Domain: Engineering — Materials Science & Engineering
Target concept: A compressed chalk block under the press, used to simulate the compaction and fragmentation process.

Video generation prompt: A white chalk block is sandwiched between two flat metal plates in a hydraulic press and is being compressed steadily from above.

Evaluation guide:
(i) Target concept: Brittle fracture of a porous calcium carbonate material under monotonic uniaxial compression.
Minimum mechanism: Chalk must behave as a cohesionless granular solid with negligible ductility; fracture must result solely from compressive stress exceeding tensile strength at internal flaws; no plastic flow, melting, or chemical reaction permitted.
(ii)Storyline: [Frame 0] Static shot: chalk centered between parallel plates, no contact. → [Motion phase] Upper plate moves vertically downward at constant visual pace, maintaining alignment; chalk surface develops visible cracks. → [Contact phase] Upper plate makes full contact; chalk compresses slightly (no visible shortening). → [Fracture phase] Chalk instantly fractures into ≥3 angular fragments, all remaining fully constrained between plates with no ejection or rotation. → [Final frame] All fragments stationary, fully visible, same color and texture as original chalk; plates remain parallel and unmoved post-fracture. Perspective: fixed frontal orthographic view; no occlusion of chalk or plate interfaces at any time.

Manual:
Experimental Procedure
1. Place a dry, intact white chalk block vertically centered between two flat, rigid, metallic plates.
2. Activate hydraulic press to move upper plate steadily downward until full contact with chalk block.
3. Continue steady compression until chalk fractures.
Observation of Experimental Phenomena
- Chalk remains white and solid before contact.
- Surface micro-cracks appear during compression.
- At final stage, chalk fractures into multiple discrete angular fragments, all confined between plates.
Summary of Experimental Principles
- Brittle fracture under uniaxial compressive load.
- Stress concentration at surface flaws initiates cracking.
- Fragmentation reflects low tensile strength and high compressive strength of chalk.

Prompt Grounding rubric:
level_1: No chalk block is visible; no metal plates are visible; no press-like structure connecting the plates is visible; no downward compressive motion occurs; the scene shows nothing related to compacting an object between plates.
level_2: At least one metal plate is visible and a white object is present, but the object does not read as a chalk block (e.g., it looks like an eraser, a candle, or an unidentifiable white cylinder); the plates never approach or touch the object; the upper plate shows no downward motion toward it.
level_3: A white, rectangular chalk block sits centered between two flat metal plates; the upper plate visibly moves straight down toward the stationary lower plate and the chalk; part of the press frame or supporting structure connecting the plates is visible; the chalk block, upper plate, and lower plate are all present and correctly positioned relative to one another.
level_4: Everything at the 3-point level holds, AND the chalk block does not shatter, crumble, or separate into pieces before the upper plate makes full contact with it (fine surface cracks appearing on the chalk while the plate is still approaching, without pieces coming apart, are expected and do not violate this level); the two plates stay parallel to each other throughout the downward motion; no hands, tools, or labels enter the frame during compression.
level_5: Everything at the 4-point level holds, AND the chalk block stays horizontally centered between the plates throughout its approach; the two plates match each other in color, surface finish, and shape; the upper plate's motion is straight down with no visible sideways drift or tilt; every frame keeps the chalk block and both plates fully visible with no cut, blur, or object blocking the view.

Scientific and Causal Correctness rubric:
level_1: The chalk block visibly changes color (e.g., turns gray, yellowish, or translucent) as it is compressed; the chalk bends, flows, or bulges like a soft or pliable material instead of cracking; the plates appear to sink into or merge with the chalk rather than pressing against its surface; the block never separates into pieces at any point.
level_2: The chalk shows brittle behavior, but only fractures well after the plates have made contact and paused, with no cracking visible while the upper plate is still descending; or the chalk crumbles apart before the plates ever touch it; or fragments scatter out beyond the gap between the plates instead of staying within it; or the chalk turns to loose powder with no identifiable angular pieces.
level_3: The chalk block stays white and solid as the upper plate approaches; fine cracks become visible on its surface while the upper plate is still moving down toward it; once the upper plate reaches full contact, the block breaks into several solid, angular fragments (not powder) that remain within the space between the two plates.
level_4: Everything at the 3-point level is true, AND at least three separate fragments are visible after the break; every fragment shows sharp, angular edges rather than rounded or melted-looking surfaces; no fragment stands taller than the original chalk block; none of the fragments or crack sites show a color change from the original white chalk.
level_5: Everything at the 4-point level is true, AND every fragment stays fully between the upper and lower plates, with none poking out above the upper plate or below the lower plate; once the pieces come to rest, none of them rotates or slides on its own afterward; no dust cloud, smoke, or spray of fine particles accompanies the moment of fracture.

Spatiotemporal Consistency rubric:
level_1: The chalk block or a plate jumps to a different position within a single frame instead of moving continuously; the plates change size or shape between frames; the shadow cast by the chalk or plates vanishes and then reappears; the chalk block flickers out of view for one or more frames during compression.
level_2: The upper plate wobbles or tilts inconsistently as it descends instead of moving in a straight line; the chalk block appears to stretch or shrink unnaturally as the plates approach it; objects in the background shift position or change scale; the direction of the shadow on the table changes partway through the compression with no change in the light in the scene.
level_3: The chalk block and both plates keep the same relative positions and orientation to each other as the compression proceeds; the upper plate's downward motion is smooth and continuous with no stutter, freeze-frame, or sudden warp; the light source stays in the same place, so shadows on the table and plates keep the same direction and darkness from start to finish; neither the chalk nor the plates bend or pass through each other in a way solid materials could not.
level_4: Everything at the 3-point level applies, AND the camera viewpoint does not pan, tilt, or zoom at any point; the edges of the plates and the chalk do not shimmer, crawl, or strobe as the plates move; the plate edges and the chalk's outline stay aligned frame to frame with no visible jump or misregistration.
level_5: Everything at the 4-point level applies, AND the depth ordering stays correct throughout: the upper plate visibly stays in front of/above the top of the chalk and the lower plate stays beneath its bottom, with no moment where this layering reverses; any motion blur on the descending plate matches its visible speed rather than appearing on a slow or stationary object; no doubled outline, ghost trail, or color fringing appears along the edges of the chalk or plates at any point.