Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Clindamycin Detection

Video generation prompt: An appropriate amount of clindamycin sample was placed in a test tube, followed by the addition of sulfuric acid and nitric acid. The solution inside the test tube was observed.

Evaluation guide:
(i) Target concept: Acid-mediated chromogenic detection of clindamycin, in which concentrated sulfuric acid dehydrates and chars the sugar (methylthio-lincosamide) portion of the molecule to produce a yellow-to-amber colored product, while concentrated nitric acid oxidizes the mixture to generate white nitrogen-oxide fumes.
Minimum mechanism: Clindamycin must be exposed to both concentrated H2SO4 and HNO3 in sequence to generate a stable, visible colored product with co-emitted fumes; color development and fuming must be causally tied to the dual-acid treatment and observable as the terminal event.
(ii)Storyline: [Phase 1: Setup] White clindamycin solid is placed into upright glass test tube: visible, unmoving, centered. [Phase 2: Reaction Initiation] Sulfuric acid flows into tube: liquid stream visible, meniscus rises. [Phase 3: Reaction Completion] Nitric acid flows in: second stream, meniscus rises further; no color/fume yet. [Phase 4: Phenomenon Onset] Within <1s after nitric acid addition, yellow-amber color emerges uniformly from bottom upward; white fumes rise continuously from liquid surface. [Phase 5: Observation] Observer maintains steady gaze on test tube; fuming and color persist without decay or fluctuation; all events occur from fixed frontal viewpoint with consistent lighting and no occlusion.

Manual:
Experimental Procedure
1. Place a small amount of white crystalline clindamycin powder into a clean glass test tube.
2. Add ~0.5 mL concentrated sulfuric acid dropwise.
3. Add ~0.5 mL concentrated nitric acid dropwise.
4. Observe the resulting solution immediately.
Observation of Experimental Phenomena
The solution develops a distinct yellow-to-amber color and emits continuous white fumes from the surface.
Summary of Experimental Principles
Concentrated sulfuric acid dehydrates and chars the sugar-containing (methylthio-lincosamide) portion of the clindamycin molecule, producing conjugated, light-absorbing degradation products that give the solution its yellow-to-amber color; clindamycin has no aromatic ring, so this coloration is not the product of nitration or sulfonation of an aromatic system. The added nitric acid acts as a strong oxidant on the acid mixture, releasing nitrogen oxide gases that are seen as the white fumes above the liquid.

Prompt Grounding rubric:
level_1: No test tube appears; no white clindamycin sample is shown; neither the sulfuric acid nor the nitric acid container appears; no acid is ever poured into anything; no one is shown watching the tube.
level_2: A test tube holds a white solid, but nothing marks or contextually implies that solid is clindamycin; only one of the two acid containers (sulfuric or nitric) is shown, not both; no pouring of any acid into the tube takes place; the tube's state after any addition is never shown.
level_3: A test tube holds a visible white solid consistent with clindamycin; containers of both sulfuric acid and nitric acid appear in frame; at least one of the two acids is shown being poured into the tube; someone is shown looking at the tube; the order placement, then acid addition, then observation is followed.
level_4: Everything required for score 3 holds, AND both acids are shown being poured in as two separate, clearly visible pouring actions; the observer keeps looking at the test tube throughout the observation phase; nothing unrelated interrupts the sequence; the test tube sits centered with the acid containers nearby and the observer sharing the same shot.
level_5: Everything required for score 4 holds, AND the sequence follows a strict order: clindamycin placed first, then sulfuric acid, then nitric acid, then observation begins right away and continues to the end; each of the three steps is visually clear, does not overlap with the next, and runs without any cut or jump; the test tube stays in the same spot and orientation the whole time; the observer's head and eyes stay turned toward the test tube for the entire observation phase.

Scientific and Causal Correctness rubric:
level_1: No color appears in the solution at any point; the liquid stays clear and colorless before and after both acids are added; no fuming, bubbling, or heat-related change is seen; the solution at the end looks the same as it did at the start.
level_2: Only one acid is added and it causes slight bubbling or a brief haze but no color develops; the solution stays colorless through to the end; there is no visible difference between the tube before and after the acid is added; an acid is poured in but nothing visibly happens as a result.
level_3: Both acids are added and the solution clearly changes color, turning yellow, amber, or pale brown; the color spreads evenly through the liquid; it stays once it appears rather than flickering in and out; the color only shows up after both acids have gone in, and it is what the observer is shown looking at.
level_4: Everything required for score 3 holds, AND once the color appears, white vapor also starts rising continuously from the liquid's surface, and this only begins after both acids are in; the fuming and the coloring show up together and last through the observation; no fuming shows up before the second acid goes in; no color shows up before both acids have been added.
level_5: Everything required for score 4 holds, AND the white fuming stays above the liquid surface rather than appearing to originate from inside the liquid or outside the tube's walls; the color looks even throughout the whole volume of liquid, without streaks, layers, or a settled solid; the inside of the tube shows no staining or residue from the reaction; nothing else happens (no boiling over, no splashing, no charring) beyond the coloring and fuming.

Spatiotemporal Consistency rubric:
level_1: The white clindamycin powder is shown already dissolved/reacted in one frame with no acid-adding action shown beforehand; the sulfuric acid or nitric acid container swaps position or is replaced by a different-looking container between the two addition shots, or the test tube or an acid container vanishes from the shot and reappears elsewhere with no motion in between; the tube's liquid is colorless in one frame and already fully amber in the next with no gradual change shown in between; the white fumes appear above the liquid before the nitric acid has been added; or the lighting on the scene flips abruptly (e.g., bright to dark) with no apparent cause, or the test tube spins or tips sharply out of position with no continuous motion shown.
level_2: The test tube shifts by more than about half its width to a noticeably different spot in the frame between the acid-addition shot and the observation shot with no hand or holder movement to explain it, or a shadow on the test tube jumps to a new position with no corresponding light-source movement; the stream of acid flowing into the tube cuts out and restarts partway through pouring rather than falling as one continuous stream; the observer's head is angled toward the test tube in one frame and then facing away in the very next frame with no turning motion shown in between.
level_3: The test tube stays in the same spot and at the same angle from the moment the clindamycin is placed in it through to the end of the observation; each acid, once its stream begins flowing into the tube, keeps flowing without interruption until that addition is done; the observer's head and gaze stay pointed at the test tube through the whole observation phase; the tube and its contents do not warp, flicker, or break apart at any point.
level_4: Everything required for score 3 holds, AND the liquid's meniscus rises smoothly, without pausing or slipping back down, during each acid addition; once fuming starts, the white vapor builds up gradually from the liquid surface rather than snapping into existence all at once; the yellow-to-amber color spreads upward from the bottom of the liquid in a steady progression rather than appearing everywhere at once; the observation phase is never shown happening before both acids have been added.
level_5: Everything required for score 4 holds, AND the incoming acid streams show natural speeding-up and slowing-down rather than moving at one constant rate throughout; the white fuming keeps getting thicker over time rather than staying at a constant density or fading in and out; the amber color keeps deepening steadily rather than jumping between shades; the test tube and the background behind it hold a steady, non-shaking framing for the entire video.