Domain: Engineering — Electrical Engineering
Target concept: Comparison of LED Driving by Precharged and Uncharged Capacitors After Switch Closure

Video generation prompt: Two identical LED–resistor–capacitor branches are placed side by side: the left branch contains a capacitor with a red housing, which is pre-charged and then disconnected; the right branch contains a capacitor with a blue housing, which is uncharged; a single switch connects both branches to their respective LEDs.

Evaluation guide:
(i) Target concept: An initially uncharged capacitor with no connected power source cannot drive a load, whereas a capacitor that was charged beforehand and then isolated still holds usable energy and can discharge through a resistor to flash an LED.
Minimum mechanism: the left-branch (red-housed) capacitor is charged to a nonzero voltage before the video begins and is then isolated (no wires attached) until the switch closes, so at closure it can only discharge through its own resistor and LED; the right-branch (blue-housed) capacitor starts at 0 V and is never connected to any battery or other source at any point in the clip, so it has no charge and no way to acquire any; its LED must therefore stay dark for the entire video; conditions are otherwise identical for both branches (same switch, same closure timing).
(ii) Storyline: [Frame 0–1] Switch open: red-housed capacitor sits isolated with no wires attached; blue-housed capacitor also sits with no wires attached; both LEDs are off. [Frame 2–3] Switch begins to close: the mechanical contacts visibly move toward each other. [Frame 4] Switch fully closed: both branches become electrically connected to their LEDs at the same instant. [Frame 5–6] Left (red) LED turns on right at closure and glows brightly at first. [Frame 7–10] Left LED's glow steadily dims as the red capacitor's stored charge depletes through its resistor, eventually going dark; right (blue) LED remains completely unlit for the entire clip, since the blue capacitor never had, and never receives, any charge. Perspective: fixed frontal viewpoint, no camera movement, no occlusion of either branch.

Manual:
Experimental Procedure
1. Place two identical LED–resistor–capacitor branches side-by-side.
2. Left branch: install the red-housed capacitor already charged to a nonzero voltage, then disconnect it from any charging source (no wires attached).
3. Right branch: install the blue-housed capacitor uncharged (0 V) with no wires attached and no connection to any battery or other source at any point.
4. Connect a single switch that, when closed, links both branches to their respective LEDs.
5. Close the switch.
Observation of Experimental Phenomena
The left LED turns on immediately at switch closure and gradually dims as the red capacitor discharges through its resistor, eventually going dark. The right LED never turns on at any point, because the blue capacitor starts with no stored charge and has no source from which to draw current.
Summary of Experimental Principles
A capacitor can only deliver current if it holds stored charge. The pre-charged, isolated capacitor still carries usable energy at switch closure and discharges it through the resistor to flash its LED, with brightness fading as the charge depletes. The uncharged capacitor, having no stored energy and no external source connected at any time, cannot supply any current to its LED, so that branch's LED remains dark throughout.

Prompt Grounding rubric:
level_1: The two side-by-side branches are missing or incomplete: no red-housed capacitor, no blue-housed capacitor, fewer than two LEDs, fewer than two resistors, no switch, or no visible sign that the red capacitor was charged and then disconnected before the clip begins.
level_2: Both branches are present, but a component is wrong or mismatched: the red housing is missing or ends up on the wrong (uncharged) capacitor, the blue housing is missing or ends up on the wrong (precharged) capacitor, the switch is missing, or either branch lacks its resistor or LED.
level_3: Both branches are fully present with the right parts: the left branch has an LED, a resistor, and a red-housed capacitor; the right branch has an LED, a resistor, and a blue-housed capacitor; one single switch connects both branches to their respective LEDs; the red capacitor is shown with no wires attached (implying it was charged and disconnected beforehand); the blue capacitor likewise shows no wires or terminals suggesting any prior charge.
level_4: Everything required for score 3 holds, and in addition the two branches sit strictly side by side from a fixed viewpoint with matching orientation and alignment; neither branch is blocked by the other; and the single switch sits centrally between them, symmetrically wired to both, without distortion or off-axis skew.
level_5: Everything required for score 4 holds, and in addition every component keeps the same visual identity for the entire clip: the red housing never fades, bleeds color, or swaps onto the other capacitor; the blue housing likewise stays fixed to its own capacitor; the switch stays a single control (never splitting into two or duplicating); and no component appears, disappears, or changes type partway through the video.

Scientific and Causal Correctness rubric:
level_1: Neither LED is distinguishable from the other in behavior: both LEDs light up at the same moment with the same brightness, or neither LED ever lights up, or the two capacitors' housing colors (red vs. blue) are not visibly linked to which LED responds.
level_2: The red capacitor's LED lights up as expected but the blue capacitor's LED also lights up at some point in the video (even if dimmer, shorter, or later than the red one); this is scientifically wrong, since the blue (uncharged, sourceless) capacitor has no way to drive its LED at all; or the reverse error occurs, where the red (precharged) capacitor's LED fails to light up even though it should.
level_3: The red capacitor's LED turns on at or immediately after switch closure and is visibly bright at that moment; the blue capacitor's LED stays completely dark for the entire video; this contrast (one branch lights, the other never does) is clearly and consistently visible.
level_4: Everything required for score 3 holds, and in addition the red capacitor's LED brightness visibly decreases over the course of the video (a gradual fade, not a sudden cutoff or re-brightening) as its stored charge is used up; the blue capacitor's LED shows zero glow in every single frame, not even a brief flicker.
level_5: Everything required for score 4 holds, and in addition the red capacitor's LED fade is smooth and steadily decreasing from its peak brightness at closure down to fully dark, with no frame where it brightens again after starting to dim; the blue capacitor's LED remains dark in the very first frame after closure and every frame after that; no frame shows the blue-side LED lit before, during, or after the red-side LED's active period.

Spatiotemporal Consistency rubric:
level_1: The red-housed or blue-housed capacitor jumps to a new position between frames, or either capacitor vanishes and reappears; the resistor or LED body suddenly splits or duplicates; the shadow cast by either branch swaps to the opposite side or blinks out and back in with no lighting or camera change to explain it; or the background jumps or rotates with no camera motion to explain it.
level_2: A branch drifts sideways or vertically by more than roughly half its own height or width between frames; the red or blue housing color flickers or washes out inconsistently from frame to frame; an LED appears lit with no visible wire connecting it to its capacitor and resistor; the switch changes from open to closed with no visible contact motion in between; or the shadow cast by a branch swings to a different angle without the light source moving.
level_3: The red-branch and blue-branch components each stay in the same place and orientation throughout: neither branch drifts, rotates, or rescales; the switch stays visible and stationary except for its own opening/closing motion; nothing from one branch blocks the view of the other in a way that breaks the fixed side-by-side framing; and the light source stays put, so neither branch's shadow shifts direction over the course of the video.
level_4: Everything required for score 3 holds, and in addition the switch's closing motion is smooth and one-directional (it does not visibly snap or jump straight from open to closed); the red LED's illumination begins only once the switch contacts visibly finish closing, not before; and neither capacitor shows a sudden, unexplained change in its wiring (the red capacitor's housing must not suddenly show new wire attachments mid-video that were not there in frame 0).
level_5: Everything required for score 4 holds, and in addition all motion across frames is smooth with no stutter, judder, or repeated frames; neither branch's components show visible warping, blurring, or distortion as the switch closes or the LED fades; brightness changes track only the switch action and the red LED's fade, with no unrelated flashes or dimming; and neither capacitor's housing, the resistors, nor the LED lenses change shape at any point.