Domain: Humanities and Social Sciences — Architecture & Urban Planning
Target concept: Snow or granular materials slide off steep roofs more frequently than they do from gentle roofs.

Video generation prompt: Two model roofs are placed side by side, with the left one having a gentler slope and the right one a steeper slope, both constructed from the same material. Subsequently, the same white granular material is spread onto both roofs. The camera focuses on the process of the white granular material sliding down the surfaces of the two roofs.

Evaluation guide:
(i) Target concept: Gravitational resolution along inclined planes determines sliding propensity of dry granular materials.
Minimum mechanism: Granular material must behave as a cohesionless solid aggregate subject to static/kinetic friction thresholds; steeper incline increases downslope force component beyond threshold earlier and more completely than gentler incline; no adhesive, electrostatic, or fluid effects dominate.
(ii)Storyline: Frame 0–2s: Static shot reveals two side-by-side roofs (left gentler, right steeper), both fully covered with white granular material. Frame 2–6s: Sliding initiates on steeper roof first or simultaneously, progressing continuously downward; gentler roof shows delayed onset and/or slower progression with visible residual accumulation. Frame 6–10s: Steeper roof is nearly or fully cleared of material; gentler roof retains substantial unmoved material near apex/mid-slope; camera remains fixed, lighting stable, no extraneous motion or occlusion.

Manual:
Experimental Procedure
1. Place two identical model roofs side-by-side in fixed frame: left roof with gentle slope, right roof with steeper slope.
2. Spread same white granular material evenly across both roof surfaces.
3. Record continuous 10-second video from fixed frontal viewpoint showing both roofs.
Observation of Experimental Phenomena
White granular material slides farther and faster down the steeper roof, while more material remains on the gentler roof; sliding motion is continuous and gravity-aligned on both surfaces.
Summary of Experimental Principles
Snow or granular materials slide off steep roofs more frequently than they do from gentle roofs due to increased gravitational component parallel to the surface.

Prompt Grounding rubric:
level_1: No two model roofs are visible, or only one roof appears, or the roofs are not placed side by side, or no white granular material appears on either roof, or the camera never shows both roofs together in one shot.
level_2: Two roofs sit side by side, but at least one of the following fails: both are visibly built from the same material (matching color/texture), granular material appears on both roofs rather than just one, or the camera holds both roofs continuously in frame without cutting or reframing between them.
level_3: Two roofs sit side by side in one continuous, fixed shot; both are visibly the same construction material; white granular material covers both roof surfaces at the outset; the left roof reads as visibly shallower and the right as visibly steeper, matching the prompt's layout; no cut or reframe occurs.
level_4: In addition, the white granular material begins visibly sliding down the surface of both roofs at some point during the video; no unrelated objects (hands, tools, labels, extra roofs) enter the shot at any point; the granular material stays visibly white and granular, not recolored or changed in texture, for the whole video; the two roofs stay rigidly in their original positions and orientations without tilting, rotating, or drifting.
level_5: The slope contrast between the two roofs (left shallower, right steeper) is unambiguous in every frame, with neither roof ever appearing to match or exceed the other's steepness; neither roof changes shape or duplicates; the granular material remains recognizable as the same white granular substance from the first frame to the last as it slides down both roof surfaces.

Scientific and Causal Correctness rubric:
level_1: The granular material never slides on either roof, or it slides the same amount and speed on both roofs regardless of slope, or more material ends up sliding off the gentler (left) roof than the steeper (right) one, or the material disappears, changes color, or turns into a cloud or liquid instead of sliding as a granular mass.
level_2: Material slides on at least one roof, but something contradicts slope-driven physics: material slides on the steeper roof yet the gentler roof somehow ends up with no residual material at all, as if it had slid off just as completely; or material appears to move upward or sideways off a roof edge instead of down-slope; or the gentler roof finishes clearing its material before the steeper roof shows any movement at all.
level_3: Material slides down-slope on both roofs; by the end of the clip, visibly more material remains behind on the gentler (left) roof than on the steeper (right) roof; nothing moves upward, hovers, or spills sideways; the material stays white and granular, with no melting, dissolving, or turning to dust.
level_4: The steeper (right) roof clears a visibly larger share of its surface, or clears it in visibly less time, than the gentler (left) roof; the gentler roof retains a noticeably larger residual patch, or a different distribution of material, at the end than the steeper roof; at no point does the steeper roof finish its slide before the gentler roof has even begun.
level_5: Either the steeper roof's material starts moving first, or at the same time as the gentler roof's, and its slide reads as an unbroken, continuous descent, or its slide is clearly faster and more complete than the gentler roof's throughout — and in either case the gentler roof keeps a clear, stable patch of unmoved material near its peak or middle by the end; no frame shows material behaving as though the gentler roof were the one shedding material faster.

Spatiotemporal Consistency rubric:
level_1: Either roof disappears and reappears in a different spot or orientation, granular material jumps across open space without visibly traveling the path in between, the lighting on the scene changes abruptly with no cause (e.g., the sun's position swaps sides), one of the roof structures visibly bends or fractures, or the camera view resets or jumps to a different framing mid-clip.
level_2: Material vanishes at one point on a roof and reappears lower down without visibly traveling the distance between; a roof edge or surface flickers or renders inconsistently between frames; a shadow cast by the material or roofs jumps to a new position with no matching change in the scene; or the overall lighting brightness or direction shifts noticeably with no visible cause.
level_3: Neither roof teleports, warps, or breaks apart; material moves down each roof's surface without gaps or jumps in its path; both roofs stay rigid and stationary; the camera holds its position and angle throughout; all visible motion, whether the material sliding or any camera drift, looks smooth and continuous rather than jumpy.
level_4: The granular material's apparent size and texture stay consistent as it slides, never suddenly looking coarser, finer, or blocky; no frame shows the material or roof edges tearing, ghosting, or blurring badly enough to lose track of their shapes; the roof surfaces' texture stays intact and unbroken under the moving material.
level_5: Every frame keeps the material looking like a coherent mass sliding together, not scattering into disconnected specks or clumping unnaturally; neither roof's geometry stretches, shears, or warps at any point; the roof edges and the material's boundary line up consistently from one frame to the next; the framing shows no drift, pan, tilt, or zoom, consistent with a genuinely static camera.