Domain: Natural Science — Chemistry
Target concept: Decomposition of hydrogen peroxide in the presence or absence of yeast catalyst (rate of bubble formation)

Video generation prompt: Two transparent beakers containing equal amounts of hydrogen peroxide are placed side by side; yeast is added to the left beaker, while the right beaker remains unchanged and is stably presented in the image.

Evaluation guide:
(i) Target concept: Catalytic acceleration of chemical decomposition via biological enzyme (catalase in yeast) leading to observable gas evolution.
Minimum mechanism: Hydrogen peroxide must be chemically stable without catalyst; yeast must introduce active catalase; oxygen gas must form as discrete, buoyant, spherical bubbles rising through liquid; no alternative gas sources or physical agitation may drive bubble formation.
(ii)Storyline: Frame opens on static wide shot showing two identical beakers side-by-side. Both contain colorless liquid at equal level. Dry yeast is introduced into left beaker only, visible as falling granules. Within seconds, spherical bubbles emerge and rise continuously from liquid interior in left beaker only. Right beaker remains completely quiescent: no bubbles, no surface disturbance, no color change. Viewpoint remains fixed, lighting stable, all motion physically coherent. No external intervention occurs after yeast addition.

Manual:
Experimental Procedure
1. Place two identical transparent beakers side-by-side on flat surface.
2. Pour equal volumes of colorless hydrogen peroxide solution into each beaker.
3. Add dry yeast powder to left beaker only; do not disturb right beaker.
Observation of Experimental Phenomena
Bubbles form continuously and exclusively in the left beaker after yeast addition; no bubbles form in the right beaker at any time.
Summary of Experimental Principles
Yeast contains catalase enzyme, which accelerates decomposition of hydrogen peroxide (H₂O₂ → H₂O + O₂), producing oxygen gas bubbles. Without catalyst, decomposition is extremely slow under room conditions.

Prompt Grounding rubric:
level_1: Fewer than two beakers appear, or only one is filled with liquid; hydrogen peroxide is not visibly present in both containers; yeast granules are never shown being added to either beaker; or the beaker that receives yeast is on the right instead of the left as instructed.
level_2: Two beakers containing liquid are shown, but the setup fails at least one of: the liquid volumes in the two beakers look clearly unequal; yeast is added to both beakers instead of only one; the camera cuts, pans, or zooms during the sequence so a fixed side-by-side view of both beakers is never established.
level_3: Two beakers filled with visibly equal volumes of colorless liquid sit next to each other in one continuous shot; granular yeast is poured into the left beaker only; the right beaker is never touched; no props other than the beakers, liquid, and yeast appear in frame.
level_4: Everything required for score 3 holds, and additionally the yeast is clearly visible as dry granules or powder rather than pre-dissolved liquid; the two beakers match in size, shape, and tilt; nothing blocks the view of either beaker's contents or liquid surface at any point.
level_5: Everything required for score 4 holds, and additionally the yeast lands only in the left beaker with no spill, splash, or drift toward the right beaker; both beakers stay planted in the same spot on the table for the whole clip; no glare or reflection ever hides the liquid surface or bubble zone in either beaker.

Scientific and Causal Correctness rubric:
level_1: Bubbles form equally in both beakers, or only in the right (untreated) beaker; or the left beaker with yeast never produces any bubbles; or bubbles are already rising before the yeast touches the liquid.
level_2: Bubbles are confined to the left beaker but the timing is wrong: they start before the yeast makes contact with the liquid, or they appear then stop then restart in a broken pattern rather than a sustained stream, or the moving specks look more like floating debris or surface ripples than gas bubbles rising from inside the liquid.
level_3: Once yeast touches the liquid, bubbles begin rising continuously from within the left beaker only; the right beaker shows no bubbles for the entire clip; the bubbles are round, rise from inside the liquid column rather than sliding along the glass wall, and keep appearing without long gaps.
level_4: Everything required for score 3 holds, and additionally several bubbles (more than about three) are visible rising at once in the left beaker rather than one occasional bubble; the bubbles look like escaping gas rather than injected air or surface fizz; the liquid itself never changes color and no foam layer builds up.
level_5: Everything required for score 4 holds, and additionally bubbling starts within a couple of seconds of the yeast reaching the liquid and continues to the end of the clip; the bubble stream stays entirely inside the left beaker with none of it drifting or spilling toward the right beaker; no swirling current, condensation, or other visual effect could be mistaken for the bubbling itself.

Spatiotemporal Consistency rubric:
level_1: A beaker's position or size suddenly changes between moments, or a beaker or the liquid inside it vanishes and reappears; the light source or shadow direction switches abruptly with nothing in the scene to explain it; a beaker's glass looks broken, warped, or inconsistently transparent from one moment to the next.
level_2: A beaker's outline visibly shifts or wobbles from its earlier position over several consecutive frames even though nothing is touching it; the curve of the liquid surface looks different from one moment to the next; a bright reflection on the liquid surface jumps to a new spot with no matching change in the room's lighting.
level_3: Both beakers stay in the same spot relative to each other and to the table for the whole clip; neither beaker's shape nor the liquid surface flickers, breaks, or disappears; the yeast falling and the bubbles rising both follow a smooth, believable path with no sudden jumps or freezing.
level_4: Everything required for score 3 holds, and additionally the yeast granules sink at a steady, continuous rate rather than floating or hovering; bubbles rise straight up rather than drifting sideways or changing shape as they ascend; no blurring or streaking hides the individual bubbles or how many there are.
level_5: Everything required for score 4 holds, and additionally the whole clip plays without stutters, freezes, or repeated frames; the distance and angle between the two beakers stays the same throughout, showing no unintended camera drift; shadows and highlights on the beakers and liquid shift only as gradually and predictably as a fixed light source would produce.