Domain: Natural Science — Biophysics
Target concept: Fluorescent samples with anti-fade mounting medium versus ordinary glycerol under continuous conditions

Video generation prompt: Two glass slides containing the same fluorescent sample are placed side by side under a fluorescence microscope and continuously illuminated: the left slide is mounted in a colorless antifade mounting medium, and the right slide is mounted in ordinary glycerol tinted pale blue for identification, with the display showing changes over time.

Evaluation guide:
(i) Target concept: Differential photostability of fluorescent samples under continuous illumination due to chemical protection against photobleaching.
Minimum mechanism: Fluorophores must be identically excited in both samples; photobleaching requires generation of reactive oxygen species upon illumination; antifade agents must suppress this pathway while glycerol does not.
(ii)Storyline: Frame 0–2: Two slides enter static view side by side. The left slide (colorless antifade medium) and the right slide (pale-blue-tinted glycerol) both show bright, congruent fluorescent signal under uniform excitation light. Frame 3–7: The fluorescent signal on the right (glycerol) slide shows monotonic, continuous dimming while retaining its shape and hue; the left (antifade) slide shows no measurable change in brightness, color, or morphology. Frame 8–10: Contrast between slides is maximized. The right slide's signal is markedly dimmer while its pale-blue tint stays visible; the left slide remains at initial intensity; both remain sharply focused, side by side, under stable illumination. Perspective: Fixed microscope-eye viewpoint; no zoom, pan, or rotation; full slides always in frame; background is dark with uniform excitation field.

Manual:
Experimental Procedure
1. Place two identical glass slides side by side on a fluorescence microscope stage.
2. On each slide, mount the same fluorescent biological sample.
3. Cover the sample on the left slide with a colorless antifade mounting medium; cover the sample on the right slide with ordinary glycerol tinted pale blue for identification.
4. Illuminate both slides continuously under identical fluorescence excitation.
Observation of Experimental Phenomena
Over time, the fluorescent signal on the right (glycerol) slide progressively dims while the left (antifade) slide retains stable brightness and color.
Summary of Experimental Principles
Antifade mounting media contain radical scavengers that inhibit photobleaching; glycerol lacks these compounds and offers no protection against reactive oxygen species generated during continuous illumination, leading to rapid fluorophore degradation.

Prompt Grounding rubric:
level_1: No two glass slides are shown at all, or no fluorescent sample is visible on either slide, or the slides are not shown next to each other, or there is no continuous illumination or passage of time depicted.
level_2: Two slide-like rectangular objects appear, but they are not clearly glass, or a liquid mounting medium is visible on at most one slide, or the left/right arrangement is not maintained, or neither slide can be told apart from the other by any visual cue (no tint, no label, no fixed position convention).
level_3: Two glass slides are shown side by side, each holding a visibly glowing fluorescent sample; the left slide's mounting medium reads as colorless while the right slide's mounting medium reads as pale blue; continuous illumination is implied by a steady, bright excitation field.
level_4: All of score 3 is satisfied, and additionally the left slide stays colorless and the right slide stays pale blue throughout (the tint never fades, shifts to the other slide, or disappears), and both slides remain stationary and fully visible in frame for the entire clip.
level_5: All of score 4 is satisfied, and additionally the two slides are arranged with even spacing and matching orientation, both stay in identical focus and magnification, the fluorescent sample sits in the same position/shape on both slides, and the excitation lighting is even across both slides with no hotspot favoring one side.

Scientific and Causal Correctness rubric:
level_1: Neither slide shows any fluorescence change over time: both stay equally bright (or equally dim) throughout, with no difference developing between them.
level_2: Both slides' fluorescence fades together at the same rate, or fades abruptly/instantly rather than gradually, or the pattern between the two slides flickers or reverses rather than settling into a stable difference.
level_3: Both slides start out equally bright, and over the course of the video one slide's brightness visibly and gradually decreases while the other stays essentially unchanged; the dimming slide keeps its original color and shape as it fades, it just gets dimmer.
level_4: All of score 3 is satisfied, and additionally the fading occurs specifically in the pale-blue (glycerol) slide, while the colorless (antifade) slide shows no measurable drop in brightness or shift in color across the whole video; there is no partial recovery or flicker in either slide's signal.
level_5: All of score 4 is satisfied, and additionally the glycerol slide's brightness only ever decreases (never brightens again), the antifade slide's color and intensity stay exactly as they started (no yellowing or hue shift), and the glycerol slide shows no change besides dimming (no bubbling, crystals, or separation in the medium), consistent with photobleaching rather than any other process.

Spatiotemporal Consistency rubric:
level_1: Slides or their fluorescent samples jump position, vanish, or reappear from one moment to the next; illumination flickers on and off or cuts out entirely; fluorescent regions blink erratically rather than changing gradually.
level_2: Slides stay in frame but drift or rotate slightly between moments; a slide's liquid boundary visibly warps or pulses in a way not explained by fading; fluorescent edges shimmer or crawl; the illumination brightness jumps noticeably instead of changing smoothly.
level_3: Both slides stay put and fully visible; each slide's liquid boundary keeps a steady shape across the video; each fluorescent region keeps a stable shape, position, and edge sharpness aside from the expected gradual dimming; the illumination looks steady with no flicker or pulsing.
level_4: All of score 3 is satisfied, and additionally the two slides show no visible stutter or sudden viewpoint shift, and neither slide's shape warps; the tint boundary and fluorescent edges on both slides stay clean and well-defined for the whole clip rather than blurring or fragmenting.
level_5: All of score 4 is satisfied, and additionally neither slide shows motion blur since neither one moves; there is no colored fringing or halo at the high-contrast edges of the slides or fluorescent regions; the fading on the glycerol slide looks like a smooth brightness change rather than a smeared or streaky effect; the softness of shadows and highlights looks the same on both slides throughout.