Domain: Natural Science — Chemistry
Target concept: Catalase-mediated decomposition of hydrogen peroxide is inhibited by copper ions.

Video generation prompt: Two identical transparent glass bottles containing catalase solution were prepared; copper sulfate was added to one, and water to the other, followed by the simultaneous addition of equal amounts of hydrogen peroxide.

Evaluation guide:
(i) Target concept: Enzyme inhibition by heavy metal ions alters reaction kinetics of H₂O₂ decomposition.
Minimum mechanism: Catalase must be functional in control (H₂O bottle) to produce O₂ gas visibly; Cu²⁺ must bind irreversibly to catalase active site, abolishing enzymatic turnover; H₂O₂ must be chemically stable enough to persist until contact with catalase, and its decomposition must be exclusively enzyme-dependent under these conditions (no spontaneous or catalyzed-by-glass decomposition).
(ii)Storyline: Frame 0–1: Static side-by-side view of two identical transparent bottles, each filled with clear liquid (catalase solution). Frame 2–3: Copper sulfate solution (blue) dispensed into left bottle; colorless water dispensed into right bottle; both actions complete before next step. Frame 4: Pause, no bubbling in either bottle. Frame 5: Identical pipettes deliver H₂O₂ simultaneously to both bottles. Frame 6–10: Immediate, vigorous bubbling emerges in right (water) bottle; left (CuSO₄) bottle remains completely quiescent (no bubble nucleation, no foam, no surface agitation), with full frontal visibility of both liquid columns and surfaces throughout.

Manual:
Experimental Procedure
1. Place two identical transparent glass bottles side-by-side.
2. Fill both with identical clear catalase solution.
3. Add copper sulfate solution to left bottle; add water to right bottle.
4. Simultaneously add equal amounts of hydrogen peroxide to both bottles.
Observation of Experimental Phenomena
- Vigorous bubbling (oxygen gas evolution) occurs immediately in the water-added bottle.
- No bubbling or complete suppression of bubbling occurs in the copper sulfate-added bottle.
Summary of Experimental Principles
Copper ions (Cu²⁺) inhibit catalase enzyme activity, preventing decomposition of hydrogen peroxide into water and oxygen — thus suppressing gas evolution.

Prompt Grounding rubric:
level_1: Neither of the two glass bottles is shown; no clear catalase solution appears in either bottle; copper sulfate and water are not added to separate bottles; hydrogen peroxide is never dispensed; the two bottles are not shown together side by side in the same shot.
level_2: Both bottles appear but differ in size, shape, or fill level; the catalase solution is not visibly identical in the two bottles before any additive is poured; only one of the two additives (copper sulfate solution or water) is actually poured in, or hydrogen peroxide reaches only one bottle, or reaches the two bottles at clearly different times; the bottles are arranged front-to-back or diagonally rather than side by side.
level_3: Two visually identical transparent glass bottles holding the same clear catalase solution sit side by side; copper sulfate solution is poured into one and plain water into the other; equal-looking volumes of hydrogen peroxide are then added to both bottles within the same continuous shot; the bottles do not move from their side-by-side positions for the remainder of the clip.
level_4: Everything required for score 3 is shown, and in addition: the copper sulfate solution is a visibly blue liquid (not a dry powder or an off-color tint) while the water stays colorless; the two liquids look equal in volume and clarity before hydrogen peroxide is added; hydrogen peroxide is delivered into both bottles from matching droppers using the same pouring motion, height, and timing; the left/right position of each bottle stays fixed and consistent throughout so the CuSO4 bottle and water bottle remain identifiable by position and color alone.
level_5: Everything required for score 4 is shown, and in addition: the camera holds a single static, fully unobstructed frontal framing that keeps both liquid columns and bottle mouths in view for the entire clip, from before the additive is poured through several seconds after hydrogen peroxide is added; the copper sulfate solution's blue color and the water's colorlessness stay visually unchanged right up to the moment hydrogen peroxide is dispensed; the two dropper actions are close enough in timing that neither bottle visibly receives hydrogen peroxide meaningfully before the other; no hand, tool, or label ever blocks either liquid surface during the addition.

