Domain: Natural Science — Chemistry
Target concept: Trimethylborate

Video generation prompt: Load an appropriate amount of trimethyl borate into the Bunsen burner and ignite the burner.

Evaluation guide:
(i) Target concept: Visual demonstration of boron-specific flame color via controlled combustion of trimethylborate in a Bunsen burner.
Minimum mechanism: Trimethylborate must be delivered to the burner's gas inlet (not mixed with air upstream); it is itself highly volatile at room temperature (boiling point ~68°C) and vaporizes readily as soon as it enters the inlet, without requiring the inlet to be pre-heated; the vapor combusts in the oxygen-rich zone at the inlet, producing excited BO radicals whose decay emits green light.
(ii)Storyline: [Frame 0–2] Static shot: intact Bunsen burner centered, inlet clearly visible; vial of transparent liquid held adjacent. [Frame 3–5] Hand moves vial to inlet and releases liquid; stream enters inlet without spillage. [Frame 6–7] Liquid enters the inlet and begins vaporizing immediately at room temperature; no visible fume or splash. [Frame 8–9] Ignition source touches inlet; flame initiates *at point of liquid contact*. [Frame 10–25] Flame stabilizes with persistent green inner cone, no color drift or instability. Perspective: fixed frontal view, full burner height in frame, inlet and flame origin unoccluded at all times.

Manual:
Experimental Procedure
1. Hold a small vial containing transparent/very pale amber trimethylborate liquid adjacent to the inlet tube of a stationary Bunsen burner.
2. Pour a small amount of liquid directly into the burner inlet.
3. Immediately apply an ignition source (e.g., match) to the inlet.
Observation of Experimental Phenomena
A steady flame emerges from the burner inlet, displaying a distinct and sustained green hue in its inner cone — characteristic of boron combustion. No soot, smoke, or yellow/orange emission is observed.
Summary of Experimental Principles
Trimethylborate (B(OCH₃)₃) is a volatile, flammable organoborane (boiling point ~68°C) that vaporizes readily at room temperature. Upon ignition, boron in the vapor is oxidized and forms excited BO (and BO₂) molecular species; the radiative decay of these molecular species emits intense green light (~546-548 nm), a hallmark flame test for boron compounds.

Prompt Grounding rubric:
level_1: No Bunsen burner appears; no container of trimethylborate liquid is shown; no ignition action takes place; no flame ever appears in the clip.
level_2: The Bunsen burner appears but is untouched by the demonstration; either the liquid container or the flame shows up, but not both; the ignition action is missing or aimed at the wrong spot (e.g., a lighter near the air vent rather than the fuel inlet); trimethylborate is never shown going into the burner.
level_3: The Bunsen burner is shown correctly oriented; a small vial of clear-to-pale-amber liquid (trimethylborate) is held near the burner's inlet; the hand tips or pours from the vial toward the inlet; a flame appears, but exactly where it starts is unclear (for instance, it appears with no visible contact between the liquid and the burner, or before the pouring motion has finished).
level_4: The Bunsen burner sits still and is fully shown; the clear-to-pale-amber liquid is visibly delivered into the burner's inlet; the ignition source is brought to the inlet only after the liquid has been shown entering it; the flame comes out of the inlet itself; nothing jumps position or teleports across the scene.
level_5: Everything required for score 4 holds, and in addition the liquid goes only into the inlet with none spilling onto the base or nearby surfaces, the flame appears right after and only at the spot where the liquid entered, no unrelated objects (gloves, labels, other containers) enter the frame, and the camera holds one fixed, front-facing view showing the whole burner, the inlet, and the flame the entire time.

Scientific and Causal Correctness rubric:
level_1: The flame burns blue-white or violet with no green at all; the liquid looks solid, opaque, or colored (red, green); a flame appears before any liquid has been introduced; or the flame comes from the burner's base, an air hole, or the tabletop instead of the inlet.
level_2: The liquid looks wrong for trimethylborate (milky, thick, yellow-brown, or clearly labeled as something else); a flame appears but its color is off (mostly orange/yellow, or flickering violently like a typical hydrocarbon flame); or the flame appears at the same instant as the liquid with no sense that one caused the other.
level_3: The liquid is clear to very pale amber and pours like a thin, watery fluid, consistent with trimethylborate; the flame has a bluish base with a hint of green, and it appears only after the liquid has reached the inlet, but the green tint is faint, comes and goes, or never really settles into the flame's core.
level_4: The liquid is clear to pale amber, thin, and held in a small vial or dropper; the flame comes out of the inlet and shows a clear, steady green color in its inner cone, matching the known boron flame-color signature; the flame burns evenly without sooting; the sequence runs loading, then a short pause, then ignition, then the green flame appearing right away; nothing shows the liquid bubbling, boiling, or giving off vapor before ignition.
level_5: Everything required for score 4 holds, and in addition the green fills the whole inner cone evenly rather than showing up only in patches or at the edges, no yellow or orange shows up anywhere in the flame (which would suggest soot/carbon contamination), the liquid shows no bubbling, fuming, or surface disturbance before ignition, and the flame keeps burning steadily for at least two seconds without sputtering, shrinking, or changing color.

Spatiotemporal Consistency rubric:
level_1: The Bunsen burner jumps to a different position between frames, the flame appears or disappears abruptly without any visible growth, the liquid container jumps from the hand directly to the inlet with no motion in between, the lighting swings dramatically partway through (bright to dark), or the burner shows a structural break (missing collar, bent tube) partway through the clip.
level_2: The flame's outline flickers or strobes noticeably; the hand blocks the inlet during pouring and then vanishes from view abruptly; the liquid looks like a flat overlay rather than something with real volume and flow; the flame wobbles with an unnatural, jerky rhythm; or the background shifts sideways by a noticeable fraction of the frame.
level_3: The hand's pouring motion looks a little uneven rather than perfectly smooth, but stays continuous; the flame grows out of the inlet but briefly flickers or dims for a moment during that growth; the liquid stream shows a small stutter rather than flowing perfectly evenly; the burner stays fully visible and intact the whole time.
level_4: Everything required for score 3 holds, and in addition the pour looks like one unbroken, natural hand motion, the liquid flows as a coherent stream with even opacity from start to finish, the flame grows continuously out of the inlet with a stable shape and brightness, the inlet is never blocked from view during the loading-to-ignition-to-flame sequence, and the lighting and the burner's shadow hold steady in direction and strength.
level_5: Everything required for score 4 holds, and in addition the liquid stream keeps a constant thickness and clarity for the whole pour, the flame's growth in height and width looks like a natural, gradually accelerating expansion rather than a straight-line ramp, motion blur never smears the burner's collar enough to lose its shape, and every part of the clip shows the burner, hand, liquid, and flame in spatially consistent, believable positions relative to each other.