Domain: Healthcare — Medicine
Target concept: Drug compatibility test (electrolyte compatibility)

Video generation prompt: A transparent test tube containing 1 mL of calcium chloride injection was placed on the table. Subsequently, 1 mL of sodium bicarbonate injection was added to the test tube. The mixture was thoroughly combined, and changes in the state of the resulting solution were observed.

Evaluation guide:
(i) Target concept: Electrolyte incompatibility manifested as rapid, irreversible precipitation upon mixing two stable parenteral solutions.
Minimum mechanism: Calcium ions (Ca²⁺) from calcium chloride must encounter bicarbonate ions (HCO₃⁻) from sodium bicarbonate to form solid calcium carbonate (CaCO₃), which lacks solubility in aqueous medium and thus precipitates as discrete white particles observable by eye.
(ii)Storyline: [Frame 0–2] Static shot: upright transparent test tube on table, filled to ~1 mL mark with clear liquid (CaCl₂); adjacent syringe/vial holds second clear liquid (NaHCO₃). [Frame 3–4] Tip of delivery device enters tube mouth; liquid flows in continuously without splashing. [Frame 5] Flow stops; meniscus stabilizes at ~2 mL. [Frame 6] Turbidity appears instantly across entire column. [Frame 7–10] White particles descend uniformly; upper zone clears slightly while lower zone densifies — all under fixed viewpoint with stable illumination.

Manual:
Experimental Procedure
1. Place a transparent test tube containing 1 mL of calcium chloride injection on table.
2. Add 1 mL of sodium bicarbonate injection into the test tube.
3. Gently swirl to mix.
Observation of Experimental Phenomena
Immediate formation of white precipitate; solution becomes turbid; precipitate gradually settles to bottom.
Summary of Experimental Principles
Calcium chloride and sodium bicarbonate react to form insoluble calcium carbonate (white precipitate) and soluble sodium chloride — a classic electrolyte incompatibility due to formation of an insoluble salt.

Prompt Grounding rubric:
level_1: No test tube is shown, or no calcium chloride solution is visible, or no sodium bicarbonate solution is visible, or both solutions are shown already combined from the start with no separate pre-mixing state, or the pouring/addition action never happens.
level_2: A test tube holding a clear liquid consistent with calcium chloride solution is present, and a separate container (syringe or vial) holding a clear liquid consistent with sodium bicarbonate solution is present, but the act of adding the second solution into the tube is missing, cut away, or happens off-screen.
level_3: The test tube containing the calcium chloride solution is shown standing on the table before anything is added; the sodium bicarbonate solution is then visibly poured or injected from a separate container into the tube; both solutions are present beforehand and end up combined in the same tube afterward, without unrelated objects or actions (labels, gloves, stirring rods) dominating the shot.
level_4: Everything in Level 3 holds, AND the addition happens as one continuous pour or injection with no cut or jump partway through; no irrelevant object enters the foreground or background during the addition.
level_5: Everything in Level 4 holds, AND the liquid fills a comparably small portion of the tube both before and after addition, consistent with combining two small volumes rather than filling or overflowing the tube; both solutions read as clearly colorless before mixing; the delivery device empties fully into the tube with no liquid visibly left clinging to its tip; no flicker, blur, or lens artifact ever obscures the tube or its contents.

Scientific and Causal Correctness rubric:
level_1: No precipitate ever forms, or a precipitate is already present before the sodium bicarbonate is added, or the precipitate has a color other than white (e.g., yellow or pink), or the liquid turns cloudy without any visible solid particles, or a precipitate that forms later fully redissolves before the video ends.
level_2: A precipitate does appear, but only more than about 2 seconds after the addition finishes (a noticeable pause with clear liquid before anything clouds), or it forms in only part of the liquid (e.g., only near the bottom or only near the surface) rather than throughout, or the solid clumps float persistently instead of ever settling, or the liquid turns uniformly hazy without any discrete particles being visible.
level_3: White precipitate becomes visible within about 1 second after the addition is complete; the particles are suspended through the liquid at first and then begin drifting downward; the liquid clearly moves from fully clear to visibly turbid with discrete white specks, with no color change, bubbling, or other unrelated effect.
level_4: Everything in Level 3 holds, AND the settling particles move steadily downward with no particles drifting back upward or re-suspending; the turbidity persists rather than clearing up again; there is no separate floating layer, foam, or other unrelated phase change; the precipitate never disappears once formed.
level_5: Everything in Level 4 holds, AND the precipitate stays purely white throughout with no tint shift; the particles look finely and evenly distributed through the whole liquid column with no clumps larger than about a third of the tube's height; the downward settling looks smooth and steady rather than erratic; there is no shimmering or rainbow-like sheen at the liquid's surface that would be inconsistent with a plain white solid suspension.

Spatiotemporal Consistency rubric:
level_1: The test tube is missing from the frame for a stretch and then abruptly back in view with no motion explaining the gap; the lighting or shadow direction flips without cause; there is an abrupt zoom or crop between shots; the tube changes shape or size mid-video; or the liquid's level jumps from one height to another without a visible pour.
level_2: The tube shifts by more than about half its width or height between the moments just before and just after the addition; the shadow cast by the tube or the hand moves in a way inconsistent with a fixed light source; the liquid surface wobbles violently with no hand or device touching the tube to explain it; or background elements flicker or change shape.
level_3: The test tube stays in the same position and orientation from before the addition through afterward; the direction and brightness of the lighting stay the same across the whole clip; the liquid surface rises and settles in a way that matches a real pour, with no part of the tube or liquid teleporting, clipping through another object, or warping.
level_4: Everything in Level 3 holds, AND the camera itself never pans, tilts, or rolls, keeping the full height of the tube in view before, during, and after the addition; the tube's outline stays aligned with the table edge or background behind it with no drifting; the liquid's surface deforms in a way consistent with gravity as it is poured, with no strobing or ghosting between frames.
level_5: Everything in Level 4 holds, AND the whole sequence reads as one unbroken take from before the addition through the onset of settling, with no duplicated, skipped, or interpolated-looking frames; no motion blur hides the moment the precipitate first appears or where the liquid surface sits; the tube wall stays in sharp focus at the same time as the liquid inside it, with no artificial defocusing of one and not the other.