Domain: Natural Science — Physics
Target concept: Water flow induced by ion gradient, using two connected chambers and a dye tracer

Video generation prompt: Two transparent chambers separated by a semipermeable membrane were initially filled with blue water; a high-concentration salt solution was added to the left chamber, and the setup was left undisturbed for several minutes.

Evaluation guide:
(i) Target concept: Osmotic water flow induced by solute concentration gradient across a semipermeable membrane.
Minimum mechanism: Membrane must be permeable to water but impermeable to salt ions and dye molecules; initial symmetry broken only by salt addition to left; water movement must generate net volume transfer causing measurable level difference.
(ii)Storyline: Frame 0–1: Static wide shot showing two identical transparent chambers, full of blue water, equal levels, clear vertical membrane between them. Frame 2–3: Salt solution introduced exclusively into left chamber (visible delivery, no overflow/crossing). Frame 4–9: Continuous, smooth rise of liquid level in left chamber concurrent with fall in right chamber; blue color unchanged and fully retained per chamber; membrane remains intact and unbreached; no dye migration; fixed side-by-side viewpoint maintained throughout.

Manual:
Experimental Procedure
1. Place two identical transparent chambers side-by-side, separated by a vertical semipermeable membrane.
2. Fill both chambers completely with blue-dyed water to identical initial levels.
3. Add high-concentration salt solution only to the left chamber.
Observation of Experimental Phenomena
After several minutes: left chamber liquid level rises; right chamber liquid level falls; blue dye remains confined to its original chamber; no dye crosses the membrane.
Summary of Experimental Principles
Water flows from low-solute concentration (right chamber) to high-solute concentration (left chamber) across the semipermeable membrane — osmosis driven by ion gradient.

Prompt Grounding rubric:
level_1: Two transparent chambers are not shown side-by-side, or no semipermeable membrane separates them, or one or both chambers lack blue-tinted water at the start, or no salt solution is ever introduced into the left chamber.
level_2: Both chambers and a divider appear, but the divider looks like a solid, non-membrane wall or is missing entirely; or blue water is present in only one chamber; or the salt solution's point of entry cannot be identified as the left chamber specifically.
level_3: Two transparent chambers stand side-by-side with a visibly distinct vertical membrane between them; both chambers begin full of blue-tinted water at matching levels; a stream or drop of salt solution is clearly introduced into the left chamber only; the chambers and membrane stay visible without being blocked by a hand or other object.
level_4: Everything in the 3-point level holds, and in addition the salt solution's entry is confined to the left chamber with no visible splash-over into the right chamber or across the membrane, the blue tint reads as the same shade in both chambers right up until the salt is added, and no hand, tool, or label lingers in front of the chambers or membrane after the pour.
level_5: Everything in the 4-point level holds, and in addition both chambers are filled to nearly the same brim height before the salt is added (no chamber shown with an unexplained partial fill), the pour itself creates no splashing or foam that hides the chamber walls or membrane, the membrane stays flat and undamaged in its mount, and the camera holds one fixed side-by-side framing of both chambers for the entire clip.

Scientific and Causal Correctness rubric:
level_1: The liquid levels stay equal for the whole clip, or the left chamber's level drops while the right chamber's rises (the reverse of the expected direction), or blue dye escapes across the membrane, or the salt solution is shown entering the right chamber instead of the left.
level_2: A level difference appears, but it starts developing before the salt is actually added, or the blue dye fades to clear or shifts to a different hue, or the membrane visibly lets colored liquid pass through it.
level_3: After the salt is added to the left chamber, its liquid level gradually rises while the right chamber's level gradually falls; the blue color stays confined to each chamber with no crossing through the membrane; no level change happens before the salt is added.
level_4: Everything in the 3-point level holds, and in addition the left chamber's rise and the right chamber's fall look proportionate to one another, reading as one connected transfer of water rather than two unrelated events, and no dye ever shows up on the far side of the membrane at any point.
level_5: Everything in the 4-point level holds, and in addition the level gap keeps widening steadily after the salt is added rather than stalling, reversing, or jumping in size; no bubbling, foaming, or precipitate appears near the membrane; and the membrane never shows a visible tear, gap, or leak path that would explain the transfer some other way.

Spatiotemporal Consistency rubric:
level_1: A chamber or the membrane disappears and reappears within the clip, a liquid level jumps to a new height with no visible flow leading up to it, or the camera framing changes (a cut, pan, or zoom) partway through.
level_2: The chambers or membrane flicker in and out for a moment, the blue liquid briefly changes shade or brightness with no explanation, or the background around the chambers visibly shifts or warps.
level_3: Both chambers, the membrane, and the blue liquid stay visible and steady in place for the whole clip; each chamber's level change unfolds as smooth, gradual motion rather than a sudden jump; no chamber, membrane, or liquid pops in or out of view.
level_4: Everything in the 3-point level holds, and in addition the chamber walls and liquid surfaces show no tearing, warping, or ghosting, the curve of each liquid surface looks physically reasonable and consistent between the two chambers, the shadows the chambers cast stay anchored to their bases without jumping, and the level never rises then falls then rises again without cause.
level_5: Everything in the 4-point level holds, and in addition each liquid surface moves calmly with no visible jitter or artificial-looking ripple, the chamber edges stay crisp rather than blurring in and out, and the side-by-side framing, chamber spacing, and membrane position all stay visually fixed for the full duration.