Scientific and Causal Correctness rubric:
level_1: Both bottles bubble the same way after hydrogen peroxide is added; or bubbling appears only in the copper sulfate bottle and not the water bottle; or neither bottle bubbles at all; or a bottle's liquid changes to an unrelated color such as red or green; or the catalase solution itself looks cloudy or tinted with no reagent to justify it.
level_2: Bubbling appears in both bottles with no noticeable difference in strength or timing; or bubbles show up in the copper sulfate bottle before the water bottle; or bubbling starts before hydrogen peroxide is added to either bottle; or the copper sulfate is shown as a dry white solid rather than a blue solution; or the water bottle stays quiet while the copper sulfate bottle bubbles, the reverse of what catalase inhibition predicts.
level_3: After hydrogen peroxide is added, bubbling shows up in both bottles, but the copper sulfate bottle's bubbling is clearly weaker or absent compared with the water bottle; neither liquid shows an unrelated color change; the catalase solution stays clear in both bottles; the copper sulfate solution keeps its blue color and the water stays colorless; no bubbling occurs in either bottle before hydrogen peroxide is added.
level_4: Everything required for score 3 holds, and in addition: the water bottle's bubbling is steady, vigorous, and fills a visible portion of the liquid with rising bubbles or foam; the copper sulfate bottle shows no bubble formation at all -- no foam, no rising gas, no disturbance at the surface -- for at least a second after hydrogen peroxide reaches it; this absence is plainly visible and not hidden by camera angle, blur, or an object blocking the view.
level_5: Everything required for score 4 holds, and in addition: bubbling in the water bottle begins right at the moment hydrogen peroxide touches the liquid; the copper sulfate bottle shows no bubble nucleation or surface disturbance for the entire comparable stretch afterward -- no brief fizzing, no scattered small bubbles anywhere in that bottle's liquid column.

Spatiotemporal Consistency rubric:
level_1: One of the two bottles vanishes or is replaced between shots, or instantly jumps to a different position on screen with no motion connecting the two frames; the lighting abruptly shifts between bright and dark with no visible cause, obscuring the bottles; the dropper delivering hydrogen peroxide jumps from one position to another without traveling through the air; the copper sulfate solution's blue color swaps to the water bottle or vice versa; the liquid level in either bottle changes with no pouring action shown; a bottle rotates or tips over with no visible cause.
level_2: One bottle shifts sideways by more than a quarter of its own width between consecutive shots; the hydrogen peroxide dropper appears already above the liquid without showing its downward approach; the pour of copper sulfate solution or water starts or stops abruptly mid-stream with no continuous flow; reflections on the bottle glass flicker or swap sides without the light source moving; the shadows cast by the two bottles point in different, changing directions from shot to shot.
level_3: The two bottles stay in the same side-by-side spot and orientation for the whole clip; the copper sulfate solution, water, and hydrogen peroxide each travel from source to bottle along a continuous, visible path when added; the shadows the bottles cast keep the same direction and darkness across the clip; neither bottle's outline warps, bends, or clips through the other object.
level_4: Everything required for score 3 holds, and in addition: neither bottle shakes or jitters against its background between frames; the frame's overall brightness does not jump or dim suddenly while the hydrogen peroxide is being added, so the bubbling contrast stays clearly visible; reflections on the bottle surfaces shift only as much as the pouring motion would cause, not randomly; the liquid meniscus in each bottle sits and moves the way a real liquid surface would, without floating bubbles or liquid spreading unnaturally across the glass.
level_5: Everything required for score 4 holds, and in addition: the dropper's downward motion into each bottle looks like a hand-controlled pour rather than a mechanically uniform glide; the stream of hydrogen peroxide stays a single connected thread until it touches the liquid surface; no frame repeats itself or blurs enough to hide whether bubbles are forming or absent in either bottle; the glass of both bottles keeps a consistent, undistorted view of the liquid inside from the first frame to the last.