Domain: Natural Science — Chemistry
Target concept: Components of a Galvanic Cell (Zinc-Copper Galvanic Cell)

Video generation prompt: A zinc plate and a copper plate are placed side by side and immersed in dilute sulfuric acid. The two electrodes are connected to an ammeter through wires, and the deflection of the ammeter needle is observed.

Evaluation guide:
(i) Target concept: Electrochemical potential difference drives electron flow from Zn to Cu in acidic medium, producing measurable current and H₂ gas evolution exclusively at the cathode (Cu).
Minimum mechanism: Zn must be more reactive (lower reduction potential) than Cu; H⁺ must be present as reducible species; Cu must serve as inert cathode surface (not participating chemically); circuit must be closed for sustained current.
(ii)Storyline: [Frame 0–2] Zinc and copper plates descend synchronously into transparent dilute sulfuric acid, coming to rest side-by-side, fully immersed. [Frame 3–4] Wires attach: one end contacts zinc surface, other end connects to ammeter negative terminal; second wire contacts copper surface and positive terminal; attachment is continuous and unbroken. [Frame 5–7] Ammeter needle begins smooth, monotonic deflection; simultaneously, first bubbles emerge at copper plate surface (not zinc) and rise continuously. [Frame 8–10] Needle stabilizes in deflected position; bubbles persist uniformly on copper; zinc surface shows progressive dulling across entire immersed area; copper retains original luster and color. All events occur from fixed frontal viewpoint with stable lighting; no object leaves frame or undergoes non-physical transformation.

Manual:
Experimental Procedure
1. Place zinc plate and copper plate side-by-side in a transparent container filled with dilute sulfuric acid.
2. Connect zinc plate to negative terminal and copper plate to positive terminal of an ammeter using insulated wires.
3. Observe ammeter needle deflection immediately after connection.
Observation of Experimental Phenomena
- Ammeter needle deflects continuously in one direction.
- Colorless spherical gas bubbles rise exclusively from copper plate surface.
- Zinc plate surface becomes dull and pitted; copper plate remains unchanged in color and texture.
Summary of Experimental Principles
Zinc oxidizes (Zn → Zn²⁺ + 2e⁻), releasing electrons; electrons flow through wire to copper, where H⁺ ions reduce (2H⁺ + 2e⁻ → H₂), forming bubbles on copper. This electron flow causes ammeter deflection, confirming spontaneous current generation.

Prompt Grounding rubric:
level_1: None or at most one of the five required elements (zinc plate, copper plate, dilute-sulfuric-acid container, connecting wires, ammeter) is visible at any point in the clip.
level_2: Exactly two of the five required elements (zinc plate, copper plate, acid container, wires, ammeter) are visible together at some point, but the other three never appear in the same shot, and the two electrodes are never shown immersed together in the same container.
level_3: Three or four of the five required elements appear together (for example the zinc plate, copper plate, and acid container are shown but the wires or ammeter are missing, or vice versa); when all five do appear, the electrodes are not both immersed side by side in the same container, or the ammeter needle never appears or never moves.
level_4: All five elements (zinc plate, copper plate, acid container, wires, ammeter) are present, with both plates immersed side by side in the same acid and wires running from each plate to the ammeter, and the needle visibly deflects; however, the deflection direction is unclear (too small to read or partly blocked from view), or one wire appears to attach to the wrong plate or the wrong ammeter terminal.
level_5: All five elements are present and correctly arranged: the grayish zinc plate and reddish-brown copper plate sit immersed side by side in clear dilute sulfuric acid; one wire runs from the zinc plate to the ammeter's negative terminal and another from the copper plate to the positive terminal; the ammeter needle is clearly visible and swings in one consistent direction, unobstructed and without random back-and-forth flicker.

Scientific and Causal Correctness rubric:
level_1: No sign of electrochemical activity appears: the ammeter needle never moves, no gas bubbles form on either plate, neither plate changes appearance, or the zinc and copper plates are rendered with swapped colors (for instance the zinc plate shown reddish-brown or the copper plate shown gray).
level_2: The needle moves, but not in keeping with a zinc-copper cell: for example it deflects while only one plate sits in the acid, or bubbles form on the zinc plate while the copper plate visibly pits or dissolves, or both plates appear to dissolve at once.
level_3: The needle deflects while both plates remain immersed, and colorless bubbles rise from the copper plate's surface, but the zinc plate shows no visible change (no dulling, pitting, or surface loss), or the bubbles instead form on the zinc plate.
level_4: The needle deflects steadily in one direction; bubbles form only on the copper plate; the zinc plate shows visible dulling or pitting indicating it is being consumed, while the copper plate keeps its reddish-brown color, but the bubbling is intermittent rather than continuous, or the zinc's surface change covers only part of its immersed area.
level_5: The needle deflects continuously in a single direction; colorless bubbles rise steadily and only from the copper plate's immersed surface; the zinc plate's entire immersed surface turns dull and pitted with no bright metallic patches remaining; the copper plate keeps a smooth, unmarked reddish-brown surface; no unrelated effects appear (no flame at the bubbles, no cloudy precipitate in the acid, no fuming from the liquid).

Spatiotemporal Consistency rubric:
level_1: The zinc plate, copper plate, or ammeter jumps to a different position or vanishes and reappears with no visible motion; the acid level in the container changes suddenly with no pouring or evaporation shown; a wire disconnects and reconnects with no hand or motion visible; or the background or lighting shifts abruptly with no visible cause (e.g., the lab bench appearance or shadows change instantly with no light source actually moving).
level_2: The zinc plate, copper plate, wires, or ammeter flicker in and out of view between frames; the depth to which a plate is immersed changes with no visible motion; the needle jumps straight from rest to full deflection with no intermediate positions; a wire's attachment point slides sideways with no sliding motion shown.
level_3: The needle begins deflecting before both wires are clearly attached, or bubbles begin forming before the plates are fully immersed, or one plate shifts slightly sideways (less than a quarter of its width) without a smooth sliding motion, but no plate, wire, or the ammeter disappears, jumps to a new location, or breaks apart.
level_4: The plates descend smoothly into the acid and settle in place, the wires keep continuous contact with the plates and ammeter terminals throughout, and the needle sweeps gradually toward its final position, but the needle is briefly hidden from view for a moment during its swing, or one wire's endpoint looks slightly misaligned with its terminal for an instant.
level_5: The plates descend with steady motion and then stay perfectly still; both wires keep unbroken contact with the plates and ammeter terminals for the entire clip; the needle sweeps smoothly and in one direction from rest to its final deflected position with no hesitation, reversal, or stutter; bubbles begin rising exactly as immersion completes and continue at a steady rate and size; the light source and the shadows cast by the plates and container do not shift or change in strength during the clip.