Domain: Natural Science — Physics
Target concept: Same dose of dye added to pure water vs. water containing an adsorbing sponge (synergistic effect)

Video generation prompt: Two identical transparent beakers are placed side by side, each containing an equal amount of water; a porous sponge is immersed in the right beaker. Equal numbers of dye drops are added to both beakers, without stirring.

Evaluation guide:
(i) Target concept: Retardation of dye dispersion caused by a water-saturated porous sponge occupying part of one beaker.
Minimum mechanism: The sponge's water-filled pore structure physically absorbs water and obstructs the free movement of dye through the space it occupies, so dye reaching the sponge region disperses more slowly and stays more concentrated there than dye spreading freely through open water; the sponge must be pre-saturated with water (not air-filled) so it can take up and slow dye-laden water rather than simply floating or repelling it; no chemical reaction or dissolution of the sponge occurs.
(ii) Storyline: Frame 0–1: Two static beakers filled with clear water, sponge fully submerged in the right beaker. Frame 2: Dye drops descend from the same height and land at about the same time in the center of each water surface. Frame 3–5: The left beaker shows the dye cloud expanding outward in a spreading plume; the right beaker shows much less outward spreading, with dye building up in the water right around the sponge. Frame 6–10: The contrast keeps growing: the left beaker approaches an even, overall tint while the right beaker keeps a visibly darker patch of water next to the sponge. Perspective: Fixed frontal view, eye-level, centered on the beaker pair; full beaker height and the sponge fully visible; no occlusion.

Manual:
Experimental Procedure
1. Place two identical transparent beakers side-by-side on a flat surface.
2. Fill both beakers with equal amounts of clear water.
3. Fully immerse a porous sponge into the right beaker.
4. Add identical numbers of dye drops simultaneously to the center of the water surface in both beakers—no stirring.
Observation of Experimental Phenomena
In the left beaker (no sponge), dye rapidly diffuses radially outward. In the right beaker (with sponge), dye disperses noticeably slower and remains visibly concentrated near the initial drop site and the sponge surface.
Summary of Experimental Principles
The sponge's porous structure absorbs water into its interior and physically obstructs and slows the free diffusion of dye through the region it occupies, so dye entering the right beaker spreads more slowly and stays more concentrated near the sponge than the dye in the sponge-free left beaker, which disperses freely throughout the water.

Prompt Grounding rubric:
level_1: The video does not show two side-by-side beakers of water: e.g., only one beaker appears, one or both beakers hold no water, the sponge is missing from the right beaker entirely, or no dye drops are ever added to the water.
level_2: Two beakers of water are shown side by side, but the setup breaks the prompt: the sponge is absent from the right beaker (or wrongly placed in the left beaker), or dye drops are added to only one beaker, or dye is added before the sponge is placed in the water.
level_3: Two beakers of water sit side by side; a porous sponge sits fully submerged in the right beaker only; an equal, small number of dye drops (matching between beakers) is added to the water surface of both beakers at roughly the same time; no stirring or mixing tool is used in either beaker.
level_4: All conditions for score 3 are met, and additionally: the sponge stays fully submerged for the entire clip (it never floats up or pokes above the waterline); each dye drop visibly lands inside the water in its beaker (not on the rim or outside the beaker); the two beakers keep the same spacing and orientation relative to each other throughout.
level_5: All conditions for score 4 are met, and additionally: the sponge's surface clearly reads as spongy/porous rather than solid or smooth (visible open texture, even if individual pores are not resolved at this framing); the dye drops look the same size and land in matching spots in both beakers; both beakers stay completely still, with no visible shift or rotation of either beaker across the clip.

Scientific and Causal Correctness rubric:
level_1: The water in both beakers changes color identically after the dye drops are added (no visible slowdown or difference caused by the sponge), or neither beaker's water shows any tint change after the drops land, or the sponge's own color changes before the dye ever reaches the water.
level_2: The right beaker (with the sponge) disperses dye noticeably faster than, or about the same as, the left beaker (no sponge), which is the reverse of what the sponge should cause; or the sponge's color darkens even though no dye has yet touched the water around it.
level_3: Dye visibly spreads outward through the water in the left beaker (no sponge); in the right beaker, the dye stays close to where the drops landed and/or spreads noticeably more slowly than in the left beaker; the sponge itself does not change color before dye reaches the water near it; neither beaker is stirred.
level_4: All conditions for score 3 are met, and additionally: in the right beaker, the dye visibly stays concentrated in the water around the sponge rather than spreading evenly, and this slower, more localized coloring (compared to the left beaker) is visible for at least three consecutive seconds after the drops first touch the water.
level_5: All conditions for score 4 are met, and additionally: the right beaker shows a comparatively sharp boundary between more-tinted water near the sponge and less-tinted water farther away, while the left beaker's dye plume spreads out smoothly with no such boundary; the sponge does not turn uniformly dark all at once (no sudden full saturation) before dye and water have had time to mix around it; the overall pattern is clear and consistent: free spreading in the left beaker versus slowed, localized coloring in the right beaker throughout.

Spatiotemporal Consistency rubric:
level_1: The left or right beaker (or the sponge) is in a different place, a different size, or simply missing compared to the previous frame with no visible cause (no hand, tool, or camera movement to explain it); or dye drops appear already inside the water without ever entering from above the surface; or the water surface ripples in a way that couldn't happen from a drop landing (e.g., ripples appear before the drop arrives); or the lighting in the scene abruptly changes brightness or color between frames with no visible cause; or a beaker's edge visibly flickers, warps, or bends unnaturally.
level_2: At least one clear inconsistency remains: a beaker visibly slides sideways or rotates by more than about 10° between frames; the sponge shifts up or down in the water by roughly a quarter of its height or more with no visible cause; dye drops enter the water at clearly different angles from one beaker to the other; or the water level in a beaker changes even though nothing was added or removed.
level_3: The two beakers keep the same spacing and position relative to each other for the whole clip; the sponge stays fully submerged and in the same spot in the right beaker; dye drops fall straight down and land inside the water in each beaker; the ripples each drop creates spread outward and settle down naturally, matching how the previous ripple looked a moment before.
level_4: All conditions for score 3 are met, and additionally: neither beaker's glass appears to bend, stretch, or warp between frames; the sponge's texture and the water's transparency don't flicker or change abruptly frame to frame; the ripples spread and fade at a steady, continuous pace with no sudden jumps in their pattern; the clip shows no repeated or skipped moments (no visible freeze-and-repeat or missing action).
level_5: All conditions for score 4 are met, and additionally: the water's curved edge where it meets the glass (the meniscus) keeps a shape that matches the beaker's rim throughout; the sponge keeps looking like the same object (same size, shape, and rough texture) in every frame it's visible; the color intensity of the dye plume in each beaker changes only in ways consistent with dye actually spreading through the water, never in an abrupt way that looks like a lighting or exposure change; if the camera moves at all, the beakers and sponge shift together in a way that stays physically consistent from frame to frame.