Domain: Natural Science — Chemistry
Target concept: The solution changes from clear to turbid, forming micelles.

Video generation prompt: Heat a 1% (w/v) Triton X-100 aqueous solution to 70°C and stir for 10 minutes.

Evaluation guide:
(i) Target concept: Heating-induced turbidity via the cloud-point phase transition of a nonionic surfactant (Triton X-100), in which small clear micelles dehydrate and aggregate into much larger, light-scattering droplets.
Minimum mechanism: at 1% w/v, Triton X-100 is already far above its critical micelle concentration (roughly 0.2-0.9 mM), so the solution starts out containing small, well-hydrated micelles and looks perfectly clear at room temperature. Heating the solution past its cloud point (approximately 64-66°C for this concentration) dehydrates the surfactant's polyoxyethylene head groups, causing the small micelles to swell and clump into much larger surfactant-rich aggregates; these larger aggregates are big enough to scatter visible light, so the liquid turns milky. Stirring helps the heat -- and therefore the transition -- reach the whole volume at roughly the same time. (Cooling back below the cloud point would reverse this, though that isn't part of this 10-minute heating clip.)
(ii) Storyline: Frame 1-2: Clear liquid sits in a static beaker under ambient light, with no thermal cue yet. Frame 3-5: A heat source activates (a glow, or rising steam) and stirring begins. Frame 6-8: Turbidity develops evenly across the whole liquid volume as the temperature crosses the cloud point, growing more pronounced while stirring and heating continue. Frame 9-10: The liquid is now fully turbid, stable, and evenly milky -- no settling, no clearing, no bubbles. Perspective: a fixed frontal or slightly angled view shows the full height of the beaker, the liquid surface, the stirrer tip, and the heat source; the stirrer should never appear to pass through the beaker wall.

Manual:
Experimental Procedure
1. Place a 1% (w/v) Triton X-100 aqueous solution in a transparent glass beaker.
2. Heat the solution to 70°C using a hotplate (visible thermal glow or steam cue), crossing the surfactant's cloud point (~64-66°C for this concentration).
3. Stir continuously for the duration of the video (representing 10 minutes).
Observation of Experimental Phenomena
The initially clear, transparent solution becomes uniformly turbid (milky, cloudy) as it is heated past the cloud point and stirred -- no sediment, no layering, no color change.
Summary of Experimental Principles
Below the cloud point, Triton X-100 exists as small, well-hydrated micelles that do not scatter enough visible light to look cloudy. Heating past the cloud point dehydrates the polyoxyethylene chains, causing the micelles to swell and aggregate into larger surfactant-rich droplets that scatter light strongly, producing macroscopic turbidity -- a reversible, temperature- and concentration-dependent phase transition.

Prompt Grounding rubric:
level_1: No liquid is visible in a container, no transparent beaker or vessel appears at all, no heat source (glow, steam, or heating element) is shown, no stirring motion occurs, and there is no sense of a sustained multi-minute process -- the setup described in the prompt (a Triton X-100 solution, a heat source, a stirrer) is essentially absent.
level_2: One piece of the setup shows up -- for example a clear liquid sitting in a beaker, or a stirrer or heat source on its own -- but heating and stirring never happen together, the liquid never appears to be actively heated while stirred, and there's no indication that time is passing (e.g., it plays like one static shot).
level_3: A clear liquid sits in a transparent beaker; a heat source (glow, warming coil, or rising steam) is visible at the same time a stirring implement (rod, spoon, or stir bar) is moving through the liquid; no unrelated objects (solids, dyes, extra containers, printed labels) are added; the sequence matches the prompt -- heating and stirring happening together.
level_4: Everything in score 3 is present, and in addition the same beaker, heat source, and stirring implement are used the whole time with nothing swapped out or added, and the heating and stirring visibly continue together for a sustained stretch rather than just a brief instant, consistent with representing a multi-minute process.
level_5: Everything in score 4 is present, and in addition every object named in the prompt -- the beaker, the Triton X-100 solution, the heat source, and the stirring implement -- keeps a consistent identity, size, and appearance from the first frame to the last, with nothing added, removed, or substituted, and the depicted order (solution in beaker, heat and stirring applied together, turbidity developing) matches the prompt's description exactly.

Scientific and Causal Correctness rubric:
level_1: The liquid stays completely clear and transparent the whole time -- no haziness, clouding, or light-scattering shows up at any point, so the heating-induced cloud-point transition described in the prompt never actually happens.
level_2: Some cloudiness appears, but the cause and effect are wrong: for example the liquid turns cloudy before the heat source is even shown activating, or it clouds only in an isolated streak or corner rather than through the bulk liquid, or the turbidity shows up and then disappears again without any cooling shown.
level_3: The liquid starts out clear; while it is being heated and stirred, it turns evenly milky/cloudy throughout the whole volume (not just near the surface or the bottom); there's no visible sediment and no split into separate layers; and once the turbidity appears, it doesn't clear back up again by the end of the clip -- consistent with the solution crossing its cloud point.
level_4: Everything in score 3 is present, and in addition the clouding only starts once heating is clearly underway (not before), builds up gradually rather than snapping on instantly, and holds at a steady milky level once fully developed, with no partial clearing or settling afterward -- matching a genuine heat-driven cloud-point transition rather than an arbitrary opacity change.
level_5: Everything in score 4 is present, and in addition the turbidity looks like a soft, even milky haze with no sharp streaks, floating flecks, or crystal-like specks, consistent with micelles clumping into larger light-scattering droplets rather than any solid crystallizing out; there are no oil droplets or trapped air bubbles that could be mistaken for the cloudiness; the liquid stays liquid with no visible thickening; and the whole volume clouds over at roughly the same pace rather than one region clouding well ahead of the rest.

Spatiotemporal Consistency rubric:
level_1: Severe continuity breaks: the beaker jumps to a different position or size between frames; the liquid disappears and reappears; the stirring implement changes length or bends unnaturally from one frame to the next; the lighting suddenly switches character, as if a different light source took over mid-clip; or the shot cuts between clearly mismatched camera angles.
level_2: Noticeable but milder glitches: the stirring motion skips or stutters instead of moving smoothly; the heat cue (glow or steam) blinks on and off erratically; the liquid surface warps or shears in a way stirring wouldn't cause; the beaker rim wobbles inconsistently; or the shadows behave as though the light source silently moved.
level_3: Nothing teleports or vanishes; the beaker stays in the same place and orientation throughout; the stirring motion is continuous with no sudden jumps in position or angle; the heat cue stays visible the whole time; the liquid surface moves in a way that plausibly follows the stirring; and the lighting looks like it comes from one fixed source for the entire clip.
level_4: Everything in score 3 is present, and in addition the stirring implement follows a smooth, natural path (e.g., a steady circular sweep rather than a jerky back-and-forth), the liquid surface's motion settles down naturally instead of staying artificially choppy, and there's no visible tearing or ghosting, nor any moment where the stirrer appears to pass behind the liquid surface in a way that breaks depth ordering.
level_5: Everything in score 4 is present, and in addition the stirrer, the ripples on the liquid surface, and the meniscus all move at consistent, coherent speeds throughout with no jarring changes in pace; motion blur on the moving stirrer looks consistent from frame to frame; the beaker and background stay in correctly matched perspective throughout; and the rotating stirrer never appears to flicker or strobe in a way that breaks the sense of continuous rotation.