Domain: Engineering — Agricultural Engineering
Target concept: Take soil rich in organic matter, add potassium dichromate reagent, and confirm that the solution changes from orange to green within 10 seconds, exhibiting a distinct color change.

Video generation prompt: Place the organic-rich soil into a transparent beaker. Add potassium dichromate reagent using a pipette. Gently rotate the container to mix. Demonstrate the reaction process of the solution within a short period. Emphasize clear equipment handling and correct procedural order.

Evaluation guide:
(i) Target concept: Redox-driven chromatic transition as proxy for organic matter content.
Minimum mechanism: Orange Cr(VI) species must be present initially; organic matter must be introduced and physically mixed to enable electron transfer; reduction must yield Cr(III) in aqueous solution, producing green hue, not dilution, contamination, or optical artifact.
(ii)Storyline: Frame 1: Static shot of empty transparent beaker. → Soil is placed into beaker (visible granular descent and settling). → Pipette enters frame, tip aligned above beaker opening. → Liquid dispensed (meniscus break visible). → Pipette withdraws. → Beaker begins slow, steady rotation around vertical axis. → During rotation, orange solution darkens and transitions uniformly to green. → Rotation completes; green solution remains stable. Perspective: Fixed frontal view, eye-level, shallow depth of field ensuring beaker occupies >60% of frame width; no cutaways, overlays, or text; all events occur in single continuous take with unobstructed visibility of liquid interior.

Manual:
Experimental Procedure
1. Place organic-rich soil into transparent beaker.
2. Add potassium dichromate reagent using pipette.
3. Gently rotate beaker to mix.
Observation of Experimental Phenomena
Solution changes from orange to green within video duration; color change is uniform and confined to liquid phase.
Summary of Experimental Principles
Potassium dichromate (orange, Cr⁶⁺) oxidizes organic matter, reducing to chromium(III) compounds (green, Cr³⁺); color shift confirms presence of oxidizable organic material.

Prompt Grounding rubric:
level_1: No transparent beaker visible; no soil placed inside; no pipette present; no potassium dichromate reagent visibly added; no container rotation shown; no demonstration of procedural sequence.
level_2: At least one of the following is present: transparent beaker, organic-rich soil, pipette, or rotation motion, but none appear in correct functional context (e.g., pipette held but no liquid dispensed; soil placed but outside beaker; rotation shown without prior addition).
level_3: Transparent beaker is present and contains soil; pipette is present and positioned near beaker opening; rotation motion occurs after pipette is shown near beaker; all core objects exist and appear in approximate functional relationship: sequence of placement → addition → mixing is visually implied but not strictly ordered.
level_4: Transparent beaker is present with soil inside; pipette is shown dispensing liquid into beaker; rotation motion begins only after pipette is withdrawn from beaker opening; all three core actions (placement, addition, mixing) occur in correct sequential order with no missing step or temporal inversion.
level_5: Transparent beaker is centered and fully visible; organic-rich soil is clearly placed inside before any other action; pipette is shown dispensing liquid directly into the beaker with no off-target delivery; rotation motion starts immediately after pipette withdrawal and continues smoothly; the beaker, soil, and pipette all stay in the same arrangement relative to one another within the frame from start to finish; no extraneous objects or actions distract from the three-step sequence.

Scientific and Causal Correctness rubric:
level_1: The video never shows a color shift: the solution stays orange from the first frame to the last, with no green ever appearing, or the color moves backward from green toward orange instead of the reverse.
level_2: Green color appears but not as a result of the mixing procedure (e.g., a pre-existing green liquid is used, or a green tint appears before the reagent is added or while the pipette is still approaching); or the solution never shows the orange starting color at all (e.g., it begins green or colorless).
level_3: Solution is initially orange and green color appears only after the pipette has finished dispensing the reagent (never before), during or after the rotation itself; the color change is visible and confined to the liquid, with no simultaneous orange and green layers that never blend; however, it is unclear from the video whether the shift to green begins while the beaker is still rotating or only becomes visible once the rotation has already stopped, leaving the precise timing within that window ambiguous.
level_4: Solution is unambiguously orange before the pipette adds reagent; the orange color persists until after the liquid is added and before rotation begins; green color appears only during or after rotation starts; the color change is continuous and confined to the mixed liquid; no residual orange patches remain after rotation is complete; the sequence of addition, mixing, and color change visually supports a causal chain.
level_5: Solution is uniformly orange in the first frame; the pipette delivers a clear amber-orange liquid; no green appears before rotation begins; rotation continues for a visible duration; green emerges progressively and uniformly across the entire liquid volume during rotation; no orange remnants remain once rotation ends; the color transition stays confined to the liquid and matches the expected hue: a true chromatic green, not blue, grey, or yellow-green.

Spatiotemporal Consistency rubric:
level_1: The beaker vanishes from the frame and reappears, or the soil appears inside the beaker without ever being poured or dropped in, or the pipette jumps from one position to another with no motion connecting the two, or the beaker's rotation snaps suddenly to a different angle (e.g., an instant quarter turn) rather than turning smoothly, or the lighting on the beaker changes abruptly with no visible cause, or the shadow the beaker casts suddenly points a different direction for no reason.
level_2: One clear spatial or timing break occurs: for example, the beaker's size or position changes noticeably between shots; the pipette tip disappears and then reappears already inside the beaker with no visible approach; the beaker's rotation begins from a complete stop and instantly reaches full speed with no ramp-up; or the light on the beaker flickers, or the shadow it casts changes inconsistently from one moment to the next.
level_3: The beaker, soil, and pipette all stay visible and in the same arrangement relative to each other; the beaker itself does not move or change shape; the rotation is smooth and continuous once it begins; the lighting on the beaker and the shadow it casts look the same throughout; whenever the pipette passes in front of or behind the beaker, it always re-emerges looking the same as it did before being occluded.
level_4: The beaker, soil, and pipette keep the same scale and the same position relative to one another throughout; the rotation is fluid from start to finish, without a frozen start or a sudden stop; the lighting on the beaker shows no unexpected glare or sudden change in exposure; the shadow cast by the hand or pipette always points consistently with a single, unchanging light source.
level_5: The beaker stays rigid, centered, and unchanged in shape throughout; the soil does not move once it has settled inside the beaker; the pipette's approach and withdrawal follow a natural, continuous hand-like path rather than sliding in a straight mechanical line or floating unsupported; the rotation follows one consistent arc around the beaker's vertical axis; the lighting's brightness and direction never change; there is no visible jitter, warping, or unnatural shift in how near or far any object appears.