Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Alkylation of Drugs (N-alkylation Reaction)

Video generation prompt: A small amount of methylamine solution was placed in a test tube. One milliliter of iodomethane was added, and the mixture was shaken uniformly at room temperature. After standing for 5 seconds, the change in the solution's appearance was observed, followed by the addition of 2 mL of distilled water for dilution.

Evaluation guide:
(i) Target concept: Nucleophilic N-alkylation of a primary amine (methylamine) by an alkyl halide (iodomethane) at room temperature, forming a water-soluble alkylammonium iodide salt (mono-N-methylation gives dimethylammonium iodide).
Minimum mechanism: Methylamine must be in aqueous solution; iodomethane must be added as a discrete, separate liquid reagent (not pre-mixed); the reaction proceeds without added catalyst or heat; the resulting ammonium iodide salt is fully water-soluble, so the bulk liquid does not separate into phases or form a precipitate; the later addition of distilled water only dilutes the solution and does not itself trigger a reaction or a state change.
(ii) Storyline: [Frame 1] Static shot: test tube centered, containing a clear aqueous methylamine solution. [Frame 2] Iodomethane is added as a separate, denser liquid, initially forming droplets or a layer before mixing. [Frame 3] The tube is shaken, with visible meniscus motion as the two liquids disperse into each other. [Frame 4] The tube is held motionless: the bulk liquid settles into a single clear, homogeneous phase with no droplets and no interface. [Frame 5] Distilled water is added: the meniscus rises smoothly and the solution stays optically clear and homogeneous. All transitions keep a fixed viewpoint, with no cuts mid-action, so each state follows visibly and directly from the action before it.

Manual:
Experimental Procedure
1. Place clear methylamine solution in a transparent test tube.
2. Add iodomethane as a separate colorless liquid.
3. Shake tube uniformly.
4. Let tube stand still for observation.
5. Add distilled water.
Observation of Experimental Phenomena
After shaking and standing, the bulk solution remains clear and homogeneous (no phase separation, no precipitate, and no shift in color), because the alkylated ammonium iodide product is fully soluble in water. After water addition, the solution remains fully clear and homogeneous.
Summary of Experimental Principles
N-alkylation: Methylamine (a nucleophile) attacks iodomethane in an SN2 reaction, displacing iodide to form a water-soluble alkylammonium iodide salt (dimethylammonium iodide from a single methylation event). Because this salt is freely soluble in the aqueous phase, the bulk liquid shows no precipitate, turbidity, or color change.

Prompt Grounding rubric:
level_1: No test tube appears; no methylamine solution is shown; iodomethane is never added; no shaking action occurs; no standing/waiting period is shown; distilled water is never added.
level_2: A test tube or a clear liquid appears, but at least three of the five required actions (methylamine present, iodomethane added, shaking, standing, water added) are missing, out of order, or replaced by an unrelated action (e.g., the tube is heated instead of shaken, or a different reagent is poured in).
level_3: All five elements appear in the correct order (methylamine solution in a test tube, iodomethane added as a second liquid, shaking, a standing/still period, and distilled water added), but one element has a fidelity error, such as iodomethane shown as a gas or solid rather than a liquid, or the water is added before the standing period ends.
level_4: All five elements appear in the correct order with correct object types: a test tube (not a beaker or flask) holds a clear methylamine solution; iodomethane is added as a separate liquid; the tube is shaken; the tube then sits undisturbed for a visible period; 2 mL of distilled water is added afterward; only a minor, non-core flaw remains, such as brief motion blur during shaking or a partially obscured label on the tube.
level_5: All five elements occur in the exact posted order with no ambiguity: a transparent test tube holds a clear, colorless methylamine solution; a colorless, visibly denser iodomethane portion is added and initially forms droplets or a distinct layer before shaking begins; the tube is shaken vigorously but stays in the shot; the tube then rests completely undisturbed for a clearly visible standing period; distilled water is then added from a clearly identifiable source (dropper, pipette, or graduated vessel) with a visible change in liquid volume; no object is substituted, no step is skipped or reordered, and no step's timing is ambiguous.

