Domain: Natural Science — Physics
Target concept: Seismic Simulation

Video generation prompt: Two transparent plastic bottles are placed side by side on a table. A metal block is placed inside the bottle on the left. A metal block of the same size is suspended inside the bottle on the right by a string attached to the bottle cap. The table is horizontally shaken, and the vibration states of the two plastic bottles are observed.

Evaluation guide:
(i) Target concept: Inertial decoupling in seismic response, differential motion between constrained and suspended masses under horizontal excitation.
Minimum mechanism: Suspension must allow free pendular degrees of freedom for the block hanging in the right bottle; direct contact and friction between the left-bottle block and its bottle's inner surface must resist relative sliding; horizontal shaking must be strong enough to set the freely suspended right-bottle block swinging (since only a small force is needed to start a pendulum moving) while remaining too weak to overcome the friction holding the left-bottle block against its bottle, so that block continues moving rigidly together with its bottle throughout.
(ii)Storyline: [Frame 0–1] Static setup: two bottles side-by-side, left with settled block, right with hanging block, string taut or gently vertical, cap sealed. [Frame 2–3] Shaking initiates: table moves horizontally → left bottle + block accelerate together; right bottle accelerates but suspended block lags due to inertia → visible string angle change. [Frame 4–6] Peak differential: suspended block reaches max swing amplitude while bottle reverses direction; contained block remains flush with bottle interior. [Frame 7–9] Shaking subsides: suspended block continues oscillating; contained block stops immediately with bottle. Perspective: fixed frontal view, full bottles in frame, no occlusion, consistent lighting, no camera motion.

Manual:
Experimental Procedure
1. Place two identical transparent plastic bottles side-by-side on a stable horizontal table.
2. Insert a metal block into the left bottle so it rests on the bottom.
3. Suspend an identical metal block inside the right bottle using a string tied securely to the bottle cap.
4. Horizontally shake the table surface steadily for ~3 seconds.
Observation of Experimental Phenomena
The metal block in the left bottle moves rigidly with the bottle. The suspended metal block in the right bottle swings or oscillates independently, showing delayed or out-of-phase motion relative to its bottle.
Summary of Experimental Principles
This demonstrates inertial decoupling: a freely suspended mass resists acceleration due to inertia, exhibiting relative motion against its container, while a constrained mass moves with the container — modeling how building foundations (fixed) vs. suspended ceilings (isolated) respond differently in earthquakes.

Prompt Grounding rubric:
level_1: No two transparent plastic bottles are placed side by side; no metal block sits inside the left bottle; no metal block hangs from a string tied to the right bottle's cap; the table shows no horizontal shaking motion; none of the required setup objects or actions from the prompt appear.
level_2: Only one bottle appears, or a bottle appears with no metal block visible inside it, or a string appears but is not tied to a bottle cap, or the two bottles are not placed next to each other on the table; at least one core structural element (the bottle pair, the left block's placement, or the right block-and-string assembly) is missing even though some individual props appear somewhere in frame.
level_3: Two transparent plastic bottles stand side by side on the table; a metal block sits inside the left bottle; inside the right bottle a metal block hangs from a string tied to the underside of the bottle cap; the table shows a repeated back-and-forth horizontal shaking motion; all objects and attachments named in the prompt are present and correctly placed, though minor setup details (exact string length, precise block sizing) may be imperfect.
level_4: Everything required at Level 3 holds, and in addition the right-bottle string keeps its block clearly off the bottle's inner walls and base at the start of the clip (a genuinely suspended block, not one resting on the bottom), the left-bottle block is shown sitting directly on the bottle's interior surface (a genuinely resting block, not itself hung from anything), and the two bottles stay in their initial positions on the table relative to each other.
level_5: Everything required at Level 4 holds, and in addition the two bottles stay at the same height and orientation on the table (neither leaning nor shifting toward or away from the camera), and the cap-to-string-to-block attachment in the right bottle and the block-on-bottle-floor placement in the left bottle both stay visually unambiguous: a viewer could identify which bottle holds the suspended block and which holds the resting block from the setup alone, with no confusion about attachment or containment.

