Domain: Natural Science — Geology & Geophysics
Target concept: Hitting halite and quartz crystals with a hammer

Video generation prompt: A small hammer gently strikes the cube-shaped halite crystal on the left and the quartz crystal on the right on the workbench.

Evaluation guide:
(i) Target concept: Cleavage vs. fracture differentiation in minerals via mechanical impact.
Minimum mechanism: Ionic lattice (halite) permits preferential bond breakage along crystallographic planes; covalent network (quartz) resists directional splitting and instead yields curved fracture surfaces under stress.
(ii)Storyline: [Frame 0–2] Static wide shot: workbench with halite (left, cubic, translucent white) and quartz (right, irregular/vitreous, translucent gray) in fixed adjacent positions. [Frame 3–5] Hammer enters frame from top-right, approaches halite, makes single contact: immediate visible cleavage (planar separation) occurs. [Frame 6–8] Hammer retracts, moves laterally to quartz, makes single contact: no cleavage; only possible minor chipping or no visible change. [Frame 9–10] Final static frame confirms both crystals retain position, halite fragments remain clustered, quartz unchanged. Perspective: fixed frontal macro view; no occlusion; full visibility of crystal faces and hammer head contact point throughout.

Manual:
Experimental Procedure
1. Place a cube-shaped halite crystal on the left side of a neutral-toned workbench.
2. Place a quartz crystal (irregular or partially faceted, non-cubic) on the right side of the same workbench, adjacent to halite.
3. Using a small geologist’s hammer, gently strike the halite crystal once.
4. Using the same hammer, gently strike the quartz crystal once.
Observation of Experimental Phenomena
- Halite cleaves along smooth, planar, right-angle surfaces, breaking into smaller cubes or rectangular prisms.
- Quartz does not cleave; it remains intact or exhibits conchoidal (curved) fractures or minor chipping.
Summary of Experimental Principles
- Halite (NaCl) has perfect cubic cleavage due to weak ionic bonds along {100} planes.
- Quartz (SiO₂) has no cleavage; its strong covalent network results in conchoidal fracture.

Prompt Grounding rubric:
level_1: None of the three core objects (the hammer, the halite cube, or the quartz crystal) appears in the video; or the objects are not shown on a workbench; or no striking action ever occurs; or left/right placement is never shown or is reversed with no clear indication.
level_2: At least one of the three objects (hammer, halite cube, quartz crystal) appears, but at least two are missing or clearly the wrong object; or the workbench is missing or hard to identify; or the striking action never touches either crystal, or is performed on the wrong object; or halite and quartz are swapped in position (e.g., quartz on the left, halite on the right) instead of matching the prompt.
level_3: All three core objects are present (the hammer, the cube-shaped halite crystal, and the quartz crystal), resting on the same visible workbench; the hammer visibly makes contact with one crystal and then the other; halite sits on the left and quartz on the right, matching the prompt; neither crystal appears twice or jumps to a new location.
level_4: Everything at the 3-point level holds, and additionally: the hammer strikes halite first, then quartz, with a clear visible gap between the two contact events; the hammer stays in frame for both strikes; both crystals stay put on the workbench before, during, and after being struck; nothing blocks the view of either crystal or the hammer's head.
level_5: Everything at the 4-point level holds, and additionally: the hammer only ever contacts the two crystals (no other object is struck); each strike is a single tap rather than repeated tapping; the hammer is held and swung the way a person would naturally hold it (handle toward the person, head square to the crystal face); both crystals keep their original cube-like or faceted shape and stay in place without shifting or spinning during or after being struck.

Scientific and Causal Correctness rubric:
level_1: Halite and quartz respond in exactly the same way to being struck: e.g., both crack apart identically, both stay completely intact, or both crumble into dust; or the quartz crystal shows any degree of clean, planar splitting when struck, from crystal faces merely looking capable of splitting evenly to displaying full cube-like cleavage (since quartz has no cleavage at all, any of these is equally wrong); or halite is shown as opaque and glassy rather than translucent and cubic, or quartz is shown breaking along neat flat planes instead of an irregular curved fracture.
level_2: The two crystals show visibly different responses to being struck, and neither response is impossible on its own, but the difference is weak, ambiguous, or only partly right: e.g., halite shows only a very faint hint of splitting that's hard to confirm as true cleavage, or quartz's break is somewhat rounded but a viewer could still mistake it for a flat plane; the colors and luster of halite (translucent white) and quartz (translucent gray-white, vitreous) are at least roughly correct.
level_3: Halite visibly splits along smooth, flat surfaces or breaks apart into smaller cube-like pieces when struck; quartz either stays intact or shows only minor, irregular chipping with no flat splitting; halite reads as translucent white with a cubic shape, and quartz reads as translucent gray-white with a glassy look and an irregular break; the cleavage-versus-fracture difference between the two is clearly visible.
level_4: Everything at the 3-point level holds, and additionally: halite's split follows flat surfaces that line up with its cubic shape (e.g., parallel faces are visible after the strike); quartz shows no flat splitting anywhere, only an irregular, curved, or grainy break, if it breaks at all; neither crystal's color or texture is swapped with the other's.
level_5: Everything at the 4-point level holds, and additionally: halite shows at least two flat splits meeting at a right angle, visibly confirming its cubic structure; quartz shows zero flat splitting anywhere, only a curved, shell-like fracture surface or no visible break at all; at no point does either crystal's color, shine, or transparency resemble the other's.

Spatiotemporal Consistency rubric:
level_1: Objects appear or disappear partway through the video; either crystal changes position or orientation with no visible motion connecting the two states; the scene's lighting suddenly changes (e.g., a flash, a flicker, or the shadows jumping to a new direction) between frames; the hammer's position changes discontinuously (jumping, warping, or stuttering); the workbench surface visibly deforms or disappears.
level_2: At least one clear flaw is present: the hammer's path from approach to impact is not continuous (e.g., it appears to jump partway through); a crystal shifts sideways or rotates with no apparent cause; the camera's view of the workbench changes (zooms, pans, or tilts) partway through; the direction of the light or shadows changes between the two strikes.
level_3: Both crystals stay in the same position relative to each other and to the workbench throughout; for each strike, the hammer moves continuously from approach to contact to pulling away; neither crystal deforms or breaks apart in a way unrelated to being struck; the light and shadows on the scene look the same before and after each strike; the camera does not pan, tilt, or zoom at any point.
level_4: Everything at the 3-point level holds, and additionally: the hammer's path is smooth and physically believable, with no sudden jump in speed and no hovering before impact; both crystals stay rigid and still except for a brief, visible shake right at the moment of contact; neither crystal's edges flicker or ghost during or between strikes.
level_5: Everything at the 4-point level holds, and additionally: the hammer's handle and head move together in the right proportion as the hammer swings; no part of the image tears, blurs beyond recognition, or duplicates or skips a frame; the surfaces of both crystals reflect the light in the same consistent way across the whole video, with no sudden bright spot or inconsistent glare.