Scientific and Causal Correctness rubric:
level_1: The video shows chemistry inconsistent with N-alkylation of methylamine by iodomethane: e.g., the liquid boils, bubbles, or emits visible gas violently; the solution turns strongly colored (yellow, brown, or otherwise) throughout its bulk; a solid precipitate settles at the bottom; or the two liquids remain permanently as separate immiscible layers even after shaking and standing.
level_2: The liquid shows at least one chemically implausible bulk change (e.g., persistent cloudiness/turbidity, a visible precipitate, or a bulk color shift) that is not consistent with formation of a water-soluble alkylammonium iodide salt; OR the two liquids show no evidence of any interaction at all (iodomethane droplets simply sit unchanged in the solution indefinitely without ever mixing).
level_3: After shaking and standing, the bulk solution appears clear and single-phase (no persistent precipitate, no bulk turbidity, no bulk color change), consistent with a fully water-soluble alkylation product; after water addition the solution remains clear and homogeneous; however the depicted timing or extent of mixing is inconsistent with the reaction proceeding at all (e.g., iodomethane droplets are shown never interacting with the surrounding liquid before the cut to a clear result).
level_4: Bulk solution stays clear and homogeneous through shaking, standing, and water addition, consistent with formation of a soluble alkylammonium iodide salt from methylamine and iodomethane; iodomethane is depicted as a distinct denser liquid that visibly disperses into the solution during shaking rather than reacting instantaneously or violently; only one minor chemistry-adjacent inconsistency remains (e.g., iodomethane is shown mixing in as readily as water despite being denser and less miscible).
level_5: Every chemical detail is consistent with N-alkylation of methylamine by iodomethane in water: iodomethane initially behaves as a denser, only partially miscible liquid that visibly disperses into the aqueous methylamine layer during shaking; the bulk solution remains clear, colorless, and single-phase through standing and after the 2 mL water addition, reflecting that the alkylammonium iodide product is fully water-soluble.

Spatiotemporal Consistency rubric:
level_1: The test tube's position, size, or orientation changes abruptly between shots with no continuous motion shown; the liquid level or meniscus jumps to a different height without a visible pour or shake causing it; the camera viewpoint or background changes without cause; the shaking motion shown skips or repeats frames so the tube appears to jump between poses; or the scene lighting abruptly brightens, dims, or shifts color between frames with no visible cause.
level_2: Two or more noticeable continuity problems occur: e.g., the tube shifts sideways slightly between the pre-shake and post-shake shots even though no camera or hand movement is shown; the liquid surface stays perfectly flat and motionless during what is depicted as vigorous shaking; or the hand pouring the distilled water enters the frame with no visible connection to where it came from.
level_3: One noticeable but non-disruptive continuity flaw occurs (for example, a brief cut interrupts the standing period, or the bottom of the tube is briefly hidden during shaking so the meniscus motion is momentarily not visible), but the tube stays in the same place on screen, the camera viewpoint does not change, and no part of the tube or liquid appears distorted or torn.
level_4: The shaking motion shows smooth, continuous back-and-forth movement with the liquid surface visibly sloshing and settling afterward; the standing period shows the tube and liquid completely still with no unexplained motion; the water pour shows a continuous stream from source to tube with the liquid level rising smoothly; the tube stays in the same screen position and scale throughout with no cuts inside any of these three actions; only one small imperfection remains, such as a brief soft-focus moment during a camera adjustment or a very short, one-time flicker somewhere in the scene.
level_5: The camera holds a fixed frontal framing throughout; the test tube's position, size, and tilt look unchanged across the whole shot; the shaking shows realistic, damped sloshing of the liquid that settles smoothly into stillness with no lingering unexplained motion; the standing period shows the tube and liquid completely at rest with no drift in the liquid surface; the water pour shows an unbroken stream and a smoothly, continuously rising meniscus with no jump in liquid level, no skipped frames, and no mismatch between the pouring motion and how the liquid responds.