Domain: Natural Science — Chemistry
Target concept: The amphiphilic behavior of fatty acids in soap causes oil-water emulsification.

Video generation prompt: Two transparent glass jars are placed side by side, containing water and edible oil; only liquid soap is added to the right jar, both jars are then sealed and vigorously shaken.

Evaluation guide:
(i) Target concept: Emulsification via surfactant-mediated stabilization of oil-in-water dispersion.
Minimum mechanism: Soap molecules must orient at oil-water interfaces with hydrophobic tails embedded in oil droplets and hydrophilic heads extended into water, sterically inhibiting coalescence, requiring sufficient agitation to form droplets *and* presence of soap *only* where emulsification occurs.
(ii)Storyline: [Phase 1: Static baseline] Two jars side-by-side, left with water (clear, colorless), right with oil (pale yellow, glossy surface); no soap visible. [Phase 2: Intervention] Liquid soap dispensed *only* into right jar; lids applied to both; no spillage or cross-contamination. [Phase 3: Action] Simultaneous vigorous shaking: fluid motion visible in both jars, but only right jar develops internal opacity. [Phase 4: Result] Post-shake stillness: left jar restores sharp biphase interface within 1 second; right jar sustains homogeneous turbidity with no settling for ≥2 seconds. [Perspective constraint: Fixed frontal view, centered on jar pair, no camera motion, full jar height visible, no occlusion.]

Manual:
Experimental Procedure
1. Place two identical transparent glass jars side-by-side on flat surface.
2. Fill left jar with clear water; fill right jar with edible oil.
3. Add liquid soap only to right jar.
4. Seal both jars with identical lids.
5. Shake both jars vigorously and simultaneously for ~2 seconds.
Observation of Experimental Phenomena
Left jar: rapid, complete separation into distinct clear water (bottom) and oil (top) layers.
Right jar: stable, uniform milky turbidity with no visible oil-water separation.
Summary of Experimental Principles
The amphiphilic behavior of fatty acids in soap causes oil-water emulsification.

Prompt Grounding rubric:
level_1: Fewer than two jars are shown, or the jars shown are not both clear glass; the two jars are not positioned next to each other on the same surface; water and edible oil are not visibly present in the jars; liquid soap is never shown being added to only one jar; no shaking action occurs; the jars are never shown with lids on.
level_2: Two transparent containers appear but are not matching glass jars, or they are positioned apart rather than adjacent to each other; water or oil is missing, or is replaced with a visually different liquid (e.g., milk instead of water, a colored syrup instead of oil); liquid soap ends up in both jars or in neither one; shaking is shown for only one jar, or shaking is absent altogether.
level_3: Two clear glass jars sit next to each other; the left jar holds water and the right jar holds edible oil; liquid soap is added only to the right jar; both jars are capped with lids before shaking; both jars are shaken together with visible back-and-forth agitation.
level_4: Everything required for score 3 holds, and additionally the glass walls of both jars stay clear and unobstructed (no labels or frosting hiding the contents); the soap is poured only into the right jar with none spilling into the left; both lids sit flush on the jar openings before shaking begins; the shaking looks about equally vigorous and lasts about the same length of time for both jars.
level_5: Everything required for score 4 holds, and additionally the left jar shows only clear water with no oil droplets or haze before shaking begins; the right jar shows only clear oil with no water layer before the soap goes in; the soap is added only after both liquids have first been shown sitting still; the lids go on right before the shaking starts; both jars begin shaking at the same moment, with neither one shaken first.

Scientific and Causal Correctness rubric:
level_1: No phase separation or mixing behavior is visible in either jar; the liquids look static and unchanged throughout; there's no visible contrast between the two jars; oil and water look identically mixed, or identically unmixed, in both jars.
level_2: Both jars behave the same way (e.g., both separate cleanly, both turn fully cloudy, or neither changes at all); an emulsion appears in the left (soap-free) jar, or fails to appear in the right (soap) jar; the oil in the right jar stays fully separate and undispersed after shaking; the water in the left jar looks cloudy or full of droplets, which pure water wouldn't show.
level_3: After shaking, the left jar quickly separates back into a clear oil layer on top and a water layer below; the right jar stays cloudy or milky with no oil layer visible for the rest of the observation; this contrast between the two jars is clear and holds for at least two seconds after the shaking stops.
level_4: Everything required for score 3 holds, and additionally the left jar shows no suspended droplets or haze in either layer; the right jar's turbidity doesn't clear, settle, or break apart into visible oil globules at any point, and looks uniformly milky through the whole volume of the jar rather than patchy in spots.
level_5: Everything required for score 4 holds, and additionally the left jar keeps a sharp, straight, horizontal boundary between its water and oil layers with no lingering ripples once the liquid settles; the right jar stays a stable, uniform, opaque milky-white for the entire time it's observed after shaking, with no clearer layer ever separating out on top or at the bottom.

Spatiotemporal Consistency rubric:
level_1: The jars jump to a different position or vanish and reappear between frames; the lighting changes so abruptly that the jars become hard to see; a jar's size or shape changes without any cause; a lid appears or disappears without anyone placing or removing it; the water or oil disappears or reappears; the shaking motion jumps, freezes, or skips instead of flowing continuously.
level_2: One jar tips over or rotates while the other stays upright; the two jars drift apart or swap positions relative to each other; a lid is on the jar in one frame, off in the next, then back on again with no hand shown moving it; the two jars shake out of sync (one moving while the other sits still), or the shaking repeatedly starts and stops.
level_3: Both jars stay side by side in the same arrangement throughout; neither jar rotates, tips, or slides out of place; both lids stay seated on the jar openings during shaking; the shaking motion is continuous and applied to both jars together without stopping partway through.
level_4: Everything required for score 3 holds, and additionally neither jar visibly drifts or wobbles out of position across the video; each lid's size and shape keep matching its jar's opening in every frame; the two jars shake with matching rhythm and force, without one appearing to slow down or speed up relative to the other; there's no flickering or sudden brightness change that gets in the way of seeing either jar.
level_5: Everything required for score 4 holds, and additionally the background behind the jars stays the same throughout, with no new shadows sweeping across it; the light on the jars stays even and doesn't shift in direction or strength; anything visible through the glass walls bends in a consistent, natural-looking way rather than warping oddly; the blur from shaking looks natural and similar on both jars rather than looking artificial on just one of them.