Domain: Natural Science — Physics
Target concept: Laser Pointer vs LED Flashlight: Speckle and Interference on a Rough Wall

Video generation prompt: In a dimly lit room, align a red laser pointer and a white LED flashlight side by side toward a rough wall. Keep the wall and camera stationary. First gently oscillate the laser pointer by itself while the flashlight stays still; then pause, and gently oscillate the LED flashlight by itself while the laser pointer stays still.

Evaluation guide:
(i) Target concept: Optical coherence-dependent interference manifestation on rough surfaces.
Minimum mechanism: Light source must emit spatially/temporally coherent radiation (laser) vs. incoherent radiation (LED); surface must be optically rough (height variations ≫ wavelength) to scatter light into multiple paths enabling random interference; observer must view scattered field where speckle can form (far-field or diffuser-integrated).
(ii)Storyline: Frame 0–2: Static setup (both devices side-by-side, wall visible, dim ambient light). Frame 3–6: Laser oscillates alone (red spot on wall develops a shifting, shimmering speckle texture); LED stays off/still and unchanged. Frame 7–8: Transition, both devices pause and hold still; the laser's speckle grain becomes stationary (no longer shifting) but remains visibly present as a static grainy texture, since coherent light striking a rough surface produces speckle regardless of motion. Frame 9–10: LED oscillates alone, white spot deforms smoothly but stays uniformly diffuse; no speckle grain ever appears in it. Throughout: Fixed viewpoint keeps wall and device spatial relationships invariant; the rough wall stays visibly textured (not blurred or smoothed) to support the scattering premise.

Manual:
Experimental Procedure
1. Set up dimly lit room with stationary rough wall and fixed camera.
2. Place red laser pointer and white LED flashlight side-by-side, aligned toward wall.
3. Gently oscillate laser pointer alone while LED remains still; observe wall.
4. Pause oscillation; then gently oscillate LED flashlight alone while laser remains still.
Observation of Experimental Phenomena
The laser spot shows a dynamic, shifting speckle pattern (granular, shimmering, high-contrast texture) while oscillating; when the laser is held motionless, the speckle grain persists as a static but still-visible granular texture, since it comes from coherent light scattering off the rough wall, not from motion itself. The LED spot shows uniform, smooth, diffuse illumination with no speckle in any case, whether still or oscillating.
Summary of Experimental Principles
Laser light is coherent → produces interference on the rough wall surface → a visible speckle grain that is present whenever the laser illuminates the wall (its shimmering/boiling quality depends on relative motion, but its presence does not depend on motion). LED light is incoherent → no sustained interference pattern forms → only smooth, diffuse reflection, with no speckle under any condition.

Prompt Grounding rubric:
level_1: None of the following are visible: a red laser pointer, a white LED flashlight, a rough-textured wall, or a dimly lit room setting.
level_2: Only one of the four setup elements (the laser pointer, the LED flashlight, the rough wall, or the dim room) is identifiable, with the rest missing or impossible to make out; the two devices are not shown side by side.
level_3: The red laser pointer, the white LED flashlight, the rough wall, and the dim room are all clearly visible; the two devices share the scene but are not side by side (e.g., one is stacked above the other, they overlap, or a large gap separates them); no oscillating motion of either device is shown, or it's too ambiguous to tell.
level_4: Everything in score 3 holds, and the two devices sit side by side: adjacent, aligned along the same plane, clearly separate and non-overlapping; the camera and wall stay fixed; at least one device is shown oscillating, but the pattern of one device moving while the other stays still, and then swapping, is not clearly established.
level_5: Everything in score 4 holds, and the wall and camera never shift position across the whole clip; the two devices oscillate strictly one at a time (the laser moves while the flashlight stays completely still, then, after a clear pause, the flashlight moves while the laser stays completely still), with an unambiguous separation between the two motion phases.

Scientific and Causal Correctness rubric:
level_1: The laser's spot on the wall looks white, or the LED's spot looks red, or the two spots look identical in texture, or no spot appears on the wall at all, or the wall looks smooth and glossy instead of matte and rough.
level_2: The laser's spot is a single smooth point of light with no visible grain, or the LED's spot has an unnaturally crisp edge with no soft spread, or either spot's color is wrong (e.g., the laser looks green or the LED looks yellow), or oscillating a device produces no visible change in its spot.
level_3: Both the red laser spot and the white LED spot appear on the wall; the laser spot shows an obviously grainy, high-contrast speckled texture whether the laser is held still or moving; the LED spot instead looks smooth and evenly diffuse with no grain, whether still or moving; when the laser oscillates, its speckle grain visibly shifts and shimmers; when the LED oscillates, its spot simply moves or changes shape smoothly with no grain ever appearing.
level_4: Everything in score 3 holds, and the speckle grain is present in the laser spot continuously (as a static-but-visible grain when the laser is held still, and as a shifting, shimmering grain when the laser oscillates), never absent in either state; the LED spot never develops any granular texture in its still or oscillating phase; while the LED oscillates, its spot's shape deforms smoothly with no internal structure appearing.
level_5: Everything in score 4 holds, and the laser spot's speckle grain is unmistakable and high-contrast in every visible frame, including frames where the laser sits motionless, clearly distinguishing it from the LED's uniformly smooth spot in every frame, including frames where the LED oscillates; no frame shows the laser spot smoothed out and grain-free, and no frame shows any granular texture appearing in the LED spot; the shifting, boiling look of the laser's speckle while it moves versus its stationary-but-still-grainy look while it's held still are both clearly distinguishable from the LED's texture-free spot throughout.

Spatiotemporal Consistency rubric:
level_1: The wall disappears and reappears abruptly, or the camera view jumps (a pan, tilt, or zoom cut), or either device suddenly appears in a different position between frames, or the light intensity flickers on and off discontinuously, or the oscillation looks so jerky that whole intermediate positions are visibly missing.
level_2: The wall visibly warps or stretches, or either device's apparent size changes inconsistently across frames, or the shadow cast by a device jumps discontinuously between frames, or the oscillation motion looks noticeably choppy or skipped, as though frames of the motion are missing.
level_3: The wall stays fully visible and geometrically stable across all frames; both devices stay fully within frame and keep a consistent relative size; the room's dim lighting stays continuous with no sudden brightening or darkening; the oscillation is continuous with no choppy skips, but the wobble path is inconsistent: its direction changes erratically or its amplitude varies unpredictably between swings.
level_4: Everything in score 3 holds, and each device's oscillation follows a single, smooth back-and-forth path with no mid-swing reversal or pause; the wall's matte, uneven texture (the grain and pores that give it its rough, scattering surface) looks the same from frame to frame; the two devices' positions relative to the wall and to each other stay aligned with no inter-frame jump.
level_5: Everything in score 4 holds, and there is no spatial discontinuity anywhere: the wall's rough surface texture and its lighting look consistently the same from the first frame to the last, with no unexplained shift in its grain pattern or in how it's lit; each device's outline stays sharp and stable, with no ghosting or smearing beyond natural motion blur during active oscillation; the oscillation path stays flat and planar, with no unexpected bobbing toward or away from the camera, and keeps the same orientation relative to the wall throughout.