Domain: Natural Science — Physics
Target concept: Moving a bar magnet back and forth within a copper wire coil connected to a galvanometer

Video generation prompt: A bar magnet is pushed into and pulled out of a copper wire coil connected to a galvanometer, whose needle is clearly visible.

Evaluation guide:
(i) Target concept: Electromagnetic induction via relative motion between a permanent magnet and a closed copper coil, producing transient current detectable by galvanometer deflection.
Minimum mechanism: Coil must be electrically closed (no breaks), made of conductive copper (not aluminum/steel), wound as a multi-turn helix; magnet must have dipole field (bar shape); galvanometer must be analog, center-zero, and sensitive to microcurrents; motion must change magnetic flux linkage through coil area.
(ii)Storyline: [Frame 0–t1] Static setup: bar magnet held near but outside coil entrance, galvanometer needle at zero; [t1–t2] Magnet moves coaxially into coil → needle deflects steadily in one direction; [t2–t3] Magnet stops fully inside → needle returns smoothly toward zero; [t3–t4] Magnet moves coaxially out of coil → needle deflects steadily in opposite direction; [t4–end] Magnet fully withdrawn → needle returns to zero. Entire sequence must be captured in single fixed-viewpoint shot with all three objects continuously visible and spatially coherent.

Manual:
Experimental Procedure
1. Hold a bar magnet horizontally and align it with the central axis of a stationary copper wire coil.
2. Push the magnet steadily into the coil until fully inserted.
3. Pull the magnet steadily back out of the coil.
Observation of Experimental Phenomena
The galvanometer needle deflects in one direction when the magnet is pushed in, returns toward zero when motion stops, then deflects in the opposite direction when the magnet is pulled out.
Summary of Experimental Principles
Relative motion between a magnetic field and a closed conductive loop induces an electromotive force (EMF), causing current flow; direction of induced current follows Lenz’s law — opposing the change in magnetic flux.

Prompt Grounding rubric:
level_1: No bar magnet, no copper wire coil, and no galvanometer appear together at any point, or none of the three objects is shown at all.
level_2: At least one of the three objects (bar magnet, copper wire coil, galvanometer) is missing, or all three appear but in an inconsistent form; e.g., the coil shows no visible copper windings, the galvanometer has no needle or scale, or the magnet is not bar-shaped.
level_3: A bar-shaped magnet, a coil with visible copper windings, and a galvanometer with a visible needle and dial are all present and correctly shaped; however, the magnet is never shown being pushed into or pulled out of the coil, or the galvanometer needle never leaves its resting position.
level_4: The bar magnet, copper coil, and galvanometer keep a consistent appearance throughout; the magnet is shown sliding into the coil and then sliding back out (two separate directional motions) within a single continuous shot that keeps all three objects visible; the galvanometer needle visibly moves away from its resting position at some point during the insertion and at some point during the withdrawal.
level_5: Everything required for score 4 holds, and in addition the magnet approaches and leaves along the coil's central axis rather than off to one side, the coil's copper windings and the galvanometer's dial stay clearly visible and unobstructed for the whole clip, and the needle's excursion is large enough on the dial that a viewer can clearly see it move away from center during both the insertion and the withdrawal.

Scientific and Causal Correctness rubric:
level_1: The galvanometer needle's motion shows no relationship to the magnet's motion: the needle stays at rest regardless of the magnet being pushed in or pulled out, or it moves at moments when the magnet itself is not moving.
level_2: The needle moves during only one of the two actions (only insertion or only withdrawal, not both); or it deflects in the same direction for both insertion and withdrawal; or after deflecting once it never drifts back toward its resting position before the next motion begins.
level_3: The needle deflects during both the insertion and the withdrawal, and drifts back toward its resting position between the two motions; however, the deflections are too small, too fast, or too obscured to tell whether the needle actually swings to opposite sides for insertion versus withdrawal.
level_4: The needle deflects during both the insertion and the withdrawal, drifts back toward rest between them, and clearly swings to opposite sides of the dial for the two actions (e.g., toward the right on insertion and toward the left on withdrawal); however, it does not fully settle back to its resting position before the second motion starts, or the size of the two deflections is very different (e.g., a wide swing on insertion but only a faint twitch on withdrawal).
level_5: The needle deflects during both the insertion and the withdrawal, returns fully to its resting position between the two motions, swings to clearly opposite sides of the dial for insertion versus withdrawal, and the two deflections are comparable in size to one another; the needle shows no motion at any time when the magnet itself is not moving.

Spatiotemporal Consistency rubric:
level_1: The single continuous shot is broken in an implausible way: the bar magnet appears already inside the coil without ever having traveled through the coil's opening, the coil or the galvanometer is missing for part of the shot and then shows up again with no camera movement to explain where it went, the lighting abruptly shifts (e.g., a new light source or flash appears, or the shadow direction jumps) with no cause, or the shot cuts away from the needle at the exact moment the magnet is inserted or withdrawn.
level_2: The magnet, coil, and galvanometer are never all shown together in the same continuous shot at once (e.g., the insertion is filmed in one shot and the needle's reaction in a separately cut shot), or the magnet's path into the coil visibly skips: it is suddenly partway inside the coil without having passed through the opening.
level_3: The magnet, coil, and galvanometer stay in one continuous shot with fixed positions relative to each other on the workbench; the magnet travels along the coil's central axis without ever clipping through the coil wall; however, its motion is not smooth: it visibly pauses and then jumps forward in steps rather than gliding continuously into or out of the coil.
level_4: Everything required for score 3 holds, and in addition each push-in and pull-out motion is one smooth glide from a clear start to a clear stop at a natural hand-driven speed, and the needle's movement is visibly confined to the time the magnet is actually in motion (it does not start moving noticeably before the magnet moves or keep moving well after the magnet has stopped).
level_5: Everything required for score 4 holds, and in addition the magnet, coil, and galvanometer keep the same coaxial arrangement and the camera keeps the same framing from first frame to last with no re-centering or zoom change, no new light source or lamp flicker appears partway through the shot, and the needle's swings visibly track the timing of the magnet's motion with no perceptible delay.