Domain: Engineering — Electrical Engineering
Target concept: A silicon diode allows current to flow in one direction but blocks current when the polarity is reversed.

Video generation prompt: On the table, connect a small battery, a silicon diode, and a miniature incandescent lamp in series, and then reverse the battery's polarity during the recording process to invert the diode's polarity.

Evaluation guide:
(i) Target concept: Unidirectional current conduction in silicon p-n junction diodes under DC bias.
Minimum mechanism: Diode must be modeled as a voltage-controlled switch: conductive only when anode voltage > cathode voltage by ≥0.7 V; lamp requires sufficient current to heat filament to incandescence; open-circuit current = zero illumination.
(ii)Storyline: Frame 1–3: Stable forward-bias setup, battery upright, diode band facing lamp, lamp lit. Frame 4–7: Battery rotates smoothly, no circuit break, no lamp state change mid-motion. Frame 8–10: Battery settled in reversed orientation: diode band still faces the lamp exactly as before; only the battery's marked terminal has swapped sides, lamp fully extinguished. Perspective: Fixed overhead or 30° oblique tabletop view; all components fully visible, no occlusion; lighting reveals object geometry and lamp state unambiguously.

Manual:
Experimental Procedure
1. Place a small cylindrical battery, a silicon diode (with visible cathode band), and a miniature incandescent lamp in a straight line on a table.
2. Connect them in series using bare wire ends or direct metal contact: battery terminal → diode anode (band-free end) → diode cathode (banded end) → lamp → battery other terminal.
3. Record while flipping the battery end-over-end to reverse its polarity.
Observation of Experimental Phenomena
The lamp is brightly lit in one battery orientation and completely unlit in the other; illumination state changes *only* upon battery polarity reversal, with no intermediate states.
Summary of Experimental Principles
A silicon diode conducts current only when forward-biased (anode positive relative to cathode); reversing battery polarity reverses bias, blocking current and extinguishing the lamp.

Prompt Grounding rubric:
level_1: No battery, no silicon diode, or no miniature incandescent lamp is visible; or the three are present but not arranged in series on the table; or no battery-polarity-reversal action is shown at all.
level_2: Battery, silicon diode, and lamp are all present on the table and appear connected, but the connection is not clearly a single series path (e.g., a wire is missing, the lamp sits off to the side rather than in-line, or a component floats without contact); or the battery is present but is never actually rotated/flipped.
level_3: Battery, silicon diode, and miniature incandescent lamp are all present on the table, visibly connected in one unbroken series loop (no gaps, no branching), and the battery is visibly rotated/flipped end-over-end during the clip, showing a clear before/after change in which terminal points which way.
level_4: All conditions for score 3 are met, and additionally: (a) the diode reads as a small cylindrical component with a printed cathode band, (b) the lamp reads as a miniature incandescent bulb (glass envelope with a visible filament, not an LED), (c) the battery is a small cylindrical or button cell scaled similarly to the diode and lamp, and (d) the diode and lamp stay in place on the table while only the battery is handled during the flip (no re-wiring or reseating of the other components).
level_5: All conditions for score 4 are met, and additionally: (a) the diode's printed band stays in the same physical position and facing relative to the lamp for the entire clip; only the battery's marked terminal (e.g., its raised + end) swaps sides during the flip, (b) the lamp sits between the diode and the battery in the series loop so the current path can be traced without doubling back, (c) the hand performing the flip never blocks the camera's view of the diode or lamp, and (d) all three components stay within the frame and in the same relative layout on the table before, during, and after the reversal.

Scientific and Causal Correctness rubric:
level_1: The lamp's lit/unlit state does not track the battery orientation at all (e.g., lit in both orientations, or unlit in both orientations), or its brightness changes for a reason unrelated to the polarity flip, or the diode appears to play no role in whether the lamp lights.
level_2: The lamp is lit in one orientation and dark in the other, but the correspondence is backwards for a silicon diode: the lamp lights up when the diode's cathode (banded end) faces the battery's positive terminal, i.e., it lights during reverse bias rather than forward bias.
level_3: The lamp is lit in exactly one battery orientation and dark in the other, the change occurs together with the battery flip, and the lit orientation matches silicon-diode forward conduction: the lamp lights only when the diode's anode (unbanded end) faces the battery's positive terminal and the banded cathode faces the lamp.
level_4: All conditions for score 3 are met, and additionally: (a) the lamp changes state only once across the whole clip, with no flicker or partial glow at any other time, (b) in the reverse-biased orientation the lamp shows no glow at all: the filament reads as fully dark, and (c) in the forward-biased orientation the lamp reaches a clearly bright, steady glow.
level_5: All conditions for score 4 are met, and additionally: (a) the lamp goes dark around the time the battery finishes rotating into the reverse orientation, without an extended lingering glow afterward, (b) the lamp lights up around the time the battery finishes rotating into the forward orientation, without a noticeable warm-up delay, and (c) the darkened lamp never shows a false glow from reflections or ambient light: its envelope reads as visibly dark against the background.

Spatiotemporal Consistency rubric:
level_1: Any component appears or disappears without traveling through the space between, jumps to a new position, or bends/deforms unnaturally; the diode or lamp moves or rotates on its own without the hand touching it; or the lamp's brightness changes while the battery is not being moved at all.
level_2: The battery flips but the circuit visibly breaks during the motion (a wire pulls free or a contact separates from a terminal); or the lamp or diode shifts position or angle during the flip even though only the battery should move; or the lamp's brightness changes before the battery has finished rotating into its new orientation.
level_3: The battery's flip reads as one continuous rotation with a visible path of motion; the diode, lamp, and any visible wiring stay fixed relative to the table and to each other throughout; the lamp's lit/unlit state changes only after the battery has settled into its new orientation; and no component vanishes, splits into copies, or warps in shape.
level_4: All conditions for score 3 are met, and additionally: (a) the battery's rotation is smooth and one-directional, without stalling, jerking, or reversing partway through, (b) any visible wiring keeps an unbroken visual connection between the battery, diode, and lamp throughout the flip, and (c) shadows cast by the battery, diode, and lamp shift together with the light source and the battery's motion rather than jumping or flipping direction.
level_5: All conditions for score 4 are met, and additionally: (a) the battery's motion reads as one coherent rigid rotation rather than parts drifting independently or flickering in place, (b) the lamp's transition between lit and unlit reads as a clean switch rather than a gradual fade or a stage where only part of the filament glows, (c) overall room lighting stays level throughout, with no sudden global brightening or dimming unrelated to the lamp switching, and (d) the diode's band and the lamp's position relative to each other never appear to shift, confirming that only the battery moved.