Domain: Natural Science — Chemistry
Target concept: Acid-base neutralization monitored by bulb brightness in a simple conductivity setup

Video generation prompt: A beaker containing clear aqueous acidic solution is connected to a battery and a small incandescent lamp via metal electrodes, while clear base is slowly added and the mixture is gently stirred.

Evaluation guide:
(i) Target concept: Electrical conductivity in aqueous solutions depends on ion concentration; strong acid + strong base neutralization reduces [H+] and [OH−] while forming low-conductivity salt water, decreasing current and lamp brightness.
Minimum mechanism: Acid and base must both be strong electrolytes (fully dissociated), solution must remain dilute and homogeneous, no side reactions (e.g., CO₂ evolution), electrodes must be inert (e.g., Pt or graphite), and lamp must be current-limited to respond visibly to conductivity change.
(ii)Storyline: Frame 1–2: Static shot showing intact circuit: beaker with clear liquid, submerged electrodes, wired lamp glowing. Frame 3–4: Dropper tip enters frame and delivers first base drop into beaker. Frame 5–6: Stirring begins simultaneously; lamp filament visibly dims frame-by-frame. Frame 7–8: Base addition continues; dimming progresses; liquid remains optically uniform. Frame 9–10: Addition ends; stirring ceases; lamp at minimum brightness (a faint, low glow rather than fully dark, since the neutralized salt solution remains weakly conductive). Perspective: Fixed frontal medium shot, beaker centered, full lamp and battery visible, no occlusion, top-down view of liquid surface not required but side view must show electrode submersion and stirrer entry point.

Manual:
1. Fill beaker with clear aqueous acidic solution; insert two metal electrodes connected in series to a battery and a small incandescent lamp.
2. Observe lamp is ON. Slowly add clear aqueous base while gently stirring.
3. Lamp brightness decreases progressively toward a dim, low-current glow as neutralization nears completion; because the resulting salt solution (e.g., NaCl) still contains mobile ions and remains weakly conductive, the lamp does not go fully dark, though it may become very faint; solution remains clear and colorless throughout.

Prompt Grounding rubric:
level_1: No beaker is shown; no battery is visible; no incandescent lamp is visible; no metal electrodes are inserted into a liquid; no acidic solution is shown; no base is being added; no stirring motion appears.
level_2: A beaker with clear liquid is shown, but the battery, lamp, or electrodes are missing or wrongly set up (e.g., an electrode sits outside the liquid, the lamp has no wire running to it, the battery is left out of the loop); base appears in the beaker before the acid does, or stirring happens with no base being added.
level_3: A beaker holding clear liquid, a battery, a lamp, and two metal electrodes are all visible and wired in one loop (battery to electrode, through the liquid, to the second electrode, to the lamp, and back to the battery); base is visibly poured or dropped into the beaker at some point in the clip; stirring is shown while the base goes in.
level_4: Everything from the 3-point level holds, and both electrodes stay under the liquid surface the whole time; the lamp is angled so its glowing filament can be seen; the base enters from a visible dropper or pipette tip; the stirring is continuous and only happens while base is being added; none shown before the first drop or after the last.
level_5: Everything from the 4-point level holds, and the base is only added after the full circuit is already lit and running (battery wired, lamp glowing, electrodes already in the acid); the stirring begins in the same moment the first drop of base lands; the lamp is visibly lit at the start, and its brightness is shown changing across the clip as base is added (the direction and amount of that change is judged separately, not here); nothing else appears in the shot (no extra props, no cut to a different angle, no on-screen text), just one continuous, fixed-camera view of the whole setup.

Scientific and Causal Correctness rubric:
level_1: The lamp stays just as bright the whole time; or it snaps off instantly instead of fading; or it flickers unevenly; or the liquid turns a new color (like pink or blue) or turns cloudy; or bubbles or corrosion show up at the electrodes; or the lamp gets brighter as base goes in.
level_2: The lamp starts lit but goes completely dark before all the base has been added; or it gets brighter partway through adding base; or the liquid turns cloudy, forms a precipitate, or separates into layers; or the electrodes visibly dissolve, change color, or give off gas; or the brightness rises at any point during the addition.
level_3: The lamp is lit at the start of the clip; its brightness steadily drops as base is poured in; the liquid stays clear with no color change, cloudiness, precipitate, or gas bubbles; the electrodes show no visible reaction; the dimming never reverses or flickers, and it tracks with when the base is being added and stirred.
level_4: Everything from the 3-point level holds, and the dimming only starts once base actually begins entering the beaker (not before the first drop); it keeps going until the base addition ends, without pausing or bouncing back partway through; stirring is visible during every moment the lamp is seen dimming; the liquid stays fully clear and see-through the entire time; even at its dimmest, the lamp keeps a faint, visible glow rather than going fully dark, consistent with the neutralized salt solution remaining weakly conductive.
level_5: Everything from the 4-point level holds, and each later frame shows the lamp at the same brightness or dimmer than every earlier frame after dimming starts; it never shows a frame brighter than one before it; there's no momentary brightening; nothing (glare, an electrode, a hand) blocks the view of the filament while it dims; the liquid's surface stays flat apart from the gentle ripples made by stirring; the lamp never reads as completely extinguished at any point, including the final frame.

Spatiotemporal Consistency rubric:
level_1: The beaker, battery, lamp, or electrodes suddenly change position or size between frames; the lamp or battery blinks out of view and turns up again later; an electrode looks detached from its wire even though it's still standing upright in the liquid; the stirring hand starts or stops moving with no visible acceleration, as if snapped instantly between motion and rest; the room's lighting flashes, strobes, or swings abruptly from bright to dark for no visible reason.
level_2: The beaker tilts or rotates for no visible reason; an electrode drifts sideways though nothing is touching it; the stirring rod's path skips ahead by more than one full stir between visible moments, breaking its circular path; a background object (like the table edge) bends or warps; the brighter side of the beaker or lamp swaps to the opposite side partway through the clip even though nothing in the room has moved.
level_3: The beaker stays put on the table for the whole clip; both electrodes stay fixed in place and upright in the liquid; the battery and lamp stay in the same position relative to the beaker; the stirring hand or rod moves in one continuous, smooth path outside the beaker's rim; the side of the beaker and lamp that looks brighter stays the same side from the first frame to the last; the liquid, electrodes, and lamp glass keep their shape with no stretching or warping.
level_4: Everything from the 3-point level holds, and the stirring motion traces a steady circular or figure-eight path with no pauses or sudden reversals; each electrode stays at the same depth in the liquid the whole time, without bobbing up or lifting out; the lamp's brightness fades smoothly from one frame to the next rather than dropping in a sudden jump; the beaker keeps the same apparent size and distance from the camera, with no background object sliding relative to it as if the camera itself had shifted.
level_5: Everything from the 4-point level holds, and the electrode tips and lamp filament hold steady in place frame to frame with no visible wobble; the stirring motion and the base entering the beaker start at the same visible moment, with no noticeable delay between the two; the brightness and highlight pattern on the lamp glass and liquid surface change only as the lamp dims; they don't otherwise brighten, flicker, or shift on their own; the blur on the moving stirrer or liquid matches how fast they're actually moving, while the stationary lamp filament and electrodes stay sharp.