Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Identification of the Cyano Group (Reaction for Ammonia Formation by Hydrolysis)

Video generation prompt: A small amount of phenylacetonitrile was placed in a test tube. Three milliliters of sodium hydroxide solution was added, and the test tube was heated in a water bath for 10 minutes. A moist red litmus paper was then placed at the mouth of the test tube to observe any color change.

Evaluation guide:
(i) Target concept: Alkaline hydrolysis of nitrile generates ammonia gas, detectable by base-sensitive litmus paper.
Minimum mechanism: Nitrile must be heated with aqueous NaOH to liberate NH₃; NH₃ must contact moist red litmus paper to induce proton abstraction and structural change in dye, causing red→blue transition; paper must be moist to dissolve NH₃ and enable ionization.
(ii)Storyline: Frame 1–2: White crystalline phenylacetonitrile placed into upright test tube. Frame 3–4: Clear NaOH solution poured into tube (meniscus visible). Frame 5–7: Tube immersed in visible water bath (water surface, gentle convection). Frame 8: Tube removed; hand positions moist red litmus paper vertically, flush with tube mouth. Frame 9–10: Paper fully and uniformly transitions from red to blue (no intermediate colors) exclusively while at tube mouth and only after heating. Perspective: Fixed frontal close-up (tube center-aligned), shallow depth of field keeping tube and paper in focus, background blurred but consistent; no occlusion of tube mouth or paper during observation.

Manual:
Experimental Procedure
1. Place a small amount of white crystalline phenylacetonitrile into a clean test tube.
2. Add 3 mL of clear colorless sodium hydroxide solution.
3. Heat the test tube in a water bath for 10 minutes.
4. Remove tube, then place a moist red litmus paper at its mouth.
5. Observe color change of the paper.
Observation of Experimental Phenomena
The moist red litmus paper turns uniformly blue at the mouth of the test tube.
Summary of Experimental Principles
Phenylacetonitrile contains a cyano group (–C≡N). Under alkaline hydrolysis (NaOH, heat), it forms phenylacetamide intermediate, then further hydrolyzes to phenylacetic acid and ammonia. Ammonia gas evolves, turning moist red litmus paper blue — confirming presence of cyano group.

Prompt Grounding rubric:
level_1: No test tube appears; phenylacetonitrile is never placed in it; no NaOH solution is added; no water-bath heating step is shown; a moist red litmus paper is never brought to the tube's mouth: none of the five setup actions (placing the solid, adding NaOH, heating, positioning the paper, holding it for observation) occurs.
level_2: At least one required object appears (the test tube, the phenylacetonitrile, the NaOH solution, or the litmus paper), but the five-step sequence (place the solid, add NaOH, heat in the water bath, position the paper at the mouth, hold it for observation) is missing steps or shown out of order.
level_3: The test tube, phenylacetonitrile, NaOH solution, water bath, and litmus paper all appear, and the sequence proceeds placement, then addition, then heating, then paper positioning, then observation; but continuity breaks somewhere (for example a cut skips the NaOH being poured in, or the paper appears at the mouth with no hand shown placing it), or the paper's moistness is not visually evident.
level_4: All five objects and all five actions from score 3 are shown in continuous, uninterrupted footage with no cut that skips a step; the litmus paper is visibly moist (a glossy sheen or damp-looking surface) and is held steady, flush with the tube's mouth, for the entire observation period.
level_5: Everything required for score 4 holds, and the paper stays exactly in position at the tube's mouth without drifting away or being pulled back early, and no object in the scene appears or disappears unnaturally at any point.

Scientific and Causal Correctness rubric:
level_1: The phenylacetonitrile is shown as a colored liquid instead of the white crystalline solid it actually is, or the NaOH solution is shown as colored rather than clear, or the litmus paper starts out blue instead of red, or the paper ends the video the wrong color entirely: yellow, orange, or purple instead of blue.
level_2: The phenylacetonitrile is shown as a solid but the wrong color (e.g., yellow or brown rather than white); the NaOH solution looks visually indistinguishable from plain water with nothing marking it as a reagent; the litmus paper looks completely dry (stiff, no sheen) instead of moist; or the paper's color changes before any heating is shown, or with no heating step at all.
level_3: The phenylacetonitrile appears as a white crystalline solid, the NaOH solution appears clear and colorless, and after the heating step the moist red litmus paper at the tube's mouth begins changing color; but the change is incomplete (only part of the paper turns blue), or it starts before the paper reaches the tube's mouth.
level_4: Everything required for score 3 holds, and the litmus paper turns fully from red to blue only after being held at the tube's mouth following heating, though the transition visibly takes a gradual, multi-stage path over more than about a second (for example red fading through a mottled purple before reaching blue) rather than a clean shift.
level_5: Everything required for score 4 holds, and the paper's red-to-blue change happens cleanly, with no lingering purple or streaky in-between shade, and only while the paper is held at the tube's mouth after heating; the paper never changes color before heating or while away from the tube's mouth.

Spatiotemporal Consistency rubric:
level_1: The test tube is missing from one shot and back in the next with nothing shown removing or replacing it; the phenylacetonitrile solid is absent then present again without being added; the litmus paper jumps to a rotated angle (e.g., a full 90°) with no motion carrying it there; the scene cuts from bright to dark with no transition; the water bath is absent then present again; or the tube appears bent, cracked, or floating with no support.
level_2: Objects keep the same shape and appearance across shots, but there is a major break in continuity: the paper is shown at the tube's mouth in one shot and then noticeably away from it in the next with no motion connecting the two; the camera angle used for the heating step doesn't match the angle used for the observation step, making the tube appear to change orientation between them; the shadow the tube casts switches to the opposite side with no change in the light; or steam appears with no visible source.
level_3: The test tube, water bath, and litmus paper keep a steady arrangement (tube upright, water bath beneath it, paper aligned vertically at the mouth), and the lighting stays on the same side at a steady brightness; the hand lowering the paper moves naturally with nothing floating; but there is one small, isolated slip, such as a brief moment where the scene goes dark, a short instant where the paper looks partly see-through, or the tube wobbling briefly during heating despite being held in a rack or clamp.
level_4: No object disappears or reappears, no structural break in the tube, no sudden lighting or shadow jump, and no physically impossible motion; every object keeps a consistent size, orientation, and position relative to the others; the paper stays aligned with the tube's mouth for the whole observation period; any steam shown rises continuously upward; but there is one small non-core flaw, such as a faint, continuous tremor in the paper's position during the otherwise-static observation phase, or a minor inconsistency in the reflection on the tube's glass from one moment to the next.
level_5: No spatiotemporal flaws are visible anywhere: the test tube sits perfectly still on the water bath, the paper is held steadily at the tube's mouth with no drift or tremor, the lighting and the shadows it casts stay on the same side at the same brightness throughout, any steam rises smoothly and vertically, and every object's position and shape stay coherent and continuous from the first frame to the last with no dropped frames or warping.