Domain: Engineering — Electrical Engineering
Target concept: Battery internal resistance effect, lighting a bulb through voltage drop

Video generation prompt: On a workbench, there are two identical bulbs connected to a battery and equipped with switches: the one on the left is new, and the one on the right is old. Turn on both switches simultaneously, wait for a period of time, then turn them off and turn them on again.

Evaluation guide:
(i) Target concept: How the resistance of a bulb's own filament (the "internal" resistance of that bulb as a circuit element) sets the voltage drop across it and therefore its brightness, when both bulbs are driven by the same battery.
Minimum mechanism: The left (new) and right (old) bulbs are each wired in an identical simple series loop (battery–switch–bulb), powered by the same battery, so the battery-and-wiring side of the two loops is held constant across the comparison; the old bulb's filament has thinned/oxidized with use, raising its own resistance relative to the new bulb's; by Ohm's law the higher-resistance filament takes a larger share of the fixed supply voltage, leaving less voltage/current to produce light, up to outright failure to light if its resistance has risen enough; no parallel paths or voltage regulators are present, and the bulb failure mode is resistive (high-resistance or open filament), not a short circuit.
(ii)Storyline: Frame 0–1: Static wide shot, workbench with battery centered, two identical bulbs side-by-side (left=new, right=old), each with dedicated switch. Frame 2–3: Both switches simultaneously depressed downward (visible lever motion). Frame 4–6: Left bulb filament glows brightly; right bulb filament either dark or faintly glowing. Frame 7: Both switches released (levers return upward). Frame 8–9: Both switches depressed again simultaneously. Frame 10–12: Left bulb reignites instantly at full brightness; right bulb remains dark or relights at visibly lower intensity, no recovery, no flicker beyond expected thermal lag. All events occur from fixed frontal viewpoint; no occlusion; lighting remains static and overhead.

Manual:
Experimental Procedure
1. Place battery centrally on workbench.
2. Connect left (new) bulb and right (old) bulb in separate series circuits, each with its own switch.
3. Simultaneously close both switches; observe bulbs for ~2 seconds.
4. Open both switches; wait <1 second.
5. Simultaneously close both switches again; observe bulbs for ~2 seconds.
Observation of Experimental Phenomena
Left bulb lights immediately and brightly in both activations. Right bulb either fails to light or illuminates with visibly lower intensity/delay in second activation.
Summary of Experimental Principles
The old bulb's filament has degraded with use, raising its own resistance relative to the new bulb's. Because both bulbs share the same battery and wiring, the higher-resistance filament takes a larger share of the fixed supply voltage per Ohm's law, leaving less power to dissipate as light — producing a dimmer glow or, if the resistance has risen enough, no light at all. Demonstrates how a bulb's own internal (filament) resistance governs the voltage drop that determines its brightness.

Prompt Grounding rubric:
level_1: No workbench present; no battery visible; no two bulbs present; no switches visible; no left/right spatial distinction between bulbs; no switch-activation sequence attempted at all.
level_2: Workbench and battery are present, and at least two bulb-like objects appear, but the bulbs are not matched in shape/size; no clear left-right layout is established; a full on-then-off-then-on switching cycle is not shown for both switches.
level_3: Workbench and a centrally placed battery are present; two visually identical bulbs sit side by side with a clear left/right arrangement; two dedicated switches are each wired to one bulb; both switches are pressed together, then both released, then both pressed together again, in that order.
level_4: All of 3, plus: wiring from the battery terminals to each switch and bulb is continuous and unbroken with correct routing; if filament detail is visible, the right (old) bulb's filament looks thinner, frayed, or the glass slightly discolored compared to the left (new) bulb's; no extraneous object blocks the view of either bulb or switch.
level_5: All of 4, plus: the camera holds one fixed frontal framing with no pan, zoom, or cut across both activation phases; the battery, both bulbs, and both switches keep identical on-screen positions from the first frame to the last; the scene shows no rendering artifacts, duplication, or warping of the workbench or wiring; the side-by-side new-vs-old bulb comparison stays legible throughout, independent of which bulb ends up lit.

Scientific and Causal Correctness rubric:
level_1: Neither bulb's lighting is tied to its switch: both light or stay dark regardless of the switch state; or both bulbs behave identically in both activations with no brightness or timing difference between them at all.
level_2: Both bulbs light after their switches close, but the two activation phases show no detectable difference between the left and right bulb (same brightness, same speed of lighting, in both rounds), giving no evidence that the aged bulb behaves differently from the new one.
level_3: On the first activation both bulbs light at comparable brightness; on the second activation the left (new) bulb lights immediately and steadily while the right (old) bulb either fails to light, lights only after a delay, or glows visibly dimmer, showing a gap tied to the old bulb's condition; however, the effect appears only weakly, or it isn't clear the gap follows directly from the second switch closure.
level_4: All of 3, plus: the old bulb's reduced or absent response on the second activation holds steady for as long as its switch stays closed, rather than being a brief flicker; the new bulb shows no comparable decline between its own first and second activation.
level_5: All of 4, plus: the old bulb's dim or dark state on the second activation reads as a steady, uniform outcome (constant low glow, or constant darkness) rather than erratic flicker, consistent with a rise in its own filament resistance; the new bulb stays fully bright and instantaneous both times; at no point does the old bulb appear brighter or faster than the new bulb.

Spatiotemporal Consistency rubric:
level_1: A bulb, the battery, or a switch vanishes and reappears between frames; a bulb or switch jumps to a new spot with no motion shown; the workbench or background changes entirely partway through; a wire appears disconnected and then reconnected without any hand or motion causing it.
level_2: A bulb or switch drifts to a slightly different position between the first and second activation; a switch lever flips state with no visible finger or hand contact; the shadow on the workbench swings to a new direction or suddenly changes strength between phases; the workbench surface's color or reflectivity changes between the two activation phases.
level_3: The battery, both bulbs, and both switches stay in the same layout on the workbench throughout; nothing disappears, reappears, or relocates; the light source and shadow direction stay the same from one phase to the next; any motion (a hand pressing a switch, a bulb's glow appearing) reads as continuous rather than as a jump-cut.
level_4: All of 3, plus: each switch's motion from open to closed shows as one continuous lever movement whose timing lines up with when its bulb's glow appears or changes; the wires between battery, switch, and bulb stay visually taut and unbroken, never stretching, snapping, or floating free; the bulb and switch regions show no tearing, ghosting, or blur that would make it hard to tell which bulb is which.
level_5: All of 4, plus: the framing never drifts; the battery, bulbs, and switches keep the same spacing and camera angle from the opening shot to the closing shot; each moment a switch closes and its bulb's glow appears or fails to appear reads as one smooth, uninterrupted action with no visible skip, shake, or camera jolt.