Domain: Natural Science — Chemistry
Target concept: **Intermediate cycle of colorless → blue → colorless in the blue bottle reaction**

Video generation prompt: Fill a transparent glass bottle with a solution of glucose, sodium hydroxide, and methylene blue, then seal it and place it on the lab bench; repeatedly shake it and set it back down to demonstrate the color change.

Evaluation guide:
(i) Target concept: Reversible oxygen-dependent redox cycling of methylene blue in alkaline glucose solution.
Minimum mechanism: Dissolved molecular oxygen must be physically introduced via agitation (shaking) to oxidize leuco-methylene blue to its blue form; glucose, present in excess under alkaline conditions, then chemically reduces the dye back to its colorless leuco form once agitation stops; this reduction unfolds gradually over several seconds while the bottle sits undisturbed, it is not an instantaneous effect of setting the bottle down; the bottle must stay sealed to prevent passive O₂ exchange with outside air between cycles.
(ii)Storyline: [Phase 1: Baseline] Sealed bottle rests upright on the bench, contents fully colorless and transparent. [Phase 2: Oxidation phase] Bottle is shaken: liquid visibly agitates, the meniscus distorts, and a uniform blue color develops during or immediately after shaking stops. [Phase 3: Reduction phase] Bottle is set back down upright on the bench and left undisturbed; over the next several seconds the still liquid fades gradually and uniformly from blue back to colorless as glucose consumes the dissolved oxygen. [Phase 4: Cycle repeat] The same shake-then-rest sequence repeats with consistent timing, color fidelity, and spatial continuity. Perspective: Fixed frontal lab-bench view; bottle occupies the center of frame; no occlusion; full bottle height and cap remain visible at all times.

Manual:
Experimental Procedure
1. Fill a transparent glass bottle with an aqueous solution of glucose, sodium hydroxide, and methylene blue.
2. Seal the bottle tightly with its cap.
3. Place the bottle upright on the lab bench.
4. Shake the bottle vigorously for ~1 second → observe blue color developing.
5. Stop shaking, set the bottle back down, and let it stand motionless on the bench → over the next several seconds, observe the blue color fading gradually back to colorless.
6. Repeat steps 4–5 to demonstrate the reversible cycle.
Observation of Experimental Phenomena
- The initially colorless solution turns uniformly deep blue upon shaking.
- The blue solution fades gradually and completely to colorless while the bottle stands undisturbed after being set down (the fade is a chemical reduction that plays out over several seconds, not an instantaneous effect of the bottle being set down).
- The cycle repeats identically with each shake-then-rest pair.
Summary of Experimental Principles
- Methylene blue acts as a redox indicator: oxidized (blue) in the presence of dissolved O₂, reduced (colorless) by glucose in the alkaline medium.
- Shaking dissolves atmospheric O₂ into the solution, oxidizing the leuco dye to its blue form.
- Once shaking stops and the bottle sits undisturbed, glucose progressively consumes the dissolved O₂ and chemically reduces the dye back to its colorless leuco form.

Prompt Grounding rubric:
level_1: No transparent glass bottle is visible; none of the three reagents (glucose, sodium hydroxide, methylene blue) are present as a liquid inside it; no shaking motion is shown; no distinct rest phase occurs; no lab bench setting or fixed viewpoint is used.
level_2: A transparent glass bottle sits on a surface resembling a lab bench, but at least two of the three reagents are absent or unidentifiable as liquid contents; the bottle is never shown sealed; shaking is missing or replaced by unrelated motion (e.g., stirring, pouring between containers).
level_3: A sealed transparent glass bottle containing all three reagents as a single liquid (no undissolved solid dominating the view) sits on a lab bench; one shaking action and one following rest (setting the bottle back down) are both shown, directed at the same bottle in the same scene.
level_4: Everything required at the 3-point level holds, and the bottle stays visibly sealed throughout; each shake is followed by the bottle being set back down and left to rest, in that order; the shake-then-rest cycle repeats at least twice with each repetition visibly distinct, all within a single continuous shot with no cuts or viewpoint changes.
level_5: Everything required at the 4-point level holds, and the bottle is upright before each shake, visibly tilts or rotates during shaking, and returns to upright and stays stationary through each rest phase, with the same orientation pattern repeating consistently across cycles; no extraneous objects enter the frame; no reagent splashes, leaks, or cap displacement occur at any point.

Scientific and Causal Correctness rubric:
level_1: The bottle's contents stay uniformly colorless or uniformly blue across the whole clip, with no transition at all, contradicting the expected oxidation/reduction behavior of methylene blue.
level_2: A colorless-to-blue change occurs after shaking, but the reverse blue-to-colorless change never appears; or a color change happens without any preceding shake; or the color reached is not a true methylene blue (e.g., a green or purple tint) rather than the expected blue.
level_3: Two full cycles are visible: colorless turns blue during or right after each shake, and the blue then fades back to colorless while the bottle rests undisturbed afterward; each fade clearly follows its own shake rather than happening spontaneously; the color stays uniform through the liquid (no stratified or patchy coloring).
level_4: Everything required at the 3-point level holds, and additionally the colorless state looks fully transparent and water-like, the blue state looks vivid, saturated, and homogeneous (not pale or grayish), and no off-target hues (purple, green, teal) ever appear; blue only ever develops during or right after a shake, and fading back to colorless only ever happens during a rest phase, never spontaneously mid-shake and never before the first shake.
level_5: Everything required at the 4-point level holds, and additionally each shake reliably produces the same rapid blue onset, and each rest phase reliably produces a full fade back to colorless over a comparable, visibly gradual span of time (not an instantaneous single-frame change) across every repetition; no residual blue tint lingers once a cycle's fade is complete; both the blue and colorless states match the canonical appearance of methylene blue in alkaline glucose solution (deep azure vs. clear aqueous).

Spatiotemporal Consistency rubric:
level_1: Severe breaks in continuity: the bottle jumps to a new position between frames; the room lighting switches abruptly (e.g., bright to dark) with no cause; the cap appears or disappears mid-action; the liquid surface jumps with no motion leading to it; the bottle warps or fractures unnaturally.
level_2: Moderate breaks: the bottle rotates more than a quarter turn with no visible rotating motion shown; the liquid level changes abruptly without a shake happening; a shadow appears on the wrong side of the bottle relative to the light source; the background changes between the shaking and resting portions of the clip; the shake and the rest phase appear to happen in different scenes or from different camera angles.
level_3: Small, non-disruptive flaws are allowed (e.g., a single brief flicker of the bottle's outline, or one duplicated frame during a shake), but the bottle's position, tilt, and liquid volume stay logically continuous across each shake-then-rest cycle; the light source and shadow stay on the same side of the bottle throughout; the bottle is never absent from a frame partway through the clip.
level_4: Everything required at the 3-point level holds, and the whole sequence (sealing, shaking, resting) plays out from one fixed camera position with no cuts; the bottle keeps a consistent size and perspective across the clip; the liquid shows believable inertia (it keeps sloshing briefly right after a shake ends, then settles smoothly before the color begins to fade); there is no unnatural stretching, warping, or see-through glitching of the bottle or liquid.
level_5: Everything required at the 4-point level holds, and the shaking motion itself looks like a smooth, rhythmic back-and-forth with the swing gradually settling down before the bottle is set to rest; the liquid surface's movement visibly tracks the bottle's motion in real time with no mistimed lag between the two; there is no strobing, tearing, or ghosting anywhere in the clip.