Domain: Natural Science — Physics
Target concept: Egg dropped onto a hard surface vs. dropped onto a pillow

Video generation prompt: Split-screen video: Two identical raw eggs are dropped simultaneously from the same height; the one on the left lands on a hard table, and the one on the right lands on a thick pillow.

Evaluation guide:
(i) Target concept: Impulse-momentum theorem (FΔt = mΔv) applied to impact survivability.
Minimum mechanism: Egg shell has fixed fracture threshold; identical initial momentum (same mass, same drop height → same velocity at impact); difference in outcome arises solely from differential impulse duration due to surface compliance; no external forces, no pre-existing damage, no rotational effects dominating.
(ii)Storyline: [Frame 0] Two identical eggs suspended motionless at equal height, aligned vertically over distinct surfaces (left: rigid table; right: compressible pillow); [Frames 1–N] Both eggs accelerate downward along parallel vertical paths with identical kinematic profile; [Critical Frame] Simultaneous first contact: table-side egg contacts rigid surface → immediate shell failure; pillow-side egg contacts yielding surface → pillow deforms while shell remains geometrically and structurally intact; [Post-contact] Table-side egg fragments and spreads liquid; pillow-side egg rests statically on depressed pillow surface with zero shell breach or leakage; all under fixed viewpoint, consistent lighting, and continuous motion.

Manual:
Experimental Procedure
1. Position two identical raw white-shell eggs at same height above two surfaces: left above a rigid, flat hard table; right above a thick, soft pillow.
2. Release both eggs simultaneously.
3. Record full descent and impact in split-screen view (left: table; right: pillow).
Observation of Experimental Phenomena
- Egg on hard table: shell fractures instantly on contact; internal liquid disperses onto surface.
- Egg on thick pillow: shell remains fully intact; no liquid leakage; pillow deforms visibly to absorb impact.
Summary of Experimental Principles
Impact force is inversely related to time over which momentum changes: the pillow increases stopping time, reducing peak force below shell’s fracture threshold; the table provides negligible stopping time, resulting in force exceeding shell strength.

Prompt Grounding rubric:
level_1: No split-screen composition is shown, or fewer than two eggs appear, or the two eggs are not both raw, white-shell eggs, or one or both landing surfaces (a hard table on the left, a thick pillow on the right) are missing or wrong, or the two eggs are not released from the same visible height at the same moment.
level_2: A split-screen is present but broken in an obvious way: the pillow-side egg and the table-side egg are swapped left-to-right from the intended layout, or one egg is already resting on its surface at the start instead of at drop height, or the two surfaces look interchangeable (e.g., both rigid or both cushioned), or the two eggs visibly differ from each other in shell color or size before the drop.
level_3: The split-screen shows the hard table on the left and the thick pillow on the right; two visually identical raw eggs are shown positioned at the same height above their respective surfaces; both eggs are released at the same moment; the table reads clearly as rigid and flat while the pillow reads clearly as soft and textured; neither egg nor surface is hidden behind another object during setup.
level_4: Everything at the 3-point level holds, and in addition: each egg stays fully in frame with its shell outline clear for the whole fall, so it is obvious the shell is still whole right up until impact; the table's edge and the pillow's shape stay fixed and recognizable from release through landing; each egg is centered over its own surface at the moment of contact rather than drifting toward an edge.
level_5: Everything at the 4-point level holds, and in addition: the two eggs' release is visibly simultaneous, with no lag between the two sides; both eggs begin the fall in the same pointed-end-up orientation with no spin; there is exactly one egg on each side at all times, with no duplicate or ghost image of either egg; the vertical line dividing the two halves of the screen stays straight and in the same place for the whole clip.

Scientific and Causal Correctness rubric:
level_1: There is no visible difference in outcome between the two eggs; or neither egg breaks; or both eggs shatter completely; or the pillow-side egg ends up just as ruptured as the table-side egg; or the table-side egg somehow survives fully intact; or the outcome contradicts basic mechanics, e.g., the pillow-side egg bounces off the pillow, or the table-side egg sinks into the tabletop.
level_2: The two eggs end up different, but the difference points the wrong way or breaks physics: the pillow-side egg cracks worse than the table-side egg; or the table-side egg visibly squashes before it even touches the table; or the pillow shows no dent or give under the egg's weight; or shell fragments appear on the pillow while the table-side egg stays whole. Any of these reverses the expected relationship between stopping distance and impact force.
level_3: The table-side egg clearly breaks: its shell splits open and yolk/white spread visibly across the tabletop. The pillow-side egg shows no break at all: its shell stays whole, with no leaking and no visible crack lines. The pillow visibly sinks and cups around the egg at the moment of contact, showing that it is absorbing the impact.
level_4: Everything at the 3-point level holds, and in addition: the pillow-side egg shows no leaking and no hairline cracking at any point in the clip; the table-side egg only breaks and spills its contents (it does not bounce, roll away, or strike a second time); the pillow's dent grows and settles smoothly rather than snapping flat or sinking implausibly deep.
level_5: Everything at the 4-point level holds, and in addition: the table-side egg stays whole right up until the instant of contact, without cracking early in mid-air; the pillow-side egg's shell keeps its round, unbroken shape through the fall, the landing, and the moment it comes to rest, with no flattening or dimpling of the shell itself; the pillow's dent eases back partway once the egg stops moving, rather than staying frozen at its deepest, most compressed shape.

Spatiotemporal Consistency rubric:
level_1: A severe break in continuity: an egg appears already resting on its surface with no visible fall shown; an egg vanishes in mid-air and reappears already landed; the scene's overall brightness or the direction of the light source jumps between consecutive frames with no visible cause; the table or the pillow changes shape or tilts on its own; the vertical divider between the two halves of the screen bends, shifts, or disappears.
level_2: The fall itself breaks down: one egg's downward path freezes for several frames and then jumps ahead; one egg's motion blurs so heavily its path can't be followed; the tabletop's surface or the pillow's fabric changes texture partway through the clip; the screen divider visibly shakes or pulses; a shadow cast by an egg swaps to the opposite side of that egg with no matching change in a light source.
level_3: Each egg falls in a single, unbroken vertical line toward the center of its own surface; neither egg disappears partway through the fall and reappears elsewhere; the scene's brightness and the direction of the light stay the same from the first frame to the last; the screen divider stays straight and sharp throughout; the fall and landing play out with no freeze-frames or repeated frames; neither egg nor surface bends or warps out of shape.
level_4: Everything at the 3-point level holds, and in addition: each egg's fall speeds up smoothly the way a dropped object should, with no floating or sudden lurch; the pillow's dent forms in a smooth, gradual curve rather than popping instantly into its final shape; the instant each egg meets its surface is a single clear moment, with no appearance of the egg sinking into or passing through the surface; the camera itself does not pan, zoom, or shift during the clip.
level_5: Everything at the 4-point level holds, and in addition: the motion of both falling eggs looks smooth and natural, with no stutter or repeated frames; the outline of each egg against its surface (white shell on the tabletop, white shell against the pillow fabric) stays crisp and easy to follow rather than flickering or breaking up; the tabletop's wood grain and the pillow's fabric weave stay recognizable rather than smearing into a blur during the motion; no frame anywhere in the clip is dropped or duplicated.