Domain: Natural Science — Chemistry
Target concept: Copper Electroplating

Video generation prompt: The iron sheet to be electroplated is connected to the negative terminal of the power supply as the cathode, and the copper sheet is connected to the positive terminal as the anode. Copper sulfate solution is used as the electrolyte. After applying electricity, observe the changes in the iron sheet and the copper sheet.

Evaluation guide:
(i) Target concept: Electrochemical copper plating via galvanic cell setup where iron acts as inert cathode and copper as active anode in CuSO₄ electrolyte.
Minimum mechanism: Reduction must occur exclusively on iron surface (Cu deposition), oxidation exclusively on copper surface (Cu dissolution); solution conductivity must enable ion migration; no competing reactions (e.g., H₂ evolution or O₂ reduction) may occur.
(ii)Storyline: Frame 1–2: Static shot showing iron sheet (grey, smooth) and copper sheet (shiny reddish-brown) side-by-side in blue solution, wires attached to correct terminals. Frame 3–8: Continuous view with no occlusion; iron sheet surface progressively acquires uniform reddish-brown layer; copper sheet surface gradually loses shine and gains subtle texture; solution remains homogeneously blue. Frame 9–10: Final stable state confirming full coverage on iron, consistent dulling on copper, no bubbles or precipitates. Perspective: Fixed frontal macro view, full sheet surfaces visible, no camera movement or zoom.

Manual:
Experimental Procedure
1. Place iron sheet and copper sheet side-by-side in a transparent container filled with blue copper sulfate solution.
2. Connect iron sheet to negative terminal of power supply; connect copper sheet to positive terminal.
3. Apply electricity for observation period.
Observation of Experimental Phenomena
- Iron sheet surface changes from grey to uniform reddish-brown.
- Copper sheet surface becomes duller and slightly rougher, retaining reddish-brown hue.
- Blue color of solution remains unchanged.
Summary of Experimental Principles
Copper ions (Cu²⁺) in solution gain electrons at the iron cathode (reduction: Cu²⁺ + 2e⁻ → Cu), plating copper onto iron. Copper metal at anode loses electrons (oxidation: Cu → Cu²⁺ + 2e⁻), replenishing ions in solution.

Prompt Grounding rubric:
level_1: No iron sheet, copper sheet, transparent container of blue copper sulfate solution, and power supply appear together in the shot, or none of them are wired to any terminal, or the wiring is fully backwards (the iron sheet connected to the positive terminal and the copper sheet to the negative terminal).
level_2: At least two of the four required items (the iron sheet, the copper sheet, the blue CuSO₄ solution container, and the power supply) are visible, but at least one is missing or mislabeled (e.g., a sheet labeled "zinc" instead of "copper"), and/or the wiring is either completely absent or fully reversed (iron to positive, copper to negative).
level_3: The iron sheet, the copper sheet, a transparent container holding blue copper sulfate solution, and a power supply with visible terminals are all present; the iron sheet is wired to the negative terminal and the copper sheet to the positive terminal, with no substituted, mislabeled, or contradictory parts.
level_4: Everything required for score 3 is shown, and in addition both sheets are fully submerged in the blue solution, the wires are visibly clipped onto the metal surfaces rather than floating loose nearby, and no unrelated equipment (a stirring rod, a thermometer, a mislabeled reagent bottle) appears in frame.
level_5: Everything required for score 4 is shown, and in addition the iron sheet and copper sheet sit side by side in the same container rather than in two separate vessels, both sheets stay fully in view without being lifted or removed at any point, and the wire-to-terminal and wire-to-sheet connections are unambiguous with no cable crossing or obscuring the contact points.

Scientific and Causal Correctness rubric:
level_1: Neither sheet visibly changes at all; or the iron sheet darkens toward black, grey, or brown as if rusting rather than gaining a copper-colored coating; or the copper sheet visibly dissolves while the iron sheet gains no coloring; or gas bubbles form on the iron sheet's surface.
level_2: The iron sheet changes color, but the new coating is patchy orange, yellow, or grey rather than a uniform copper hue; or the copper sheet visibly thins without its surface losing shine or becoming rough; or any coloring on the iron sheet only appears after the power supply is switched off; or the blue solution fades uniformly everywhere rather than the change staying localized to the sheet surfaces.
level_3: The iron sheet's surface turns from metallic grey to a uniform reddish-brown, copper-like coating while current flows; the copper sheet's surface goes from shiny to duller and slightly roughened while keeping its reddish-brown color; the solution stays visibly blue throughout, with no bleaching or cloudy precipitate.
level_4: Everything required for score 3 holds, and in addition the copper coating on the iron sheet appears only on the submerged face directly opposite the copper sheet, not on any dry or back surface; the copper sheet develops no green or blue-green patina and no white crust; and neither electrode produces visible gas bubbles.
level_5: Everything required for score 4 holds, and in addition the copper coating covers the iron sheet's entire submerged face evenly in a consistent reddish-brown tone with no orange, yellow, or black patches remaining; the copper sheet's dulling is even across its whole submerged surface with no shiny patches left; and the solution stays clear and blue with no discoloration, cloudiness, or sediment appearing at any point.

Spatiotemporal Consistency rubric:
level_1: The iron sheet or copper sheet disappears from one frame and reappears in another; either sheet suddenly rotates or changes size by an obvious, unexplained amount between consecutive frames; the scene lighting flips from fully shadowed to fully bright within a single cut; or the container's outline warps away from its original shape (e.g., a rectangular tank appearing to curve).
level_2: The point where a wire touches a sheet flickers in and out of view across frames; a sheet's surface texture visibly toggles between smooth and grainy inconsistently; the reflection on the solution's surface shifts direction or brightness with no corresponding change in the scene; or one sheet tilts relative to the other with no hand or tool shown causing it.
level_3: The iron sheet and copper sheet stay side by side at the same spacing and orientation throughout; the container never tilts or shifts; the wires stay taut at the same attachment points; the solution's surface stays level and calm; and the light's direction and brightness on the sheets and solution look the same from the first frame to the last.
level_4: Everything required for score 3 holds, and in addition the submersion depth of each sheet and the visible wire contact points stay exactly the same from frame to frame with no flicker, and no shimmering or flashing appears on either metal surface as its color develops.
level_5: Everything required for score 4 holds, and in addition the outlines of both sheets and the container keep the same shape and position across the entire video, the solution surface stays flat with no stray ripples appearing or vanishing, and there is no doubling or trailing of the sheet or wire edges as the plating color changes.