Domain: Natural Science — Chemistry
Target concept: Characteristic Reaction of Glucose

Video generation prompt: A test tube contains an appropriate amount of glucose solution. An freshly prepared copper hydroxide suspension (an alkaline suspension prepared using excess sodium hydroxide solution) is added to the solution in the test tube, and the test tube is heated until the solution boils.

Evaluation guide:
(i) Target concept: Alkaline copper hydroxide reduction by glucose yielding brick-red Cu₂O precipitate.
Minimum mechanism: Glucose must be in solution; Cu(OH)₂ must be freshly prepared (to avoid decomposition to black CuO); alkaline condition (excess NaOH) must be present to stabilize Cu(OH)₂ and enable enolization of glucose; heating must supply activation energy for redox reaction.
(ii)Storyline: Frame 1–2: Static shot of test tube with clear glucose solution. Frame 3–4: Blue cloudy suspension is poured into tube; mixture appears blue-homogeneous. Frame 5–6: Heating applied (flame appears beneath tube base); no immediate change. Frame 7–8: Blue color fades progressively; brick-red particles nucleate, grow, and descend. Frame 9–10: Boiling commences with vigorous bubbling; red precipitate fully settled at bottom; supernatant becomes colorless. Viewpoint: Fixed frontal close-up, full test tube in frame, no occlusion, consistent lighting, no cutaways.

Manual:
Experimental Procedure
1. Place glucose solution in test tube.
2. Add freshly prepared copper hydroxide suspension (blue, cloudy) to the test tube.
3. Heat the test tube until boiling occurs.
Observation of Experimental Phenomena
The initial blue suspension fades; a brick-red precipitate forms and settles during boiling.
Summary of Experimental Principles
Glucose reduces Cu²⁺ in alkaline Cu(OH)₂ to Cu₂O (copper(I) oxide), which is brick-red and insoluble — a positive test for reducing sugars.

Prompt Grounding rubric:
level_1: No test tube present; no glucose solution visible; no copper hydroxide suspension shown; no addition action depicted; no heating action depicted; no boiling state shown.
level_2: At least one correct object present (e.g., test tube) but all core actions missing: no addition of copper hydroxide suspension to glucose solution, no heating, no boiling. Objects appear disconnected or unrelated to the posted_prompt sequence.
level_3: Test tube is present and contains a clear liquid (glucose solution); freshly prepared copper hydroxide suspension is visibly added into the test tube; heating action is depicted (e.g., flame or hotplate under test tube); boiling state is indicated by continuous vigorous bubbling or vapor emission from liquid surface; all in correct sequential order (add → heat → boil).
level_4: All elements of score 3 are present AND spatial relationships are preserved: copper hydroxide suspension is added directly into the same test tube containing glucose solution (not adjacent tube or separate container); heating source is placed under that same test tube; boiling occurs only after addition and during heating (no boiling before heating or without addition). No extraneous objects interfere with core sequence.
level_5: All elements of score 4 are present AND temporal continuity is flawless: addition completes before heating begins; heating begins before boiling appears; boiling persists continuously during heating and ceases when heating stops (if shown); no visual discontinuity (e.g., jump-cut insertion of boiling), no object duplication or disappearance, no misaligned viewpoint shift during the sequence.

Scientific and Causal Correctness rubric:
level_1: No scientifically plausible color change observed; no precipitate formation; no color transition from blue to red/brown; liquid remains uniformly blue or unchanged throughout; no thermal decomposition effect visible.
level_2: Blue suspension appears but no color change occurs at any point; or color changes to incorrect hue (e.g., green, yellow, purple); or precipitate forms but is white/gray instead of brick-red; or color change occurs before addition or before heating.
level_3: Freshly prepared copper hydroxide suspension is visibly blue; after addition to glucose solution and during heating, the blue color disappears and a brick-red precipitate appears; precipitate is granular/sedimenting and distinct from background liquid; color change and precipitate formation occur only after heating begins and persist through boiling.
level_4: All elements of score 3 are present AND causal fidelity is intact: blue suspension must be present *before* addition; mixture must be initially blue or blue-tinted *immediately after addition* (before heating); color fade and brick-red precipitate emergence must begin *only after heating starts* and intensify *during boiling*; no brick-red appearance before heating or without heating.
level_5: All elements of score 4 are present AND state evolution is fully coherent: suspension is visibly heterogeneous (cloudy blue) pre-heating; post-addition mixture retains cloudiness; upon heating, cloudiness reduces as blue fades and brick-red particles nucleate, grow, and settle; final state shows clear separation: upper liquid layer becomes colorless or pale, lower layer contains abundant settled brick-red solid; no dissolution, no re-dispersion, no fading of red after boiling ends.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal violation: test tube teleports between frames; flame appears/disappears without motion; precipitate flashes in/out; liquid level jumps; lighting shifts abruptly (e.g., bright → dark mid-sequence); camera angle rotates or zooms erratically.
level_2: Multiple medium violations, at least two of the following: abrupt brightness change >1 frame duration; precipitate appears without particle growth progression; flame flickers inconsistently (e.g., static then sudden large size); test tube wobbles unnaturally; liquid surface ripples discontinuously (no fluid motion continuity).
level_3: All objects maintain fixed relative positions: test tube remains centered/stationary; heating source stays consistently under test tube base; suspension addition shows smooth downward motion into tube; boiling shows continuous, rhythmic bubbling/vapor emission without freezing, skipping, or stutter; lighting and shadow remain stable across entire sequence.
level_4: All elements of score 3 are present AND motion fidelity is preserved: addition motion is smooth and unbroken (no jump-cut insertion of suspension inside tube); heating onset shows gradual flame growth or thermal shimmer onset; boiling bubbles emerge progressively (small → larger → vigorous) with consistent bubble size distribution and upward trajectory; no object edge tearing, warping, or transparency flicker.
level_5: All elements of score 4 are present AND inter-frame coherence is perfect: zero frame drops or interpolation artifacts; no motion blur inconsistency (e.g., sharp object against smeared background); no parallax shift between tube wall and contents; no reflection mismatch on glass surface; no depth cue conflict (e.g., precipitate appearing behind meniscus when it should be submerged).