Domain: Natural Science — Chemistry
Target concept: Mercury vapor gas-discharge tube emits blue light.

Video generation prompt: A sealed gas-discharge tube filled with mercury vapor, connected in a closed loop, is observed when electrified.

Evaluation guide:
(i) Target concept: Gas discharge luminescence from mercury vapor under electrical excitation.
Minimum mechanism: Mercury must be in gaseous phase inside a sealed, low-pressure tube; applied voltage must exceed ionization threshold to sustain plasma; emitted photons must correspond to Hg spectral lines (~404.7 nm, ~435.8 nm) perceived as blue.
(ii)Storyline: Frame 1–2: Static shot showing intact closed-loop circuit with an identifiable sealed gas-discharge tube (glass tube, two electrodes, wires forming full loop). Frame 3–4: Clear depiction of circuit activation (e.g., hand flipping switch, or battery connecting). Frame 5–10: Lamp illuminates *only after* activation: full-tube blue glow appears instantaneously, uniformly, and persists stably while circuit remains closed; glow extinguishes fully and immediately upon deactivation. Viewpoint is fixed frontal medium shot; lamp occupies central visual weight; background is neutral/uncluttered to ensure unambiguous visibility of color, shape, and causality.

Manual:
Experimental Procedure
1. Place a sealed glass gas-discharge tube pre-filled with mercury vapor into a visible closed electrical circuit.
2. Close the circuit to apply electric current.
Observation of Experimental Phenomena
The entire length of the lamp emits uniform, steady blue light immediately upon circuit closure; no other colors appear; light ceases instantly when circuit opens.
Summary of Experimental Principles
Mercury vapor, when excited by electric current in a low-pressure discharge tube, emits characteristic blue light due to electron transitions in Hg atoms.

Prompt Grounding rubric:
level_1: No gas-discharge tube is shown, no closed electrical loop is visible, no electrification action occurs (no power source, switch, or wire connection), or the mercury is shown as liquid droplets, a visible vapor cloud, or held in a separate container rather than sealed inside the tube; none of the setup described in the prompt is present.
level_2: A lamp-shaped glass object and some wiring are present, but the tube doesn't clearly read as a sealed gas-discharge tube (for instance it looks solid or open-ended), or the loop is incomplete (a broken wire, an open switch, or a missing return path), or there's no visible sign that current is flowing, such as no connected battery or no switch action shown.
level_3: A sealed glass tube consistent with a gas-discharge tube is shown, the electrical loop is fully connected end to end (power source, wires, tube, and return path), and a clear switching action is shown (a switch closing, a battery being connected, or an indicator lighting up), with nothing substituted or missing from the setup.
level_4: The setup matches level 3, and in addition the loop stays fully connected and in view for the whole clip, with no part of it coming loose or leaving the frame at any point.
level_5: The tube is the sole focal object, with no extra equipment such as pumps, valves, or a separate mercury container cluttering the shot; the loop is visibly continuous end to end with no ambiguous gaps or floating wire ends; and the switching action clearly happens before any light appears, never at the same instant or after.

Scientific and Causal Correctness rubric:
level_1: The light that appears isn't blue at all (it reads as white, yellow, red, orange, or green), or no light appears whatsoever, or light shows up before the switch is closed with no connection to the switch state, or the mercury is shown condensed as a visible liquid inside the tube rather than glowing as a gas.
level_2: A blue glow does appear, but only in part of the tube rather than along its length, or it's mixed with a clearly different hue at the edges such as a pink or yellow fringe, or the glow starts noticeably before the switch has finished closing, or the tube's brightness flickers or shifts in a way unrelated to whether the circuit is open or closed.
level_3: A blue glow fills essentially the whole length of the tube and only appears once the switch has fully closed, with no other colors mixed in, and it turns on and off in step with the circuit opening and closing, though the shade may lean slightly toward violet or cyan rather than a clean blue.
level_4: The blue glow stays steady with no pulsing, strobing, or brightness change while the circuit stays closed; no sparks or arcing appear at the electrodes; and the color reads as a consistent blue across the whole lit region with no patchy shift from one end of the tube to the other.
level_5: The blue glow appears only while the circuit is closed and disappears essentially the moment it opens, with no lingering afterglow or fade-out; the color reads clearly as blue throughout, without a noticeable violet or cyan cast that would suggest a different gas is inside the tube.

Spatiotemporal Consistency rubric:
level_1: The tube's position or size changes abruptly between shots with no camera motion to explain it, the tube is missing from a shot and back again a moment later, a wire detaches and reattaches with no visible hand or motion causing it, the lighting or shadows in the scene flip abruptly between shots with no cause, or the lit tube fractures or bends with no apparent cause.
level_2: The camera view jumps or reframes without a smooth pan or zoom, the tube shifts or rotates with no visible cause such as a hand or support moving it, the glow's brightness changes without matching whether the circuit is open or closed, or reflections on the glass appear and disappear inconsistently from one moment to the next.
level_3: The tube stays in a fixed position and orientation, the wiring layout stays the same throughout, the room lighting stays even without unexplained bright or dark stretches, the tube doesn't warp or deform, and the switch's motion looks smooth and physically plausible.
level_4: In addition to the above, the glass consistently looks like glass, showing the background faintly through it when unlit and a touch of refraction when lit, and the wires stay attached at the same points on the tube and power source without slipping or stretching.
level_5: The whole clip runs smoothly with no stutter, freeze, or repeated frame; the tube stays at a constant distance and scale relative to the background with no unexplained shift in perspective; and any blur or sharpness difference between foreground and background stays consistent from one frame to the next.