Domain: Natural Science — Atmospheric Science
Target concept: By steam condensation and external pressure flattening of aluminum cans

Video generation prompt: Heat a small amount of water in an open aluminum soda can until steam is released, then quickly invert the hot can and place the mouth downward into a shallow bowl of cold water.

Evaluation guide:
(i) Target concept: Atmospheric pressure differential driving mechanical collapse via rapid vapor condensation.
Minimum mechanism: (1) Can must be heated with water to generate saturated steam, (2) Steam must be trapped momentarily upon inversion, (3) Mouth must seal against cold water to prevent air inflow and enable conductive cooling of interior vapor, (4) Condensation must occur faster than air leakage, creating net pressure deficit.
(ii)Storyline: Phase 1 (Pre-contact): Can upright, mouth open, steam visibly rising, which confirms internal vapor saturation. Phase 2 (Transition): Can lifted, rotated to inverted orientation, which establishes mouth-down trajectory with no tilt. Phase 3 (Contact): Mouth meets water surface: seal forms, steam halts instantly, no bubble release. Phase 4 (Collapse onset): Within same shot, top of can buckles inward, with no delay, no external force. Phase 5 (Collapse propagation): Deformation travels downward continuously: preserves structural integrity until failure, no rebound. Visibility constraint: All phases must be visible in fixed frontal/slightly angled view; no occlusion of can mouth or water interface; lighting must reveal steam, surface contact, and buckling details.

Manual:
Experimental Procedure
1. Fill aluminum soda can with ~10 mL water. Heat on stove until vigorous steam escapes from open mouth.
2. Using tongs, quickly lift can, invert it 180°, and place mouth-down into shallow bowl of cold water.
Observation of Experimental Phenomena
Can violently collapses inward within 1 second of mouth submersion; collapse is asymmetric, starts at top, and proceeds downward; steam ceases immediately upon water contact.
Summary of Experimental Principles
Steam inside hot can condenses rapidly when cooled by cold water, reducing internal pressure; external atmospheric pressure exceeds internal pressure, crushing the thin aluminum can.

Prompt Grounding rubric:
level_1: No aluminum soda can appears anywhere in the shot; no bowl of water is shown; nothing depicts heating or steam; the can is never inverted or placed mouth-down into any liquid. The scene bears no resemblance to the heat-can/cold-water setup described in the prompt.
level_2: Only a piece of the setup is present: for example, an aluminum can appears but is never heated (no steam is ever seen), or a bowl appears but holds no visible liquid (it is dry, or the liquid is not water), or the can is shown but is never turned upside down and lowered into anything.
level_3: An aluminum can, a bowl holding visible liquid, and an inverting motion of the can are all present; a plume of vapor is visible rising from the can's mouth before it is turned over; the can is then flipped mouth-down and moved toward the bowl.
level_4: All of the above, and the actions occur in the right order: the can sits upright with visible steam escaping while on a heat source, it is then lifted and rotated until fully mouth-down, then lowered until its mouth touches the water's surface, and it ends up standing upright in the bowl with its mouth submerged, not tipped onto its side, not resting on its rim, and not floating.
level_5: All of the above, and the setup is shown with no ambiguity: the can is a standard cylindrical aluminum soda can (silver metal, intact rim, open mouth, no cap), steam is clearly visible rising from the mouth before the flip, the can completes a full turn from upright to fully inverted, and it comes to rest mouth-down and completely submerged in a shallow bowl of visibly cold water (for example, beads of condensation on the outside of the bowl) without re-emerging or shifting position for the rest of the shot.

Scientific and Causal Correctness rubric:
level_1: No collapse happens at all, or the can changes shape for reasons unconnected to the demonstration (for instance it is visibly crushed by a hand or already dented before the sequence begins); there is no steam and no other cue that the can or its contents were ever heated.
level_2: The can does collapse, but the timing contradicts the mechanism: it starts caving in before its mouth ever reaches the water, or it crumples while still being flipped through the air, or steam is only seen after the can is already sitting in the water (implying there was no vapor left to condense).
level_3: The can stays intact and unchanged until its mouth is submerged in the cold water; only then does it begin to buckle inward, and the crumpling is uneven and asymmetric rather than a neat, uniform squeeze; the steam that was visible before the flip is gone by the time the can touches the water.
level_4: All of the above, and the buckling clearly begins at the top of the can, nearest the water, and spreads down the walls rather than showing up as a single crease at the rim; the collapse follows submersion promptly, without the can sitting unchanged in the water for several seconds first, and there is no re-expansion or a second separate collapse afterward.
level_5: All of the above, and the inward buckling begins essentially the instant the can's mouth is fully submerged rather than after a noticeable pause; the can keeps its cylindrical shape right up until it starts to crumple, with no outward bulging at any point; the steam that was rising before the flip has stopped almost immediately (within roughly a second of the mouth touching the water) with no lingering wisps; and there is no boiling, bubbling, or splashing during the collapse that would suggest escaping gas rather than condensing steam.

Spatiotemporal Consistency rubric:
level_1: The can or bowl jumps between positions with no motion shown connecting the two moments (for example, the can is upright, then suddenly inverted with no turning motion shown); the bowl appears or disappears between shots; the scene's lighting shifts abruptly partway through for no reason; steam appears or disappears from one moment to the next with no plume forming or dispersing naturally.
level_2: The turn from upright to inverted is shown as an abrupt cut rather than a visible rotation; the can's position or orientation changes with no in-between motion shown; the moment the mouth enters the water is skipped over (cutting from mid-air to already submerged); the steam plume has no clear point of origin at the can's mouth, or fades out unnaturally instead of dispersing.
level_3: The heating, steam release, lifting, flipping, lowering, water contact, and collapse are all shown as one continuous sequence with no cuts skipping past any of these actions; the can keeps a consistent size, shape, and metallic look right up until it begins to buckle; the water's surface stays level and calm except where the can disturbs it.
level_4: All of the above, and the flipping motion looks like a smooth, natural wrist rotation rather than an abrupt re-orientation; the can descends in a straight, vertical, mouth-first path into the bowl; contact with the water produces an immediate, modest ripple rather than an implausible splash; the buckling visibly spreads downward from the top of the can in one continuous motion rather than jumping between separate deformation stages.
level_5: All of the above, and the can's motion, the water's ripple, and the collapsing walls all move together believably: no mismatched motion blur, no shadow lagging behind or detached from the can, no sudden jump in the can's apparent size or position between moments; the disturbance on the water appears exactly where and when the mouth makes contact, and each stage of the crumpling clearly and smoothly follows the one before it rather than looking like separate clips stitched together.