Domain: Natural Science — Physics
Target concept: Comparison of Electromagnets with and without Iron Cores in Lifting Metal Objects

Video generation prompt: On the table, there are two coils, one with an iron core and one without a core, sharing the same power supply and located above a steel washer; the power supply is turned on and off simultaneously.

Evaluation guide:
(i) Target concept: Magnetic field amplification via ferromagnetic core in electromagnets.
Minimum mechanism: Steel washer must be ferromagnetic; iron core must be magnetically permeable; current must flow identically through both coils; air gap between coil and washer must be identical for fair comparison.
(ii)Storyline: [Phase 1: Setup] Two identical coils placed side-by-side on table, one with visible iron core, one without; steel washer centered below both; power supply wired to both. [Phase 2: Activation] Power-on event triggers simultaneous magnetic field generation; only iron-core coil produces sufficient field to attract and lift washer into contact. [Phase 3: Sustained State] Washer remains stably attached only to iron-core coil while powered; zero movement toward air-core coil. [Phase 4: Deactivation] Power-off terminates magnetic field; washer detaches vertically and lands fully on table surface with no delay or adhesion. [Perspective constraint] Fixed top-down or oblique frontal view ensuring full visibility of both coils, washer, and power interface; no occlusion; lighting enables clear discrimination of iron core and metallic washer luster.

Manual:
Experimental Procedure
1. Place two identical wire coils side-by-side on a flat table.
2. Insert an iron core into the left coil only; leave the right coil air-filled.
3. Position a steel washer centered directly beneath both coils.
4. Connect both coils to the same power supply.
5. Turn power on simultaneously; observe washer behavior.
6. Turn power off simultaneously; observe washer behavior.
Observation of Experimental Phenomena
- During power-on: steel washer lifts and attaches only to the coil with iron core; no attachment occurs to the air-core coil.
- During power-off: washer detaches immediately from iron-core coil and rests on table; no residual attraction.
Summary of Experimental Principles
- Iron core increases magnetic flux density in the coil, producing stronger electromagnetism.
- Without iron core, magnetic field is too weak to lift the steel washer under identical current.

Prompt Grounding rubric:
level_1: No wire coils appear at all; no steel washer is visible; no power supply or switch is shown; nothing resembling the described tabletop setup of two coils above a washer is present in the scene.
level_2: Only one coil is shown instead of two, or the steel washer is missing entirely, or no power source/switch is visible anywhere in the shot, or the coils sit stacked or scattered rather than positioned together above the washer.
level_3: Two coils (one holding a visible metal core inside its windings, one left hollow) sit on the table with a steel washer positioned beneath them; wires connect both coils to a shared power source; some switching action is shown, but it is not clear whether the two coils are switched on and off at the same moment.
level_4: Both coils sit side by side directly above the same steel washer and are wired to one shared power supply; when the switch is operated, the activation cue for each coil (such as an indicator light turning on or an audible click) appears for both coils together, with no perceptible lag between the two.
level_5: All of score 4, plus the two coils look alike in size, shape, and winding density, differing only in that one clearly shows a solid metal core through its windings while the other is visibly hollow; the washer stays centered beneath both coils without drifting; nothing blocks the view of the coils, washer, or power switch/indicator at any point in the sequence.

Scientific and Causal Correctness rubric:
level_1: The washer never moves toward either coil at any point; its position and contact status stay unchanged from beginning to end, so no lifting phenomenon is observed at all.
level_2: The washer moves toward one of the coils, but the video gives no way to tell whether that coil is the iron-core one; or the washer lifts toward the hollow (air-core) coil; or the washer appears already attached to a coil before the power is switched on.
level_3: The washer lifts and stays attached to the iron-core coil for as long as the power is on, while showing no comparable attraction toward the hollow coil; once the power is switched off, the washer separates from the iron-core coil; the whole sequence follows the correct order of power-on, lift, power-off, drop.
level_4: All of score 3, plus the washer makes contact with the iron-core coil only, never touching or brushing the hollow coil, and after power-off the washer drops and settles on the table promptly, without pausing partway or clinging to the coil.
level_5: All of score 4, plus the washer shows no upward movement or attraction toward the hollow coil at any point in the video, and once the power is switched off the washer's fall is a single continuous vertical drop that ends with it flat and at rest on the table: no bounce, sliding, or lingering suspension in mid-air.

Spatiotemporal Consistency rubric:
level_1: The washer, either coil, or the table itself appears to jump to a different position, or blinks out of view and back; a coil or the table surface visibly stretches, warps, or melts out of its normal shape; the scene's overall brightness suddenly jumps as though two differently-lit shots were spliced together, with no visible cause.
level_2: The washer or a coil drifts sideways during the lift or drop in a way unrelated to the magnetic attraction; the spacing between the two coils visibly changes between the powered and unpowered states; the shadows cast by the coils or washer point in different directions at different moments for no apparent reason.
level_3: The coils or washer show only brief, small position jitter between frames; a short flicker appears right at the moment of switching on or off; the ambient brightness shifts slightly between phases while the shadow direction itself stays the same; the washer's resting angle on the table changes a little after it lands.
level_4: The two coils stay fixed side by side and the washer stays centered beneath them for the whole sequence, with no drifting, rotating, or resizing of any object; shadows keep the same direction and softness throughout; the lift and the drop both play out smoothly, with no freezing or warping of any object.
level_5: All of score 4, plus the motion blur during the lift and drop matches how fast the washer is actually moving; the relative framing of the coils and washer shows no camera-parallax shift; the washer keeps its round shape without stretching while attached to the coil or while falling; no object shows clipping, tearing, or transparency glitches at any point.