Domain: Engineering — Instrument and Meter Engineering
Target concept: U-tube manometer

Video generation prompt: Set up a U-tube manometer measurement device, connecting the two ends of the manometer to the upstream and downstream pressure measurement points of the horizontal pipeline. Introduce clear water into the pipeline, gradually open the pipeline valve to continuously increase the flow velocity, and aim the camera at the liquid surface inside the U-tube.

Evaluation guide:
(i) Target concept: Visual demonstration of pressure differential measurement via U-tube manometer under controlled flow conditions.
Minimum mechanism: Water must be incompressible and immiscible; U-tube must be open to atmosphere at both ends or referenced to same datum; pipeline must be horizontal to isolate static pressure difference from elevation effects; valve motion must induce monotonic flow increase.
(ii)Storyline: Frame opens on static setup: U-tube connected to horizontal pipeline, water settled at equal levels. Valve begins closed. As valve opens, upstream pressure exceeds downstream pressure → water displaced asymmetrically → upstream leg level falls, downstream leg level rises → height difference widens progressively. Camera maintains fixed frontal view of U-tube throughout; no occlusion; all components remain fully visible and structurally intact; liquid motion is smooth, continuous, and exclusively driven by valve action.

Manual:
Experimental Procedure
1. Mount U-tube manometer with both legs connected to upstream and downstream ports of horizontal pipeline.
2. Fill pipeline and U-tube with clear water.
3. Close valve, then gradually open it to increase flow velocity.
Observation of Experimental Phenomena
Liquid levels in the two legs of the U-tube become unequal; the upstream leg level drops while downstream leg rises — difference increases as valve opens further.
Summary of Experimental Principles
U-tube manometer measures pressure difference: higher upstream pressure pushes water down in upstream leg and up in downstream leg; flow velocity increase correlates with growing pressure differential per Bernoulli principle.

Prompt Grounding rubric:
level_1: No U-tube manometer visible; no horizontal pipeline shown; no valve present; no water visible in any container; no camera view focused on a liquid column.
level_2: U-tube manometer is present but disconnected from any pipeline; horizontal pipeline appears without attached manometer ends; valve is absent or non-functional; water is present but not inside the U-tube or pipeline; camera does not frame liquid surface.
level_3: U-tube manometer is visibly connected to two points on a horizontal pipeline; valve is present and appears manipulable; clear water is visible inside the U-tube; camera view includes the U-tube liquid surface; all required objects and connections are present, but sequence of operation (valve opening → level change) is not visually indicated.
level_4: All required objects present and correctly connected: the U-tube manometer has both legs attached to the upstream and downstream taps on the horizontal pipeline; a valve is visibly mounted on the pipeline with a handle or lever that looks operable (not just a plain pipe segment); clear water fills the lower portion of both U-tube legs; camera view is fixed and centered on the U-tube liquid surface for the whole clip, with no reframing or recentering.
level_5: All elements of 4-score satisfied, AND the entire clip is a single continuous shot with no cuts, jump cuts, or camera repositioning; no pipeline segment, valve, or U-tube leg is added, removed, or occluded at any point; the valve handle and both U-tube legs stay simultaneously visible and unobstructed in every frame from start to finish.

Scientific and Causal Correctness rubric:
level_1: Liquid levels in both legs of U-tube are identical throughout; no pressure difference indicated; water appears static and level across both sides; no causal link between valve action and liquid movement.
level_2: U-tube contains liquid but one leg is empty or dry; liquid color is non-aqueous (e.g., blue dye, opaque, or colored beyond clear water); liquid levels change without valve motion; or level difference decreases when valve opens.
level_3: U-tube contains clear water; two distinct liquid levels appear in the two legs; valve is shown in open position or motion; level difference is present, but no visible correlation between valve state/motion and level asymmetry; levels may be static or inconsistent with flow increase.
level_4: Clear water is present in both legs; liquid levels are unequal; valve is shown transitioning from closed toward open; level difference is stable or increasing during that transition; no reversal or contradiction in direction of level change relative to valve opening.
level_5: Clear water in both legs; unequal liquid levels; valve motion is unambiguously from closed to open; level difference begins small and monotonically increases during valve motion; no frame shows equal levels after valve starts opening; no discontinuity in level progression or unnatural jump in height difference.

Spatiotemporal Consistency rubric:
level_1: U-tube or pipeline disappears/reappears abruptly; liquid surface flickers, teleports, or fractures between frames; lighting changes drastically mid-clip; camera viewpoint shifts (pan/tilt/zoom) or cuts to another angle; structural integrity of U-tube breaks (e.g., leg bends, detaches, leaks unrealistically).
level_2: U-tube remains visible but one leg deforms or changes length inconsistently; liquid surface wobbles violently without cause; shadow or reflection moves independently of light source; pipeline geometry warps (e.g., bends, shortens, rotates) between frames.
level_3: The U-tube maintains a fixed position and shape; the pipeline remains rigid and horizontal; the liquid surface is continuous and coherent across both legs; the highlight/reflection on the water surface shifts smoothly and stays roughly where the surface is as the level changes, with no sudden flash or blackout; no visible cuts or viewpoint shifts; a small, visible wobble in the liquid surface is still tolerated at this level.
level_4: All elements of 3-score satisfied; liquid surface is smooth and stable with no visible vibration or distortion; no parallax inconsistency between U-tube legs and pipeline attachments; no inter-frame misalignment of connection points; no temporal discontinuity in motion or stillness.
level_5: All elements of 4-score satisfied; the liquid surface moves smoothly and continuously during the level change: no strobing, freezing, skipping, or frame-dropping; no geometric stretching or squashing of the U-tube; the joints where the U-tube legs meet the pipeline show no visible shifting, gap, or separation across frames; lighting and reflections on the water evolve naturally with its motion.