Domain: Humanities and Social Sciences — Arts
Target concept: Mix gray paint into a puddle of bright red paint

Video generation prompt: On a white palette, a pool of vivid red pigment is placed side by side with a pool of neutral gray pigment. A brush adds an equal amount of gray pigment to the red pigment and rotates to mix them thoroughly.

Evaluation guide:
(i) Target concept: Subtractive color mixing via pigment dilution and neutralization.
Minimum mechanism: Gray pigment must be physically transferred and mechanically blended into red pigment matrix; resulting hue must be perceptually intermediate and achromatically influenced, not merely darkened or shifted along hue circle.
(ii)Storyline: [Frame 0–2] White palette enters view; red and gray pools appear simultaneously, side-by-side, stable and distinct. [Frame 3–4] Brush approaches and contacts gray pool; visible loading (gray material adheres uniformly to bristles). [Frame 5–6] Brush lifts and traverses to red pool; no pigment loss en route. [Frame 7–8] Brush contacts red pool surface and initiates continuous rotational motion inside boundary. [Frame 9–10] Red pool visibly homogenizes into uniform neutralized tone; original red chroma is suppressed; gray contribution is fully integrated. Perspective: Fixed frontal, eye-level shot; entire palette and both pools remain fully visible at all times; brush never occludes full view of mixing zone.

Manual:
Experimental Procedure
1. Place a pool of vivid red pigment and a pool of neutral gray pigment side-by-side on a white palette.
2. Dip a brush into the gray pigment pool until visibly loaded.
3. Transfer the brush to the red pigment pool and rotate it thoroughly inside to mix.
Observation of Experimental Phenomena
The vivid red pigment pool transforms into a uniform, desaturated, neutralized red-gray hybrid tone; the original red and gray pools cease to exist as separate entities; no unmixed streaks or zones remain.
Summary of Experimental Principles
Mixing neutral gray (an achromatic color) into vivid red (a chromatic color) reduces chroma and value, producing a muted, lower-intensity red-gray tone — demonstrating subtractive color mixing principles in pigment-based media.

Prompt Grounding rubric:
level_1: No white palette visible; no vivid red pigment pool present; no neutral gray pigment pool present; no brush visible; no mixing action shown.
level_2: The white palette is present, but either the red pigment pool or the gray pigment pool is missing; a brush is present but never contacts either pool; no mixing motion occurs.
level_3: White palette, red pigment pool, gray pigment pool, and brush are all present, with the two pools placed side-by-side; the brush contacts the gray pool and visibly picks up gray pigment, then moves to and touches the surface of the red pool, but stops there with no rotation, stirring, or blending motion, so the red pool's color remains visibly unchanged.
level_4: All objects present and correctly positioned: white palette, side-by-side red and gray pigment pools, brush; the brush visibly picks up gray pigment from the gray pool, transports it to the red pool, makes contact, and rotates inside the red pool, but the rotation is discontinuous or incomplete, so no clear color gradient or uniform blended tone emerges during the motion.
level_5: All objects present and correctly positioned: white palette, side-by-side red and gray pigment pools, brush; the brush visibly loads gray pigment, transports it to the red pool, makes clear contact, and rotates continuously and fully inside the red pool, producing a single unified mixed pool that replaces the original red pool while staying within the same location on the palette.

Scientific and Causal Correctness rubric:
level_1: No color change occurs; red pool remains unchanged; gray pool remains unchanged; no causal link between brush action and color state observed.
level_2: Red pool changes to a non-gray-influenced hue (e.g., orange, pink, brown) or becomes desaturated without gray input; gray pigment pool disappears without transfer; mixing action produces no discernible effect on red pool color.
level_3: Red pool and gray pool are both present and distinct; brush contacts gray pool and then red pool; red pool shows partial or localized color shift (e.g., gray streaks, mottled patches, or edge darkening), but overall red pool retains dominant red identity and no uniform mixed color emerges.
level_4: Brush visibly transfers gray pigment to red pool; red pool undergoes progressive color transition from vivid red to a less saturated, darker red or muted maroon during rotation; final state is a uniform, homogeneous pool with no residual red-only or gray-only zones, but the final color is not a neutralized tone (e.g., appears too warm, too cool, or retains chromatic bias inconsistent with equal gray + red mixture).
level_5: Brush transfers gray pigment to red pool; red pool undergoes continuous, coherent color transition from vivid red → progressively desaturated/darker red → final uniform neutralized tone (i.e., a distinctly less chromatic, lower-intensity red-gray hybrid, visually intermediate between pure red and pure gray, with no residual chromatic dominance or unmixed regions).

Spatiotemporal Consistency rubric:
level_1: The white palette is missing from one or more frames or is replaced by a different background between shots; the red or gray pigment pool jumps to a different position or size between frames; the brush vanishes mid-stroke or reappears in a different pose; the overall lighting flips between clearly different setups from one frame to the next; a pigment pool's edge distorts into jagged, non-liquid shapes.
level_2: Palette remains fixed but exhibits severe warping or perspective instability; one pigment pool shrinks/grows disproportionately without cause; brush motion contains visible jumps or frame drops; rotation lacks continuity (e.g., starts/stops without deceleration/acceleration cues); pigment surface fails to reflect consistent light direction.
level_3: Palette remains fixed and planar; both pigment pools maintain stable positions and boundaries; brush moves continuously from gray pool to red pool; rotation occurs inside red pool; minor motion artifacts exist (e.g., slight jitter in brush tip, brief occlusion of pigment surface by brush, momentary loss of pigment sheen), but no violation of object permanence or spatial coherence.
level_4: Palette, pools, and brush maintain fixed spatial relationships throughout; all motion is smooth and physically plausible (no floating, no acceleration violations); pigment surfaces retain consistent wet appearance and specular response; no abrupt lighting shifts, no object clipping, no temporal skips, but one minor inconsistency exists (e.g., brush briefly loses pigment adherence during transit, or rotation halts briefly before resuming).
level_5: Palette remains rigidly fixed in frame; red and gray pools retain identical size, shape, and relative side-by-side positioning from start to end; brush maintains full visibility, consistent scale, and uninterrupted motion path from gray pool → transit → red pool contact → full in-pool rotation; pigment surfaces exhibit continuous wet texture, consistent specular highlights, and no visible discontinuities in motion, lighting, or structure.