Domain: Engineering — Chemical Engineering
Target concept: Prevent electrochemical corrosion

Video generation prompt: Take two iron blocks of the same specification, one connected to a zinc block through a copper wire, and the other not connected, both immersed in a 3% sodium chloride aqueous solution, placed under ambient temperature conditions, and continuously recorded for 24 hours with the camera aimed at the setup.

Evaluation guide:
(i) Target concept: Electrochemical corrosion prevention via galvanic coupling (sacrificial anode protection).
Minimum mechanism: Zinc must be more active (lower reduction potential) than iron, enabling spontaneous electron donation to iron; the presence of an electrolyte (NaCl solution) completes the circuit; physical contact via conductor (copper wire) enables charge transfer; absence of contact isolates the control iron, allowing normal rusting; because a sacrificial zinc anode is designed to corrode only slowly, the zinc block may show a slightly dulled shine or a thin whitish film after 24 hours, or may show no visible change at all; either outcome is consistent with it protecting the iron.
(ii)Storyline: Frame 0–1: Static shot reveals two identical iron blocks side-by-side in clear aqueous solution. One iron is visibly linked to a distinct zinc block by a continuous copper wire. Frame 2–8: Gradual emergence of reddish-brown solid deposits exclusively on the surface of the unconnected iron block, progressing contiguously from nucleation to coverage. Frame 9–10: Final state confirms rust only on the unconnected iron block; the connected iron block remains uniformly silver-gray; the zinc block may retain its bright metallic appearance or show only slight dulling, either being consistent with its role as the sacrificial anode; the copper wire stays intact and uncorroded. Perspective: Fixed frontal view, no occlusion, full visibility of all critical interfaces (Fe–Zn wire junction, Fe–solution meniscus, rust zones).

Manual:
Experimental Procedure
1. Place two identical iron blocks into separate but adjacent compartments of a transparent container filled with 3% NaCl solution.
2. Connect one iron block to a zinc block using a copper wire making direct metallic contact.
3. Leave the other iron block unconnected.
4. Fix camera to capture both setups simultaneously in full view.
Observation of Experimental Phenomena
After 24h (simulated): Rust (reddish-brown solid) appears only on the unconnected iron block; the connected iron block remains rust-free; zinc block shows no rust but may show slight dulling; copper wire unchanged.
Summary of Experimental Principles
Zinc acts as a sacrificial anode: it oxidizes preferentially to protect iron from electrochemical corrosion in saline electrolyte. The connected iron becomes the cathode and remains intact.

Prompt Grounding rubric:
level_1: No iron blocks are visible; no zinc block is visible; no copper wire is visible; no sodium chloride solution is visible; the two iron specimens are never shown together in one comparable view; there is no fixed camera view of the setup.
level_2: At least one iron block is present, and a sodium chloride solution is visible, but either the zinc block is absent, the copper wire is absent, or the second (control) iron block is missing; the two iron specimens are not shown positioned comparably in the same frame.
level_3: Two iron blocks are present and visually identical in size and shape; one iron block is connected to a zinc block via a visible copper wire; both iron blocks are immersed in a liquid that looks homogeneous and aqueous (clear to pale-tinted); both sit within the same field of view under a fixed camera position.
level_4: Everything in score 3 holds, and the copper wire makes direct metallic contact between the zinc and the connected iron block (no gap, no insulation, no broken connection); the zinc block is visibly distinct from the iron blocks in color and metallic luster; the liquid fully submerges both iron blocks to a comparable depth; nothing extraneous blocks either specimen.
level_5: Everything in score 4 holds, and the two iron blocks occupy clearly comparable positions within the frame; the zinc block connects exclusively to the first iron block, never touching the second; the copper wire is taut or naturally draped without touching the unconnected iron block or the liquid surface; no visual artifact disrupts the identity or placement of any object.

Scientific and Causal Correctness rubric:
level_1: No corrosion-related visual change occurs on either iron block; both remain uniformly silver-gray throughout; there is no differential appearance between the two iron blocks at any point.
level_2: Corrosion appears on both iron blocks equally (same degree, same location, same color change); or corrosion appears only on the unconnected iron block but lacks the expected reddish-brown rust color; or rust appears on the connected iron block instead of being suppressed there.
level_3: Rust (a reddish-brown solid deposit) appears exclusively on the iron block not connected to zinc; the iron block connected to zinc remains silver-gray or shows significantly less rust; no rust appears on the zinc or the copper wire.
level_4: Everything in score 3 holds, and the rust is localized to the exposed/submerged surface of the unconnected iron block rather than just at the air-liquid interface; the connected iron block shows no reddish-brown deposits anywhere on its surface; the zinc block may look unchanged or may show a slight dulling of its shine or a thin whitish coating; either is acceptable and neither disqualifies the result; the copper wire stays unchanged in color and stays intact.
level_5: Everything in score 4 holds, and the rust stays confined to the unconnected iron block with no trace on the connected iron, even at its edges; the zinc block shows no rust-colored deposits, and whether it looks essentially pristine or only slightly dulled, it shows no significant pitting, flaking, or heavy corrosion buildup; either appearance is consistent with it protecting the iron as the sacrificial anode; the copper wire keeps its orange-red metallic color without green patina; no loose rust particles are visible floating near the connected iron block.

Spatiotemporal Consistency rubric:
level_1: The iron blocks, zinc block, or copper wire vanish and reappear, or shift position with no motion shown between frames; the liquid level jumps up or down without cause; the camera viewpoint cuts abruptly; the lighting changes drastically from one frame to the next.
level_2: The zinc block disappears for two or more consecutive frames; the iron blocks change apparent size inconsistently across frames; the liquid surface looks unnaturally rigid or shimmers excessively with no ambient light source to explain it; rust appears all at once rather than building up gradually.
level_3: Both iron blocks, the zinc block, and the copper wire keep the same position and scale throughout; the liquid surface looks continuous and consistent; rust builds up gradually (from bare metal, to speckled spots, to a coalesced reddish-brown patch) only on the unconnected iron block; nothing fragments, merges, or warps; there is no abrupt shift in lighting or in the shadow the setup casts.
level_4: Everything in score 3 holds, and any sway in the copper wire is gentle and physically plausible; the liquid's meniscus at the container wall stays steady; the rust spreads as a contiguous patch rather than appearing as isolated floating spots; there is no tearing, ghosting, or flicker between frames.
level_5: Everything in score 4 holds, and the spatial relationships stay fixed: the distance between the two iron blocks never changes; the point where the copper wire touches the zinc and the connected iron stays the same relative to both; the rust never crosses onto the connected iron block's surface; there is no parallax shift, no lens-distortion change in proportions, and no duplicated or stuttering frames.