Domain: Natural Science — Chemistry
Target concept: Lucas Test: Comparison of Turbidity Formation between Tert-Butyl Alcohol and Ethanol in the Reaction to Produce Alkyl Chlorides

Video generation prompt: Two test tubes containing Lucas reagent: the left tube was added with tert-butyl alcohol, and the right tube was added with ethanol. After gentle shaking, they were left at room temperature.

Evaluation guide:
(i) Target concept: Differential carbocation stability governs SN1 reaction rate in alcohols with Lucas reagent.
Minimum mechanism: Formation of a stable tertiary carbocation from tert-butyl alcohol enables immediate chloride capture and precipitation of alkyl chloride; primary carbocation from ethanol is energetically inaccessible, preventing reaction and turbidity.
(ii)Storyline: Frame sequence must show: (1) Two empty tubes placed side-by-side → (2) Lucas reagent added to both → (3) tert-butyl alcohol added to left, ethanol to right → (4) simultaneous gentle shaking of both tubes → (5) cessation of motion → (6) stillness phase where left tube develops uniform turbidity while right tube retains perfect clarity. All phases must be captured from fixed frontal viewpoint with full tube visibility; no close-ups, no cuts, no angle changes; turbidity must emerge *only* after motion ends and persist uniformly.

Manual:
1. Experimental Procedure: Place two identical test tubes side-by-side. Add Lucas reagent to both. Add tert-butyl alcohol to left tube, ethanol to right tube. Gently shake both tubes simultaneously. Stop shaking and leave both tubes undisturbed at room temperature.
2. Observation of Experimental Phenomena: Within seconds after shaking stops, the left tube (tert-butyl alcohol) becomes turbid/milky; the right tube (ethanol) remains completely clear and transparent.
3. Summary of Experimental Principles: Tert-butyl alcohol undergoes rapid SN1 substitution with Lucas reagent (ZnCl₂ in HCl) to form insoluble tert-butyl chloride, causing turbidity. Ethanol cannot undergo SN1 under these conditions and remains unreacted, so no turbidity forms.

Prompt Grounding rubric:
level_1: The clip shows no two test tubes at all, or shows tubes with no Lucas reagent added, with tert-butyl alcohol and ethanol never poured in, with the tubes stacked or overlapping instead of placed next to each other, with no shaking motion performed, and with no quiet settling period after shaking.
level_2: Two test tubes are placed next to each other, but at least one required element is missing: Lucas reagent is not visible in both tubes, the two alcohols are not visually distinguishable or correctly assigned, the shaking action is skipped, or the post-shaking stillness period is skipped; tert-butyl alcohol or ethanol may also be poured into the wrong tube (e.g., tert-butyl alcohol ends up in the right-hand tube).
level_3: Two test tubes sit next to each other, each holding Lucas reagent; tert-butyl alcohol has been added to the left tube and ethanol to the right tube, matching the posted prompt; both tubes are shaken (together or one after the other) and then left undisturbed; every object and action from the prompt is present, but no turbidity difference between the tubes is required at this level.
level_4: All of score 3 holds, and the entire sequence (from pouring in the alcohols, through shaking, to the stillness phase) plays out in one continuous shot from the same fixed viewpoint with no cut or repositioning; both tubes stay fully visible throughout, without being zoomed in on, panned away from, or blocked from view; neither tube disappears or duplicates.
level_5: All of score 4 holds, and the left tube contains only tert-butyl alcohol plus Lucas reagent with nothing else added, the right tube contains only ethanol plus Lucas reagent with nothing else added; the two tubes match each other in size, tilt, and lighting; no extra objects such as labels, hands, or droppers remain in frame during the observation phase; the shot runs continuously from the first pour to the final still moment with no editing cuts.

Scientific and Causal Correctness rubric:
level_1: No turbidity appears in either tube and both stay equally clear; or turbidity shows up in the ethanol tube first or only; or turbidity appears before shaking even starts; or a color change (such as yellowing or browning) is the dominant visible effect instead of cloudiness.
level_2: Turbidity develops in only one tube, but it is the wrong one: cloudiness in the ethanol (right) tube, or no cloudiness at all in the tert-butyl alcohol (left) tube; or both tubes turn cloudy at the same time; or the cloudiness appears while the tubes are still being shaken rather than after they stop.
level_3: Turbidity appears only in the left tube (tert-butyl alcohol) once shaking has stopped, and the right tube (ethanol) stays clear the whole time; no unrelated color change competes with the turbidity; the cloudiness in the left tube looks like genuine milky opacity rather than settled sediment, bubbles, or a lighting artifact.
level_4: All of score 3 holds, and the left tube's turbidity appears only during the stillness phase, never while the tubes are still being shaken; the right tube stays fully transparent throughout, with no faint haze or distortion near the liquid surface; once formed, the left tube's turbidity does not fade or reverse before the clip ends.
level_5: All of score 4 holds, and the left tube's turbidity is even from top to bottom of the liquid column with no layering, settling, or patchiness; the right tube shows no departure at all from how it looked before shaking: same clarity, same meniscus shape, same light passing through it; the turbidity's onset is unambiguous, meaning the left tube is still clear in the very last moment of shaking and already cloudy as soon as stillness begins.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: one or both test tubes jump to a different position or size between frames with no shaking motion to explain it; the liquid inside suddenly resets to a different fill level or clarity between frames; the shaking motion freezes mid-swing then resumes with no continuity; visible jump cuts separate the addition, shaking, and stillness phases; or the lighting abruptly shifts (e.g., a sudden brightness or shadow change) with no visible cause.
level_2: Moderate rupture: one tube is blocked from view for more than a couple of frames while the other is not; the shaking motion starts or stops abruptly with no deceleration into stillness; during the stillness phase the tubes visibly sway, drift, or vibrate on their own; the two tubes shake with noticeably different amplitude or timing from each other despite being handled the same way; or the lighting flickers or shifts in intensity partway through the sequence.
level_3: Minor but noticeable flaws: the tube rim or liquid surface is briefly hidden from view for a moment, or there is a slight residual wobble during stillness that doesn't obscure whether turbidity is present; but overall the side-by-side layout, the presence of both tubes, and the sequence (addition, then shaking, then stillness, then turbidity difference) remain clear and easy to follow.
level_4: All of score 3 holds, and additionally: the shaking motion of the two tubes is smooth and matches in amplitude and timing between left and right; each tube's outline and position stay fixed relative to the frame except for the shaking motion itself; the liquid meniscus in each tube moves continuously while shaking and settles into a smooth, still curve once shaking stops, with no tearing or double-image glitches between frames.
level_5: All of score 4 holds, and additionally: the shaking traces a gentle, natural arc that decelerates smoothly into stillness with no sudden jerks or speed spikes; the two tube walls and liquid menisci stay aligned frame-to-frame with no visible misregistration; once still, both tubes remain completely motionless with no residual sway; the entire sequence from first addition through final stillness plays out as one continuous, uncut shot from a fixed frontal view.