Domain: Natural Science — Geology & Geophysics
Target concept: Moving a handheld magnetometer or compass over the ground above buried metallic objects

Video generation prompt: A person holds a portable compass and walks in a straight line over exposed soil, sweeping left and right above a buried ferromagnetic object (e.g., iron or steel), then repeats the process from the opposite direction.

Evaluation guide:
(i) Target concept: Magnetic anomaly detection via portable compass over buried ferrous object.
Minimum mechanism: A ferromagnetic object must be buried beneath uniform, non-magnetic soil; Earth"s geomagnetic field must be present and dominant; compass must be magnetically sensitive and free of shielding; no strong external EM sources nearby.
(ii)Storyline: [Phase 1] Person initiates first pass: standing start → forward walking begins → sweeping starts → needle begins rotating as center approached. [Phase 2] Needle peaks at center → begins recovering → sweeping continues → walking ends. [Phase 3] Person turns in place (no cut) → initiates second pass in reverse direction → sweeping resumes → needle rotates again with mirrored timing and direction. [Visibility constraints] Fixed eye-level viewpoint; compass always in frame and unobstructed; soil surface fully visible beneath compass at all times; needle orientation must be legible throughout motion.

Manual:
Experimental Procedure
1. Person stands at one end of an exposed soil patch, holds portable magnetic compass at waist-to-chest height.
2. Walks forward in straight line while smoothly sweeping compass left and right just above soil surface.
3. Upon reaching far end, turns and repeats identical straight-line walk from opposite direction, sweeping again.
Observation of Experimental Phenomena
Compass needle visibly rotates away from magnetic north only during sweeping motion over soil — deflection peaks near center of path and reverses symmetrically on both passes.
Summary of Experimental Principles
Buried ferrous metal distorts Earth"s local magnetic field; handheld compass detects this anomaly as needle deflection; repeated bidirectional sweeps confirm spatial consistency of anomaly and rule out transient interference.

Prompt Grounding rubric:
level_1: No person holding a portable compass appears; no exposed soil is visible; no left-right sweeping motion above the ground occurs; no straight-line walking path is shown; the walk is never repeated from the opposite direction; none of these required elements appear.
level_2: A person holds an object that could be a compass, but it isn't clearly held at waist-to-chest height; the exposed soil is only partly visible, obscured by grass, pavement, or debris; the sweeping motion is missing or replaced by tapping or holding the compass still; no straight walking path is discernible; the return pass from the opposite direction is missing.
level_3: A person holds a portable compass at waist-to-chest height and walks a straight line across exposed soil while sweeping the compass left and right; the same path is walked a second time from the opposite end; both passes occur in one continuous, fixed-viewpoint shot.
level_4: Everything required for score 3 is present, and the compass stays visibly level (not tipped up or down) during both passes, the person keeps a consistent forward-facing posture while sweeping, the soil stays uniformly exposed with no patches of grass, rock, or mulch breaking it up, and no extra objects (tools, markers, signage) enter the frame.
level_5: Everything required for score 4 is present, and the compass is clearly a magnetic compass (a round face with a needle and direction markings, distinct from a phone or GPS unit), the sweeping motion is smooth and covers a visually consistent left-right range on both sides of the walking line, and both passes follow the same ground path (same start and end points), confirmed by a fixed landmark (the edge of the soil patch, a shadow, or another fixed feature) staying in the same place relative to the path.

Scientific and Causal Correctness rubric:
level_1: The compass needle shows no movement at all and stays aligned north throughout; there's no sense that anything is buried; nothing links the person's motion to the needle's behavior.
level_2: The needle deflects, but inconsistently: swinging randomly or reversing with no clear cause; deflection happens only while the person stands still or turns, not while sweeping; there's no visible correlation between position over the soil and the needle's behavior; the needle looks frozen, blurred, or digitally pasted on rather than physically moving.
level_3: The needle visibly swings away from north specifically while sweeping over the soil; the swing grows larger near the middle of the walked path, where the buried object is implied to be, and eases back toward north once the sweep moves past; the same pattern repeats on the second pass from the opposite direction.
level_4: Everything required for score 3 is present, and the needle always swings toward the buried object's location (turning toward the center of the path during both passes, not away from it or sideways); the swing starts as the person nears the center, peaks near the center, and eases as they move past it, with no unrelated reversal or oscillation.
level_5: Everything required for score 4 is present, and the needle only swings while actively sweeping over the soil, never while approaching, pausing, or walking away; the swing looks the same on both passes (similar peak timing relative to the center, similar angular extent, similar recovery); the needle's markings stay clearly readable throughout every swing.

Spatiotemporal Consistency rubric:
level_1: The person jumps between positions with no walking shown connecting them; the compass jumps discontinuously; the soil's texture or height changes abruptly mid-walk; the lighting shifts dramatically between shots; background elements flicker or disappear; the motion shows visible dropped frames or warping.
level_2: The person stops and restarts walking with an abrupt change in speed; the compass's orientation snaps to a new angle with no rotation shown; the soil's shadows or brightness look inconsistent between the first and second pass; background objects shift position between passes; the camera's framing wobbles or drifts noticeably.
level_3: The walk is continuous and moves forward without pausing or backtracking; the compass sweeps left-right smoothly without freezing or jerking; the soil keeps a consistent texture, color, and flatness for the whole shot; the background stays in place; the camera holds one steady, fixed framing throughout.
level_4: Everything required for score 3 is present, and the person's stride length and walking pace look the same on both passes, the compass's sweep width and rhythm match between passes, the soil shows no cracks, footprints, or disturbances that would contradict an undisturbed burial site, and there's no gap between the two passes (no fade-out, cutaway, or time-lapse jump).
level_5: Everything required for score 4 is present, and the spatial relationships stay intact throughout: the person's feet stay on the ground with no floating or sinking, the compass stays at a constant height above the soil with no rising or dropping, the distance between the person and the ground looks constant, and the foreground and background stay aligned with each other consistently as the person moves.