Domain: Engineering — Nuclear Engineering
Target concept: There are four core bright lines in the characteristic ultraviolet discrete spectrum of mercury atoms.

Video generation prompt: A mercury vapor discharge device is placed inside a vacuum glass tube, connected to a high-voltage power supply. After turning on the power supply, the spectrometer is adjusted to the ultraviolet wavelength range for observation.

Evaluation guide:
(i) Target concept: Discrete UV line emission from excited mercury vapor under electrical discharge.
Minimum mechanism: Mercury atoms must be in low-pressure gaseous state inside sealed transparent tube; sufficient high-voltage electric field must ionize and excite atoms; emitted photons must correspond to ΔE = hν transitions yielding four specific UV wavelengths; spectrometer must resolve these as spatially separated lines, not blended or continuous.
(ii)Storyline: [Frame 0] Vacuum glass tube (empty, clear, sealed) shown with unconnected electrodes. → [Action 1] HV power supply connected to electrodes. → [Frame ~2] Power switched on → localized bluish-violet glow initiates at electrodes and fills vapor path. → [Action 2] Spectrometer rotated/adjusted to face tube output port. → [Frame ~5] Spectrometer eyepiece/display reveals four sharp, isolated, bright lines against dark UV-scale background. → [Causal lock] Lines appear only after glow stabilizes and vanish immediately upon power-off. Visibility constraint: All key elements (tube interior glow, spectral lines, electrode contacts, HV label) must remain fully in-frame and unoccluded throughout; fixed frontal viewpoint with shallow depth of field emphasizing tube and spectrometer view.

Manual:
Experimental Procedure
1. Place mercury vapor discharge device inside vacuum glass tube.
2. Connect tube electrodes to high-voltage power supply.
3. Turn on power supply.
4. Adjust spectrometer to observe UV wavelength range.
Observation of Experimental Phenomena
Bluish-violet glow appears inside tube; spectrometer shows four discrete bright lines in UV region (no continuous spectrum).
Summary of Experimental Principles
Mercury atoms emit four characteristic bright lines in ultraviolet due to electron transitions between quantized energy levels.

Prompt Grounding rubric:
level_1: No mercury vapor discharge device visible; no vacuum glass tube present; no high-voltage power supply shown; no spectrometer visible; none of the four required experimental objects appear.
level_2: At least one object appears (e.g., a generic tube or power supply), but the mercury vapor discharge device is absent or unidentifiable; vacuum glass tube is missing or mislabeled (e.g., labeled as “air-filled” or “plastic”); spectrometer is absent or clearly non-UV-capable (e.g., labeled “visible only” or showing red/green filters); sequence of setup steps is completely absent or reversed.
level_3: Mercury vapor discharge device is visibly present inside a transparent cylindrical tube; tube is explicitly labeled or visually consistent with “vacuum glass tube” (e.g., sealed, no bubbles, no liquid, clear walls); high-voltage power supply is connected via wires to tube electrodes; spectrometer is present and oriented toward tube output; all four core objects exist in correct functional roles, but at least one lacks correct labeling, orientation, or contextual integration (e.g., spectrometer pointed away, power supply disconnected, tube not sealed).
level_4: All four core objects are present and correctly identified: (1) mercury vapor discharge device (visible electrode structure + vapor path inside tube), (2) vacuum glass tube (sealed, cylindrical, transparent, no condensate or particulates), (3) high-voltage power supply (labeled or iconographically indicated as HV, with active connection to tube electrodes), (4) spectrometer (labeled “UV” or showing UV-range scale, physically aligned to receive light from tube exit port); all objects coexist in same scene with fixed viewpoint; no extraneous devices or contradictory labels.
level_5: All conditions for score 4 are satisfied, and additionally: (a) mercury vapor discharge device is visibly activated (i.e., faint glow visible inside tube, localized to vapor region, not full tube illumination), (b) spectrometer display or eyepiece view shows discrete spectral lines (not continuous band), and (c) all labels, icons, and physical configurations are fully consistent with nuclear engineering instrumentation standards (e.g., no consumer-grade multimeter substituted for HV supply; no smartphone used as spectrometer).

