Domain: Engineering — Nuclear Engineering
Target concept: Atomic Physics

Video generation prompt: A hydrogen atom spectral demonstration apparatus is placed on the experimental table. After connecting the power supply, adjust the focal length of the spectrometer and align it with the hydrogen atom excitation light source of the discharge tube. The image displays the field of view of the spectrometer.

Evaluation guide:
(i) Target concept: Visual verification of discrete hydrogen emission lines via spectrometric observation of a powered discharge tube.
Minimum mechanism: Hydrogen gas must be present and energized to produce line emission; spectrometer must be optically coupled and focused to resolve wavelength-separated lines; Balmer series requires visible-light transitions (n→2, n≥3) yielding four resolvable lines in standard classroom spectrometers.
(ii)Storyline: [Frame 0–2] Table with discharge tube (off, dark) and spectrometer (idle, unaligned); [Frame 3–4] Power cable connects → tube ignites with a pale pink-to-magenta glow; [Frame 5–6] Hand rotates focus knob → spectrometer optical axis pivots smoothly toward tube; [Frame 7–10] Eyepiece view stabilizes, revealing four sharp, ordered, colored lines (red leftmost, violet rightmost) with persistent glow and no extraneous features; viewpoint remains fixed, front-facing, eye-level, no UI overlays or cutaways.

Manual:
Experimental Procedure
1. Place hydrogen discharge tube on experimental table.
2. Position spectrometer adjacent to tube, aligned optically.
3. Connect power supply to tube; observe glow onset.
4. Adjust spectrometer focus knob until spectral lines appear sharp in eyepiece.
Observation of Experimental Phenomena
A stable pale pink-to-magenta glow from the discharge tube (the naked-eye blend dominated by the bright red Hα line); in spectrometer eyepiece: four discrete, vertically aligned, colored spectral lines in order — red, cyan, blue, violet — against dark background.
Summary of Experimental Principles
Hydrogen atoms excited by electric discharge emit photons at specific wavelengths corresponding to electron transitions to n=2 level (Balmer series); observed lines verify quantized energy levels predicted by Bohr model.

Prompt Grounding rubric:
level_1: No hydrogen discharge tube is shown, or no spectrometer appears, or no experimental table is shown, or the power cable is never connected to the tube, or the focus knob is never touched, or the eyepiece's field of view is never shown to the viewer.
level_2: The discharge tube, spectrometer, and table each appear at some point, but not arranged together on one surface (e.g., the spectrometer floats apart from the table, or the tube sits somewhere else); the power cable is never shown connected to the tube; no hand ever turns the focus knob; the eyepiece view is never framed for the camera.
level_3: The discharge tube sits on the table beside the spectrometer, and a power cable is visibly plugged into the tube; the eyepiece view is shown to the viewer at some point; but no hand or mechanism turns the focus knob, and the spectrometer's optical axis is not clearly pointed at the tube's glowing region.
level_4: The discharge tube and spectrometer sit together on the table with the power cable connected to the tube; a hand visibly turns the focus knob; the spectrometer's optical axis points at the tube's glowing region without another object blocking the view; but the eyepiece view shown to the camera drifts off-center or briefly loses focus rather than staying sharp and centered.
level_5: The discharge tube and spectrometer sit together on the table; the power cable is connected and the tube glows; a hand turns the focus knob while the spectrometer stays aimed squarely at the tube's glowing region; the eyepiece view fills the frame as a centered, steady, in-focus field showing only the spectral lines, with no on-screen labels, interface overlays, or unrelated objects entering the shot.

Scientific and Causal Correctness rubric:
level_1: No spectral lines appear in the eyepiece view, or the discharge tube shows no glow at all, or the eyepiece field is blank or a single flat color, or the glow and lines bear no resemblance to hydrogen emission (e.g., a continuous rainbow band with no distinct lines, or an all-green glow).
level_2: The discharge tube glows, but with a color that doesn't match hydrogen emission (e.g., a sodium-like orange-yellow glow, a plain incandescent white glow, or a blue-violet glow with no pink or red tint at all); or the eyepiece shows fewer than three distinct lines, or shows them in the wrong left-to-right order (e.g., the red line appears on the right instead of the left).
level_3: The discharge tube emits a pale pink-to-magenta glow once powered (the naked-eye blend dominated by the bright red Hα line), and the eyepiece view shows at least three sharp, separated spectral lines in the correct left-to-right order: red (Hα), cyan/teal (Hβ), and blue-violet (Hγ), with a fourth violet line (Hδ) optional, all against a dark background with no flicker.
level_4: The tube's pink-to-magenta glow and the correctly ordered spectral lines from level 3 are both present, and additionally the four lines' brightness follows the expected Balmer hierarchy (the red Hα line is visibly the brightest, with Hβ, Hγ, and Hδ progressively fainter), no extraneous lines from other elements appear (no yellow sodium line, no green mercury line), and the glow and spectral display appear together rather than one lagging noticeably behind the other.
level_5: Building on level 4, the four lines keep their relative spacing and color order steady for as long as the eyepiece view is shown, with no line bending, blurring into its neighbor, or picking up a stray color fringe; the glow stays confined to the tube's gas-filled bore rather than spreading onto the electrodes; the glow and the spectral lines hold steady together with no mismatch in timing between the two.

Spatiotemporal Consistency rubric:
level_1: The spectrometer or discharge tube appears in a different spot between shots with no motion shown getting it there; the video drops frames or flickers severely; the room's brightness suddenly flashes or goes dark for no reason connected to the tube igniting; the table surface distorts or disappears; the spectrometer appears to rotate on its own with no hand touching it.
level_2: The discharge tube or spectrometer shifts slightly out of place during an otherwise still moment; there's a brief flash or brightness spike exactly when the power cable connects that isn't explained by the tube actually igniting; one of the spectral lines momentarily doubles, or the tube briefly shifts position; a hand covers the apparatus for a noticeably long stretch without moving away to reveal it again.
level_3: The discharge tube and spectrometer keep the same positions relative to each other and to the table throughout; neither object rotates, resizes, or shifts perspective in a way a fixed camera angle couldn't explain; the room's brightness stays even from shot to shot with no unexplained jump; aside from the single, continuous transition into the eyepiece view that the setup calls for, there are no hard cuts, wipes, or extra zooms; the hand's focusing motion runs continuously rather than jumping between poses.
level_4: The steady arrangement and lighting from level 3 hold, and in addition the hand's motion while turning the focus knob follows a natural, curved path rather than a stiff linear jump; the eyepiece view stays geometrically steady with no keystoning or skewed distortion; shadows cast by the tube and spectrometer on the table stay in positions consistent with one unmoving light source.
level_5: The stability from level 4 holds throughout the whole clip: there is no visible drift, wobble, or parallax shift between the discharge tube, spectrometer, and table; no strobing, ghosting, or motion blur that mismatches the speed of the hand's motion; the highlights and shadows on the tube's glass and the spectrometer's housing stay fixed in position and brightness relative to the objects themselves; the tube's glass and the spectrometer's housing keep their shapes and surface textures without warping.