Domain: Natural Science — Chemistry
Target concept: Reaction between carbon and copper(II) oxide

Video generation prompt: A mixture of black carbon powder and copper(II) oxide powder is placed in a hard glass tube. The tube is heated with an alcohol lamp, and the gas escaping from the mouth of the tube is passed into clear lime water.

Evaluation guide:
(i) Target concept: Redox reaction where carbon acts as reducing agent for copper(II) oxide, producing elemental copper and carbon dioxide.
Minimum mechanism: Carbon must contact copper(II) oxide in solid state under heating; CO₂ must be generated and delivered to lime water; Ca(OH)₂ in lime water must react with CO₂ to form insoluble CaCO₃ precipitate causing milkiness.
(ii)Storyline: Frame 1–2: Static shot showing black powder mixture inside horizontal hard glass tube; lime water clear in separate container; delivery tube idle. Frame 3–4: Alcohol lamp flame appears beneath tube midsection; no immediate change. Frame 5–6: First visible red specks emerge within black powder zone; simultaneous subtle gas flow begins in tube. Frame 7–8: Red solid expands continuously to replace black region; bubbles enter lime water. Frame 9–10: Lime water fully milky; red solid occupies original powder area; flame remains steady; all spatial relationships preserved. Perspective: Fixed frontal view, eye-level, centered on tube-lime water axis; no camera movement; full visibility of tube interior (via transparency), flame contact point, and lime water surface.

Manual:
Experimental Procedure
1. Mix black carbon powder and black copper(II) oxide powder evenly.
2. Load mixture into hard glass tube.
3. Heat tube midsection with alcohol lamp flame.
4. Connect tube mouth to clear lime water via delivery tube.
Observation of Experimental Phenomena
- Black powder mixture gradually turns into shiny red solid (copper metal).
- Clear lime water turns milky white.
Summary of Experimental Principles
Carbon reduces copper(II) oxide to copper metal, producing carbon dioxide gas, which turns lime water milky.

Prompt Grounding rubric:
level_1: No black carbon powder visible; no copper(II) oxide powder visible; no hard glass tube present; no alcohol lamp visible; no lime water container visible; no gas delivery tube connecting tube mouth to lime water.
level_2: At least one of the following is present: black powder, black-and-black mixture, hard glass tube, or lime water container, but no spatial arrangement matches the posted_prompt (e.g., powders not inside tube; tube not heated; lime water not receiving gas from tube mouth).
level_3: All required objects are present and correctly assigned: black carbon powder AND copper(II) oxide powder BOTH inside a hard glass tube; alcohol lamp positioned under the tube; clear lime water in a separate container; a gas delivery tube visibly connects the mouth of the hard glass tube to the lime water container.
level_4: All objects from score 3 are present AND correctly positioned: powders fully confined within tube (no spillage); alcohol lamp flame visibly adjacent to tube midsection; lime water container placed lower than tube mouth; gas delivery tube forms continuous unbroken path from tube mouth into lime water solution.
level_5: All conditions from score 4 are met AND spatial relationships are unambiguous: tube is horizontal or slightly tilted downward toward lime water; powder mixture occupies central third of tube length; flame contacts tube surface (not floating above or beside); lime water surface is still and level; gas delivery tube enters lime water below surface (bubbling visible in score 5 only if SCC confirms it; PG does not require bubbling, only correct physical setup).

Scientific and Causal Correctness rubric:
level_1: No scientifically valid color/state change observed: lime water remains clear throughout; no black-to-red color transition in tube; no gas evolution visible; no color change in solids at all.
level_2: At least one incorrect phenomenon dominates: lime water turns blue/pink/green; powder turns silver/grey/yellow; black powder disappears without replacement; red solid appears before heating; gas bubbles appear in lime water without any prior heating or tube mouth activity.
level_3: Correct sequence of phenomena appears: (a) black powder mixture visible inside tube before heating; (b) heating applied; (c) black powder gradually transforms into shiny red solid (copper metal) in same location; (d) lime water turns milky white during/after heating.
level_4: All phenomena from score 3 occur AND causal timing is preserved: lime water milking begins only after heating starts AND after red solid first appears; no milking before red solid formation; no red solid appears before heating begins; no simultaneous appearance of red solid and milking at frame-zero.
level_5: All phenomena from score 4 occur AND state transitions are exclusive and complete: entire black powder region converts fully to red solid (no residual black patches); lime water changes from fully clear to fully milky (no partial/translucent intermediate); no co-occurrence of incorrect byproducts (e.g., no yellow residue, no charring, no smoke, no vapor cloud unrelated to CO₂).

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal breaks: tube teleports between frames; powders vanish/reappear discontinuously; lime water container jumps position; flame flickers on/off with frame-level inconsistency; lighting shifts abruptly (e.g., daylight → candlelight mid-sequence).
level_2: Multiple structural violations: tube bends/kinks unnaturally; powder layer collapses vertically as if gravity reversed; gas tube disconnects mid-sequence then reconnects; lime water surface ripples violently without cause; shadow direction flips between frames.
level_3: All objects maintain fixed relative positions: tube remains stationary; powders stay inside tube without spilling; flame stays adjacent to same tube section; lime water container remains fixed; gas tube maintains continuous connection; lighting and shadows remain consistent in direction and intensity.
level_4: All conditions from score 3 hold AND motion is physically plausible: flame shows gentle, natural flicker (not strobing); powder transformation progresses smoothly left-to-right or uniformly (no jumping zones); lime water turbidity increases gradually without sudden opacity jumps; no object exhibits unnatural rigidity or floatiness.
level_5: All conditions from score 4 hold AND inter-object continuity is perfect: no frame where tube mouth and gas tube endpoint are misaligned; no frame where red solid appears outside original powder boundary; no frame where lime water surface breaks continuity (e.g., splash, ripple mismatch); no inter-frame occlusion inconsistencies (e.g., tube suddenly hides flame then reveals it with no movement).