Domain: Humanities and Social Sciences — Linguistics
Target concept: Demonstrate the relationship between frequency and pitch using an oscilloscope.

Video generation prompt: Input a low-frequency sound signal and display its waveform. Keep the amplitude constant while gradually increasing the frequency of the sound. As the frequency increases, observe the periodic changes in the waveform on the screen.

Evaluation guide:
(i) Target concept: Visual representation of frequency-dependent waveform compression under constant amplitude on an analog oscilloscope display.
Minimum mechanism: A functional signal generator must produce a pure sine wave whose frequency is controllably varied; the oscilloscope must be in triggered AC-coupled mode with fixed timebase and voltage scale; the display must render continuous, stable periodicity without aliasing or distortion.
(ii)Storyline: [Frame 0–2] Static shot: powered oscilloscope showing stable low-frequency sine wave (2–3 clear cycles across screen width); sound generator visible, connected via cable, frequency knob at leftmost position. [Frame 3–6] Knob rotates rightward continuously; waveform begins increasing cycle density smoothly: each successive frame shows 1+ additional full cycle within identical horizontal bounds; vertical amplitude unchanged. [Frame 7–9] High-frequency state: 6+ cycles visible, tightly packed, all sinusoidal and symmetric; knob at rightmost position; no pause, jump, or amplitude deviation. Perspective: fixed frontal medium-close shot capturing knob, cable, and full oscilloscope screen; no occlusion; screen fully legible at all times.

Manual:
Experimental Procedure
1. Connect sound generator output to oscilloscope input channel.
2. Power on both devices; set oscilloscope to display stable sine wave.
3. Set sound generator to low frequency; observe initial waveform.
4. Gradually increase frequency while keeping amplitude fixed.
5. Observe waveform becoming denser (more cycles per screen width) with unchanged vertical height.
Observation of Experimental Phenomena
A stable sinusoidal waveform appears on oscilloscope screen; as frequency increases, the number of complete cycles visible within the same horizontal screen segment increases steadily; vertical peak-to-peak amplitude remains constant throughout.
Summary of Experimental Principles
Frequency determines pitch: higher frequency → higher pitch. On an oscilloscope, frequency is inversely related to wavelength displayed — increasing frequency compresses the waveform horizontally, increasing cycle density without altering amplitude.

Prompt Grounding rubric:
level_1: No oscilloscope present; no sound signal generator visible; no waveform display on screen; no frequency adjustment action shown; none of the required objects or actions from the prompt appear.
level_2: Oscilloscope is present but inactive (screen blank or static non-waveform image); sound generator appears but is disconnected or not interacting with oscilloscope; at least one object (e.g., oscilloscope OR generator) is present, but zero evidence of signal input or frequency variation.
level_3: Oscilloscope is powered and displays a visible waveform on screen; the sound generator is visibly connected to the oscilloscope via a cable; a hand is shown touching and turning the frequency knob at some point in the sequence, but the knob-turning action itself is an incomplete or inconsistent depiction of the prompt's 'gradually increasing frequency' instruction: for example, the hand releases the knob partway through and the knob sits idle for several seconds, the knob is turned back and forth rather than in one direction, or there are extended stretches where the knob goes untouched while the sequence continues.
level_4: Oscilloscope is powered and shows a live, legible waveform trace on screen; the sound signal generator is visibly connected to it via a cable; the frequency knob is turned continuously in a single direction throughout the sequence, consistent with the prompt's instruction to gradually increase frequency; no control other than the frequency knob is adjusted (e.g., no amplitude/volume knob is touched); the waveform display is never blanked, paused, or replaced by an unrelated screen while the knob is being turned.
level_5: All elements of 4-score are present AND: (a) the waveform's vertical baseline position and the oscilloscope's voltage/div scale setting remain visibly unchanged throughout; (b) the horizontal timebase (sweep-speed) dial is never touched or adjusted, so the display never zooms in or out; (c) no extraneous UI overlay, on-screen label, or editing artifact ever obscures the waveform or the knob; (d) the connecting cable between generator and oscilloscope stays taut with visually consistent routing; (e) the hand maintains continuous grip on the frequency knob throughout the turning action, never releasing it and re-gripping at a different angular position.

