Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Vitamin D Testing

Video generation prompt: Place an appropriate amount of vitamin D sample in a test tube, and add a chloroform solution of antimony trichloride. Observe the solution in the test tube.

Evaluation guide:
(i) Target concept: Visual confirmation of the antimony trichloride color reaction for vitamin D; cholecalciferol reacts with antimony trichloride dissolved in chloroform to develop a yellow-to-orange color, used as a qualitative identification test (this is distinct from the classic blue Carr-Price reaction used for vitamin A).
Minimum mechanism: Vitamin D must be present as a solid reactant; antimony trichloride must be dissolved in chloroform (not aqueous or dry); the reaction requires direct contact in a common solvent phase; the yellow-to-orange color arises exclusively from the formed vitamin D–antimony complex in solution, not from impurities, oxidation, or light scattering.
(ii)Storyline: [Phase 1] Static shot: empty upright test tube centered in frame. [Phase 2] Hand enters frame holding the vitamin D sample (white crystalline solid), places it into the tube; solid rests visibly at the bottom. [Phase 3] Hand re-enters with a labeled dropper containing a clear liquid (the antimony trichloride/chloroform solution), dispenses drops into the tube; liquid flows continuously into the tube, contacting the solid. [Phase 4] 1–2 seconds pause: the solution remains colorless. [Phase 5] A yellow-to-orange color emerges homogeneously in the liquid volume while the solid remains intact and white; camera holds steady on the tube for the full observation window. Perspective: fixed frontal view, eye-level, no occlusion, sufficient resolution to distinguish solid vs. liquid and the onset of color.

Manual:
Experimental Procedure
1. Place a small amount of white crystalline vitamin D solid into a clean, dry test tube.
2. Add chloroform solution of antimony trichloride dropwise into the same test tube.
Observation of Experimental Phenomena
A yellow-to-orange color develops uniformly in the liquid phase of the test tube shortly after addition.
Summary of Experimental Principles
Vitamin D reacts with antimony trichloride in chloroform to form a yellow-to-orange colored complex, used for qualitative identification; this reaction is distinct from the blue Carr-Price reaction characteristic of vitamin A under the same reagent.

Prompt Grounding rubric:
level_1: No test tube is shown; no white crystalline vitamin D solid appears; no antimony trichloride/chloroform solution appears; nothing is placed into a test tube; no observation of the tube's contents takes place.
level_2: A test tube containing some liquid is shown, but no identifiable white crystalline solid is placed into it, or the antimony trichloride solution is absent, unlabeled, or clearly the wrong container/color; the placement of the solid or the addition of the liquid is shown happening to the wrong object or is skipped entirely.
level_3: A test tube is shown; a small amount of white crystalline solid (the vitamin D sample) is placed into it; a clear, colorless liquid (the chloroform solution of antimony trichloride) is then added into the same tube; the camera's attention moves to the test tube right after the liquid is added; the solid is added before the liquid, in that order.
level_4: Everything required at level 3 is shown, plus: the test tube stays upright and still while the solid is added and while the liquid is poured in; the vitamin D solid is clearly visible as a distinct solid piece before it goes into the tube; the liquid is delivered from a labeled dropper or pipette held near the tube; nothing blocks the view of the tube while its contents are being observed.
level_5: Everything required at level 4 is shown, plus: the test tube stays centered in the frame for the whole clip; the solid goes in first, then the liquid is added in one continuous pour with no back-and-forth; the camera holds a fixed view with no panning, tilting, or zooming for the full sequence; no object appears twice, goes missing, or is swapped for a different one at any point.

Scientific and Causal Correctness rubric:
level_1: No color change occurs in the test tube; the solution stays colorless throughout; or the vitamin D sample or the antimony trichloride solution is misrepresented (e.g., a pre-colored powder is used instead of a white crystalline solid, or the liquid is already colored before it is added); no yellow, orange, or any other color develops at any point.
level_2: A color does appear, but it is the wrong hue for this reaction (e.g., blue, green, purple, or deep red instead of yellow-to-orange); or the color is visible before the antimony trichloride solution is added, or appears with no addition action shown; or the coloration shows up outside the liquid (e.g., on the tube wall or the solid's surface only) with no visible link to the addition step.
level_3: After the chloroform solution of antimony trichloride is added to the vitamin D sample, a distinct yellow-to-orange color appears in the liquid inside the test tube; the color stays within the liquid phase and does not appear on the solid residue; the color only appears after the addition is complete and stays visible for the rest of the clip.
level_4: Everything required at level 3 is shown, plus: the yellow-to-orange color is even across the liquid, without obvious streaking, layering, or isolated patches of darker or lighter color; no clearly different competing hue (such as blue or green) appears anywhere in the liquid; the solid vitamin D sample keeps its white color and shape after the liquid is added.
level_5: Everything required at level 4 is shown, plus: the color visibly deepens from colorless to yellow-to-orange within about 1–2 seconds of the liquid reaching the solid, showing a clear, continuous progression rather than an instant jump; no bubbling, precipitation, or cloudiness accompanies the change; by the end of the clip the liquid is a clear, evenly colored yellow-to-orange solution with the solid vitamin D particles still visible resting at the bottom.

Spatiotemporal Consistency rubric:
level_1: The test tube's contents change with no visible cause between shots (e.g., it is empty in one frame and full in the next with no pour shown); the vitamin D solid appears inside the tube without the hand ever placing it there; the antimony trichloride solution pours in from off-screen with no dropper or source container visible; the room lighting or the tube's shadow changes suddenly partway through the clip with no corresponding change in the scene.
level_2: The test tube's apparent width or height changes noticeably between shots; the vitamin D solid shrinks, grows, or briefly disappears right after being placed; the liquid stream from the dropper freezes, skips forward, or jumps in level instead of flowing continuously; the camera view switches abruptly between distances (e.g., close-up to wide shot) with no smooth transition.
level_3: The test tube, hand, dropper, and solid keep the same size and the same position relative to each other from shot to shot; the hand's motion from holding the sample to placing it in the tube, and later from the dropper to the tube opening, is continuous rather than jumping between poses; the direction and brightness of the light on the tube stay the same for the whole clip; the sequence plays as one continuous take or as cuts that preserve the scene's spatial layout.
level_4: Everything required at level 3 is shown, plus: the test tube stays upright with no visible wobble or tilt while the solid is added and the liquid is poured; the hand's movements follow a natural, smooth path with no sudden jumps or unnatural bending; objects in the background stay still and do not distract from the tube; the relative positions of the tube, hand, and background stay consistent as the camera view changes.
level_5: Everything required at level 4 is shown, plus: the poured liquid keeps a coherent, unbroken stream shape rather than breaking into disconnected droplets or freezing mid-air; no blurring obscures the solid or the liquid's color; there is no flickering, doubling, or ghosting of the tube or hand between frames; the test tube's base stays flush with the surface it rests on, and its round cross-section is never visibly warped or stretched.