Domain: Natural Science — Microbiology
Target concept: Comparison of Fermentation between Heat-Inactivated Yeast and Active Yeast in Sugar Solutions

Video generation prompt: Two transparent bottles containing sugar water: the left one was inoculated with boiled and cooled yeast, while the right one was inoculated with active yeast. Balloons of the same type were placed over the bottle mouths, and the process was recorded over time under warm, thermostatically controlled conditions.

Evaluation guide:
(i) Target concept: Differential CO₂ production due to enzymatic activity in viable vs. denatured yeast under fermentation-permissive conditions.
Minimum mechanism: Yeast cells must be structurally intact and metabolically active to catalyze glycolysis and alcoholic fermentation; boiling irreversibly denatures all proteins including pyruvate decarboxylase and alcohol dehydrogenase, eliminating CO₂ generation capacity; sugar water provides substrate; warmth enables enzymatic kinetics without killing active culture.
(ii)Storyline: Frame 0–2: Static wide shot showing two identical bottles side-by-side, both filled with clear liquid, empty mouths. Frame 3–4: Left-hand inoculation: spoon dips into visibly cooled (non-steaming, room-temp appearance) yeast vial and deposits into left bottle. Frame 5–6: Right-hand inoculation: spoon dips into frothy/active yeast vial and deposits into right bottle. Frame 7–8: Both balloons placed and fully sealed over mouths. Frame 9–10: Bottles resting under warm condition (e.g., soft ambient glow, no condensation); right balloon begins visible expansion; left balloon remains flat; right liquid shows bubbling; left liquid remains still. All events occur in fixed frontal viewpoint with no occlusion or repositioning.

Manual:
Experimental Procedure
1. Place two identical transparent bottles side-by-side.
2. Fill both with equal volumes of clear sugar water.
3. Inoculate left bottle with boiled-then-cooled yeast; inoculate right bottle with active yeast.
4. Immediately seal both bottle mouths with identical balloons.
5. Place setup under warm, thermostatically controlled conditions (a stable, gently heated environment).
Observation of Experimental Phenomena
- Left bottle balloon remains completely flat; no bubbling in liquid.
- Right bottle balloon inflates progressively; liquid shows continuous bubbling/effervescence.
Summary of Experimental Principles
Active yeast metabolizes sugar via aerobic/anaerobic respiration, producing CO₂ gas; heat-inactivated yeast has denatured enzymes and cannot ferment — no CO₂ produced.

Prompt Grounding rubric:
level_1: Neither bottle is transparent or visible; no sugar water is visible in either bottle; no yeast inoculation is shown for either bottle; no balloons are present; the two bottles are not shown next to each other; nothing in the scene suggests a warm, controlled environment.
level_2: Two transparent bottles are visible but are not placed next to each other; at least one bottle holds liquid, but no inoculation action is shown; balloons are missing, or are visibly not sealed over the bottle mouths; nothing suggests a warm, controlled setting.
level_3: Two transparent bottles sit next to each other, both holding clear liquid (sugar water); matching balloons sit sealed over both bottle mouths; an inoculation action is shown for at least one bottle, but nothing in the video distinguishes which bottle got the boiled-and-cooled yeast versus the active yeast (no visible difference in how the two yeast samples are handled).
level_4: Two transparent bottles sit next to each other, both holding clear liquid; matching balloons are sealed over both bottle mouths; an inoculation action is shown for both bottles, and there is some visible difference between the two yeast samples as they're added (e.g., one looks cooled/still while the other looks freshly stirred or frothy, or one vial reads as 'boiled' while the other doesn't), but the balloons' behavior over time is not yet shown.
level_5: Two transparent bottles sit next to each other in a fixed camera view, both holding clear liquid; matching balloons are fully sealed over both bottle mouths; the inoculation is clearly differentiated: the left bottle receives visibly cooled yeast (steam has dissipated, added from a room-temperature-looking vial) and the right bottle receives visibly active yeast (frothy or freshly stirred); the setting visually reads as warm and controlled (e.g., the bottles rest on a warming pad or inside an enclosed, gently heated space, with no condensation suggesting a cold environment).

Scientific and Causal Correctness rubric:
level_1: Neither balloon shows any inflation; both stay completely flat for the whole video; the two bottles behave identically to each other; neither the liquid nor either balloon shows any visible change.
level_2: At least one balloon inflates, but both balloons inflate in the same way with no difference between them and no delay between the two; the liquid in both bottles stays still with no bubbling in either.
level_3: Only the right-hand balloon (active yeast) inflates; the left-hand balloon (boiled-then-cooled yeast) stays completely flat; the left bottle's liquid shows no bubbling or surface disturbance; the right bottle's liquid visibly bubbles or stirs before or alongside the balloon's inflation.
level_4: The right-hand balloon inflates progressively and grows visibly larger than the left-hand balloon, which stays completely flat throughout; the right bottle shows ongoing bubbling/effervescence in its liquid; the left bottle's liquid stays completely still and clear; the size difference between the two balloons never reverses or evens out.
level_5: The right-hand balloon inflates steadily and is the only one that ever inflates; the left-hand balloon stays flat and unchanged in shape and size for the entire video; the right bottle's liquid keeps bubbling visibly throughout; the left bottle's liquid stays still, clear, and bubble-free the whole time; the left balloon never inflates even briefly, and the right balloon never deflates or shrinks back; the bubbling in the right bottle visibly precedes and drives the balloon's inflation, and this cause-and-effect only ever happens on the right.

Spatiotemporal Consistency rubric:
level_1: A bottle abruptly appears or disappears between frames; a balloon appears or disappears without ever visibly being attached; the liquid level changes suddenly with no smooth transition; the camera viewpoint jumps to a different angle; the lighting flickers or suddenly changes brightness for no reason; a bottle or balloon's shape breaks or distorts in an unnatural way.
level_2: One balloon comes loose from its bottle partway through the video; a bottle's position shifts sideways with no visible motion causing it; a balloon inflates without any bubbling shown before or during that inflation; the liquid surface switches from still to visibly agitated in a single cut rather than gradually.
level_3: Each bottle keeps its place relative to the other bottle and to the bench for the whole clip; neither bottle nor balloon teleports, detaches, or breaks apart; the lighting on the two bottles stays even and doesn't shift unexpectedly; any motion shown (like a balloon expanding) looks smooth and physically reasonable rather than snapping into a new shape.
level_4: Everything in the 3-point description holds, and in addition: both bottles stay upright and stationary the whole time; if a balloon inflates, it expands evenly outward rather than bulging to one side; if a liquid shows bubbling, it starts subtly and builds up gradually rather than beginning at full intensity; there's no visible shaking of the bottles or balloons from frame to frame; no balloon ever appears to clip through or intersect its bottle's neck.
level_5: Everything in the 4-point description holds, and in addition: both bottles, both balloons, and both liquid surfaces stay steady and aligned across the whole clip; any inflating balloon grows in a smooth, even, roughly symmetric way; any bubbling builds up gradually, with more bubbles appearing over time rather than jumping straight to heavy bubbling; there's no visible flicker, ghosting, or blurring that would hide whether a balloon is inflating or a liquid is bubbling; the camera viewpoint never drifts or shifts throughout.