Scientific and Causal Correctness rubric:
level_1: Waveform does not change with frequency adjustment; waveform disappears, distorts into noise, or becomes non-periodic during adjustment; amplitude visibly varies (e.g., peaks shrink/grow) while frequency changes; no causal link between knob turn and waveform density observable.
level_2: Waveform is periodic but shows no discernible density change (e.g., same number of cycles visible before/after adjustment); or waveform changes density but amplitude also changes; or frequency knob turns opposite direction while waveform density increases; or waveform becomes non-sinusoidal (e.g., clipped, square, or chaotic) without justification.
level_3: Waveform maintains periodic shape and constant amplitude; frequency knob turns in one direction; waveform density increases (more cycles per fixed horizontal screen segment), but density change is non-monotonic (e.g., cycles briefly disappear, reappear with skipped phase, or show irregular spacing); or waveform exhibits transient instability (flicker, jump, or momentary flatline) during transition.
level_4: Waveform remains sinusoidal and stable throughout; amplitude (peak-to-peak vertical extent) is visually identical before, during, and after frequency increase; frequency knob turns unidirectionally; waveform density increases steadily and continuously (no skipped cycles, no phase jumps, no compression artifacts); all cycles retain consistent shape and symmetry.
level_5: All elements of 4-score are present AND: (a) no baseline drift (waveform centerline remains fixed vertically); (b) no harmonic distortion (all cycles identical in shape, no flattening or sharpening); (c) the sine curve stays visually smooth with no jagged, staircase-like, or moiré-patterned edges even at the highest cycle density; (d) the repeating waveform pattern shows no visible stutter, skipped repeat, or freeze-frame as frequency increases; (e) waveform retains smooth curvature at all densities: no angular corners or straight-line approximations.

Spatiotemporal Consistency rubric:
level_1: Oscilloscope screen flickers violently or blacks out; the frequency knob appears in a new rotational position between frames with no visible turning motion in between; the waveform jumps horizontally or vertically without continuity; the connecting cable disconnects and reconnects abruptly; the room's or screen's brightness swings abruptly between consecutive frames with no cause.
level_2: Camera view shifts (pan/tilt/zoom) during sequence; oscilloscope screen refreshes with visible tearing or scan lines; waveform moves laterally without knob motion; knob rotates but waveform remains static for >1 second; multiple discontinuous cuts or scene breaks occur.
level_3: Single fixed camera angle is maintained; the oscilloscope and the sound generator remain fully in frame; the knob's rotation is continuous and smooth; the waveform evolves without abrupt jumps, but minor inconsistencies are present, such as a single-frame flicker in the screen's trace brightness, a slight vertical jitter in the waveform's baseline position, or a brief near-imperceptible lag between how fast the knob turns and how fast the cycle density changes on screen.
level_4: Fixed viewpoint maintained; no camera motion, no cuts, no zoom; all objects remain stationary in frame; the knob's turning speed visibly matches how quickly the waveform's cycle density changes on screen; the waveform stays horizontally centered with no lateral drift; the screen's trace brightness and the knob's cast shadow stay consistent as the knob turns, without flickering or shifting position on their own; no geometric distortion or perspective warp of the equipment is observed.
level_5: All elements of 4-score are present AND: (a) no inter-frame motion blur that obscures the knob's position or the waveform's detail; (b) no parallax mismatch between the knob in the foreground and the screen in the background; (c) no reflection glare or specular highlight on the screen glass that intermittently masks the waveform; (d) no depth-of-field blur affecting either the knob or the screen; (e) no visible warping, stretching, or smearing distortion in the knob, cable, or waveform trace as they move.