Domain: Natural Science — Physics
Target concept: A current passing through the coil turns the iron nail into an electromagnet.

Video generation prompt: On the table, an iron nail wrapped with copper wire is connected to a battery and a switch, with a paper clip placed nearby; a hand alternately moves the switch.

Evaluation guide:
(i) Target concept: Electromagnetism induced by current-carrying solenoid acting on ferromagnetic material.
Minimum mechanism: Closed circuit → current flow → magnetic flux generation in coil → domain alignment in soft iron → net external magnetic field → ferromagnetic attraction. Requires intact conductive path, ferromagnetic core, and proximity-based force.
(ii)Storyline: Frame 0–2: Static setup (all objects visible, switch open, paper clip stationary beside nail). Frame 3–5: Hand contacts and closes switch (circuit completes, current begins). Frame 6–8: Paper clip accelerates linearly toward nail tip, makes contact, adheres. Frame 9–10: Hand opens switch, paper clip detaches and settles back to original position. Perspective: Fixed overhead or 30° oblique tabletop view; all objects fully in-frame; no occlusion of nail-paper clip interaction zone during motion; lighting consistent and directional (single dominant source).

Manual:
Experimental Procedure
1. Place iron nail on table.
2. Wrap copper wire tightly around nail shaft (10–15 turns).
3. Connect wire ends to battery terminals via a switch in series.
4. Place paper clip adjacent to nail (within 2 cm).
5. Hand presses switch to close circuit, then releases to open circuit — repeated once.
Observation of Experimental Phenomena
Paper clip moves toward and attaches to iron nail only when switch is closed; paper clip remains stationary when switch is open.
Summary of Experimental Principles
Electric current flowing through coiled copper wire generates a magnetic field, magnetizing the iron nail into a temporary electromagnet that attracts ferromagnetic objects like the paper clip.

Prompt Grounding rubric:
level_1: None of the five required objects (iron nail, copper wire coil, battery, switch, paper clip) appear together in the tabletop scene, or the hand never appears at all.
level_2: At least three of the five objects are present, but the setup contradicts the prompt: the copper wire is not wound around the nail, the battery shows no visible connection into the circuit, the switch is missing from the wire path, or the paper clip is not placed near the nail; the hand never visibly touches the switch.
level_3: All five objects appear together: an iron nail with copper wire coiled around its shaft, a battery and switch wired in series with the coil, and a paper clip resting near the nail tip; the hand visibly moves the switch between two positions (open and closed) at some point.
level_4: All 3-point conditions hold, AND the switch's two positions are visually unambiguous (e.g., a toggle clearly up vs. down, or a button clearly pressed vs. released), AND the paper clip stays visible on screen for the entire clip (never cropped out of frame), AND whenever the switch is open (both before the first closure and after the circuit is broken again), the paper clip sits still in its resting spot beside the nail.
level_5: All 4-point conditions hold, AND the copper coil fully encircles the nail shaft with no bare gaps between winds, AND both wire ends are clearly attached at the battery terminals with no loose or floating ends, AND the paper clip's resting orientation lines up lengthwise with the nail's shaft, AND the hand only ever touches the switch, never brushing the nail, wire, battery, or paper clip.

Scientific and Causal Correctness rubric:
level_1: The paper clip never moves during the clip, or it moves independently of the switch (e.g., it drifts before the switch is ever touched), or it visibly moves away from the nail instead of toward it.
level_2: The paper clip moves, but not tied correctly to the switch: it moves while the switch is open, keeps moving after the switch has reopened, or drifts sideways instead of heading toward the nail.
level_3: The paper clip moves toward the nail only while the switch is closed and stays still whenever the switch is open; its path heads directly toward the nail rather than wandering.
level_4: All 3-point conditions hold, AND the paper clip only makes contact with the nail after the switch has fully closed (not partway through the hand's motion toward it), AND once the switch reopens, the paper clip visibly separates from the nail and settles into a resting position after a clearly visible interval of motion: the separation is shown happening, not skipped straight to the resting state.
level_5: All 4-point conditions hold, AND the paper clip stays stuck to the nail the entire time the switch is closed with no bouncing loose mid-hold, AND as soon as the switch opens, the paper clip begins visibly pulling away almost immediately with no noticeable pause beforehand, AND once free of the nail it settles into stillness without further wobbling.

Spatiotemporal Consistency rubric:
level_1: The nail, coil, battery, switch, or paper clip appears in a different spot or orientation from one frame to the next with no hand movement to explain it; the paper clip goes missing from the shot for a stretch and turns up again later with no motion shown carrying it away or back; the coil's winding breaks apart or reconnects in a way that could not physically happen; or the lighting shifts abruptly between consecutive frames with no cause (e.g., the scene jumps from full shadow to full brightness with no change in light source).
level_2: The nail visibly shifts or rotates without any hand contact; the paper clip slides a noticeable distance with no attraction motion toward the nail; the switch appears to flip with no hand touching it; the coil's winding spacing changes noticeably between the open and closed states; the background flickers or warps.
level_3: The nail stays in the same spot and orientation the whole time; the paper clip holds its position and orientation whenever it isn't moving toward or away from the nail; the switch and battery stay fixed relative to the nail; the hand enters the frame only to work the switch and fully withdraws afterward; nothing on screen flickers, disappears, or bends impossibly.
level_4: All 3-point conditions hold, AND the hand's motion toward and away from the switch is smooth and natural, never jerking or passing through other objects, AND the paper clip's trip toward the nail plays out as continuous travel rather than jumping partway there, AND the coil's winding keeps even spacing and alignment along the nail in every frame.
level_5: All 4-point conditions hold, AND the nail visibly holds its exact spot, angle, and size the whole time it isn't being touched, AND the paper clip's approach toward the nail moves steadily forward the entire way without ever visibly sliding backward before reaching the nail, AND the hand's grip on the switch looks correct for each position (a finger visibly presses the toggle down when closing it and lifts clear when it's open), AND the shadows cast by the nail, coil, and paper clip shift only gradually and track a single consistent light source rather than jumping in brightness or direction.