Domain: Natural Science — Physics
Target concept: Decrease in atmospheric pressure leads to a lower boiling point.

Video generation prompt: Withdraw about one-third of a syringe's volume of warm water, then block the needle hole and pull the plunger backward firmly and steadily to expand the enclosed volume.

Evaluation guide:
(i) Target concept: Pressure-dependent boiling point depression in a closed, expandable system.
Minimum mechanism: Water must be warm (above ambient but below 100°C), syringe must be airtight when needle is blocked, and plunger pull must reduce internal pressure sufficiently to reach vapor pressure of warm water, requiring both thermal energy (warmth) and mechanical work (volume expansion) to trigger phase change.
(ii)Storyline: [Phase 1] Syringe held vertically, warm water drawn to ~1/3 level: water appears still, meniscus stable, no vapor. [Phase 2] Needle tip fully covered: occlusion visually confirmed, no air escape visible. [Phase 3] Plunger pulled firmly and steadily backward; barrel volume increases, internal pressure drops, triggering nucleation: bubbles emerge *within bulk water*, rise, and reach surface; simultaneous faint vapor/mist appears *only above water*. [Phase 4] Pull stops or occlusion breaks; bubbling ceases within <1 second, vapor dissipates, water calms. Perspective: Fixed frontal view showing syringe full-length, water level, plunger position, and needle tip simultaneously; no cuts, no zoom, no angle shift.

Manual:
Experimental Procedure
1. Draw ~1/3 volume of warm water into syringe barrel.
2. Firmly block the needle hole with finger or cap.
3. Firmly and steadily pull plunger backward to increase internal volume.
Observation of Experimental Phenomena
Warm water spontaneously forms rising bubbles and mild surface vapor *only during plunger pull under blocked needle*.
Summary of Experimental Principles
Decrease in atmospheric pressure inside sealed syringe lowers boiling point, causing warm water to boil at room temperature.

Prompt Grounding rubric:
level_1: No syringe appears anywhere in the video; or a syringe appears but is never filled with water, its needle is never blocked, and the plunger is never pulled: none of the three actions (draw warm water in, seal the needle tip, retract the plunger) occurs.
level_2: A syringe with water is shown, but the three-step sequence is broken: for example the plunger is retracted while the needle tip is still open, the needle is blocked only after the plunger has already started moving, or water is added but never withdrawn to a partial fill. The required order (fill, then seal, then retract) is not respected.
level_3: The syringe barrel holds water filled to roughly the one-third mark, the needle tip is covered by a finger or cap, and the plunger is then pulled backward in that order; but at least one step is hard to confirm, e.g. the water's fill line is not clearly readable against the barrel markings, the covering of the needle tip is only implied rather than shown in contact, or the direction of plunger travel is ambiguous.
level_4: All three elements are unambiguous and correctly ordered: water sits at approximately one-third of the barrel's length with a visible meniscus, the needle tip is shown fully covered by a finger or cap before any plunger motion begins, and the plunger is then drawn backward so the internal volume visibly increases; no step is skipped, reordered, or faked (no pulling with the tip still open, no water shown already withdrawn without a withdrawal shot).
level_5: Everything in level 4 holds, and additionally: the graduation marks on the barrel stay legible throughout so the one-third fill level can be read both before and during withdrawal; the covering over the needle tip is maintained without interruption for the entire time the plunger is retracted; the plunger's backward travel is a single continuous retraction that does not stop partway and reverse before the pull is complete; and the syringe is held at a steady, near-vertical orientation so the water column, the covered tip, and the plunger position stay visible together in the same shot.

Scientific and Causal Correctness rubric:
level_1: No bubbles or vapor ever appear in or above the water; the water surface stays completely flat and undisturbed for the whole video regardless of whether the plunger is pulled.
level_2: Bubbles or vapor appear before the needle tip is sealed or before the plunger is pulled (e.g. the water is already fizzing while still being drawn into the syringe, or vapor rises while the needle tip is open), so the phenomenon is not tied to the pressure-reduction step.
level_3: Once the tip is sealed and the plunger is pulled, a few small bubbles form somewhere inside the water column, but they stay isolated near where they formed, never rise to the surface, or vanish within an instant with no further bubbling; the water otherwise looks largely unaffected by the retraction.
level_4: After the tip is sealed and while the plunger is being pulled, a steady stream of small bubbles rises through the warm water toward the surface and the surface itself shows mild agitation, with a faint wisp of vapor visible just above the water; this activity starts only once the pull begins and dies down again as soon as the plunger stops moving or the seal is broken; no bubbling occurs earlier.
level_5: Everything in level 4 holds, and additionally: the bubbles are seen originating from within the body of the water rather than from the barrel wall or the covered tip, the vapor wisp stays confined to the space just above the water surface rather than clinging to the glass walls, and the water's meniscus visibly drops as the bubbling continues, showing the plunger's retraction, the bubbling, and the falling water level all occurring together, consistent with the water boiling because the pressure above it has dropped.

Spatiotemporal Consistency rubric:
level_1: The syringe or the water inside it vanishes and reappears at a different fill level between shots; the plunger jumps from one position to another without traveling through the space in between; the lighting flips abruptly between shots (e.g., a sudden bright-to-dark change) with no cause; or the syringe suddenly appears rotated more than about 30° or at a different tilt or location with no motion carrying it there.
level_2: One clear continuity break occurs: the plunger slides backward and then snaps back to its starting position without being pushed forward again, the finger or cap covering the needle tip appears only after the plunger has already started moving, or the syringe's apparent size changes between frames as if swapped for a different prop.
level_3: The syringe stays the same size and in the same general position and orientation throughout; the plunger's backward motion is continuous with no jump-cuts; but small imperfections are visible, such as a brief flicker as the plunger moves, a slight hand tremor while holding the syringe, or the finger momentarily blocking the view of the water's fill line. None of these breaks the sense that one continuous event is being filmed.
level_4: There is no teleporting or duplication of the syringe, plunger, or water; the plunger's backward travel is smooth and moves in one direction only, never partway forward again; the water level falls in step with how far the plunger has been pulled rather than jumping ahead of or lagging behind it; the covering over the needle tip stays in place for the whole retraction; and the syringe, the water, and the covered tip are all visible together in every frame of the pull.
level_5: Everything in level 4 holds, and additionally: the syringe's long axis stays oriented the same way relative to the camera for the whole sequence, never rotated or tilted mid-shot in a way that would hide the fill line or the covered tip; the pace of the plunger's retraction looks even from start to finish rather than suddenly speeding up or slowing down; and the water column, the plunger seal, and the covered needle tip remain simultaneously visible in frame for the entire pull with no part of the action moving off-screen.