Domain: Engineering — Agricultural Engineering
Target concept: Place spinach in a sealed container together with clear lime water under illuminated conditions, and verify that the lime water remains clear without becoming turbid.

Video generation prompt: Place fresh spinach leaves into a transparent, airtight container and position a small beaker containing clear lime water inside the container. Seal the container. Place the container under strong light. Maintain illumination for a relatively short period to demonstrate the experimental process.

Evaluation guide:
(i) Target concept: Photosynthetic CO₂ uptake by living plant tissue prevents carbonic acid formation and subsequent calcium carbonate precipitation in limewater.
Minimum mechanism: Spinach must be metabolically active (fresh, green, unsealed exposure prior to test), lime water must be chemically unreacted (clear, saturated Ca(OH)₂ solution), container must be gas-tight to isolate internal atmosphere, and illumination must be sufficient to drive photosynthesis (not respiration-dominant).
(ii)Storyline: Frame 0–2: Open container shown with spinach leaves and beaker placed inside; Frame 3–4: Lid visibly lowered and sealed; Frame 5–9: Sealed container under uniform illumination, with continuous clear view of lime water surface and spinach leaves in fixed side-by-side arrangement; No visual indication of gas exchange, leakage, or chemical reaction; Lime water clarity is verifiably maintained across all frames where visible.

Manual:
Experimental Procedure
1. Place fresh spinach leaves and a small beaker containing clear lime water inside a transparent, airtight container.
2. Seal the container completely.
3. Place the sealed container under strong illumination.
Observation of Experimental Phenomena
The lime water remains continuously clear — no cloudiness or turbidity develops.
Summary of Experimental Principles
Under illumination, spinach performs photosynthesis and consumes CO₂, preventing CO₂ accumulation that would otherwise react with lime water (Ca(OH)₂) to form insoluble CaCO₃ precipitate — thus the lime water stays clear.

Prompt Grounding rubric:
level_1: None of the five required elements is shown at all: no fresh spinach leaves, no transparent container, no small beaker, no clear lime water, and no light source or illuminated scene appear anywhere in the video.
level_2: At least one of the five elements (spinach leaves, transparent container, beaker, clear lime water, illumination) is shown, but the setup is incomplete or wrong: fewer than three of the five elements appear, or a substitute stands in for a required element, such as an opaque or non-see-through container in place of the transparent one, a container with no visible lid or seal mechanism at all, a colored or already-cloudy liquid standing in for the clear lime water, or a non-leaf plant part used instead of spinach leaves.
level_3: All five elements are present and correctly identified: fresh green spinach leaves, a see-through container built with an airtight-style lid or seal (e.g., a clamp-lid or gasket-sealed jar, not a container that is obviously open or gapped), a small beaker, clear lime water filling the beaker, and a visible light source or brightly lit scene, with the beaker and the spinach leaves both visible inside the container together at some point before or during illumination.
level_4: All level-3 elements are present and correctly identified, AND the container is shown being closed as a distinct action (the lid or seal is visibly lowered and pressed shut over the opening), AND the spinach leaves and the beaker of lime water remain visible together inside the container throughout the illuminated phase, AND the light source or bright illumination is clearly active for the entire time after the container is shown sealed.
level_5: All level-4 conditions hold, AND the seal is shown fully seated with no visible gap or opening anywhere around the lid, AND the spinach leaves and the beaker keep a fixed side-by-side arrangement inside the container that never changes for the rest of the video, AND the light source or bright illumination remains visibly on without interruption for the entire sealed phase, AND no hands, tools, labels, or objects other than the spinach, beaker, lime water, and container appear at any point in the video.

