Domain: Natural Science — Chemistry
Target concept: Take a small amount of anhydrous copper sulfate powder, add one drop of water, and observe that the powder immediately changes from white to blue without any intermediate color transition.

Video generation prompt: Place a small pile of white anhydrous copper(II) sulfate powder on a clean petri dish. Add exactly one drop of water onto the powder using a pipette. Fix the camera position and take a close-up shot of the powder, pipette, and reaction area. The procedure is simple and continuous.

Evaluation guide:
(i) Target concept: Instantaneous, binary, stoichiometric hydration-induced color change in anhydrous CuSO₄.
Minimum mechanism: Water must make direct molecular contact with CuSO₄ crystals to trigger immediate coordination bond formation with Cu²⁺ ions, resulting in a discrete electronic transition that manifests as a sharp, saturated blue hue: no kinetic intermediates, no partial hydration states visible macroscopically.
(ii)Storyline: [Frame 0] Static close-up: clean petri dish with isolated white powder pile; pipette tip stationary above center. [Frame 1–N] Pipette tip descends smoothly; single water drop detaches and falls vertically with spherical integrity. [Contact Frame] Drop fully contacts powder surface: no splatter, no rebound. [Immediate Next Frame] Contacted region transforms *exclusively* and *completely* from white to vivid blue: no hue gradient, no temporal lag, no mixed pixels. [Sustained Frame] Blue remains stable, uniform, and saturated for remainder: no fading, no spreading, no desaturation. Perspective: fixed frontal close-up; visibility: all critical elements (powder surface, drop, contact interface) remain in sharp focus and unoccluded throughout.

Manual:
Experimental Procedure
1. Place a small, distinct pile of white anhydrous copper(II) sulfate powder on a clean, flat petri dish.
2. Hold a pipette vertically with tip centered directly above the powder pile.
3. Release exactly one spherical water drop from the pipette tip so it falls and makes full-surface contact with the powder.
4. Maintain fixed close-up camera framing throughout.
Observation of Experimental Phenomena
The white powder instantly and completely transforms to vivid blue at the exact location of water contact, with no intermediate colors, no delay, and no residual white within the contacted region.
Summary of Experimental Principles
Anhydrous copper(II) sulfate (CuSO₄) is white; upon hydration, it forms copper(II) sulfate pentahydrate (CuSO₄·5H₂O), which is characteristically deep blue—a rapid, stoichiometric, and visually binary color transition.

Prompt Grounding rubric:
level_1: No petri dish is visible, no white powder is present, no pipette appears, no water drop is shown, and there is no close-up framing of the reaction area; none of the required elements are shown.
level_2: The petri dish is present but empty or holds the wrong material; a pipette is visible but not positioned near the powder; a water drop is missing or looks detached from the pipette tip with no visible link between them; or the shot never frames the powder and pipette tip together.
level_3: The petri dish, the white powder pile, the pipette held above it, and a visible water drop (in transit or touching the powder) are all in the same shot; the camera holds a fixed close-up of the powder-pipette area, but the powder doesn't look clearly white, the pipette never actually appears to release the drop (it stays suspended without touching), or something else (labels, a hand, another object) overlaps the powder pile.
level_4: The petri dish, white powder pile, pipette, and single water drop are all present and clearly identifiable by shape; the pipette tip sits directly above the powder pile; the drop is released and reaches the powder; the camera stays fixed in a close-up framing throughout with nothing extraneous entering the shot, but the powder pile looks a little blurred or partly obscured, the pipette is slightly off-center over the pile though still above it, or the drop is a bit out of focus right as it lands.
level_5: The petri dish is clean and flat, the white powder forms one distinct pile with no mixing-in of other material, the pipette is held straight with its tip centered above the pile, the water drop stays clearly visible and roughly round throughout its fall and makes unambiguous contact with the powder's surface, and the camera stays completely fixed on a close-up of the dish, powder, pipette tip, and drop with no blur, no cropping, and no shift in perspective.

Scientific and Causal Correctness rubric:
level_1: No color change occurs at all; the powder stays white throughout; or it turns a non-blue color (green, gray, purple); or blue appears before the water drop actually touches the powder; or the change happens gradually over more than a second with visibly intermediate shades (pale blue, turquoise) rather than a sharp jump.
level_2: The powder turns blue, but unevenly: patches of blue and white persist side by side without blending, or blue appears only at the edges of the wetted area while the center stays white, or there's a noticeable pause between contact and the color change, or the blue fades back within the video.
level_3: The powder changes from white to blue right where the water touches it, and the resulting blue looks fairly uniform across that area with no visibly separate intermediate shades in between, but the starting white looks slightly off (cream or yellowish) instead of clean white, the final blue looks washed-out or grayish rather than vivid, or a sizeable rim of the wetted area stays clearly white.
level_4: The powder starts a clean white; the moment the drop makes contact, the wetted area turns fully blue with no visible in-between shade and no noticeable delay, and essentially no white is left showing within that wetted area, but a thin halo of blue slightly bleeds into the surrounding dry powder beyond where the water actually spread, or the boundary between blue and white looks a little soft rather than crisp.
level_5: The powder is unmistakably white before contact, the drop makes clean contact with the surface, and right at that moment the wetted region turns completely and vividly blue with no in-between shade, no white left showing within it, no color bleeding past the wetted boundary, no fading, and no noticeable delay between contact and the full color change.

Spatiotemporal Consistency rubric:
level_1: The pipette appears already in position mid-air with no entry into frame, or the powder is already blue at the very first frame; the lighting jumps to a different brightness or direction mid-sequence; the petri dish or powder flickers, disappears, or reappears; the water drop vanishes and reappears; or the shot cuts to a different framing.
level_2: The pipette moves erratically (jerky oscillation, sudden lurch); the water drop moves unnaturally (drifts sideways, speeds up unrealistically, or deforms asymmetrically while falling); the powder pile shifts position with no visible cause; the lighting changes brightness or direction during the contact moment; or background elements visibly warp or distort.
level_3: The pipette descends smoothly and continuously toward the powder; the water drop falls with a consistent, roughly spherical shape until contact; the powder pile stays still; the lighting stays steady, but a small flaw appears, such as slight wobble in the pipette's descent, minor asymmetry in the drop's shape at the moment of impact, or a highlight on the petri dish shifting slightly across the video.
level_4: The pipette moves straight down in one smooth, continuous motion; the water drop keeps a rounded shape during its fall and lands without breaking apart or bouncing back; the powder pile stays undisturbed in position and shape; the lighting stays even and stable throughout; the only imperfection is something minor and non-core, such as a barely visible tremor in the powder right at impact, or a faint, brief brightness change somewhere in the shot that doesn't affect judging the color change.
level_5: The pipette's downward path looks essentially straight and steady; the water drop keeps a clean rounded shape through its entire fall and landing with no visible bounce or splash; the powder pile shows no visible shifting or disturbance; the petri dish stays visually stable with no warping; the lighting stays uniform throughout with no flicker or shifting highlight anywhere in the frame.