Domain: Natural Science — Geology & Geophysics
Target concept: A steel nail is temporarily magnetized by rubbing it against a magnet, and subsequently attracts small iron filings.

Video generation prompt: A steel nail is rubbed several times in the same direction with a bar magnet; then the magnet is removed, and loose iron filings are brought close to the steel nail and gently shaken.

Evaluation guide:
(i) Target concept: Contact-induced transient ferromagnetic alignment in soft magnetic material.
Minimum mechanism: Steel must be unmagnetized initially; magnet must be ferromagnetic with defined polarity; rubbing must be unidirectional to produce net domain alignment; iron filings must be unmagnetized and ferromagnetic to respond to induced field.
(ii)Storyline: Frame 1–2: Static shot showing isolated steel nail and bar magnet side-by-side. Frame 3–5: Magnet moves unidirectionally along nail length (contact maintained). Frame 6–7: Magnet exits frame fully; nail remains centered. Frame 8–10: Iron filings enter frame near nail tip, then undergo visible oscillatory shaking — during which filings adhere and persist on nail surface. Perspective: Fixed frontal view, full nail visible throughout; no camera movement; all actions occur within same continuous plane.

Manual:
Experimental Procedure
1. Hold steel nail stationary. Rub one pole of a bar magnet along nail length 5–6 times, always in same direction.
2. Remove magnet completely from scene.
3. Bring loose iron filings close to nail and gently shake them.
Observation of Experimental Phenomena
Iron filings visibly adhere to the steel nail — especially near its ends — and remain attached during shaking motion.
Summary of Experimental Principles
Rubbing aligns magnetic domains in the steel nail, inducing temporary magnetism; the nail becomes a weak magnet with north/south poles and attracts ferromagnetic materials like iron filings.

Prompt Grounding rubric:
level_1: No steel nail appears; no bar magnet appears; no iron filings appear - none of these three required objects are shown at any point.
level_2: At least one of the nail, magnet, or filings appears, but the required sequence - rubbing the nail with the magnet, removing the magnet, then bringing filings close and shaking them - never plays out.
level_3: The steel nail, bar magnet, and iron filings are all shown; the nail is rubbed with the magnet, the magnet is then removed before the filings appear, and the filings are brought near the nail and shaken - but at least one detail is off: the rubbing goes back and forth rather than one direction, the magnet is still visible when the filings are introduced, or the filings are just held near the nail without any shaking.
level_4: The nail is rubbed with the magnet several times in the same direction along its length; the magnet is completely removed from the frame before the filings appear; the filings are brought close enough to plausibly test attraction and are clearly, visibly shaken; and nothing in the scene contradicts the described sequence.
level_5: Everything required for a 4 is met, and in addition: the rubbing motion is clearly one-directional with no back-and-forth slipping; once the magnet leaves the frame it never re-enters or partially reappears; and the filings only touch or cluster on the nail after the shaking motion has begun, showing the attraction is being actively tested rather than the filings simply resting on the nail beforehand.

Scientific and Causal Correctness rubric:
level_1: The iron filings show no attraction to the nail at all - they stay scattered, fall straight down, or only stick if the nail happens to be tacky or wet, with nothing suggesting the nail itself has become magnetic.
level_2: Filings stick to the nail before the rubbing happens, or while the magnet is still touching it, or filings attach with no shaking at all - any of these breaks the cause-and-effect chain of rubbing inducing magnetism.
level_3: The rubbing, magnet removal, and filings-plus-shaking sequence all happen in order, and some filings do visibly stick to the nail during or after the shaking - but the effect is weak or spotty (e.g., only one or two filings stick, or they cling only near the tip while the rest of the nail attracts nothing), or the filings fall off the instant the shaking stops.
level_4: Filings stick specifically to the nail itself (not to the magnet or anything in the background), and only after both the rubbing and the magnet's removal have happened; once attached, they stay on the nail through the shaking (moving with it or vibrating in place, not dropping off); and no filings end up stuck to any surface other than the nail.
level_5: Everything required for a 4 is met, and in addition: (a) filings cluster more densely near the nail's tip and head, consistent with the induced magnetic poles being strongest at the ends, while the mid-shaft attracts noticeably fewer or none; (b) no filings are stuck to the nail before rubbing begins or while the magnet is still touching it; (c) filings only stick at the moment they actually make contact with the nail's surface during shaking - none appear to drift or snap onto the nail from a visible gap, which would look like an implausibly strong, long-range pull for a nail that was only briefly rubbed.

Spatiotemporal Consistency rubric:
level_1: The nail's position suddenly changes between frames as if teleported; the magnet vanishes and reappears mid-rub without a continuous path; iron filings appear on the nail with no visible approach; or the lighting or shadow on the scene changes abruptly from one frame to the next.
level_2: The hand appears to lose and regain contact with the nail during rubbing without a visible slide in between; the magnet's exit from the frame is not a continuous motion - it seems to vanish, then reappear off to the side; or the filings' approach toward the nail looks jerky or warped rather than a smooth, continuous motion.
level_3: The nail, magnet, and filings all move in a continuous, physically reasonable way with no teleporting or sudden warping, and overall lighting stays even throughout - but there is a small hiccup, such as the nail rotating slightly with no hand touching it, filings scattering before the shaking motion actually starts, or the magnet's exit briefly blocking the nail from view before it becomes fully visible again.
level_4: The nail stays fixed in position and orientation the whole time; the hand keeps steady, continuous contact with the nail during rubbing with no visible slipping or lifting; the magnet exits the frame in one smooth motion with no pause or backtrack; and the filings enter as a coherent group, stay together on approach, and respond to the shaking with natural, granular movement rather than passing through each other or stretching unnaturally.
level_5: Everything required for a 4 is met, and in addition: the nail's position, size, and framing stay visually unchanged across the whole sequence with no perceptible drift or zoom; the hand's rubbing motion keeps a steady, even pace with no sudden speed-ups or freezes; and the filings that stick to the nail appear to shake together with it as a single unit rather than moving independently of one another or of the nail.