Domain: Natural Science — Physics
Target concept: Repulsion between like magnetic poles of a bar magnet

Video generation prompt: Take two identical bar magnets and mark their N poles and S poles. Place the two magnets with their N poles facing each other and bring them close together. Release them and observe the state of the magnets.

Evaluation guide:
(i) Target concept: Magnetic repulsion between like poles (N–N) in permanent magnets.
Minimum mechanism: Two ferromagnetic dipoles with aligned north poles generate a net repulsive force along their common axis; this force must produce observable translational separation as soon as the magnets are no longer held in place, with no physically motivated pause.
(ii)Storyline: Phase 1 (0–2s): Static setup (two identically shaped bar magnets lie side-by-side, parallel, N-ends facing inward, fully visible, unmoving, with clear N/S labels). Phase 2 (2–3s): Release (hands withdraw or supports vanish); the magnets begin visibly drifting apart within this same phase, since the repulsive force acts as soon as the constraint is removed. Phase 3 (3–7s): Repulsion response (both magnets translate apart symmetrically along the N–N axis, maintaining orientation); no rotation or contact. Phase 4 (7–10s): Stabilization (motion slows and stops with increased separation); magnets remain still, fully visible, N-ends now pointing away from each other. Perspective: Fixed frontal view, full-body visibility of both magnets at all times; no occlusion, no camera motion.

Manual:
Experimental Procedure
1. Place two identical bar magnets side-by-side on a flat surface.
2. Mark each magnet clearly with "N" at one end and "S" at the other.
3. Orient both magnets so their "N" ends face each other.
4. Release them simultaneously from rest.
Observation of Experimental Phenomena
Both magnets move apart from each other along the line connecting their N poles; no contact occurs.
Summary of Experimental Principles
Like magnetic poles (N–N) repel each other; this repulsive force causes observable separation when magnets are released in close proximity with like poles facing.

Prompt Grounding rubric:
level_1: No bar magnets appear, or only a single magnet is shown; the magnet(s) shown have no visible N/S markings; the N poles are not oriented toward each other before release; no release action (hand withdrawal or support removal) is shown; no separation motion follows.
level_2: Two bar magnets appear with N/S markings, but at least one setup element is missing: the N poles are not both oriented toward each other before release, or no release action is shown, or one magnet leaves the frame at some point during the sequence.
level_3: Two identical bar magnets are shown, each clearly marked with N and S; both N poles face each other before release; a release action is visible (hands pull away or a support is removed); both magnets stay inside the same fixed frame for the whole sequence.
level_4: The two magnets are the same size and shape as each other; the N/S markings are legible and placed in the same relative spot on each magnet (e.g., both red bands at the N end); no cup, hand, or prop blocks either magnet from view at any point in the sequence.
level_5: Both magnets sit stationary, side-by-side, and horizontally aligned before release; each magnet's N-pole marking faces the camera and sits at the same distance from that magnet's center as the other magnet's marking; the two magnets and their markings remain fully identifiable and correctly labeled (no swapped or smeared N/S text) from the first frame to the last.

Scientific and Causal Correctness rubric:
level_1: The magnets drift toward each other, collide, or stay motionless after release, or one magnet spins in place without moving away from the other, none of which is consistent with N–N repulsion producing separation.
level_2: The magnets do separate, but not as N–N repulsion predicts: only one magnet moves while the other stays put, or the two magnets separate along a direction that is not the line joining their original N-pole faces, or their centers don't both visibly shift apart.
level_3: After release, both magnets visibly move apart along the line that joined their N poles; the separation starts as soon as the hands or support are gone, with no stationary pause, and continues without either magnet touching the other.
level_4: The separation motion for both magnets is a straight-line slide apart with no visible spinning or flipping of either magnet during the separation; once the magnets stop, they stay stopped: no coming back together or oscillating apart-then-together.
level_5: The gap between the magnets grows without ever shrinking, from the moment of release to the moment they settle; both magnets keep their original orientation the whole time: the same N-end still identifiable, now pointing outward instead of inward; nothing in the frame (a puff of air, a nudge, a visible tap) suggests any force pushed them apart other than the magnets themselves.

Spatiotemporal Consistency rubric:
level_1: A magnet's position jumps between frames with no visible path connecting the two positions; a magnet appears to break apart or warp in shape; the lighting or a magnet's shadow changes abruptly between frames (e.g., a flash, or a shadow that suddenly appears on the wrong side); the video visibly freezes, skips, or jump-cuts.
level_2: One clear flaw appears: a magnet's position changes between frames without a visible in-between path; the shadow beneath a magnet jumps to a new position or brightness abruptly; a magnet's edges warp, stretch, or flicker in transparency; the camera view pans, zooms, or cuts partway through the sequence.
level_3: Neither magnet ever jumps position, breaks apart, or flickers in transparency; there is no abrupt change in the lighting or in either magnet's shadow; the camera viewpoint never pans, zooms, or cuts; both magnets keep the same size, shape, and opacity from first frame to last.
level_4: Each magnet's separation path is a smooth, unbroken slide with no visible stutter or sudden speed change; each magnet's shadow moves and changes gradually in step with that magnet's own motion, never jumping ahead of or lagging behind it; the edges of both magnets stay crisp and stable, with no flicker or doubled edge as they move.
level_5: The two magnets begin moving apart at the same moment and separate at a visually matched pace (neither is clearly ahead of or slower than the other); the amount of blur on each magnet visibly matches its own speed (sharp while nearly still, softer only while moving fastest); the background behind the magnets stays fixed and doesn't shift or warp relative to the magnets' positions.