Domain: Natural Science — Physics
Target concept: Copper-iron thermocouple junction heated by a candle causing simulated galvanometer n

Video generation prompt: A copper-iron thermocouple junction connected to a model galvanometer is heated by a candle on the workbench, and then the candle is removed.

Evaluation guide:
(i) Target concept: Thermoelectric voltage generation via Seebeck effect in a Cu-Fe junction under localized heating.
Minimum mechanism: Two electrically connected, dissimilar metals form a closed circuit with a galvanometer; differential heating at the junction creates charge carrier diffusion imbalance, producing measurable current; no external power source; deflection polarity depends on metal pairing and hot-junction location.
(ii)Storyline: [Phase 1: Baseline] Junction and galvanometer stationary, needle at zero, candle off-frame or idle nearby. [Phase 2: Initiation] Candle enters frame and is positioned adjacent to junction; flame ignites and makes stable contact. [Phase 3: Causal Response] Within <1s of stable contact, needle begins smooth unidirectional deflection; localized air shimmer emerges precisely at junction. [Phase 4: Intervention] Candle is physically displaced away from junction (no re-contact); flame separates cleanly. [Phase 5: Decay] Needle begins smooth return only after separation is complete; shimmer vanishes concurrently; needle settles exactly at zero. All phases observed from fixed frontal workbench-level viewpoint; no cuts, no POV shifts, no object occlusion during critical events.

Manual:
Experimental Procedure
1. Place copper-iron thermocouple junction on workbench and connect its two leads to a model galvanometer.
2. Position candle adjacent to junction and ignite flame to heat junction directly.
3. Observe galvanometer needle deflection during heating.
4. Extinguish candle and remove it from junction.
5. Observe needle returning toward zero.
Observation of Experimental Phenomena
- Galvanometer needle deflects unidirectionally to one side only while flame contacts junction (the specific direction depends on which metal strip is wired to which galvanometer terminal).
- Visible air shimmer appears locally above junction during heating.
- Needle smoothly returns to zero position only after candle is fully removed.
Summary of Experimental Principles
- A temperature gradient across dissimilar metals (copper and iron) generates a thermoelectric EMF (Seebeck effect).
- This EMF drives current through the closed circuit, causing galvanometer deflection.
- Removing heat eliminates the gradient, stopping current and allowing needle to return.

Prompt Grounding rubric:
level_1: No copper-iron thermocouple junction is visible; no galvanometer is visible; no candle appears; no heating action or removal action is shown; the scene does not read as a workbench setup at all.
level_2: At least one required element is missing or unusable: for example the junction and galvanometer are both shown but no wire visibly connects them, or the candle never comes near the junction, or the removal action never happens or is applied to the wrong object; whenever wiring is meant to connect junction to galvanometer, none is visible.
level_3: The thermocouple junction, galvanometer, and candle are all present on a workbench, and a wire visibly runs from the junction to the galvanometer; the candle is positioned near the junction, a heating action (flame touching the junction) occurs, and the candle is later removed, but the ordering is off (e.g., the candle appears removed before the heating is shown) or the spatial arrangement is awkward (e.g., the galvanometer sits unusually far from the junction, making the wire's path hard to follow).
level_4: All objects are present and correctly arranged: the junction connects to the galvanometer via two visible leads (one copper-toned, one iron/steel-toned, so the two metals are distinguishable), the candle sits next to the junction on the same workbench, the flame is clearly shown touching the junction, and the candle is later clearly moved away, all from one fixed camera viewpoint, in the order: idle junction, candle approaches, flame contacts junction, candle withdrawn.
level_5: The junction clearly shows two bonded strips in visibly different colors or textures (copper-toned and iron/steel-toned), connected to the galvanometer through leads whose wire color matches their respective strip; the needle rests at zero before the candle ever makes contact; the flame stays steadily against the junction throughout the heating phase without flickering away from it; the candle's later removal is unambiguous: it fully exits the frame or is clearly pulled well clear of the junction with no accidental re-contact; the sequence (idle junction, candle approaches, flame contacts junction, candle withdrawn) is followed exactly, with the wire visibly and continuously connecting junction to galvanometer throughout.