Scientific and Causal Correctness rubric:
level_1: No ultraviolet emission observed; no spectral lines visible; tube emits white or broad-spectrum light; spectrometer shows no lines or only continuous rainbow; mercury-specific phenomenon is entirely absent.
level_2: Tube glows but color is incorrect (e.g., blue-white instead of bluish-violet characteristic of Hg UV excitation); spectrometer shows continuous spectrum or only 1–2 indistinct bands; no discrete line pattern visible; causal link between power-on and spectral appearance is missing (e.g., glow appears before power connection, or spectrum appears without tube activation).
level_3: Tube emits bluish-violet glow upon power application; spectrometer shows discrete lines in UV range (wavelengths <400 nm implied by context, e.g., labeled scale, dark background, absence of visible colors); at least two discrete bright lines are visible in spectrometer view; causal chain is partially intact: power-on → tube glow → spectral lines appear, but timing or spatial alignment is inconsistent (e.g., lines appear before glow stabilizes, or spectrometer view is static while tube flickers).
level_4: Tube emits stable bluish-violet glow exclusively during power-on; spectrometer view shows exactly four distinct, bright, narrow, non-blended lines in UV-dominant region (no visible red/orange/yellow lines present); lines appear only after tube glow is established and persist while power remains on; no extraneous phenomena (e.g., arcing, flashing, color shifts); all four lines are spatially separated and equally resolvable (no merging, smearing, or occlusion).
level_5: All conditions for score 4 are satisfied, and additionally: (a) the four spectral lines are arranged in correct relative spacing order matching known mercury UV lines (185 nm, 254 nm, 297 nm, 302–313 nm group; verified by proportional spacing on calibrated scale, not absolute values), (b) no fifth line or artifact line appears, (c) tube glow remains confined to vapor region (no electrode glow or glass fluorescence), and (d) spectral lines vanish immediately upon power-off with no afterglow or persistence.

Spatiotemporal Consistency rubric:
level_1: Objects teleport (e.g., tube appears/disappears mid-video); sudden lighting changes unrelated to power action; abrupt camera cuts or zooms that break continuity; tube shatters or deforms without cause; spectrometer rotates 90° instantly; multiple incompatible viewpoints shown.
level_2: At least one major spatiotemporal discontinuity: (a) power connection appears after tube glow starts, (b) spectrometer view switches abruptly from wide shot to close-up without motion, (c) shadow direction flips between frames, (d) tube changes transparency/opacity mid-sequence without cause, or (e) wires disconnect/reconnect without motion.
level_3: All objects maintain fixed relative positions throughout; no teleportation or structural breaks; lighting remains consistent except for expected change upon power-on (e.g., ambient dimming or glow onset); motion is limited to natural hand adjustment of spectrometer focus or minor camera stabilization; no abrupt cuts: single continuous take or seamless crossfade; tube retains rigid cylindrical shape and uniform transparency; no distortion of glass curvature or electrode geometry.
level_4: All conditions for score 3 are satisfied, and additionally: (a) wire connections remain taut and unbroken across frames, (b) spectrometer alignment motion is smooth and monotonic (no backtracking or jitter), (c) glow onset propagates gradually from electrodes into vapor region (not instantaneous full-tube illumination), and (d) no inter-frame flicker, strobing, or frame duplication.
level_5: All conditions for score 4 are satisfied, and additionally: (a) depth cues are fully consistent (e.g., tube edges remain sharp while background softens appropriately; no floating objects), (b) specular highlights on glass tube move continuously and coherently with camera motion or light source position, (c) no inter-frame misalignment (e.g., pixel-shift, shear, or scaling artifacts), and (d) all motion (including focus adjustment and glow propagation) is temporally monotonic and physically plausible (no acceleration reversals or zero-velocity jumps).