Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Identification of Phenolic Hydroxyl Groups (Ferric Chloride Color Reaction)

Video generation prompt: Weigh a small quantity of acetaminophen reference substance powder, place it in a transparent test tube, and add 5 mL of anhydrous ethanol to dissolve. Add 3 drops of 1% ferric chloride reagent, shake uniformly, and observe the changes.

Evaluation guide:
(i) Target concept: Detection of phenolic hydroxyl group via FeCl₃-mediated complexation.
Minimum mechanism: Acetaminophen must be present in molecularly dispersed (dissolved) state in anhydrous ethanol; Fe³⁺ ions from ferric chloride must directly contact the phenolic oxygen; complex formation requires no hydrolysis or pH shift; anhydrous ethanol ensures neutrality and prevents Fe(OH)₃ precipitation.
(ii)Storyline: Frame 1: White acetaminophen powder visible inside stationary transparent test tube. Frame 2: Colorless ethanol poured in → powder dissolves → liquid becomes optically clear. Frame 3: Yellow-brown FeCl₃ droplets descend into tube and contact liquid surface. Frame 4: Immediate localized color emergence at impact site. Frame 5: During shaking, color propagates uniformly → entire liquid column becomes homogeneous violet-purple. Visibility constraint: Tube must remain fully in-frame; no occlusion during dissolution, droplet entry, or color development; viewpoint fixed frontal/slightly angled to show meniscus and liquid column depth.

Manual:
Experimental Procedure
1. Place small quantity of white acetaminophen powder into transparent test tube.
2. Add 5 mL colorless anhydrous ethanol — powder dissolves to clear solution.
3. Add 3 drops of yellow-brown 1% ferric chloride reagent.
4. Shake tube uniformly.
5. Observe color development.
Observation of Experimental Phenomena
Clear colorless solution turns uniformly violet-purple after shaking.
Summary of Experimental Principles
Acetaminophen contains a phenolic hydroxyl group; it forms a violet-purple complex with Fe³⁺ in neutral/weakly acidic conditions.

Prompt Grounding rubric:
level_1: None of the four required items (acetaminophen powder, a clear test tube, anhydrous ethanol, or the 1% ferric chloride reagent) ever appears; or none of the required actions (placing the powder, adding ethanol, adding FeCl₃, shaking) takes place; the sequence is missing or unrecognizable.
level_2: At least one of the four items appears, but two or more are missing (e.g., no ferric chloride reagent visible, or no ethanol); or the order of actions is clearly wrong or scrambled: e.g., FeCl₃ is added before the ethanol, or shaking happens before any reagent is added.
level_3: All four items are clearly shown: white acetaminophen powder, a clear cylindrical test tube, colorless anhydrous ethanol, and a yellow-brown ferric chloride solution added drop by drop; the five actions occur in the correct order (powder into the tube, ethanol added, FeCl₃ drops added, tube shaken, then a final observation moment), with no substitution (no beaker standing in for the test tube, no water standing in for ethanol).
level_4: Everything in level 3 holds, plus: the powder and ethanol are clearly together in the same tube before any FeCl₃ is added; the FeCl₃ drops visibly enter the tube only after the ethanol is already there; shaking only starts after both are combined; no duplicate tubes and no extra reagents (no water, no HCl, no phenol) appear, and the container never switches from a test tube to something else.
level_5: Everything in level 4 holds, plus: the sequence of cause and effect reads clearly to a viewer. The FeCl₃ dropper is visibly positioned above the tube before any drop lands; the powder sits still in the tube before the ethanol is poured; the ethanol settles into a calm, clear liquid before FeCl₃ is added; shaking begins only once the drops have visibly touched the liquid surface, never before.

Scientific and Causal Correctness rubric:
level_1: No color change happens at all; or the final liquid ends up colorless, blue, green, red, or black instead of any shade of violet; or the powder only forms a cloudy, undissolved suspension; or a color shows up before any FeCl₃ has touched the liquid.
level_2: A color change does happen, but it settles into a clearly wrong hue (e.g., orange, brown-black, or blue-green rather than any shade of violet or purple); or the color appears while the ethanol is still being poured, before FeCl₃ is ever added; or the powder never fully dissolves and yet a color still appears after shaking; or the color takes more than a second to develop with no clear moment tied to the FeCl₃ contact.
level_3: A violet or violet-purple color appears only after the FeCl₃ drops are added, and only becomes uniform after shaking; the color stays within the liquid itself, not smeared on the tube wall or on any undissolved powder; before FeCl₃ is added, the ethanol-powder mixture looks fully clear and colorless; once mixed, the color looks even throughout the liquid without a competing tint like yellow or pink showing through.
level_4: Everything in level 3 holds, plus: the color visibly starts right where the FeCl₃ droplet first touches the liquid surface, then spreads outward and becomes even as the tube is shaken, so a viewer can see the color originate at the point of contact rather than appear everywhere at once; the powder is clearly visible as a solid before it dissolves, confirming the acetaminophen was actually present.
level_5: Everything in level 4 holds, plus: the resulting color reads clearly as violet or violet-purple (not orange, not green, not a washed-out gray), with even, well-saturated color across the whole liquid column; no other part of the shot (tube rim, background, hand) picks up any of the color; the hue looks strong and consistent rather than faint or patchy.

Spatiotemporal Consistency rubric:
level_1: Severe breaks in continuity: the test tube jumps to a different position or tilts instantaneously; the liquid level changes with no visible pour or motion causing it; the powder vanishes or reappears without ever dissolving; the lighting flickers wildly; the tube visibly cracks, bends, or deforms partway through the clip.
level_2: Noticeable but less severe issues: the tube spins more than a quarter turn with no continuous motion shown; the powder already looks dissolved before any ethanol has touched it; the ethanol seems to pour in from nowhere with no visible bottle or container; FeCl₃ droplets appear already inside the tube with no visible path of entry; the shaking motion starts or stops instantly with no ramp-up or slow-down.
level_3: The test tube stays upright and in the same spot on the surface the whole time; the powder stays within the tube's boundaries before and after the ethanol is added; the ethanol's level rises smoothly as it's poured in; the FeCl₃ drops fall straight down into the tube; the shaking looks like a steady back-and-forth motion with a consistent swing and rhythm; a hand or tool never fully hides the tube during moments that matter, like the drop landing or the color appearing.
level_4: Everything in level 3 holds, plus: the powder looks like it settles under gravity before the ethanol reaches it; the ethanol's surface curves naturally where it meets the glass, like a real liquid meniscus; the FeCl₃ droplet visibly disturbs the liquid surface right before the color starts to show; the shaking produces smooth swirling in the liquid with no sudden splashing or trapped air bubbles.
level_5: Everything in level 4 holds, plus: the tube looks like real glass or plastic, with no warped or distorted refraction through its wall; the liquid stays clear enough to see the bottom of the tube both before and after the powder dissolves; there's no doubling of edges and no blurred smearing over key moments like the droplet landing or the first appearance of color; the light on the scene looks like it's coming from the same place with the same strength for the whole clip.