Domain: Natural Science — Marine Science
Target concept: Achieving depth-dependent color attenuation using stratified water and colored objects (red fading gradually)

Video generation prompt: From the side, a transparent tank is illuminated from above, with a vertical rod gradually submerging red, green, and blue objects into deeper water.

Evaluation guide:
(i) Target concept: Wavelength-selective absorption in aqueous media leads to progressive spectral attenuation with increasing optical path length.
Minimum mechanism: Light must travel through a homogeneous, particle-free water column; objects must be spectrally distinct and opaque; illumination must be broadband and top-down; viewing must be orthogonal to light path to observe depth-resolved attenuation.
(ii)Storyline: Frame 0–1: Rod held above water, all three objects fully visible and vividly colored. Frame 2–3: Red object crosses water surface → immediate reduction in red saturation relative to air. Frame 4–6: Green object crosses surface → red now visibly duller than green; green begins attenuating but less than red. Frame 7–9: Blue object crosses surface → green now duller than blue; red is most desaturated. Throughout: side-view perspective remains fixed; no occlusion violates depth ordering; attenuation manifests solely as saturation loss — no hue shift, no brightness-only change, no color bleeding.

Manual:
Experimental Procedure
1. Position transparent rectangular tank sideways in frame.
2. Illuminate from directly above with uniform white light.
3. Attach red, green, and blue opaque objects to a vertical rod.
4. Lower rod steadily into water so objects enter sequentially: red first, then green, then blue.
Observation of Experimental Phenomena
- Red object loses saturation earliest and most strongly as depth increases.
- Green object retains more saturation than red at same depth, but less than blue.
- Blue object remains most saturated at all depths; attenuation is weakest.
Summary of Experimental Principles
Water absorbs longer wavelengths (red) more strongly than shorter ones (blue); attenuation increases with path length (depth), causing depth-dependent color loss — red fades first and fastest, blue persists longest.

Prompt Grounding rubric:
level_1: No transparent tank is visible from the side; no vertical rod is present; none of the red, green, or blue objects appear; there is no top-down illumination; the shot is not framed from the side; no submerging motion is shown.
level_2: The transparent tank is visible but not shot from the side (e.g., it is framed front-on or from directly overhead); a rod is present but not held vertically; at least one colored object appears but the wrong colors or count are shown (e.g., only a red object, or red plus a yellow object); the objects move laterally or float rather than being submerged downward.
level_3: The transparent tank is shown from the side; a vertical rod is present and held vertically; red, green, and blue objects are all attached to the rod; the lighting reads as coming from above, brighter near the surface and darker toward the bottom; the rod and its objects are shown moving downward into the water.
level_4: The scene meets the 3-point description, and in addition the three colored objects stay fixed to the rod during the descent, with none detaching, spinning independently, or moving on its own, and they keep the same horizontal alignment along the rod's length throughout.
level_5: The scene meets the 4-point description, and in addition the rod starts fully above the water surface with all three objects visible, then descends so that the red object enters the water first, the green object second, and the blue object third, matching the intended one-at-a-time order with no color entering out of turn, and all three objects stay visible and unobstructed throughout.

Scientific and Causal Correctness rubric:
level_1: No color attenuation is visible at all: the red, green, and blue objects keep their full saturation at every depth shown, with no depth-related difference in how saturated they look, and the red object does not look any less vivid than the green or blue ones at any point.
level_2: At least one object's color visibly shifts (e.g., the red object darkens), but the shift is not consistent with depth (e.g., red fades at a shallow depth then looks vivid again deeper); or the wrong object fades most (e.g., green fades more than red); or all three objects appear to fade at the same time instead of in a depth-dependent progression.
level_3: When compared at the same depth, the red object looks less saturated than the green and blue objects, the green object looks less saturated than the blue object, and the blue object keeps the highest saturation of the three at every depth where they can be compared, with no point where red looks more saturated than green at a matching depth.
level_4: The saturation ordering meets the 3-point description, and in addition red stays visibly less saturated than green, and green less saturated than blue, at every depth as the rod continues its descent, with no moment where two of the objects look identical in saturation despite being at different depths, and no sudden jump in how saturated an object looks.
level_5: The saturation ordering meets the 4-point description, and in addition, at every frame where two or more objects sit at different depths, the deeper object always looks equally or less saturated than the shallower one, and the red object is visibly the first to noticeably fade, the green object second, and the blue object third, with no ambiguity about which object starts fading first.

Spatiotemporal Consistency rubric:
level_1: The rod jumps between positions with no visible motion connecting them; one of the objects vanishes and reappears mid-descent; the tank's shape visibly warps or stretches; the lighting suddenly switches direction (e.g., a top-lit frame is followed by a side-lit one); the water surface flickers or disappears intermittently.
level_2: The rod's motion looks jerky or uneven (e.g., it pauses then suddenly speeds up); the objects wobble or rotate on their own, independent of the rod; the water surface's reflection or refraction pattern changes character abruptly (e.g., sharp in one frame, blurred in the next with no visible cause); shadows detach from their objects or flip direction with no change in the light source.
level_3: The rod moves downward with smooth, continuous translation; the objects stay rigidly attached and keep a fixed orientation; the water surface stays level and stable; the lighting keeps coming from the same direction with no visible intensity change; no object visibly overlaps another in a way that contradicts their depth order (e.g., the blue object never appears in front of the red object once blue is deeper).
level_4: Motion meets the 3-point description, and in addition the depth ordering stays visually correct throughout: the red object is always the shallowest of the objects still visible together, green is always in between, and blue is always the deepest, with no frame showing blue above green or green above red once all three are submerged; the apparent size and perspective of each object changes consistently as it descends.
level_5: Motion meets the 4-point description, and in addition the motion reads as fully continuous with no visibly duplicated or skipped frames and no strobing; the water surface's ripples stay visually similar in how often and how strongly they appear rather than becoming noticeably choppier or calmer without cause; the tank and objects show no visible warping, color fringing, or blurring beyond what depth alone would explain.