Domain: Natural Science — Marine Science
Target concept: Phycobiliprotein, a red algal pigment that emits red fluorescence under blue/green light illumination.

Video generation prompt: Red and green algae are placed side by side in a dim aquarium, with the overhead lighting cycling continuously between white light and blue-green light.

Evaluation guide:
(i) Target concept: Light-dependent fluorescence emission from phycobiliprotein pigments in red algae, selectively activated by blue-green excitation wavelengths, contrasted against non-fluorescent green algae under identical illumination.
Minimum mechanism: Phycobiliproteins must be present and optically active in red algae; blue-green light must contain wavelengths absorbed by phycobiliproteins (~480–580 nm); red fluorescence must result solely from emission (not reflection); green algae must contain only chlorophyll a/b with negligible red fluorescence quantum yield under blue-green excitation.
(ii)Storyline: Frame 0–3s: White light phase: aquarium visible, red algae appear brownish/maroon, green algae appear green, no red emission. Frame 3–6s: Transition begins: overhead light hue shifts smoothly from white to blue-green; red algae surface begins uniform red glow; green algae show no color change or emission. Frame 6–9s: Blue-green light phase: red algae sustain full red fluorescence across entire visible biomass; green algae retain unchanged green appearance. Frame 9–10s: Transition reverses: red fluorescence extinguishes synchronously with hue shift back to white; green algae remain visually stable. Throughout: Fixed viewpoint, side-by-side spatial layout preserved; no occlusion; lighting change is global and uniform across scene.

Manual:
Experimental Procedure
1. Place red algae and green algae side-by-side in a dimly lit aquarium.
2. Illuminate from above with light that cycles continuously between white light and blue-green light.
Observation of Experimental Phenomena
Under white light: red algae appear brownish/maroon; green algae appear green. Under blue-green light: red algae emit bright red fluorescence; green algae remain green with no fluorescence.
Summary of Experimental Principles
Phycobiliproteins in red algae absorb blue-green light and re-emit energy as red fluorescence. Green algae lack phycobiliproteins and rely on chlorophyll, which does not fluoresce under blue-green light in this context.

Prompt Grounding rubric:
level_1: No aquarium is shown; or neither red nor green algae is visible; or no overhead light source is shown; or the algae are not placed side by side; or the lighting never changes at all.
level_2: A dimly lit aquarium is shown, but only one type of algae (red or green, not both) appears; the overhead lighting stays a single, unchanging color; the two algae are not positioned side by side; or no overhead light fixture is identifiable in the shot.
level_3: The dim aquarium, both the red and the green algae side by side, and an overhead light that cycles between two different states are all present, but the two lighting states are not clearly distinguishable as white versus blue-green (e.g., both look white, or both look like the same single color with no visible spectral difference).
level_4: The dim aquarium is shown with the red and green algae side by side in the same frame; the overhead light cycles between two clearly different states: one that reads as neutral white light and one that reads as distinctly blue-green (cyan/teal, without any red or yellow tint); neither alga disappears or jumps position at any point; and both remain visible throughout the video.
level_5: In addition to the 4-point requirements, the aquarium's walls are clean and clearly transparent, and the red and green algae are visually distinguishable from each other by shape (e.g., one is more filament-like, the other more sheet-like) and are placed directly next to each other with no barrier or wide gap between them; the light cycles smoothly between white and blue-green across the whole tank at once, not just part of it, and both algae stay fully inside the frame at every point in the video.

Scientific and Causal Correctness rubric:
level_1: No fluorescence is visible: the red and green algae look the same color under every lighting condition, the red algae show no color shift between white and blue-green light, and there is no visible contrast between the two algae under either light.
level_2: The red algae show no color change between the two lighting states; or the green algae glow or brighten unnaturally under white light; or the red algae go dark under blue-green light without any red glow appearing; or the green algae emit a red glow (which would be inconsistent with a chlorophyll-based pigment that does not fluoresce this way).
level_3: Under white light, the red algae look brownish-maroon and the green algae look green; under blue-green light, the red algae visibly glow red while the green algae stay green with no glow, but the red glow flickers, cuts in and out, or only covers part of the red algae's mass, or the green algae also show a faint glow at the same time.
level_4: Under white light, the red algae look brownish-maroon and the green algae look green; under blue-green light, the red algae glow red steadily and evenly over their whole visible surface, while the green algae show no glow at all; the red glow appears only during the blue-green light phase and never during the white-light phase, and the green algae never glow under either light.
level_5: The red algae's red glow appears only while the blue-green light is on, covering the entire visible red algal surface, and turns off as soon as the light returns to white; the green algae keep a steady, unchanging green color under both lighting states with no brightening or color shift at any point; and the red glow itself looks like a pure red with no orange, yellow, or purple tint bleeding into it.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: the red or green algae vanish and reappear between frames; the aquarium itself disappears and reappears; the overhead light switches from white to blue-green (or back) instantly with no transition; the tank glass appears bent or warped, or an alga appears to float with no visible support; or the shadows change direction or intensity with no matching change in the light.
level_2: Noticeable break in continuity: the algae's position or apparent size changes inconsistently between the white-light and blue-green-light phases; the lighting switches with a hard cut rather than any fade; the water surface or the algae's swaying motion stutters or skips frames; or the shadows flicker on and off or vanish without any corresponding change in the light source.
level_3: Small but noticeable flaws: one alga is briefly hidden from view during the lighting transition; the aquarium shows slight jitter in its framing; the lighting transition appears abrupt (snapping from white to blue-green, or back, without any visible fade) rather than gradual; and the red and green algae stay in the same relative position and orientation to each other throughout.
level_4: The red and green algae stay side by side with the same spacing and alignment between them throughout; the aquarium's shape stays undistorted; the lighting transition fades smoothly between white and blue-green rather than cutting sharply; any motion of the water surface or gentle swaying of the algae looks physically natural; and shadows or highlights shift gradually in step with the changing light color, not abruptly.
level_5: There is no visible drift or repositioning of the aquarium, the algae, or the overhead light across the whole video; the tank shows no warping, stretching, or change in perspective; the lighting fades between white and blue-green with a smooth, continuous shift in hue and brightness rather than any visible jump; any ripple on the water surface looks subtle and consistent everywhere in the tank; both algae sway in the same natural, synchronized way if they move at all; and there is no visible ghosting, smearing, or flicker of the image between frames.