Domain: Healthcare — Medicine
Target concept: pH Test of Nasal Drops

Video generation prompt: Take 1 mL of naphazoline hydrochloride nasal solution and apply it to a pH indicator paper. Allow it to stand for 1 minute, then compare the color change with the standard color chart to determine the pH range.

Evaluation guide:
(i) Target concept: Acidic pH detection via a localized, protonation-driven dye color change in indicator paper.
Minimum mechanism: Indicator dye must be chemically stable, water-soluble, and exhibit a clear, reproducible color change at pH ~5 when contacted by the aqueous nasal solution; the paper should wick the solution mainly within the contacted area so the color change stays visually distinguishable from the surrounding dry paper; the color chart must encode a correct, ordered pH-color mapping for visual comparison.
(ii)Storyline: [Frame 0–2] Bottle and dropper enter view; dropper draws up the solution → [Frame 3–4] Dropper moves toward the stationary paper → [Frame 5] The solution contacts the paper's center, visibly wetting an area of the strip → [Frame 6–15] Paper remains completely still, the wetted zone darkens uniformly to orange-yellow → [Frame 16–18] Chart slides into an adjacent position (same plane, same lighting) → [Frame 19–20] Static side-by-side view: the wetted zone and the pH 5 band are co-visible, identically illuminated, and chromatically matched. Perspective: fixed frontal close-up (paper/chart fill ≥70% of frame width); occlusion-free; no hand/body parts in the final comparison frame.

Manual:
Experimental Procedure
1. Hold the naphazoline hydrochloride nasal solution bottle upright; use the dropper to draw up solution and dispense about 1 mL onto the center of dry pH indicator paper, wetting a defined area of the strip (not the whole strip).
2. Place the paper flat on a neutral background; allow it to stand undisturbed for 1 minute.
3. Position the standard pH color chart adjacent to the paper in the same frame; compare the wetted-zone color directly to the chart bands.
Observation of Experimental Phenomena
The pH indicator paper turns orange-yellow within the wetted zone after 1 minute; this color matches the pH 5 band on the standard chart.
Summary of Experimental Principles
Naphazoline hydrochloride nasal solution is weakly acidic (pH ≈ 5); pH indicator paper contains mixed dyes that undergo a protonation-dependent color shift in the acidic range (pH 4–6), producing orange-yellow.

Prompt Grounding rubric:
level_1: No naphazoline hydrochloride nasal solution bottle, no pH indicator paper, and no dropper or pipette are visible; no liquid transfer action is shown; no color comparison scene is present.
level_2: At least one correct object is present (e.g., the bottle or the paper), but at least two of the following are missing: the nasal solution bottle, the dropper, the indicator paper, or the color chart; the liquid transfer action is absent or shows the wrong liquid (e.g., plain water instead of the nasal solution); no side-by-side color comparison is shown.
level_3: All core objects are present: the naphazoline hydrochloride nasal solution bottle, a dropper/pipette, the pH indicator paper, and the standard color chart; the liquid transfer action is shown (solution applied to the paper); the paper and chart appear in the same frame; the sequence shows application → stillness → comparison, but either the paper/chart labels are illegible, the paper is not lying flat on a neutral background, or the dropper tip never visibly contacts the paper.
level_4: All core objects are present and clearly identifiable; the dropper visibly contacts the paper's surface while dispensing; the paper and color chart are adjacent and fully visible in the same frame; the paper lies flat with no curling or occlusion; the applied solution stays within a bounded area of the paper (no runoff beyond the paper's edges); no extraneous objects (e.g., gloves, fingers) obstruct the view of the paper or chart.
level_5: Everything required for the 4-point level is met, AND: the bottle label clearly shows 'naphazoline hydrochloride nasal solution'; the dropper delivers a single, discrete droplet, with no splattering beyond the paper, no multiple drops, and no dripping off its edge; the wetted zone on the paper stays sharply in focus and unobstructed throughout the stillness period; the color chart is oriented upright with the standard pH scale legible (pH 4–7 range visible); the paper and chart are aligned at the same visual height with no rotation or perspective skew; there is no motion blur during the stillness phase.

Scientific and Causal Correctness rubric:
level_1: The paper shows no color change after application; or the paper changes to a color outside the pH 4–7 range (e.g., deep blue for pH >8, or violet for pH <3); or the color chart shows an incorrect pH mapping (e.g., red assigned to pH 7).
level_2: The paper changes color, but the hue is inconsistent with an acidic result (e.g., green or blue-green suggesting neutral/alkaline); or the chart shows a reversed or nonstandard color-pH order; or the paper's color change appears before the solution actually contacts it; or the color change appears only at the paper's edge, unrelated to where the solution was applied.
level_3: The paper changes to a color within the acidic range (orange, yellow-orange, or light orange); the chart displays the standard color progression (red → orange → yellow → green) in the correct order; the color change is localized to the area where the solution was applied; the change appears only after contact and persists during the stillness period, but the paper's color does not match any chart band within about one pH unit (e.g., the paper looks orange but the nearest chart bands are red [pH 4] or yellow [pH 6]).
level_4: The paper's color matches one of the chart's bands within the pH 4–6 range; the chart's bands are correctly ordered (red at low pH, yellow at higher acidic pH); the color stays stable during the stillness period (no fading or shifting); there are no secondary color artifacts (e.g., a halo or an uneven gradient at the edge of the wetted zone); the paper outside the wetted zone stays white/unaffected.
level_5: Everything required for the 4-point level is met, AND: the paper's color matches the pH 5 band (orange-yellow) on the chart with no perceptible hue difference; the chart shows a smooth, gap-free progression between the pH 4 (red-orange) and pH 6 (yellow) bands; the wetted zone shows even saturation and brightness matching the chart band; there is no color cast from lighting or glare that could make the true color hard to judge.

Spatiotemporal Consistency rubric:
level_1: Objects jump instantly between positions with no visible transition (e.g., the paper appears or disappears between frames); there is a severe spatial break (e.g., a hand enters holding the paper, then the paper is suddenly next to the chart with no visible transit); the lighting abruptly shifts (e.g., bright to dark mid-sequence); the chart or paper rotates more than about 30 degrees with no visible cause.
level_2: A minor positional jump occurs (e.g., the dropper's position changes with no visible motion); the paper shifts position between the application step and the comparison step with no hand movement shown; the chart flickers or vanishes and reappears; the lighting changes in intensity or direction between steps; the paper curls or lifts during the stillness period for no physical reason.
level_3: The bottle stays off-screen or stationary at the left; the dropper moves continuously into frame, contacts the paper, then withdraws; the paper stays flat and still on the surface the whole time; the chart stays static and fully visible once placed; the lighting stays consistent; nothing tears, folds, or breaks structurally; the motion is continuous with no jump cuts or repeated frames.
level_4: Everything required for the 3-point level holds, AND: the dropper's motion is smooth and slows down before contact; the paper shows no visible shaking or fluttering during the 1-minute stillness period; the chart and paper stay parallel to the camera and in the same plane; the background elements do not shift position relative to the paper/chart edges; the hand never blocks the chart while the paper is being viewed, or vice versa.
level_5: Everything required for the 4-point level holds, AND: there is no visible blur during the dropper's approach or contact; the paper's surface texture and the chart's printed bands stay consistently sharp across the whole clip; the dropper's shadow keeps a proportional size and shape as it nears the paper (no sudden shape distortion); the action unfolds at a natural, consistent pace with no visible speed-up or slow-motion effect; the camera viewpoint stays rigidly fixed with no pan, tilt, zoom, or focus shift.