Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Identification of Gentamicin by the Ninhydrin Colorimetric Method

Video generation prompt: Demonstrate weighing the gentamicin sample, dissolving it in water in a test tube, adding ninhydrin reagent using a pipette, heating the test tube in a water bath, and then removing it for result observation. Clearly show the equipment used, the process of reagent addition, and the sequential order of the heating step.

Evaluation guide:
(i) Target concept: Visual verification of ninhydrin-mediated color development specific to gentamicin"s primary amine groups under controlled thermal activation.
Minimum mechanism: Gentamicin must be physically present as soluble solid, ninhydrin must be delivered as aqueous reagent, heating must occur *after* mixing, and color formation must be thermally triggered and observable *post-removal*; all steps require intact molecular integrity and correct stoichiometric accessibility.
(ii)Storyline: [Frame 0–2] Gentamicin powder placed into test tube → [Frame 3–4] Water added and stirred (visually confirmed dissolution: no sediment, uniform clarity) → [Frame 5–6] Pipette approaches and delivers ninhydrin (tip contacts liquid, meniscus drops) → [Frame 7–8] Test tube lowered into water bath (steam/ripple visible, tube fully immersed) → [Frame 9] Test tube lifted out, held stationary → [Frame 10] Final frame shows homogeneous rust-brown solution; all transitions occur from fixed frontal-midrange viewpoint with consistent lighting; no cutaways, no POV shifts, no off-screen actions: every causal step fully visible and temporally contiguous.

Manual:
Experimental Procedure
1. Weigh gentamicin sample and place in clean test tube.
2. Add distilled water to dissolve gentamicin completely.
3. Using a pipette, add ninhydrin reagent to the solution.
4. Place test tube in boiling water bath for heating.
5. Remove test tube and observe color development.
Observation of Experimental Phenomena
After heating and removal, solution turns rust-brown or brownish-orange — no blue, purple, or red hues.
Summary of Experimental Principles
Gentamicin contains primary amines that condense with ninhydrin under heat to form a rust-brown Ruhemann’s purple analog; this colorimetric reaction is specific for primary amines in aminoglycoside antibiotics.

Prompt Grounding rubric:
level_1: No gentamicin sample, no test tube, no water, no ninhydrin reagent, no pipette, no water bath apparatus, and no observable heating or observation step. None of the six required objects or actions from the posted_prompt appear.
level_2: At least one correct object appears (e.g., test tube or pipette), but zero correct sequential actions: weighing is absent, dissolution is absent, reagent addition is absent, heating is absent, and post-heating observation is absent; all core steps are missing or replaced with unrelated actions.
level_3: All six core objects present: gentamicin sample (solid powder/granules), test tube, water (liquid in tube), ninhydrin reagent (liquid in pipette), pipette (held/used), and water bath (visible heated container); and at least three of the five core actions occur in correct order: (a) gentamicin placed in test tube, (b) water added to dissolve, (c) ninhydrin added via pipette, (d) test tube placed in water bath, (e) test tube removed for observation, but one or two actions are out-of-order, omitted, or misattributed (e.g., pipette used before water addition, or observation occurs before removal from bath).
level_4: All six core objects present and correctly identified by form/appearance; all five core actions occur in correct sequential order, with no omissions or inversions; however, one non-core flaw exists, e.g., pipette tip not visibly contacting liquid surface during addition, or water bath lacks visible steam/condensation despite heating, or gentamicin sample shown as clumped solid *after* dissolution claim without visible mixing motion.
level_5: All six core objects present and visually unambiguous: gentamicin appears as fine white solid before dissolution, test tube is transparent cylindrical glass, water is clear liquid filling ~1/3 tube before addition, ninhydrin reagent is pale yellow liquid in calibrated pipette, pipette tip makes direct contact with water surface during delivery, water bath shows consistent thermal cues (e.g., gentle surface ripple, uniform steam haze, or visible water level), and test tube is fully removed from bath before final observation. All five actions occur in strict sequence with correct spatial execution and no visual ambiguity.

Scientific and Causal Correctness rubric:
level_1: No color change occurs at any stage; solution remains colorless throughout; no heating is depicted; no reaction outcome is shown, completely inconsistent with ninhydrin-gentamicin chemistry.
level_2: A color change occurs, but it is incorrect: e.g., blue/purple (indicating amino acids like glycine) or red (indicating reducing sugars), or color appears *before* heating or *without* ninhydrin addition, violating causal chain and subject-specific principle.
level_3: Color change occurs *only after* heating and *only after* ninhydrin addition, and the final color is brownish-orange or rust-brown, matching expected ninhydrin-gentamicin product; however, either (a) the color appears while test tube is still in water bath (not after removal), or (b) the initial solution is visibly turbid or colored *before* heating, contradicting gentamicin solubility and ninhydrin stability.
level_4: Brownish-orange or rust-brown color appears exclusively *after* test tube removal from water bath, and only *after* ninhydrin addition and heating; pre-heating solution is colorless and transparent; gentamicin is fully dissolved before ninhydrin addition (no undissolved solids visible); however, one non-core scientific flaw exists, e.g., color develops gradually *during* heating but is not yet visible at removal, or slight greenish tint persists in final hue (minor deviation from canonical rust-brown).
level_5: Final observed color is exclusively rust-brown or uniform brownish-orange: no trace of blue, purple, red, yellow, or green; color appears *only* in the liquid phase *after* full removal from water bath and *only* following completion of heating; pre-ninhydrin solution is colorless and transparent; post-dissolution solution remains colorless until ninhydrin addition; ninhydrin addition causes no immediate color change; heating induces *no* visible bubbling or boiling; color develops uniformly across entire liquid volume with no phase separation, precipitate, or cloudiness, fully consistent with gentamicin-specific ninhydrin condensation under controlled conditions.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: test tube teleports between locations; pipette appears/disappears mid-action; water bath light flickers violently; test tube shatters or deforms between frames; or camera angle shifts abruptly (e.g., overhead → extreme close-up) with no motion transition.
level_2: Multiple discontinuities: at least two of the following: pipette tip moves without arm motion, water level changes without pouring action, test tube rotates without physical contact, steam appears then vanishes instantly, or lighting changes abruptly (e.g., shadow direction flips) between consecutive shots.
level_3: One minor spatiotemporal flaw: e.g., brief frame duplication causing momentary freeze, or single-frame lighting inconsistency (e.g., reflection on test tube appears only in one frame), or test tube position shifts slightly between insertion and removal without visible hand motion, but all objects maintain consistent size, orientation, and relative placement; no object violates physical continuity.
level_4: All objects maintain fixed relative positions: pipette remains adjacent to test tube throughout addition; test tube stays centered in water bath during heating; water bath surface shows continuous, stable thermal motion (no sudden stillness or acceleration); no lighting/shadow discontinuity across the entire sequence; no object deformation, scaling, or occlusion inconsistency, except one non-core flaw: e.g., steam density fluctuates non-monotonically, or hand enters frame inconsistently (once fully, once partially) without breaking spatial logic.
level_5: Zero spatiotemporal violations: pipette approaches test tube in continuous motion, contacts liquid surface, retracts, all with smooth velocity and consistent perspective; test tube is lowered into water bath with steady descent, remains motionless during heating, and is lifted vertically with uninterrupted motion; water bath surface exhibits uniform, low-amplitude ripple throughout heating; steam rises continuously and coherently; lighting remains physically consistent (shadow direction, intensity, and softness constant); no frame-level artifacts, no jitter, no occlusion mismatches, no scale/rotation anomalies; full cinematic continuity.