Domain: Natural Science — Marine Science
Target concept: Two clear aquariums, one fertilized and the other unfertilized, demonstrate the algal growth process through time-lapse photography.

Video generation prompt: Two identical transparent aquaria are placed under the same light conditions; fertilizer is added only to the left one, and time-lapse images of algal growth are recorded over several days using a fixed camera position.

Evaluation guide:
(i) Target concept: Nutrient enrichment drives differential microalgal bloom formation in controlled aquatic environments.
Minimum mechanism: Photosynthetic microalgae require light + nutrients to proliferate; in absence of added nutrients, growth remains limited despite light; fertilizer introduces limiting nutrients, triggering exponential population increase visible as greenish water turbidity and biofilm.
(ii)Storyline: Frame 1: Two clear, identically lit aquariums side-by-side; left receives discrete fertilizer application (visible pour/drop). Frames 2–N: Left aquarium shows cumulative, frame-ordered increase in greenish suspended particles and/or surface film; right aquarium retains original clarity and neutral water color throughout; all frames maintain fixed viewpoint, stable lighting, and rigid spatial alignment; no external interference or physical disturbance visible.

Manual:
Experimental Procedure
1. Place two identical transparent aquariums side-by-side under uniform light.
2. Add fertilizer to left aquarium only; leave right unfertilized.
3. Record time-lapse video from fixed frontal viewpoint.
Observation of Experimental Phenomena
Left aquarium develops progressive greenish turbidity and surface film over time; right aquarium remains clear and colorless.
Summary of Experimental Principles
Fertilizer provides nutrients (e.g., nitrates, phosphates) that accelerate microalgal reproduction; identical light and container conditions isolate nutrient availability as the sole variable driving differential growth.

Prompt Grounding rubric:
level_1: No two transparent aquariums are shown, or only one aquarium appears, or the aquariums are not placed side by side, or no fertilizer-adding action is shown, or the camera view changes between shots (panning, zooming, or repositioning) rather than staying fixed.
level_2: Two transparent aquariums are present side by side, but fertilizer is added to both, to neither, or to the wrong (right) aquarium; or the camera visibly pans, tilts, zooms, or shifts position between frames; or the video gives no sense of elapsed time (e.g., the two tanks look identical in every frame with no indication of a time-lapse).
level_3: Two visually identical transparent aquariums sit side by side under matching lighting; fertilizer is added only to the left aquarium in a single, visible pour or drop; the camera position stays fixed throughout; and the footage is structured as a time-lapse (i.e., successive shots are presented as separated points in time rather than one continuous real-time clip).
level_4: In addition to the 3-point requirements, the fertilizer-adding action is depicted as a single, contained event (e.g., one pour or one drop) that visibly touches only the left aquarium, with no spillage or contact reaching the right aquarium; no extraneous objects (hands, tools, labels) remain in frame after the fertilizer is added; and the two aquariums keep the same relative size and position across every shot.
level_5: In addition to the 4-point requirements, the fertilizer is added exactly once, only into the left aquarium, with no ambiguity about which tank received it; the two aquariums remain perfectly aligned side by side with the same spacing and framing in every shot; and no extra elements (a reflection of a person, an added label, a camera shadow) intrude into the frame at any point in the sequence.

Scientific and Causal Correctness rubric:
level_1: No sign of nutrient-driven algal growth: greenish coloration or turbidity appears equally in both aquariums, or appears in the right (unfertilized) aquarium instead of the left, or no color change happens in either tank across the whole time-lapse.
level_2: Greenish growth appears in the left aquarium but also shows up, even faintly, in the right aquarium; or the right aquarium becomes discolored (yellowing, cloudiness) in a way not explained by algae; or both aquariums change color at the same time with no delay that would reflect the fertilizer's effect building up.
level_3: Greenish coloration or turbidity develops only in the left aquarium over the course of the time-lapse; the right aquarium stays visually clear with no green tint; the greenish appearance in the left tank looks like a diffuse haze, suspended particles, or a thin surface film consistent with algae, not like added paint or dye; and any greening in the left tank only begins after the fertilizer is shown being added.
level_4: In addition to the 3-point requirements, the green coloration or turbidity in the left aquarium increases from one time-lapse frame to the next without ever fading or reverting to a clearer state; and the right aquarium keeps the same clarity and neutral water color across the entire sequence, with no yellow/brown tinge and no particles appearing on its walls or floor.
level_5: In addition to the 4-point requirements, every later frame of the left aquarium shows a visibly greater green coverage or density than every earlier frame (a steady, one-directional increase); the right aquarium shows no shift from its starting clarity or color in any frame; and the algal growth in the left tank looks gradual and organic — never an instantaneous full bloom or an unnatural crystalline or moving pattern.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: the aquariums vanish and reappear in different positions between shots; the lighting abruptly switches (e.g., from daylight to a spotlight) mid-sequence with no transition; the aquarium shape warps or stretches; the shadows shift with no visible light-source cause; or the shots are shown out of temporal order (later, denser growth appears before earlier, sparser growth).
level_2: Noticeable break in continuity: the two aquariums keep the same layout but change size relative to each other between shots; the camera visibly pans, tilts, or zooms despite the fixed-viewpoint premise; a shadow on a tank's base shifts position with no corresponding change in the light; the water surface reflection flickers in an unnatural way; or the algal growth jumps from sparse to dense between consecutive shots with no intermediate stage shown.
level_3: The two aquariums stay in the same relative position and size across all shots; the camera position does not detectably move; the lighting keeps the same color and intensity throughout; shadows and reflections stay geometrically consistent; and the shots are ordered so that earlier ones show less green coloration than later ones.
level_4: In addition to the 3-point requirements, the water surface in both tanks stays calm with no ripples, waves, or splashes that would be inconsistent with an undisturbed setup; no visible seam, glow, or clipping artifact appears at the aquarium edges; the background and tank walls do not flicker between shots; and nothing enters or exits the frame abruptly (e.g., a hand appearing then vanishing without a visible exit).
level_5: In addition to the 4-point requirements, there is no visible shake or trembling of the aquariums between shots; the aquarium edges stay sharp and steady; the water's surface shimmer looks equally natural and subtle in both tanks across every shot; the two aquariums show no parallax shift relative to each other; and there is no strobing or ghosting in the growth's appearance between shots.