Scientific and Causal Correctness rubric:
level_1: No observable galvanometer response; the needle stays at rest throughout, even while the candle flame is in contact with the junction; there is no visual indication that heating the junction is doing anything electrically, and no plausible thermal-to-electrical link is depicted at all.
level_2: The needle moves, but not in a way consistent with heating: for example it moves before the flame ever touches the junction, only after the candle has been pulled away, or it swings one way and then reverses while the flame is still steadily in contact for no apparent reason; the junction shows no visible sign of localized heating (no air shimmer, no faint glow) while the needle is supposedly responding to it.
level_3: While the candle flame is in steady contact with the junction, the needle deflects to one side and holds that direction; after the candle is pulled away, the needle moves back toward center; a faint air-shimmer or heat-haze appears near the junction during heating; however the motion is not clean: the needle jitters or reverses briefly during otherwise steady contact, the return begins before the candle is fully removed, or the shimmer appears only after the needle has already started moving.
level_4: The needle deflects smoothly toward one side and remains deflected that same way for the entire time the flame stays in contact with the junction: it never flips direction while contact is continuous; the needle begins returning toward center only once the candle is fully withdrawn; the air-shimmer at the junction appears together with flame contact and disappears together with removal; there are no stray deflections before heating begins or after the needle has returned to zero.
level_5: The needle deflects to one consistent side only while the flame is in contact with the junction, holding that direction without flipping throughout the contact period, and moves back toward center only once the candle is fully withdrawn; the size of the deflection grows smoothly as the flame settles into stable contact (no sudden jump), and the return afterward is smooth and monotonic rather than overshooting or stalling partway; the air-shimmer stays confined to the junction area only, never spreading along the wires or over the galvanometer body; nothing about the junction, wires, or needle contradicts the thermoelectric mechanism (no glow, sparking, or visible melting), and there are no stray deflections before heating begins or after the needle has returned to zero.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal breaks: the junction jumps to a different position between frames, the galvanometer or candle disappears and reappears without explanation, the flame pops in or out of existence, a shadow vanishes and reappears without cause, wires disconnect and reconnect on their own, or the camera viewpoint suddenly shifts or rotates.
level_2: Multiple moderate inconsistencies: the junction's position relative to the galvanometer drifts noticeably between the heating and removal phases, the candle flame's size changes abruptly between frames without a matching camera or distance change, a wire's visible length changes inconsistently across frames, the workbench texture behind the objects warps or repeats oddly, or the galvanometer's casing appears to deform while the needle is moving.
level_3: One minor continuity slip is present but the overall scene holds together: for example the needle's motion looks briefly jerky or frozen for a couple of frames without derailing its overall path, the candle's position relative to the junction shifts slightly (by roughly a junction's width) between the start and end of heating, or the shimmer appears a frame or two before the flame actually reaches the junction; otherwise the spatial layout and lighting stay consistent throughout.
level_4: No teleporting objects, no warped geometry, no lighting that switches abruptly, and no camera viewpoint change; the junction, galvanometer, and candle all keep the same relative spatial layout throughout; the candle's approach and its later withdrawal both move continuously and at a physically plausible speed; there is no inter-frame flicker or popping of any object.
level_5: The junction, galvanometer, and candle keep a completely stable relative layout throughout, with no teleporting, warping, lighting jump, or camera shift of any kind; the candle's approach and its later withdrawal each move continuously and at a physically plausible, non-jerky speed; the wire connecting junction to galvanometer keeps a constant amount of sag or tension throughout; the junction's surface appearance doesn't suddenly change texture or shininess purely from the heating; no motion blur ever obscures whether the flame is touching the junction or where the needle is pointing; and the sense of depth between the junction and the workbench background stays consistent as the candle moves in and out of frame.