Domain: Natural Science — Environmental Science
Target concept: Air Quality: Ozone (O₃) Determination (Indigo Disulfonate Colorimetric Method)

Video generation prompt: Add 2 mL of indigo disulfonate solution to a test tube, and pass an air sample containing O₃ through it for 2 seconds.

Evaluation guide:
(i) Target concept: Oxidative bleaching of indigo disulfonate by ozone, producing a visually unambiguous, uniform color loss.
Minimum mechanism: Ozone must contact dissolved indigo; reaction requires aqueous-phase molecular collision; decolorization is stoichiometric and irreversible under experimental conditions; blue-to-yellow/colorless transition reflects complete chromophore destruction.
(ii)Storyline: [Frame 0–3] Static shot: upright test tube enters view → [Frame 4–6] Deep blue liquid is dispensed into tube, filling ~1/3 height → [Frame 7–8] Air delivery tube descends and submerges tip into liquid → [Frame 9–12] Continuous stream of small, spherical, rising bubbles traverses entire liquid column → [Frame 13–18] Blue hue progressively diminishes across entire solution volume, culminating in uniform pale yellow/colorless state → [Frame 19–25] Final state persists with stable meniscus and no reversion; all elements remain in fixed spatial configuration; camera viewpoint is static, frontal, medium-close, ensuring full tube and bubble path are continuously visible.

Manual:
Experimental Procedure
1. Place a clean, transparent test tube vertically.
2. Add 2 mL of deep blue indigo disulfonate solution into the tube.
3. Insert air delivery tube tip below solution surface and pass ambient air sample containing ozone through it for ~2 seconds.
Observation of Experimental Phenomena
Deep blue solution decolorizes uniformly to pale yellow or colorless during/after ozone exposure.
Summary of Experimental Principles
Ozone oxidizes indigo disulfonate, cleaving its chromophore and eliminating blue color — basis of colorimetric O₃ quantification.

Prompt Grounding rubric:
level_1: No test tube present; no indigo disulfonate solution visible; no air sample introduction shown; none of the three core objects (test tube, indigo solution, air inlet) appear.
level_2: At least one core object appears (e.g., a tube or liquid), but no evidence of adding 2 mL indigo solution, and no air passage event; sequence is absent or reversed (e.g., air introduced before solution added).
level_3: Test tube is present; indigo disulfonate solution is visibly added to the tube; an air sample is passed through the solution; all three core objects are present and actions occur in correct order: (1) solution addition, (2) air passage, but spatial relationship is ambiguous (e.g., air inlet not visibly connected to tube, or solution volume not clearly associated with tube interior).
level_4: All core objects present and correctly identified: clear cylindrical transparent test tube, blue indigo disulfonate solution inside it, and an air delivery tube visibly inserted into the solution; addition occurs first, then air passage; spatial relationship is unambiguous: air tube terminates inside liquid column; no missing or extra steps.
level_5: All conditions for score 4 satisfied, AND the air passage event shows continuous, coherent motion of gas bubbles rising through the blue liquid column during the entire duration of air flow; no frame drops, occlusions, or visual discontinuities in the bubble stream; tube remains stationary and upright throughout; solution level remains stable and visibly contained within tube.

Scientific and Causal Correctness rubric:
level_1: No color change observed; solution remains unchanged (e.g., stays blue or turns wrong color like green/yellow/brown); or no solution present at all; or color change occurs without air passage.
level_2: Solution is blue initially, but changes to any color other than pale yellow or colorless (e.g., purple, gray, orange); or color change occurs before or after air passage; or change is instantaneous and disconnected from air flow timing.
level_3: Blue indigo disulfonate solution is present initially; color change to pale yellow or colorless occurs; the change begins during or immediately after air passage; however, the final state lacks full decolorization (e.g., residual blue streaks remain, or only partial region fades).
level_4: Initial deep blue color is fully present before air passage; during/after air passage, the entire liquid volume transitions uniformly to pale yellow or colorless; no residual blue hue anywhere in the solution; color change is temporally locked to air flow (starts upon initiation, completes by cessation).
level_5: All conditions for score 4 satisfied, AND the pale yellow/colorless final state is stable and persistent (no reversion or fading over remaining video time); no discoloration of tube walls or meniscus artifacts; hue matches standard indigo bleaching outcome (no cyan/green tint, no brown oxidation byproduct appearance).

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal violations: test tube jumps position between frames; solution appears/disappears abruptly; air tube teleports; lighting shifts violently; multiple disjoint scenes stitched together.
level_2: Moderate violations: tube wobbles excessively or rotates >30° off vertical; solution surface ripples violently without cause; air bubbles appear frozen or skip frames; major light/shadow inconsistency across consecutive frames (e.g., highlight moves from left to right without light source motion).
level_3: Minor but detectable motion flaws: slight tube sway (<10° tilt) or slow drift; bubbles rise with minor irregularity (e.g., occasional pause or merge); consistent lighting and shadow orientation; no object teleportation or structural break.
level_4: All objects maintain fixed spatial relationships: tube remains upright and stationary; air tube stays inserted at same depth; liquid surface stable; bubbles rise continuously and directionally upward; lighting and shadows remain fully consistent across all frames.
level_5: All conditions for score 4 satisfied, AND motion is perfectly smooth: bubble ascent shows uniform velocity and spacing; no inter-frame jitter, no pixelation on moving edges; no temporal aliasing (e.g., no strobing or ghosting); no parallax shift indicating camera motion or zoom.