Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Identification of Sulfide Bonds (Oxidation Color Reaction)

Video generation prompt: Take a small amount of dimethyl sulfide in a transparent test tube, add 1 mL of hydrogen peroxide solution, shake well, then add 1 drop of dilute nitric acid, and observe the solution.

Evaluation guide:
(i) Target concept: Acid-triggered oxidative color development in dimethyl sulfide via peroxide oxidation followed by reaction with nitric acid.
Minimum mechanism: Dimethyl sulfide and its oxidation products (dimethyl sulfoxide, and with excess peroxide, dimethyl sulfone) have no aromatic ring or conjugated system, so nitration cannot produce a conjugated chromophore here. Hydrogen peroxide first oxidizes dimethyl sulfide toward dimethyl sulfoxide; the subsequently added dilute nitric acid then reacts with this readily oxidizable sulfoxide, being itself partially reduced and releasing dissolved nitrogen-oxide species that impart the observed yellow color to the solution, requiring sequential reagent addition or the color does not appear.
(ii)Storyline: [Frame 0] Static shot: transparent cylindrical test tube containing small volume of colorless dimethyl sulfide. [Frame 1–2] Pipette enters frame, dispenses clear liquid (H2O2) into tube: volume increase visible. [Frame 3] Hand grasps tube and shakes vigorously → liquid oscillates with natural damping. [Frame 4] Dropper enters, positions vertically above tube opening, releases single spherical drop → drop falls, contacts surface, merges. [Frame 5] Within one observable fusion interval, entire liquid column transitions uniformly from colorless to yellow; no bubbling, precipitate, or phase change. Perspective: fixed frontal close-up, centered on tube mid-section, shallow depth of field isolating tube from background; all events fully visible, no occlusion.

Manual:
Experimental Procedure
1. Place dimethyl sulfide in transparent test tube.
2. Add 1 mL hydrogen peroxide solution.
3. Shake tube thoroughly.
4. Add 1 drop dilute nitric acid.
Observation of Experimental Phenomena
Colorless solution turns uniformly yellow only after nitric acid addition.
Summary of Experimental Principles
Hydrogen peroxide oxidizes dimethyl sulfide toward dimethyl sulfoxide. Dimethyl sulfide and its oxidation products have no aromatic ring, so nitration cannot explain the color. Instead, the readily oxidizable sulfoxide reduces part of the added nitric acid, releasing dissolved nitrogen-oxide species that give the solution its yellow color.

Prompt Grounding rubric:
level_1: No transparent test tube appears, no dimethyl sulfide is shown being placed in it, no hydrogen peroxide is added, no dilute nitric acid drop is applied, and none of the steps in the posted_prompt's sequence are shown.
level_2: A test tube or some liquid appears, but none of the required additions happen (no dimethyl sulfide going in, no hydrogen peroxide added, and no nitric acid drop), with the steps missing or replaced by unrelated objects or actions.
level_3: A transparent test tube holds a colorless liquid identifiable as dimethyl sulfide; hydrogen peroxide is visibly poured in; the tube is shaken; a single distinct drop of dilute nitric acid is then added; all three reagents and the shaking step appear in the right order, with no container or reagent swapped for something else.
level_4: Everything in score 3 holds, and the test tube stays still except when being shaken, the hydrogen peroxide and the nitric acid are delivered by visibly different means (e.g. a pipette or cylinder for the peroxide, a dropper for the acid), the shaking looks like a brief manual motion rather than mechanical vibration, and nothing extra (labels, gloves, other containers) enters the shot during this sequence.
level_5: Everything in score 4 holds, and the test tube is a clear cylinder with a rounded bottom showing no distortion or odd reflections, the initial dimethyl sulfide fills less than about a quarter of the tube, the hydrogen peroxide addition looks like roughly 1 mL by the change in liquid level, the nitric acid arrives as exactly one discrete drop with no spatter or trailing liquid, the shaking is vigorous but the liquid never leaves the tube, and there are no cuts, zooms, or viewpoint changes during the whole sequence.

Scientific and Causal Correctness rubric:
level_1: The liquid looks exactly the same color at the end of the clip as it did before any reagent was added, or it changes to a color that doesn't fit an oxidation reaction at all (e.g. it turns blue, green, or black, or the color fades away with no clear cause).
level_2: A color appears, but not in the way the reaction should work: for instance the liquid turns colored as soon as the hydrogen peroxide is added, before the nitric acid ever goes in, or the resulting color is something other than yellow (pink, purple, brown) and it doesn't need the acid to trigger or sustain it.
level_3: The liquid stays colorless right up until the nitric acid drop is added, then turns yellow with no in-between shades (no white cloudiness, no orange or amber phase); the yellow spreads evenly through the liquid and stays visible for at least a second after the drop is added.
level_4: Everything in score 3 holds, and the yellow only appears once the nitric acid drop has actually merged into the peroxide/dimethyl-sulfide mixture, never earlier and never just at the edges, with no bubbling, no precipitate, and no separate layer forming alongside the color change; the yellow looks even throughout, not patchy or streaked.
level_5: Everything in score 4 holds, and the yellow appears almost immediately once the acid drop merges with the liquid, the color's strength looks the same throughout the whole liquid column, it doesn't fade, darken, or shift shade for the rest of the clip, and the yellow stays a clean, stable, saturated shade rather than drifting toward brown, green, or a duller tone.

Spatiotemporal Consistency rubric:
level_1: The test tube is absent from the shot for a moment and then simply present again in a different spot, the liquid's volume jumps suddenly (full, then empty, with no pouring shown), the tube appears to shake with nothing touching it, a drop of acid appears in mid-air with no dropper or source visible, or the lighting flickers in a way that casts shadows that don't make physical sense.
level_2: The tube rotates more than about 90 degrees with nothing holding or supporting it, liquid splashes out of the tube during shaking and then is simply gone with no trace, the acid drop lands outside the tube or on its rim and then appears to jump inside, or something in the background shifts position between shots even though the camera hasn't moved.
level_3: The test tube stays centered and upright the whole time, any hands shown only touch the tube, dropper, or pipette, the liquid level only changes when something is actually added and never rises or falls on its own, shaking makes the liquid surface rock back and forth in a way that settles down naturally afterward, and nothing in the shot clips through another object, warps, or turns transparent unexpectedly.
level_4: Everything in score 3 holds, and the motions look physically sensible: the dropper comes down vertically and releases its drop without hesitating, the peroxide pours in as a smooth, even stream, the shaking's back-and-forth motion settles down gradually over at least three swings rather than stopping abruptly, there are no sudden jumps in brightness or contrast, and the light reflecting off the tube stays consistent with a single, unmoving light source.
level_5: Everything in score 4 holds, and the motion from one frame to the next flows smoothly with nothing skipping or strobing, the liquid's surface during shaking moves as a single coherent wave rather than breaking into disconnected pieces, the drop hitting the liquid dips the surface briefly before it settles back, and the tube's shape and the reflections on it stay geometrically consistent with no warping, no stray shadows, or highlights that don't move naturally with the tube.