Domain: Natural Science — Physics
Target concept: Comparison of Crystallization of Salt Solution in a Shallow Dish under Slow and Rapid Cooling Conditions

Video generation prompt: Pour the same saturated potassium nitrate (KNO₃) solution into two identical shallow glass dishes; cool one in an ice-water bath, and the other on an exposed tabletop.

Evaluation guide:
(i) Target concept: Crystallization morphology depends on cooling rate due to nucleation vs. growth competition, demonstrated using potassium nitrate (KNO₃), a salt whose solubility drops sharply as temperature falls.
Minimum mechanism: Saturated KNO₃ solution must remain supersaturated during cooling because KNO₃ solubility falls steeply with temperature (roughly 32 g per 100 g water near room temperature down to about 13 g per 100 g water near 0°C); nucleation is thermally favored at the lower ice-water temperature and produces many small crystals quickly, while the slower tabletop cooling favors growth of fewer, larger crystals by ion diffusion over more time.
(ii)Storyline: [Frame 0–2] Two empty shallow glass dishes centered side-by-side; saturated potassium nitrate solution poured sequentially or simultaneously into both; [Frame 3–4] Left dish lowered into visible ice-water bath (condensation forms instantly on dish exterior); right dish placed on bare tabletop; [Frame 5–7] First crystals nucleate in ice-water dish (small, clustered, at multiple points along edge/base); [Frame 8–10] Crystals remain absent or appear minimally in tabletop dish, while ice-water dish fills with dense granular layer; all events occur under fixed frontal macro view with full dish visibility and no occlusion.

Manual:
Experimental Procedure
1. Pour identical volumes of the same saturated potassium nitrate (KNO₃) solution into two identical shallow glass dishes.
2. Immediately place one dish into an ice-water bath (about 0°C); place the other on an exposed room-temperature tabletop.
3. Observe crystallization over time.
Observation of Experimental Phenomena
Crystals form quickly and densely in the ice-water dish, appearing as a fine, uniform, sand-like layer. Crystals form slowly and sparsely in the tabletop dish, appearing as a few larger, well-separated crystals with visible facets.
Summary of Experimental Principles
Potassium nitrate's solubility falls sharply as temperature drops (from roughly 32 g per 100 g water at room temperature to about 13 g per 100 g water near 0°C). The abrupt cooling in the ice-water bath drives the solution far past saturation almost immediately, favoring many simultaneous nucleation sites and yielding numerous small crystals. The gradual cooling on the tabletop keeps supersaturation low, so only a few nuclei form, and each grows larger via ion diffusion before additional nuclei appear.

Prompt Grounding rubric:
level_1: No shallow glass dishes appear in the video; no potassium nitrate solution is visible; neither an ice-water bath nor a bare tabletop surface is shown; none of the setup elements from the prompt (two dishes, solution, two cooling surfaces) are present.
level_2: Only one shallow glass dish is shown, or the second dish is missing or mismatched in size/shape; potassium nitrate solution is poured into only one dish or into neither; only one of the two cooling environments (ice-water bath or bare tabletop) appears, with the other omitted; pouring occurs after, rather than before, a dish is placed in its cooling environment.
level_3: Two visually matching shallow glass dishes are shown; the same clear potassium nitrate solution is poured into both dishes; one dish sits in a visible ice-water bath (a container holding ice and water, contacting the dish's underside), the other sits directly on the bare tabletop with no surrounding container; pouring into both dishes finishes before either dish contacts its cooling surface.
level_4: Everything in score 3 holds, and additionally the two dishes stay side by side in the same relative arrangement for the whole clip: neither dish is lifted, swapped, or blocked from view once placed; the pouring into the two dishes is shown as one continuous action that finishes before either dish is set into its cooling environment.
level_5: Everything in score 4 holds, and additionally both dishes stay entirely inside the frame with no edge cropping or lens distortion of their circular rims; the two pours start and finish close together in time rather than minutes apart; the ice-water dish visibly shows condensation beading on its underside/sides while the tabletop dish shows none, and both cooling surfaces stay visually unchanged (the ice-water bath doesn't dry out, the tabletop gains no new objects) for the whole clip.

Scientific and Causal Correctness rubric:
level_1: Neither dish shows any solid crystal formation: both remain clear liquid; or, if crystals do appear, the ice-water dish and the tabletop dish show the same crystal size and number with no visible difference between them.
level_2: Crystals form in only one of the two dishes; or crystals appear in both dishes but look the same in size and packing density; or crystals appear before a dish is placed in its cooling environment; or the crystals are visibly colored (e.g., blue, yellow) rather than white/clear, which would be wrong for potassium nitrate.
level_3: Crystals appear in both dishes; the ice-water dish develops many small crystals clustered close together (a grainy, packed texture), while the tabletop dish develops only a few crystals that are individually larger and spaced apart; all crystals are white or colorless/transparent; once formed, no crystal melts back into solution or visibly changes shape.
level_4: Everything in score 3 holds, and additionally the ice-water dish's crystals appear distinctly earlier than the tabletop dish's crystals (the delay between the two dishes is clearly visible, not simultaneous); once a crystal has formed it does not shrink, flow, or move position afterward in either dish.
level_5: Everything in score 4 holds, and additionally the size contrast is unmistakable to the eye: the ice-water dish shows a fine, uniform, sand-like layer with no standout large crystals, while the tabletop dish shows at least one clearly larger crystal with visible flat faces or branch-like arms, at least three times the size of any single grain in the ice-water dish; neither dish shows a mixture of fine grains and large crystals together.

Spatiotemporal Consistency rubric:
level_1: A dish is missing from one frame and inexplicably present again in a later frame, or its shape suddenly changes (e.g., a round dish becomes oval or square); the solution or the crystals inside a dish appear or disappear abruptly with no pouring or growth shown; the background scene changes to a different location partway through; or the lighting swings abruptly from full brightness to near-total darkness with no environmental cause shown (e.g., no lamp, shade, or cloud passing).
level_2: One of the two dishes jumps to a new spot on the table (farther than its own width away) rather than being carried or slid there; the poured solution's surface goes from still to violently splashing and back to still with no smooth transition; a fully formed crystal appears in a single frame with no visible growth leading up to it; condensation appears on the tabletop dish, or disappears from the ice-water dish, partway through the clip for no visible reason.
level_3: Both dishes stay in the same place, size, and orientation relative to the table and to each other throughout; after pouring, the liquid surface settles and stays calm rather than sloshing continuously; each crystal grows outward gradually from where it first appears rather than popping into full size; condensation stays visibly present on the ice-water dish and visibly absent from the tabletop dish for the whole clip; no dish or object flickers or breaks apart between frames.
level_4: Everything in score 3 holds, and additionally the pour into each dish follows one smooth, continuous arc rather than starting and stopping; setting each dish into its cooling environment is a single unbroken motion, not a hover-then-drop; each crystal's outward growth is visible in small, gradual increments frame to frame rather than sudden jumps in size; the direction and length of shadows cast by the dishes and the ice-water bath stay the same throughout, with no shadow suddenly flipping to face a different direction or vanishing.
level_5: Everything in score 4 holds, and additionally no object's edges blur in a way that doesn't match its actual speed of motion; nothing strobes or freezes unnaturally between frames; the two dishes keep the same distance and alignment relative to each other with no sign of the camera itself shifting or drifting; there is no camera zoom or refocusing during the clip; the background behind the dishes stays visibly identical (same objects, same brightness) from the first frame to the last.