Domain: Natural Science — Physics
Target concept: Opposite poles of a bar magnet attract each other.

Video generation prompt: Mark the north (N) and south (S) poles of two identical bar magnets. Hold one magnet with its north pole facing the south pole of the other magnet, and bring them close together. Then release your hands and observe the state of the magnets.

Evaluation guide:
(i) Target concept: Magnetic attraction between antiparallel dipoles.
Minimum mechanism: Each bar magnet must behave as a rigid dipole with fixed, opposing poles; no external force (e.g., air current, vibration, adhesive) may contribute to joining; attraction must arise solely from magnetic interaction between N and S poles.
(ii)Storyline: Frame 1–2: Two stationary, labeled magnets side-by-side, one held, one resting. Frame 3–4: Held magnet oriented with N toward resting magnet"s S. Frame 5–6: Magnets in close proximity, no contact yet. Frame 7–8: Release event, hands withdraw completely. Frame 9–10: Magnets translate linearly toward each other, make contact, and settle into stable, aligned, end-to-end configuration. Perspective: Fixed frontal view, full-body visibility of both magnets at all times; no occlusion by hands after release; lighting uniform and directional to reveal orientation and contact state.

Manual:
Experimental Procedure
1. Place two identical bar magnets on a flat surface. Label one end of each magnet "N" and the opposite end "S".
2. Hold Magnet A so its "N" end faces Magnet B"s "S" end. Bring them close until ~2 cm apart.
3. Release both magnets simultaneously.
Observation of Experimental Phenomena
The two magnets move toward each other and attach firmly end-to-end, remaining joined without separation or rotation.
Summary of Experimental Principles
Opposite poles of a bar magnet attract each other.

Prompt Grounding rubric:
level_1: No bar magnets visible; or only one magnet present; or magnets are not identical in appearance (e.g., different size, color, labeling); or no manual holding action shown; or north/south pole markings absent on both magnets; or magnets never brought into proximity.
level_2: Two bar magnets visible and identical in shape and size, but at least one of the following is missing: (a) N/S labels on both magnets, (b) one magnet held with N pole oriented toward the other magnet’s S pole, (c) clear visual indication of intentional alignment before release.
level_3: Two identical bar magnets, each clearly labeled N and S; one magnet is held stationary with its N pole facing the other magnet’s S pole; the two magnets are brought close together (visibly adjacent in frame) and then released; all steps appear in correct sequential order.
level_4: All conditions for score 3 satisfied, and additionally: (a) both magnets remain fully visible throughout the entire sequence (no occlusion), (b) spatial relationship is side-by-side with fixed viewpoint (no camera repositioning or zoom during core action), (c) no extraneous objects or hands interfering with magnet alignment after release.
level_5: All conditions for score 4 satisfied, and additionally: (a) labels N and S are legible and correctly positioned on opposite ends of each magnet, (b) orientation of poles is unambiguously visible before and during approach (no rotation ambiguity), (c) both magnets are centered in frame with consistent framing from start to end, and (d) no visual artifacts obscure pole identification or alignment at any frame.

Scientific and Causal Correctness rubric:
level_1: Magnets repel, fly apart, or show no motion after release; or magnets attract but then separate without sustained contact; or attraction occurs between like poles (N–N or S–S); or no observable motion after release.
level_2: Magnets move toward each other after release, but either (a) contact does not occur, or (b) contact occurs but magnets do not remain stably joined, or (c) movement direction contradicts N–S alignment (e.g., N–N visibly approaching).
level_3: After release, the two magnets move toward each other and make physical contact; contact persists for ≥1 second of visible stillness; motion direction matches N–S orientation (i.e., the held magnet’s N pole moves directly toward the other’s S pole).
level_4: All conditions for score 3 satisfied, and additionally: (a) no unintended rotation or sliding during attraction (motion is direct linear translation along alignment axis), (b) magnets remain in full face-to-face contact (no gap, tilt, or edge contact), (c) no reversal or separation after initial contact.
level_5: All conditions for score 4 satisfied, and additionally: (a) contact is immediate and continuous from first frame of motion until final stillness, (b) no wobble, bounce, or micro-separation upon contact, (c) final joined state shows magnets aligned end-to-end with no lateral offset or angular deviation visible.

Spatiotemporal Consistency rubric:
level_1: Teleportation (magnets change position without intermediate frames), structural break (magnet visibly fractures or deforms), abrupt light/shadow shift (e.g., lighting changes mid-sequence), or camera jump that disrupts spatial continuity.
level_2: At least one major spatiotemporal flaw: (a) discontinuous motion (jitter, frame drop, or freeze lasting >0.5s), (b) visible hand removal causing magnet to vanish/reappear, (c) inconsistent shadow direction or intensity across frames, (d) magnet edges pixelating or warping during motion.
level_3: All motion is continuous and physically plausible; no teleportation, no structural breaks, no lighting jumps; shadows and reflections remain consistent in direction and relative position; magnets retain rigid shape and uniform surface texture throughout.
level_4: All conditions for score 3 satisfied, and additionally: (a) no parallax inconsistency (e.g., background elements remain fixed relative to magnet positions), (b) no inter-frame scale fluctuation (zoom drift), (c) no unnatural acceleration/deceleration (motion speed changes only via smooth ramp, not step-change).
level_5: All conditions for score 4 satisfied, and additionally: (a) motion trajectory is perfectly smooth with zero velocity discontinuity (no jerk), (b) magnet surfaces show consistent specular highlights and diffuse shading across all frames, (c) no temporal aliasing (e.g., no strobing, moiré, or rolling shutter distortion during motion).