Scientific and Causal Correctness rubric:
level_1: No scientifically meaningful contrast between the two blocks: both blocks move identically with their bottles, the right-bottle block never swings independently of its bottle, or the left-bottle block appears to slide loosely inside its bottle; the shake produces no differential behavior between a constrained mass and a freely suspended one.
level_2: A difference exists but violates inertial-decoupling physics: the right-bottle block stays perfectly still on its string while its bottle shakes violently (a real pendulum could not stay motionless under horizontal excitation), or the left-bottle block visibly separates from the bottle's inner surface and floats freely, or the dominant block motion is vertical bouncing rather than following the horizontal shake direction.
level_3: Both blocks move during the shaking: the left-bottle block moves together with its bottle with no visible sliding relative to the bottle's interior, and the right-bottle block shows some independent motion relative to its own bottle (swinging or lagging on its string); however this contrast appears only briefly or inconsistently across the shake rather than being sustained.
level_4: Everything at Level 3 holds, and in addition the right-bottle block's swinging motion is consistently out of step with its bottle's own back-and-forth movement throughout the shake (it visibly lags or leads rather than tracking the bottle exactly), the left-bottle block never separates from the bottle's inner wall or base at any point, and no unphysical event interrupts the contrast (the string does not detach, the swinging block does not strike the cap, neither bottle warps).
level_5: Everything at Level 4 holds, and in addition the right-bottle block swings with a smooth, pendulum-like motion whose timing is clearly out of phase with the bottle's own motion (a visible lag or lead in amplitude and timing), the left-bottle block shows no perceptible relative motion against its bottle's interior at any frame, and the contrast between the two is unambiguous: no moment of string slack, odd camera angle, or unusual block placement could make a viewer doubt which block is truly suspended and which is truly constrained.

Spatiotemporal Consistency rubric:
level_1: Severe breakdown of physical continuity: one or both bottles instantly appear in a different spot on the table rather than sliding there through the shake; the metal block or the string vanishes from view and reappears later; the bottle cap detaches from the bottle and reattaches unnaturally partway through the shake; the table's shaking motion is frozen or stutters like a slideshow with no smooth in-between frames; the room's lighting switches abruptly partway through the shake for no in-scene reason.
level_2: A single clear break, less severe than Level 1: the right bottle's string visibly stretches, compresses, or changes length between frames without the block's swing explaining it; either bottle rotates or tilts noticeably without any physical cause; the bottle cap appears to move independently of the bottle body it's sealed to; the left-bottle block passes through the bottle's wall or base rather than staying inside it; the cast shadows on the table jump to a different direction from one frame to the next with no reason in the scene; the shaking starts or stops instantly at full speed with no ramp-up or ramp-down.
level_3: The two bottles stay in the same side-by-side spot on the table for the whole clip, the string in the right bottle stays connected between the cap and its block, and both metal blocks stay fully inside their own bottle's outline throughout; the table's shaking runs continuously and horizontally without freezing or skipping; small imperfections are acceptable, such as the string's lower end wobbling slightly frame to frame or the cap's shadow shifting a little as the bottle rocks.
level_4: Everything at Level 3 holds, and in addition neither bottle bulges, flattens, or otherwise changes shape as it shakes: both keep a consistent cylindrical outline; the direction and softness of the room's cast shadows on the table stay the same from the first frame to the last, with no sudden shadow jump or flicker; the block and bottle motions look like smooth, physically continuous shaking rather than sudden jumps in position or an instant reversal of direction.
level_5: Everything at Level 4 holds, and in addition the shake plays out as one continuous, fluid motion with no repeated or skipped frames; the containment relationships stay visually clear at every moment (the left block always reads as inside its bottle, the right block always reads as hanging from its string tied to the cap), and the bottles' transparent walls stay clear enough that a viewer can always tell where each block sits relative to its bottle, with no moment where the block or string becomes indistinguishable from the bottle body.