Domain: Humanities and Social Sciences — Linguistics
Target concept: Nasal consonant (/m/): Bilabial closure, with air flowing out through the nasal cavity in gaseous form.

Video generation prompt: In a cold room where breathing produces visible white vapor, a person closes their lips together and continuously produces a sustained humming sound (/m/) for several seconds while facing the camera.

Evaluation guide:
(i) Target concept: Nasal consonant /m/ requires simultaneous bilabial occlusion and velopharyngeal opening to permit airflow solely through the nasal cavity; visible vapor forms only when warm, humid exhaled air meets cold ambient air, causing condensation.
Minimum mechanism: Ambient air must be sufficiently cold (<~15°C) and dry enough to support condensation; exhaled air must be warm/humid; lip closure must be complete and sustained; velopharyngeal port must be open (inferred via exclusive nasal emission and absence of oral escape).
(ii)Storyline: [Cold-room context established] → [Person inhales (not scored, but ambient vapor confirms cold air)] → [Lips close fully and remain sealed] → [Voiced /m/ begins: immediate onset of bilateral, continuous, non-turbulent vapor emission from nostrils only] → [Emission persists synchronously with lip closure] → [No competing emissions (mouth/chin), no timing mismatch, no spatial drift]. Perspective: Fixed frontal medium-close shot capturing full lips, nose, and immediate perinasal region; lighting ensures clear visibility of nostril apertures and vapor trajectory without glare or occlusion.

Manual:
Experimental Procedure
1. Person stands in a cold room (ambient temperature visibly low: e.g., frost on window, visible ambient breath vapor).
2. Person closes lips fully and continuously produces the nasal consonant /m/.
3. Observe vapor emission exclusively from both nostrils.
Observation of Experimental Phenomena
White vapor appears continuously and only from both nostrils while lips remain fully closed; ambient breath vapor is present before and during articulation.
Summary of Experimental Principles
/m/ is a bilabial nasal consonant: complete lip closure blocks oral airflow, forcing exhaled air through the nasal cavity, where rapid cooling in the cold environment causes water vapor to condense into visible white plume.

Prompt Grounding rubric:
level_1: No person is shown in the scene, or the room shows no cold-weather cues (no frost, no condensation, no vapor from ordinary breathing) and the person's lips are never closed together; there is no sustained humming posture at all, and no white vapor of any kind appears in the shot.
level_2: A person appears in an indoor setting, but the room shows no clear cold cue before the hum begins (no frost on glass, no condensation, no vapor visible during ordinary breathing); the lips open and close irregularly instead of staying shut, and any stretch of full lip closure lasts under roughly a second.
level_3: The room shows at least one clear cold cue (frost on a window, condensation on a cold surface, or vapor visible on the person's ordinary breaths); the person's lips are pressed fully together for a continuous stretch of at least a few seconds while appearing to vocalize; the camera keeps the person's face, mouth, and nose region in frame for that stretch.
level_4: The room's cold cues are visible throughout the segment; the person's lips stay fully pressed together for the entire humming stretch with no visible reopening or gap; the camera holds a steady frontal or near-frontal framing that keeps the nose and mouth continuously visible; some white vapor is visible near the person's face during the hum, and the person makes no unrelated movement (no talking, no hand near the face) during the segment.
level_5: The room's cold cues (frost or condensation) are visible both before the hum starts and continuously afterward, with none of them disappearing partway through; the person's lips stay visibly sealed for the entire segment with no parting, gap, or trembling large enough to see; the camera holds one steady, unmoving frontal framing for the whole clip, with the nose and mouth never leaving view or being blocked by hair, hands, or a change in angle; the person performs no extraneous action (no sniffing, no swallowing, no adjusting clothing, no speech) during the segment.

Scientific and Causal Correctness rubric:
level_1: Visible vapor comes from the mouth or gathers at the chin while the lips are shown closed for the hum, or vapor appears with no connection to any cold cue in the room; no vapor is visible near the nostrils at any point during the hum.
level_2: A trace of vapor appears from only one nostril, or vapor appears well before the lips close or only after the hum has already ended so it is not timed with the period of lip closure; some vapor is also visible escaping near the lip line during the hum.
level_3: Vapor is visible from both nostrils while the lips stay closed during the hum, and ordinary breath vapor is visible elsewhere in the room; however, a wisp of vapor is also visible near the lip seam at some point, or the vapor from one nostril is clearly heavier or longer-lasting than the other with no visible reason such as a head tilt.
level_4: Vapor is visible from both nostrils only for the entire hum, with none visible at the lips, chin, or cheeks at any point; the vapor from the two nostrils looks similar in thickness and direction; ordinary breath vapor remains visible in the room both before and during the hum.
level_5: Vapor from both nostrils begins at essentially the same moment the lips first press together and continues without interruption for as long as the lips stay closed, tapering off if the lips later separate; the two nostril streams stay visually matched in thickness and direction the whole time; no vapor at any point drifts from the mouth, chin, or cheeks, and the nostril streams look like a steady gentle flow rather than a sudden puff or a wavering, wind-blown wisp.

Spatiotemporal Consistency rubric:
level_1: The clip contains a visible cut where the person's position, pose, or the room background changes abruptly from one moment to the next; or the white vapor instantly blinks out of existence rather than gradually drifting and fading, breaking the sense of one continuous recording; or the room's lighting abruptly brightens, dims, or shifts color with no visible cause.
level_2: At some point the lips appear to snap from closed to open (or the reverse) with no visible motion in between; or the vapor plume blinks off and back on within what is otherwise a single continuous take; or a background cold cue (such as window frost) changes appearance abruptly partway through the clip with no visible cause.
level_3: The shot runs as one continuous take with no cuts; the person's head and body stay in roughly the same position and pose throughout with no sudden relocation; the vapor drifts and dissipates gradually rather than switching on and off; a minor, gradual lighting or shadow shift may occur but does not break the sense of a single continuous recording.
level_4: The shot is one continuous, uninterrupted take with a fixed or smoothly moving camera; the person's head position, facing direction, and the room background stay consistent throughout with no unexplained jump; the vapor plume moves and fades gradually and naturally without ever blinking off and on; lighting stays even across the whole clip with no sudden brightening, darkening, or reversal of shadow direction.
level_5: The shot is one continuous take from a fixed camera position with no perceptible cut, jolt, or reframing; the person's head, shoulders, and the room's cold-weather cues keep the same relative positions in every visible moment, with no unexplained repositioning; the vapor plume's path is smooth and gradual from first appearance to dissipation, with no stretch where it goes fully invisible and then visible again; lighting and shadow on the face stay even for the full duration, with no visible flicker or brightness pulse.