Domain: Natural Science — Physics
Target concept: Connect equal-length copper and iron wires into the same circuit, and verify that the bulb is brighter when using the copper wire, with a noticeable visual difference.

Video generation prompt: Build a simple circuit consisting of a battery, a switch, and a light bulb. First, connect a copper wire of fixed length into the circuit and close the switch. Then replace it with an iron wire of the same length and reconnect the circuit. Clearly demonstrate the comparison process, emphasizing the correct wiring sequence and maintaining consistent conditions.

Evaluation guide:
(i) Target concept: Electrical resistance determines current magnitude in a simple DC circuit, which governs bulb brightness.
Minimum mechanism: Identical voltage source, identical bulb resistance, identical wire length and cross-section, and ohmic behavior of both metals, such that resistivity difference alone causes measurable current difference and thus luminance difference.
(ii)Storyline: [0–3s] Copper wire connected; switch closed → bulb illuminates brightly and steadily. [3–4s] Switch opened; copper wire visibly removed from terminals. [4–6s] Iron wire placed onto identical terminals. [6–9s] Switch closed → bulb illuminates dimly and steadily. Throughout: fixed overhead/frontal viewpoint; bulb centered; no occlusion; consistent lighting; all connections fully visible; brightness difference immediately apparent upon switch closure in each trial.

Manual:
Experimental Procedure
1. Assemble circuit: connect battery (+) → switch → bulb → battery (−) using copper wire of fixed length.
2. Close switch; observe bulb brightness.
3. Open switch; replace copper wire with iron wire of identical length, maintaining same connection points.
4. Close switch again; observe bulb brightness.
Observation of Experimental Phenomena
Bulb emits significantly brighter light with copper wire than with iron wire; brightness difference is immediate, stable, and visually unambiguous.
Summary of Experimental Principles
Copper has lower electrical resistance than iron; for equal length and cross-section, more current flows through copper, producing greater power dissipation in the bulb filament → brighter light.

Prompt Grounding rubric:
level_1: No battery, no switch, no bulb, no wires, or none of the required objects appear; or only one wire type appears without any comparison setup; or no circuit closure action is shown.
level_2: At least three core objects present (battery, switch, bulb), and at least one wire appears, but copper and iron wires are not both shown; or comparison sequence is absent (e.g., only copper wire tested, or only iron wire tested, or both wires shown simultaneously without sequential replacement); or switch is never closed in either condition.
level_3: All five required objects present (battery, switch, bulb, copper wire, iron wire); switch is closed in both conditions; wires are replaced sequentially (copper first, then iron); wiring is visible and connected to same terminals across both trials; no extraneous objects dominate frame.
level_4: All conditions for score 3 met, AND both wire types are visually distinguishable by color/appearance (e.g., copper shows reddish-brown metallic sheen, iron shows dull gray metallic appearance); AND bulb is shown in same physical position and orientation across both trials; AND no object enters/exits frame mid-sequence except the wire being swapped.
level_5: All conditions for score 4 met, AND wire swap occurs within a single continuous shot (no cut between copper and iron trials); AND bulb remains fully visible and centered throughout entire sequence; AND both wire connections are shown with identical terminal contact points (same battery pole, same bulb base, same switch terminal) in both trials; AND no occlusion, blur, or framing shift affects identification of any core object or connection.

Scientific and Causal Correctness rubric:
level_1: Bulb is equally bright in both trials; or bulb is off in both trials; or bulb is on only in iron trial; or brightness difference contradicts physics (e.g., iron brighter than copper); or no bulb illumination change is visible at all.
level_2: Bulb illuminates in at least one trial, but brightness difference is not visually discernible (e.g., both appear equally dim or equally bright); or brightness change occurs without switch closure; or bulb flickers or changes brightness without wire swap.
level_3: Bulb is visibly brighter when copper wire is connected AND visibly dimmer when iron wire is connected; brightness difference is consistent with wire substitution (i.e., change occurs only after wire replacement and switch closure); no other light sources or reflections interfere with bulb luminance perception.
level_4: All conditions for score 3 met, AND brightness difference is stable (no flicker, pulsing, or fluctuation during each trial); AND bulb state (on/off) matches switch state precisely in both trials (off when open, on when closed); AND no visual artifact (e.g., glare, bloom, overexposure) masks or exaggerates brightness difference.
level_5: All conditions for score 4 met, AND relative brightness difference is unambiguous and persists for full duration of each closed-switch interval; AND no ambient lighting change (e.g., shadow sweep, flash, exposure shift) coincides with wire swap; AND bulb filament (if visible) shows higher incandescence intensity in copper trial and lower in iron trial, directly correlating with wire identity.

Spatiotemporal Consistency rubric:
level_1: Objects teleport (e.g., bulb jumps position between trials); or wire appears/disappears without motion; or switch toggles without hand/object interaction; or severe motion blur makes object identity impossible; or abrupt lighting/contrast shift breaks continuity.
level_2: Minor spatial discontinuity: e.g., bulb shifts >1/3 frame height between trials; or camera zooms/crops significantly between copper and iron trials; or wire replacement involves unnatural motion (e.g., floating, non-hand-driven, or instant materialization); or light/shadow direction changes between trials.
level_3: All objects maintain consistent spatial relationships: battery, switch, bulb remain fixed relative to each other; wires connect same terminal points; hand motion (if shown) moves wire into/out of frame smoothly; no visible cuts, jumps, or structural distortions; lighting and shadow remain stable across entire sequence.
level_4: All conditions for score 3 met, AND wire replacement motion is continuous and physically plausible (e.g., hand removes copper wire from terminals, then places iron wire onto identical terminals); AND no object deforms, stretches, or compresses unnaturally during motion; AND frame composition remains fully stable (no pan/tilt/zoom); AND inter-frame motion is smooth without strobing or judder.
level_5: All conditions for score 4 met, AND temporal pacing is uniform: time between switch closure and brightness stabilization is perceptually equivalent in both trials; AND no latency mismatch (e.g., bulb lights instantly in copper trial but delays in iron trial); AND no parallax shift or perspective warp during hand motion; AND zero inter-frame inconsistency in object boundaries, edges, or occlusion handling.