Domain: Engineering — Geotechnical Engineering
Target concept: Stability of soil aggregates upon immersion in water (aggregation vs. dispersion)

Video generation prompt: Two transparent bowls containing still clear water are placed side by side; at the same time, a dry, dark-colored soil block is placed into the left bowl, and a lighter, loose soil block is placed into the right bowl.

Evaluation guide:
(i) Target concept: Differential stability of soil aggregates in water due to inherent binding capacity.
Minimum mechanism: Soil aggregate stability requires physical/chemical binding agents (e.g., clay coatings, humus, Fe/Mn oxides) that resist slaking; the dry, dark-colored block used in this setup is understood to carry such binding agents and therefore resists particle detachment, while the lighter, loose block lacks them and disperses immediately upon wetting.
(ii)Storyline: Frame 0–1: Static wide shot showing two identical transparent bowls side-by-side, both filled with still, clear water, no soil present. Frame 2–3: Two hands (or mechanical actuators) enter symmetrically from top, each holding one soil block: left hand holds dark, dense block; right hand holds light, crumbly block. Frame 4: Both blocks reach water surface simultaneously. Frame 5–6: Blocks submerge vertically; right block instantly fractures with a turbid plume rising; left block sinks whole or breaks into clean, non-coalescing grains without clouding the water. Frame 7–9: Right bowl shows sustained cloudy suspension; left bowl shows clear water with settled particles at bottom. Perspective: Fixed frontal orthographic view, eye-level, no parallax shift; entire bowls and full water column must remain fully visible and unoccluded throughout.

Manual:
Experimental Procedure
1. Place two identical transparent bowls side-by-side on a flat surface.
2. Fill both bowls with equal volumes of still, clear water.
3. Simultaneously place a dry, dark-colored, cohesive soil block into the left bowl and a lighter-colored, loose, non-cohesive soil block into the right bowl.
Observation of Experimental Phenomena
Left bowl: minimal dispersion — the dark soil block settles largely intact or breaks into a few clean, discrete pieces; the water stays clear.
Right bowl: rapid dispersion — the light, loose soil fragments and releases a cloudy suspension into the water.
Summary of Experimental Principles
Stability of soil aggregates upon immersion depends on binding agents (e.g., clay, organic matter, iron oxides): dark soils often contain more stabilizers, resisting dispersion; lighter, sandy/loamy soils lack cohesion and disperse readily.

Prompt Grounding rubric:
level_1: This is the failure floor: no two matching transparent bowls of still, clear water, or only one bowl shown, or the two bowls sitting apart rather than adjacent to each other, or the water already cloudy before either block enters, or no soil block ever placed into either bowl.
level_2: Both bowls are present, side by side, filled with still, clear water, but the block placement breaks the prompt's design: only one block appears rather than both, the two blocks are placed at clearly different moments instead of together, the two blocks look alike in color and texture instead of one dark-dense/one light-loose, or the dark block ends up in the right bowl while the light block goes into the left (the bowls are swapped).
level_3: Two transparent bowls sit side by side, each holding still, clear water; a dry, dark-colored, dense soil block is lowered into the left bowl while a lighter-colored, loose soil block is lowered into the right bowl at essentially the same moment, as one continuous action with no visible gap between the two placements.
level_4: Beyond level 3, both blocks stay clear of the water surface until the instant of first contact, with neither pre-dunked nor partly submerged early; both bowls show the same stillness and clarity in the moments before the blocks enter; and nothing (hands, tools, labels) blocks the camera's view of either bowl during the placements.
level_5: Beyond level 4, the left block visibly holds together as a solid, cohesive mass with no crumbling before it touches the water; the right block visibly looks loose and granular with no clumping or bridging; and both blocks drop straight down into the center of their respective bowls without tilting, splashing, or spinning on the way in.

Scientific and Causal Correctness rubric:
level_1: No contrast in behavior shows up between the two blocks after they enter the water: both disperse the same way, or both remain fully intact, or both bowls turn cloudy (or stay clear) together. No aggregation-versus-dispersion phenomenon is visible in either bowl.
level_2: A difference between the two bowls does appear, but it runs opposite to the underlying soil chemistry: for example, the dark block (which should hold together, being rich in clay/humus binding agents) is the one that clouds the water, while the light, loose block stays clear and intact; or only a partial, ambiguous difference shows without either bowl clearly clouding.
level_3: After both blocks submerge, the right bowl clouds quickly as the light, loose soil block breaks apart and releases a turbid plume, while the left bowl stays comparatively clear as the dark, dense block either sinks as one piece or breaks into a few clean, non-coalescing chunks that do not cloud the water: the correct pairing of dispersion (light, loose, binding-agent-poor block) versus stability (dark, dense, binding-agent-rich block).
level_4: Beyond level 3, the cloudiness in the right bowl visibly originates from the light block itself rather than from stirred sediment or an outside source, and keeps building rather than settling out early; in the left bowl, any grains that do break off settle individually at the bottom rather than clumping into a floating haze.
level_5: Beyond level 4, the right bowl's turbidity begins the instant the light block touches the water and spreads evenly rather than in one direction only; the left bowl's water stays clear from first contact onward, with no delayed clouding, no momentary haze that later clears, and no sudden late collapse of the dark block.

Spatiotemporal Consistency rubric:
level_1: Severe continuity break: the bowls jump to new positions between frames, the water surface flickers or vanishes, a soil block vanishes and then reappears, the lighting flips from one shot to the next with no transition, the camera cuts to a different angle mid-sequence, or the background shifts with no camera motion to explain it.
level_2: Moderate break: one bowl or block changes size with no corresponding movement; the water in one bowl ripples for no reason while the other stays glassy still; a soil block's position jumps by more than about 10% of the bowl's width in a single instant instead of moving continuously; or the shadows on the bowls point a different way than the light source would suggest.
level_3: The two bowls keep their side-by-side placement for the whole sequence; each soil block travels from the hand into the water as one continuous motion, with no jump cuts, freezes, or warping along the way; the water surface is still in both bowls before the blocks enter and settles back to still afterward; and the scene's lighting and the bowls' cast shadows hold the same direction and brightness from start to finish.
level_4: Beyond level 3, each block's descent looks physically natural: no sudden speed-up, no freezing mid-fall; no block is ever half-hidden in one frame and fully visible in the next without a visible transition between them; and the bowls stay perfectly round with a flat water surface, with no lens warping visible in either bowl.
level_5: Beyond level 4, the motion of both blocks and the settling of the water show no visible stutter or dropped frames; the water's surface reflects the light source the same way in both bowls, with matching highlight shape and brightness; and fine texture on the soil blocks (grain edges, visible pores) stays sharp and readable all the way through the descent, without blurring.