Domain: Natural Science — Geology & Geophysics
Target concept: Comparing the flow of colored water through a sand column and a clay column to evaluate their permeability.

Video generation prompt: Two identical transparent vertical columns are placed side by side, one filled with coarse sand and the other with compacted clay; colored water of equal volume is poured into both.

Evaluation guide:
(i) Target concept: Permeability as a function of sediment pore structure and connectivity.
Minimum mechanism: Water must behave as an incompressible Newtonian fluid under gravity; sand grains must be macroscopically visible and separated by voids; clay particles must be densely packed with nanoscale pores insufficient to permit gravitational drainage within observable timeframe.
(ii)Storyline: Frame 0–2: Static shot showing two identical transparent columns side-by-side, labeled or visually distinguishable as sand (left) and clay (right). Frame 3–5: Colored water begins pouring into both columns at identical height and rate. Frame 6–8: Water descends continuously through sand column (passing visible horizontal markers), while remaining motionless at clay column surface. Frame 9–10: Final state shows water accumulated at base of sand column and fully pooled at top of clay column; no intermixing, leakage, or secondary flow. Perspective: Fixed frontal view, eye-level, centered on column midlines; full columns always in frame; no occlusion of water-column interface.

Manual:
Experimental Procedure
1. Place two identical transparent vertical columns side-by-side.
2. Fill left column with coarse sand; fill right column with compacted clay.
3. Pour equal volume of colored water into both columns simultaneously.
Observation of Experimental Phenomena
Water rapidly percolates through the sand column and appears at the bottom; water remains pooled at the top of the clay column with no visible downward movement.
Summary of Experimental Principles
Coarse sand has high permeability due to large interconnected pore spaces; compacted clay has very low permeability due to tiny, poorly connected pores — demonstrating how sediment type controls groundwater flow.

Prompt Grounding rubric:
level_1: No two transparent vertical columns visible; no sand or clay present; no colored water; no side-by-side arrangement; no pouring action shown.
level_2: Two vertical containers are present but not transparent or not identical in shape/size; at least one column contains neither coarse sand nor compacted clay; colored water is absent or applied to only one column; spatial arrangement is not side-by-side.
level_3: Two identical transparent vertical columns are present and placed side-by-side; one column contains a granular material, the other a dense material; colored water is poured into both columns simultaneously or sequentially; materials are visibly distinct (e.g., grainy vs. smooth texture), but labeling or explicit identification of sand/clay is missing.
level_4: Two identical transparent vertical columns placed side-by-side; left column contains coarse sand (visibly granular, non-uniform surface, interstitial gaps visible), right column contains compacted clay (visibly dense, smooth surface, no visible pores); equal-volume colored water is poured into both columns; pouring action is clearly directed into the top opening of each column.
level_5: Two identical transparent vertical columns placed side-by-side with fixed viewpoint; left column filled with coarse sand (granular, high-porosity appearance), right column filled with compacted clay (homogeneous, low-porosity appearance); colored water (same hue and saturation) is poured into both columns in identical volume (visually matched meniscus height pre-pour, same pour duration and flow rate implied by continuous stream); no extraneous objects, labels, or overlays; all elements fully consistent with posted_prompt.

Scientific and Causal Correctness rubric:
level_1: No permeability-related phenomenon observed; water remains static in both columns; or water disappears, overflows, or flows sideways; no contrast in descent speed or depth; color changes or vanishes during observation.
level_2: Water descends in both columns but at indistinguishable speeds; water accumulates identically in both; or water drains completely from both columns; or water appears to rise or spread laterally; no visual evidence of differential infiltration.
level_3: Water descends visibly faster in one column than the other; water level drops or rises differently between columns; some descent occurs in sand column, while water remains pooled at top of clay column, but descent in clay column is continuous (not stalled) or descent in sand column is discontinuous (e.g., jerky, segmented).
level_4: Water descends continuously and rapidly through the sand column (visible downward movement past multiple horizontal reference points within frame); water remains pooled at the top of the clay column with no visible downward progression beyond initial contact; no lateral seepage, leakage, or overflow; color remains stable and uniform in both columns; descent in sand column is unimpeded and linear-appearing, while clay column shows zero downward penetration beyond surface wetting.
level_5: Water descends rapidly and continuously through the sand column with clear percolation (individual droplets or streams visible moving between grains); water remains fully pooled at the top of the clay column with zero downward displacement: no wetting front advancement, no capillary rise, no edge seepage; color intensity and hue identical in both columns throughout; no mixing, fading, or diffusion artifacts; causal relationship (sand → fast flow / clay → no flow) is visually unambiguous and fully supported by observed states.

Spatiotemporal Consistency rubric:
level_1: Columns teleport between frames; water appears/disappears without pouring action; sudden lighting shifts or shadow jumps; columns change orientation, size, or transparency mid-video; background flickers or warps.
level_2: One column shifts position relative to the other between frames; water stream disconnects from pourer’s hand or source between frames; visible cuts or jump cuts in motion; container edges distort or wobble unnaturally; lighting changes abruptly (e.g., spotlight appears only in second half).
level_3: Columns remain fixed in position and orientation; water pours continuously without disconnection; no teleportation or structural break; lighting and shadows remain consistent; minor frame-to-frame jitter or slight focus drift is present but does not obscure core objects or actions.
level_4: Columns maintain rigid side-by-side spatial relationship with constant relative distance and alignment; water stream maintains continuity from source to column entry point across all frames; no visible motion blur that obscures state (e.g., sand grain boundaries or water surface); no parallax shift or perspective distortion; lighting and shadow direction remain stable and physically plausible.
level_5: Zero spatial discontinuity: columns retain identical size, shape, transparency, and relative position across every frame; water stream is fully continuous, unbroken, and correctly occluded where it enters column top; no motion blur degrading object boundaries; no lens flare, chromatic aberration, or vignetting affecting visibility of core phenomena; shadows cast consistently with light source position; no temporal stutter, frame duplication, or dropped frames.