Domain: Natural Science — Chemistry
Target concept: Color reaction between phenol and ferric chloride

Video generation prompt: A test tube containing 10 mL of diluted phenol solution was treated with ferric chloride solution, shaken, and the resulting liquid in the test tube was observed after the reaction.

Evaluation guide:
(i) Target concept: Formation of a stable, soluble violet coordination complex between phenol and ferric(III) ions in aqueous solution.
Minimum mechanism: Phenol must be present in molecular form (not ionized), FeCl₃ must be aqueous and freshly prepared (avoiding hydrolysis products), and pH must be near neutral; under these conditions, [Fe(OC6H5)6]³⁻ complex forms instantly upon mixing and shaking, yielding uniform violet color without side reactions.
(ii)Storyline: Frame 1: Static shot of upright test tube containing colorless liquid (diluted phenol). Frame 2: Ferric chloride solution delivered from adjacent container into test tube (visible droplet entry). Frame 3: Test tube grasped and shaken side-to-side with visible liquid sloshing. Frame 4: Shaking stops; test tube held still with upright orientation. Frame 5: Final still frame showing homogeneous violet/purple liquid filling test tube (same viewpoint, lighting, and framing as Frame 1). All transitions must preserve object identity, spatial adjacency, and causal order (add → shake → observe color). No off-screen actions; all critical events occur within continuous field of view.

Manual:
Experimental Procedure
1. A test tube holds 10 mL of colorless diluted phenol solution.
2. Ferric chloride solution is added dropwise into the test tube.
3. The test tube is shaken gently and uniformly.
4. The resulting liquid is observed after shaking.
Observation of Experimental Phenomena
The originally colorless solution turns violet or purple after addition and shaking — no precipitate, gas, or phase separation occurs.
Summary of Experimental Principles
Phenol forms a violet-colored complex with Fe³⁺ ions from ferric chloride — a characteristic qualitative test for phenolic –OH groups.

Prompt Grounding rubric:
level_1: No test tube is shown; no phenol solution is visible; no ferric chloride solution or dropper is shown; no shaking motion occurs; no post-addition observation moment appears.
level_2: A test tube holding some liquid appears, but the liquid is not identifiable as the diluted phenol solution (e.g., no clear colorless liquid at a plausible fill level); ferric chloride solution is never added; no shaking occurs; there is no separate still moment after mixing to observe the result.
level_3: A test tube containing a colorless liquid consistent with diluted phenol solution is shown; a ferric chloride solution is visibly added from a dropper or a separate vessel into the test tube; the test tube is then shaken by hand (visible side-to-side or rotational motion); a still frame afterward shows the liquid inside the test tube. The objects and the add-then-shake-then-observe sequence from the prompt are all present.
level_4: Everything in the 3-point level is present, and additionally: the ferric chloride is added from a container clearly distinct from the test tube (e.g., a dropper bottle held beside it); the shaking consists of at least two clearly separate back-and-forth or swirling motions; the liquid surface settles calmly after shaking with no spill over the rim; the same test tube is shown throughout, never swapped for another or cut away mid-action.
level_5: Everything in the 4-point level is present, and additionally: the ferric chloride container is visible next to the test tube just before the addition; both the test tube and the dropper/container stay in frame during the addition; the shaking stays within the test tube's own vertical axis, tilting no more than about 30° from upright rather than being flipped sideways; the progression from standing liquid, to addition, to shaking, to final still observation plays out as one continuous, uncut view of the same test tube in the same setting.

Scientific and Causal Correctness rubric:
level_1: No color change appears in the liquid (it stays colorless throughout); or a color other than violet/purple appears (e.g., the liquid turns blue, green, yellow, red, or black) with no violet or purple hue ever appearing, even briefly.
level_2: The liquid takes on a color that does not match the phenol–ferric chloride reaction (e.g., brown, orange, gray, or pink); or a violet/purple tint appears only briefly and then fades away before the final still frame; or any color change happens before the ferric chloride is added.
level_3: After the ferric chloride is added and the tube is shaken, the liquid takes on a visible violet or purple hue that is clearly different from the original colorless liquid, and this hue is still present in the final frame; there is no precipitate, cloudiness, or layering competing with the color change.
level_4: Everything in the 3-point level holds, and additionally: the violet/purple hue only becomes visible once the shaking is finished, not merely during the addition of ferric chloride; the color looks the same from the top of the liquid column to the bottom, without separate bands or patches of a different shade; there is no bubbling, fizzing, or steaming that would suggest an unrelated reaction.
level_5: Everything in the 4-point level holds, and additionally: violet/purple is the only color change visible anywhere in the liquid, with no lingering brown, green, or yellow tint mixed in; the hue looks even through the entire visible depth of the liquid; the color does not flicker, fade, or shift once it appears; the shade is consistent with the known phenol–ferric chloride violet complex under normal, neutral (non-tinted) lighting.

Spatiotemporal Consistency rubric:
level_1: The test tube is missing from a frame and then shows up again later with no motion carrying it away or back into view; the liquid's volume or level changes with no visible cause; the camera cuts between an extreme close-up and a wide shot with no transition; or the test tube itself bends, cracks, or turns to liquid.
level_2: The test tube stays on screen but its position or tilt changes abruptly between frames (e.g., it appears rotated a different way with no motion shown in between); the liquid surface jumps from still to sloshing with no shaking motion shown; the ferric chloride dropper appears only in the final frame with no prior addition ever shown.
level_3: The test tube stays visible in the same place and orientation throughout; the sequence of adding ferric chloride, shaking, and then observing the liquid happens either in one continuous shot or through cuts that keep the tube in the same spot; the liquid level stays constant, without spilling, evaporating, or leaking out.
level_4: Everything in the 3-point level holds, and additionally: the shaking motion looks physically real, speeding up and slowing down naturally, with the liquid sloshing slightly behind the tube's own motion rather than moving in perfect lockstep with it; the dropper tip never passes through the wall of the test tube; the shaking is never shown ending before it visibly begins.
level_5: Everything in the 4-point level holds, and additionally: the tube's and liquid's motion during shaking is smooth and continuous rather than skipping between poses; the liquid surface curves naturally into a concave meniscus rather than staying flat or wobbling like gelatin; objects visible behind the test tube keep the same relative position as the tube moves, and neither the tube nor the liquid warps out of its normal cylindrical shape.