Target concept: Enzyme inhibition demonstrated via differential catalytic activity under identical substrate exposure.
Minimum mechanism: Catalase must be functionally active in one tube and fully inhibited in the other; H₂O₂ must be chemically identical in both deliveries; visual contrast (color) must serve solely as an inhibitor marker, not affect catalysis itself.
(ii)Storyline: [Frame 0–1] Two adjacent upright transparent tubes in static frame: left colorless, right colored. [Frame 2–3] Identical hydrogen peroxide delivery initiates synchronously into both tubes. [Frame 4–6] Bubbling emerges exclusively in colorless tube; colored tube surface remains perfectly still. [Frame 7–10] Bubbling persists continuously in colorless tube; colored tube shows zero effervescence, no color change, no meniscus disturbance, confirming complete inhibition. Perspective: Fixed frontal view, centered on tube pair, no occlusion, consistent lighting.

Manual:
Experimental Procedure
1. Place two upright, transparent test tubes side-by-side in fixed view.
2. Fill left tube with colorless catalase solution; fill right tube with catalase solution + visible dye (e.g., blue food coloring) to indicate inhibitor presence.
3. Simultaneously add equal volumes of hydrogen peroxide to both tubes using identical technique.
Observation of Experimental Phenomena
- Colorless tube produces immediate, continuous bubbling (oxygen gas evolution).
- Colored (inhibitor) tube shows no bubbling or gas evolution at any time.
- Both tubes retain original color and transparency; no mixing, fading, or precipitation.
Summary of Experimental Principles
Catalase decomposes hydrogen peroxide into water and oxygen gas. In the presence of a specific inhibitor, catalase activity is blocked — no decomposition occurs, hence no bubbling.

Prompt Grounding rubric:
level_1: Two adjacent transparent test tubes are not both visible; or no catalase-containing liquid is shown in either tube; or hydrogen peroxide is never added to either tube; or there is no visible difference between a colored and colorless tube; or the camera visibly pans, zooms, or repositions during the clip.
level_2: Two test tubes are present and next to each other, but at least one is not upright or does not clearly hold liquid; there is nothing (label or prior context) tying either tube to catalase; hydrogen peroxide is added to only one tube or not shown being added at all; or the color difference between the two tubes is too subtle to tell apart.
level_3: Two upright, transparent test tubes sit next to each other for the whole clip, each holding liquid; one liquid is visibly colored (e.g. blue, green, or purple) and the other is colorless; hydrogen peroxide is added to both tubes at essentially the same moment, using a similar delivery method for each; and the camera stays in one fixed position without panning, tilting, or zooming.
level_4: Everything required at the 3-point level holds, and in addition the colored tube is clearly set apart as the one meant to contain the inhibitor (through a label, or through a color contrast strong enough that the two tubes cannot be confused), neither tube is blocked from view during the addition or afterward, and both tubes stay fully visible side by side without one being cropped out of frame.
level_5: Everything required at the 4-point level holds, and in addition both tubes keep the same orientation, size, and lighting for the entire clip, the hydrogen peroxide is added to both tubes in a visually equivalent way and roughly equal amount (without requiring an identical drop count or identical trajectory for each), the colored liquid keeps a steady, even color with no fading or bleeding, and the colorless tube stays clear and uncolored throughout.

Scientific and Causal Correctness rubric:
level_1: Neither tube shows any reaction; or both tubes behave the same way (both bubble, or neither does); or the bubbling/oxygen-gas evolution happens in the wrong tube (the colored tube bubbles while the colorless one does not); or there is no visible difference in reaction between the two tubes.
level_2: One tube shows bubbling, but it is the colored tube rather than the colorless one, or both tubes bubble with similar intensity and duration; or the colorless tube changes color; or the inhibited tube reacts more strongly than the uninhibited one.
level_3: Bubbling (oxygen gas escaping as the peroxide decomposes) appears only in the colorless tube and starts sometime after the hydrogen peroxide is added; the colored tube shows no bubbling at any point; the colorless tube itself never changes color; the colored tube keeps its original color; and this contrast between the two tubes is sustained for at least a couple of seconds after the addition.
level_4: Everything required at the 3-point level holds, and in addition the bubbling in the colorless tube is steady and clearly visible (rising bubbles or a persistent foam layer) for the rest of the clip, while the colored tube shows no bubbles, shimmer, or fizzing at any point, and neither tube shows unexpected cloudiness or layering.
level_5: Everything required at the 4-point level holds, and in addition the bubbling in the colorless tube starts within roughly a second of the hydrogen peroxide reaching it and continues without stopping until the end of the clip, the colored tube's liquid surface stays visibly calm and undisturbed the whole time, and there is no ambiguous halfway state (like a long delay before bubbling starts, or a few stray bubbles in the colored tube).

Spatiotemporal Consistency rubric:
level_1: Either test tube's position or shape changes abruptly between frames with no connecting motion; the liquid level jumps without cause; the hydrogen peroxide appears already added, or vanishes partway through being poured; the lighting shifts abruptly (a flash, flicker, or sudden shadow jump); or a tube's outline bends or stretches unnaturally.
level_2: One or both tubes look inconsistent in shape from frame to frame (e.g. switching between cylindrical and tapered, or the base disappearing in some frames); the liquid surface jumps to a new height with no addition to explain it; the peroxide stream stutters, stopping and restarting mid-pour; or the camera visibly drifts or shakes across several consecutive frames.
level_3: Both tubes keep a consistent shape, position, and size throughout; the liquid levels only change in ways that make sense (a slight rise when peroxide is added, then settling); the peroxide is poured in one continuous, unbroken stream; the lighting and shadows do not jump around; and nothing is blocked from view in a way that breaks the fixed camera view.
level_4: Everything required at the 3-point level holds, and in addition the liquid surface in each tube curves in a physically ordinary way and stays that way, there is no blur or ghosting around the tube edges or liquid surface, the addition to one tube does not finish noticeably before the other one even starts, and there is no sideways drift suggesting unintended camera movement.
level_5: Everything required at the 4-point level holds, and in addition each liquid surface keeps a smooth, convex curve where it meets the tube wall, the peroxide drops look like coherent rounded droplets as they land rather than breaking apart oddly, there is no repeated or frozen frame, and the two tubes stay level and aligned with each other in every frame of the clip.