Scientific and Causal Correctness rubric:
level_1: The lime water is visibly turbid (milky, white, or cloudy) at every point where it can be seen in the video, including at the very start, showing that CO2 built up and reacted with the Ca(OH)2 despite the spinach being present, so the core photosynthesis-preserves-clarity outcome is never demonstrated; OR the lime water's clarity is never shown clearly enough at any point to judge it.
level_2: The lime water starts out clear but is shown turning cloudy, hazy, or white partway through or by the end of the video (a partial or delayed loss of clarity, distinct from level 1 where the water is already turbid whenever it is shown), indicating the spinach's CO2 uptake is depicted as incomplete or as failing partway through the process.
level_3: The lime water is shown clear at the first moment it is visible and stays clear (no cloudiness, whitening, or precipitate forming) for every later moment it is shown, matching the expected result of the spinach photosynthesizing and absorbing CO2 before it can react with the Ca(OH)2; the spinach leaves stay green and firm rather than wilting, browning, or rotting, consistent with living, photosynthetically active tissue.
level_4: All level-3 conditions hold, AND there is no intermediate frame anywhere in the video where the lime water looks even slightly hazier or whiter than the frame before it, AND no white flecks, film, or ring of precipitate ever appears on the lime water's surface or the beaker's inner wall, AND the spinach leaves show no curling, blistering, or color shift that would suggest they are sitting in a CO2-saturated, low-photosynthesis atmosphere.
level_5: All level-4 conditions hold, AND the lime water stays visibly see-through enough at every frame to make out the far wall or bottom of the beaker through it, AND the spinach leaves keep a uniform, vivid green across their entire surface with no yellow, brown, or pale patches anywhere, AND the beaker's contents never show even a faint wisp of cloudiness or sediment; the entire visible record is consistent with the spinach continuously absorbing CO2 through photosynthesis and preventing any calcium carbonate from forming.

Spatiotemporal Consistency rubric:
level_1: The beaker or the spinach leaves appear, vanish, or jump to a new position with no continuous motion linking the frames: for instance, the beaker is suddenly inside the container with no hand or motion ever shown placing it, or the spinach leaves disappear from one frame and reappear elsewhere in the next; OR the container's walls switch from transparent to opaque (or back) between frames; OR the whole scene's brightness jumps sharply from dark to fully lit, or the reverse, within a single frame with no transition.
level_2: A smaller but still visible break in continuity occurs: a hand reaches in to place the beaker or close the lid but never withdraws from the shot, or the container is shown open in one frame and completely sealed in the next with no lid motion shown in between, or the lime water's surface line jumps up or down abruptly between adjacent frames, or the spinach leaves shift position, size, or angle between frames with no cause such as being placed or touched.
level_3: The beaker, spinach leaves, and container keep the same relative arrangement throughout: the beaker never slides, rotates, or changes size relative to the container walls, and the spinach leaves stay where they were placed rather than drifting; once the lid is shown closed, it stays fully closed for the remainder of the video; the overall brightness of the scene only changes gradually, if at all, with no sudden jump within a single frame; no object blocks the view of the lime water for more than about a second at a time.
level_4: All level-3 conditions hold, AND the outlines of the beaker, spinach leaves, and container stay sharp and steady from frame to frame with no visible wobble, flicker, or warping of their shapes, AND the background visible behind or through the container does not shift relative to the container, AND the container walls show a consistent amount of glass/plastic-like distortion of whatever is behind them throughout rather than warping in and out, AND there is no frozen, skipped, or duplicated frame anywhere in the video.
level_5: All level-4 conditions hold, AND the container keeps one single rigid, undistorted shape in every frame with no bending or stretching of its walls, AND the beaker and spinach leaves sit at the exact same location and orientation relative to the container in the first sealed frame and the last frame, consistent with a genuinely static, tripod-mounted shot with zero drift, AND the meniscus (top surface line) of the lime water inside the beaker is the same height and shape in the last frame as in the first sealed frame, confirming no liquid was ever added, removed, or splashed, AND no object shows motion blur despite nothing in the scene actually moving, AND the camera's framing (crop, angle, and zoom) in the final frame exactly matches the framing in the first frame.