Domain: Natural Science — Chemistry
Target concept: Oil and water separate into two distinct liquid phases in a transparent container.

Video generation prompt: Add water and oil to a transparent glass jar, shake gently for a few seconds, then place it on the table to stand still.

Evaluation guide:
(i) Target concept: Immiscibility-driven density stratification of polar and nonpolar liquids.
Minimum mechanism: Two chemically incompatible liquids with different densities must be introduced into a shared gravitational reference frame and allowed to reach mechanical equilibrium without external force.
(ii)Storyline: [Phase 1: Setup] Transparent jar placed centrally on flat table surface; [Phase 2: Addition] Water added first → visible meniscus forms at bottom; oil added second → floats atop water without mixing; [Phase 3: Agitation] Jar shaken → liquids temporarily homogenize into cloudy suspension; [Phase 4: Equilibration] Jar stilled → turbidity clears, interface nucleates at center and propagates laterally → sharp horizontal boundary emerges and stabilizes; [Perspective constraint] Fixed frontal camera angle showing full jar height and table contact; [Visibility constraint] No occlusion of jar body or liquid interface during Phases 2–4; lighting enables clear contrast between layers and interface definition.

Manual:
Experimental Procedure
1. Place empty transparent glass jar on table.
2. Add water to jar until ~1/3 full.
3. Add oil to jar until ~2/3 full.
4. Cap jar lightly and shake gently for 2–3 seconds.
5. Place jar upright on table and let stand still.
Observation of Experimental Phenomena
After standing still: two distinct horizontal layers form — clear water at bottom, translucent oil at top — separated by a sharp, continuous, straight interface line across full jar width.
Summary of Experimental Principles
Oil and water are immiscible due to polarity mismatch; water molecules form hydrogen bonds, excluding nonpolar oil molecules. Density difference (water > oil) causes stratification upon cessation of agitation.

Prompt Grounding rubric:
level_1: None of the required setup elements are shown together: there is no transparent glass jar, no water, no oil, and no table visible, and neither a shaking motion nor a stillness phase appears; the scene does not depict this jar experiment at all.
level_2: Only one or two of the four required elements (transparent jar, water, oil, table) are visible at the same time; the shaking motion is missing or replaced by an unrelated action (e.g., liquid poured straight onto the table, or stirred with a spoon instead of shaken); or no stillness phase follows whatever motion does occur.
level_3: The transparent jar, water, oil, and table are all visible together at some point; the jar is shaken; the jar is then set down and stays motionless on the table for at least a couple of seconds; the events proceed in the order jar placed on table -> water and oil added -> jar shaken -> jar left standing still.
level_4: Everything described at the 3-point level is present, AND both the water and the oil are shown being poured directly into the jar itself (not beside it or off-screen); the shaking happens with the jar upright and fully inside the frame; once set down, the jar shows no sliding, wobbling, or drifting on the table; no hand, cloth, or other object blocks the view of the jar during the pouring, shaking, or stillness phase.
level_5: Everything described at the 4-point level is present, AND the water and the oil are shown entering the jar as two separate, sequential pours (with a clear pause or break between them), so a viewer can tell two different liquids were added rather than one continuous pour; the shake itself is visibly gentle, with no liquid splashing over the rim and no violent spinning; the jar is then left undisturbed long enough that a boundary between the two liquids is visibly beginning to form before the clip ends.

Scientific and Causal Correctness rubric:
level_1: No stratification occurs at all: the water and oil stay mixed as a single cloudy or uniform liquid, or they form a persistent emulsion with no visible boundary between them; the two liquids cannot be told apart by color or clarity; by the end of the clip the jar's contents still look like one continuous liquid or a gel rather than two liquids.
level_2: A boundary between two layers is absent or too indistinct to read as two separate liquids; or the liquids' identities are visually implausible (e.g., the layer that should be less dense sits at the bottom, or dye is used in a way that erases which layer is water and which is oil); the two layers show no difference in meniscus shape, clarity, or how they cling to the glass, so any layering present looks arbitrary rather than driven by density and polarity.
level_3: Two layers are visible in the jar once it stops moving: an upper layer and a lower, denser layer, separated by a line running the full width of the jar; the upper layer has a smoother, more rounded meniscus where it meets the glass, while the lower layer's surface sits flatter and clings more to the glass wall, consistent with oil's lower surface tension compared to water's higher surface tension.
level_4: Everything described at the 3-point level is also true here, AND the boundary between the two layers is crisp, with no hazy or blurred band of intermixing at the interface; the upper layer visibly lets more light through and looks optically thinner than the lower layer; the lower layer's top surface stays flat against the interface instead of bulging up into the layer above it.
level_5: Everything described at the 4-point level is also true here, AND the upper layer reads clearly as oil (pale yellow or near-colorless, thin and runny in appearance, with no floating particles), while the lower layer reads clearly as water (colorless and visibly clearer, with a sharply defined meniscus at the glass); the boundary between the two liquids is a single flat, unbroken line, consistent with the two liquids being fully phase-separated rather than a partially mixed or slowly settling emulsion.

Spatiotemporal Consistency rubric:
level_1: The jar's position, size, or tilt changes abruptly between two moments with no shaking or hand contact shown to explain it; the glass appears to crack, warp, or partially dissolve mid-clip; the water or oil inside appears or disappears without any pour or spill being shown; the room lighting shifts abruptly (e.g., a sudden switch from bright to dim with no cause) or the shadow cast by the jar disappears and reappears inconsistently; the tabletop's edge or the camera's vantage point contradicts itself from one moment to the next (e.g., the table edge is on the left, then on the right, with no camera movement shown).
level_2: Several smaller spatiotemporal breaks occur together: the jar's tilt changes with no rotation shown leading up to it; the liquid volume inside the jar rises or falls between shots without a matching pour or spill; the tabletop briefly is not visible under the jar during shaking and then reappears shifted to a different spot; how brightly light passes through the stacked oil and water layers changes noticeably at least twice in ways unrelated to the jar's own motion.
level_3: The jar stays in the same spot on the table throughout; the water and oil never spill past the jar's rim or appear outside its walls; nothing else in the shot (a hand, a second container) ever fully hides the jar during pouring, shaking, or stillness; how light passes through the stacked liquids (brighter through the thinner oil layer, dimmer through the water below) stays consistent from one moment to the next; the shaking looks like a real hand-driven back-and-forth or circular motion rather than the jar sliding in a straight line.
level_4: Everything described at the 3-point level remains true, AND the jar does not creep or slide along the table once it is set down to rest; the liquid levels inside do not suddenly surge above the rim and then snap back down between shaking and stillness; the jar's outline shows no visible tearing, warping, or doubling at any transition; the tabletop and any visible background (wall, counter) stay in place and keep the same perspective throughout.
level_5: Everything described at the 4-point level remains true, AND the shaking shows a believable back-and-forth or swirling rhythm with several (at least three) discernible repeated cycles rather than one abrupt jolt; once the jar is set down, its outline, the liquid surfaces, and the meniscus at the glass all appear completely at rest (no lingering sloshing, quivering, or surface ripple) for the rest of the stillness phase, and no moment in the footage looks duplicated, strobed, or skipped.