Domain: Engineering — Communications Engineering
Target concept: AM radio transmission: The microphone modulates the carrier amplitude, as observed on the oscilloscope.

Video generation prompt: On the test bench, a microphone is connected to an AM transmitter and antenna; when a person speaks softly and then loudly into the microphone, the oscilloscope displays the corresponding signals.

Evaluation guide:
(i) Target concept: Amplitude modulation via acoustic pressure driving microphone diaphragm, which linearly varies transmitter gain to produce time-varying envelope on carrier wave.
Minimum mechanism: Microphone must be functional (diaphragm responsive), transmitter must be AM-mode (not FM or unmodulated), oscilloscope must be AC-coupled and triggered to display envelope, and audio input must drive sufficient voltage swing to visibly alter carrier amplitude.
(ii)Storyline: [Frame 0–2] Person silent, microphone idle, oscilloscope shows steady carrier waveform (constant amplitude). [Frame 2–5] Person begins soft speech → oscilloscope envelope begins smooth, proportional contraction. [Frame 5–8] Person transitions to loud speech → envelope expands smoothly and fully, maintaining carrier frequency integrity. [Frame 8–10] Person ends loud speech → envelope contracts smoothly back toward baseline. All events occur from fixed frontal viewpoint; microphone, transmitter, antenna, and oscilloscope remain fully visible and spatially anchored; no cutaways, zooms, or perspective shifts.

Manual:
Experimental Procedure
1. Connect microphone to AM transmitter input; connect transmitter output to antenna and oscilloscope input.
2. Person speaks softly, then loudly into microphone.
Observation of Experimental Phenomena
Oscilloscope displays a continuous carrier waveform whose amplitude increases visibly during loud speech and decreases visibly during soft speech.
Summary of Experimental Principles
AM radio transmission: The microphone modulates the carrier amplitude, as observed on the oscilloscope.

Prompt Grounding rubric:
level_1: None of the five required elements (the microphone, AM transmitter, antenna, oscilloscope, and person) appear together in the same shot; the AM test-bench setup is never established.
level_2: At least one of the five elements appears (for example only the oscilloscope, or only the microphone), but the test bench is not recognizable as a connected AM setup: no cable is shown linking any of the pieces, and several of the required elements are missing entirely.
level_3: The person, microphone, AM transmitter, antenna, and oscilloscope all appear together in one fixed shot, and the person is shown speaking into the microphone, but no cable is visibly connecting the microphone to the transmitter, the transmitter to the antenna, or the transmitter to the oscilloscope.
level_4: All five elements are present and visibly wired together: a cable runs from the microphone into the transmitter, a lead runs from the transmitter to the antenna, and a cable runs from the transmitter's output to the oscilloscope's input, and these three connections stay intact and visible while the person speaks.
level_5: Everything required at level 4 holds for the entire clip: the three cable connections stay traceable end to end, the person remains centered and facing the microphone, and none of the five elements changes position, becomes hidden, or leaves the frame at any point during the recording.

Scientific and Causal Correctness rubric:
level_1: The oscilloscope screen shows no waveform at all (a blank screen, a frozen flat line, or random noise), and the trace's amplitude bears no relation to whether the person is speaking loudly, softly, or staying silent.
level_2: The oscilloscope shows a carrier waveform, but its amplitude stays essentially the same size whether the person speaks softly or loudly, or the amplitude changes at the wrong moments; for instance growing while the person is silent and staying flat while they speak.
level_3: The carrier waveform's amplitude visibly grows when the person speaks loudly and visibly shrinks when they speak softly, but the change happens as an abrupt jump between two fixed sizes, momentarily drops to nothing, or runs backward (shrinking on loud, growing on soft) at some point.
level_4: The amplitude envelope rises within roughly a second of the person switching to loud speech and falls within roughly a second of switching to soft speech, tracking each loud/soft change with matched direction and timing across every switch shown.
level_5: The amplitude envelope rises and falls smoothly for every loud/soft switch (with no dip, kink, stall, or overshoot partway through a rise or fall), and the amplitude reached during loud passages stays clearly and repeatably larger than the amplitude reached during soft passages each time the pattern repeats.

Spatiotemporal Consistency rubric:
level_1: One of the bench items (the microphone, transmitter, antenna, or oscilloscope) disappears from its spot and reappears somewhere else with no hand or camera motion carrying it there, the oscilloscope screen cuts to solid black and resets mid-shot, the lighting on the bench swings violently between bright and dark with no visible cause, or a bench item's structure breaks: the antenna bends at an impossible angle or the oscilloscope casing visibly splits apart.
level_2: One bench item drops out of view for more than a second and then reappears in a different spot without any visible motion explaining the change, or the oscilloscope trace freezes on screen for several seconds while the person keeps speaking, or the light source over the bench visibly disappears and then comes back.
level_3: Every bench item and cable stays in its original place for the whole clip with no cable detaching or re-routing, but the oscilloscope trace's baseline wanders slightly, or the person's head snaps to a noticeably different angle for an instant without a matching camera cut.
level_4: All bench items and cables stay fixed in position and orientation, the oscilloscope trace updates smoothly with no stutter, freeze, or blank flash, and the person's head and mouth motion while speaking looks continuous from one frame to the next.
level_5: Every bench item keeps the same size, angle, and position relative to the others across the entire clip, the oscilloscope trace updates continuously with no skipped or repeated frames, and the person's speaking motion stays smooth and consistent throughout with no flicker, stutter, or shape distortion in any object.