Domain: Natural Science — Chemistry
Target concept: Sodium Acetate Crystallization: Rapid Instantaneous Crystallization vs. Slow Cooling Crystallization

Video generation prompt: Two identical beakers containing sodium acetate solution: one beaker (covered by a red sleeve) is placed in contact with a seed crystal; the other beaker (covered by a blue sleeve) is left undisturbed; both beakers sit together in a shallow, still water bath.

Evaluation guide:
(i) Target concept: Metastability of supersaturated solutions and nucleation-dependent crystallization kinetics.
Minimum mechanism: Solution must be supersaturated and thermodynamically primed for crystallization; seed crystal must provide heterogeneous nucleation site; absence of disturbance in blue beaker must preserve kinetic barrier against spontaneous nucleation.
(ii)Storyline: Frame 0–1: Two identical beakers side-by-side, both filled with clear solution, red sleeve on left, blue on right, shallow water bath visible beneath. Frame 2: Seed crystal placed onto surface of red-sleeved beaker solution (contact visible). Frame 3–4: Instantaneous opaque white crystallization propagates continuously from contact point in red beaker. Frame 5–9: Red beaker fully crystallized (solid, opaque, static); blue beaker remains fully liquid, clear, and undisturbed: no crystallization, no meniscus disruption, no convection. All events occur from fixed frontal viewpoint; no occlusion; critical regions (seed contact, crystallization front, blue beaker clarity) remain fully visible throughout.

Manual:
Experimental Procedure
1. Place two identical beakers side-by-side, each filled with clear, supersaturated sodium acetate solution.
2. Attach a red sleeve to left beaker; attach a blue sleeve to right beaker.
3. Gently place a seed crystal onto surface of solution in red-sleeved beaker.
4. Submerge both beakers up to their rims in a shallow, still water bath.
Observation of Experimental Phenomena
- Red-sleeved beaker: rapid, opaque white crystallization spreads instantly from seed crystal contact point.
- Blue-sleeved beaker: remains completely clear and liquid, with no solid formation or turbidity.
Summary of Experimental Principles
Sodium acetate supersaturated solution is metastable. Seed crystal provides nucleation site triggering instantaneous crystallization (rapid pathway). Undisturbed blue-sleeved beaker remains metastable without nucleation, requiring slow cooling or spontaneous nucleation (slow pathway).

Prompt Grounding rubric:
level_1: The scene doesn't show two sodium-acetate beakers positioned next to each other; neither the red sleeve nor the blue sleeve is visible; no seed crystal is shown touching either beaker; no shallow water bath is present beneath the beakers.
level_2: Two beakers appear, but they are not next to each other (e.g., one is stacked, distant, or on a different surface); only one sleeve color (red or blue) is visible, not both; the seed crystal is missing or cannot be identified as a solid crystal; the water bath is missing, too deep, overflowing, or otherwise not a shallow basin.
level_3: Two beakers of sodium acetate solution sit next to each other; a red sleeve wraps one beaker and a blue sleeve wraps the other; a seed crystal visibly touches the solution surface in the red-sleeved beaker; a shallow water bath is present beneath both beakers; no extra props (tongs, thermometer, labels) contradict the setup.
level_4: The level-3 setup is shown, and in addition the seed crystal is fully immersed at the solution surface rather than floating above it or resting outside the liquid; each sleeve fully wraps its beaker's rim with no gap or slippage; the water bath's level is even and shallow, wetting only the lower portion of both beakers rather than covering their bodies; no tools, hands, or labels intrude into the frame.
level_5: The level-4 setup is shown, and in addition the red sleeve appears only on the beaker touched by the seed crystal while the blue sleeve appears only on the undisturbed beaker; both sleeves are solid-colored and unpatterned, with red clearly distinguishable from pink/orange and blue clearly distinguishable from cyan/purple; the water bath surface is calm and mirror-still; the two beakers match each other in shape, size, glass clarity, and solution fill level.

Scientific and Causal Correctness rubric:
level_1: Neither beaker shows any crystallization (both stay fully liquid for the whole clip), or both beakers crystallize together, or solid forms in the red beaker before the seed crystal actually touches the solution.
level_2: Only one beaker crystallizes, but the cause-and-effect is wrong: the blue (undisturbed) beaker crystallizes first or crystallizes without ever being cooled; the red beaker crystallizes without the seed crystal visibly touching the solution; or the change looks like bubbling, clouding, or a liquid split rather than solid crystal growth.
level_3: Crystallization starts only in the red-sleeved beaker, immediately after the seed crystal touches the solution, and spreads as an opaque solid outward from that contact point; the blue-sleeved beaker stays fully liquid and clear the entire time, with no solid forming anywhere in it.
level_4: Beyond the level-3 behavior, the red beaker's crystallization advances without stopping and restarting or resetting to liquid; the blue beaker shows no cloudiness, floating solid specks, or solidification creeping in from its walls; the crystallized region in the red beaker is opaque white rather than translucent or tinted; no part of the red beaker's solid re-melts back to liquid.
level_5: Beyond the level-4 behavior, the crystal growth in the red beaker spreads outward roughly evenly in all directions from the seed-crystal contact point; the blue beaker's liquid stays perfectly clear with a flat, undisturbed surface: no ripples, no swirling currents; no crystal forms anywhere in the red beaker before the seed crystal makes contact, and no second patch of solid starts growing elsewhere in the red beaker independent of the seed site.

Spatiotemporal Consistency rubric:
level_1: The two beakers jump to different positions between shots with no continuous motion connecting the frames; a sleeve switches from red to blue (or the reverse) partway through; the seed crystal appears or disappears without ever being visibly placed or removed; the water bath's surface flickers on and off or disappears; the overall lighting shifts to a noticeably different color temperature or brightness between one shot and the next.
level_2: The beakers swap sides or drift apart/closer without any visible cause; a sleeve slides off or detaches from its beaker; the seed crystal floats upward off the surface or sinks out of the solution; the water bath level rises or drops in a sudden jump rather than gradually; the camera zooms or pans in a way that breaks the fixed viewpoint.
level_3: The red beaker and blue beaker each stay on their own side of the frame for the whole clip, without swapping places or changing distance from each other; no beaker, sleeve, or the seed crystal blinks out of view and reappears out of nowhere; the room lighting keeps the same brightness and color cast throughout; the water bath surface stays calm; the beaker walls show no warping or odd reflection artifacts; any camera or object motion is smooth, without stutter.
level_4: Beyond the level-3 behavior, the seed crystal stays in continuous contact with the solution surface in the red beaker for the entire clip, never lifting away with a visible gap or sinking out of view; both sleeves stay aligned with their beaker rims across the whole clip; the liquid meniscus in each beaker keeps a stable, symmetric curve rather than distorting.
level_5: Beyond the level-4 behavior, both beakers stay equally sharp and in the same focal plane with no mismatched blur between them; no motion blur obscures the seed crystal or either sleeve's edge; no lens flare, bloom, or glare covers the seed-contact point or the growing crystallization front; the crystallization front in the red beaker advances outward gradually, never appearing to leap from a small patch to the whole beaker being solid between one frame and the next.