Domain: Natural Science — Physics
Target concept: Pressure

Video generation prompt: Place a transparent glass cup filled with water on a table, cover the mouth of the cup with a postcard that is larger than the mouth of the cup, ensuring that the postcard completely covers the mouth without any gaps, and then invert the cup with your hand.

Evaluation guide:
(i) Target concept: Atmospheric pressure exerting net upward force on postcard exceeds hydrostatic pressure of water column, enabling mechanical equilibrium in inverted configuration.
Minimum mechanism: Water must be liquid and incompressible; postcard must be impermeable and rigid enough to transmit pressure; air must be excluded from cup interior during inversion (no trapped air pocket breaking seal); ambient air pressure must be present and uniform.
(ii)Storyline: [Phase 1: Setup] Cup upright on table, water visible inside, postcard placed flat and fully covering mouth; coverage confirmed by unbroken rim contact. [Phase 2: Inversion] Hand grips cup, lifts slightly, rotates 180° around horizontal axis while maintaining postcard contact; no gap opens at interface. [Phase 3: Stabilization] Cup reaches fully inverted orientation; postcard remains flush, water surface settles into static convex meniscus; no leakage, no postcard deformation. [Perspective constraint] Fixed frontal-view camera showing full cup-postcard-table system; no occlusion of cup mouth or postcard edges at any phase; lighting enables clear visibility of water surface and postcard adhesion.

Manual:
Experimental Procedure
1. Place transparent glass cup filled with water on table.
2. Cover cup mouth fully with postcard larger than mouth, ensuring no gaps.
3. Hold cup firmly and invert smoothly in one motion.
Observation of Experimental Phenomena
After inversion, postcard remains sealed to cup mouth and water does not spill — cup hangs stably upside-down with water fully contained.
Summary of Experimental Principles
Atmospheric pressure acting upward on postcard exceeds downward pressure from water weight, preventing detachment and leakage.

Prompt Grounding rubric:
level_1: No transparent glass cup is shown, or the cup contains no visible water, or no postcard appears, or the cup never rests on a table before the flip, or the postcard does not cover the cup's mouth, or the cup is never inverted at all.
level_2: The cup, water, and postcard are all present, but something core is wrong: the cup is opaque or tinted so the water can't be seen, the postcard is smaller than the mouth of the cup (no overhang at the rim), the cup contains no water or a different liquid, the cup is already upside down at the start, or the cup gets flipped before the postcard is ever placed over its mouth.
level_3: A transparent glass cup holding visible water sits on a table; a postcard bigger than the mouth of the cup lies flat over the opening with no visible gap at the rim; a hand grips the cup and turns it upside down; the cup, the water, the postcard, and the flipping action all appear in this order and match the roles described in the prompt.
level_4: Everything shown for a 3 is present, and the postcard also stays touching the rim all the way through the flip (no visible tilt, slide, or momentary lift as the cup turns), and the turn itself is one continuous motion from upright to inverted, with the hand never blocking the view of the rim during the turn.
level_5: Everything shown for a 4 is present, and once the cup is fully inverted the postcard sits flush against the rim with no gap visible at any point afterward, the cup stays completely upside down rather than drifting back toward upright or being set back down, and no water is seen escaping past the edge of the postcard; the whole sequence matches the setup described in the prompt.

Scientific and Causal Correctness rubric:
level_1: The video contradicts the physics: water pours out the moment the cup is inverted, the postcard falls away before or during the flip, or water is seen passing straight through the postcard; no containment is shown at all.
level_2: The postcard comes loose or water starts leaking before the flip is even finished, or the postcard visibly bows away from the rim by roughly a third of its height or more partway through the turn, or the water surface breaks apart (splits or splashes past the card) during the motion; the seal fails early in the sequence.
level_3: The postcard stays sealed against the rim for the entire flip and keeps covering the mouth afterward, with no water escaping during or after; the video shows the correct phenomenon: atmospheric pressure pushing on the postcard's outer face holds the water column inside the inverted cup.
level_4: Everything shown for a 3 holds, and the seal also holds up over time rather than just for a moment: the postcard doesn't re-lift and reseal, drip, or let air in at the rim once the cup is fully inverted, and no leak opens up later along an edge or corner after the initial seal is achieved.
level_5: Everything shown for a 4 holds, and the inverted cup stays in this sealed, full state with no sign of the seal slowly giving way (no gradual seep, no bubble breaking through, no incremental sagging of the postcard); the whole sequence reads as a stable balance between atmospheric pressure and the weight of the water column, sustained rather than momentary.

Spatiotemporal Consistency rubric:
level_1: A serious break in continuity occurs: the cup or the postcard jumps to a new position or vanishes and reappears in a later frame, the table's look changes abruptly under the cup, the room's lighting flips between bright and dark with no light source change or hand motion to explain it, or the cup or postcard visibly breaks apart with no physical cause.
level_2: A smaller but still noticeable break occurs: a hand covers the cup's mouth completely while the postcard is being placed, then moves away to reveal the postcard already in position with no visible placement motion; the cup's rotation jumps forward in steps rather than turning smoothly; the tabletop's texture warps under the cup; or the shadow the cup casts swings to a new direction with no change in the light source to explain it.
level_3: The cup stays over the same spot on the table the whole time; the postcard stays centered on the cup's mouth before, during, and after the flip; the hand's grip-and-turn motion looks smooth and physically plausible; and the shadows cast by the cup and postcard hold a steady direction and brightness throughout.
level_4: Everything shown for a 3 holds, and the hand also fully lets go of the cup before the final inverted pose settles (it doesn't linger and block the mouth), the cup and postcard keep their rigid shape without stretching, squashing, or warping, and the tabletop and background stay fixed with no shifting or distortion behind the cup.
level_5: Everything shown for a 4 holds, and the cup's rotation follows one continuous arc with no pause, reversal, or sudden change in speed, the postcard shows no visible sliding or turning relative to the cup's mouth as the cup rotates and comes to rest, and the table's surface keeps the same texture and perspective before, during, and after the flip.