Domain: Natural Science — Microbiology
Target concept: Detection of Mucor (Potato Dextrose-Congo Red Colorimetric Method)

Video generation prompt: Place the Mucor sample on a slide, add potato dextrose agar mixed with Congo red dye, gently cover with a coverslip, and observe under a light microscope.

Evaluation guide:
(i) Target concept: Visual confirmation of Mucor via Congo red staining of chitin- and glucan-containing components of its fungal cell wall in a prepared microscopic mount (Congo red is not a chitin-exclusive dye; it also binds other ordered cell-wall polysaccharides).
Minimum mechanism: Congo red must be in direct physical contact with Mucor hyphae within a hydrated, semi-solid matrix (agar) that permits dye diffusion and binding; staining requires no fixation or heating: binding occurs spontaneously at room temperature upon contact.
(ii)Storyline: [0–2s] Static overhead view: clean slide enters frame → Mucor sample (fuzzy, filamentous, off-white) is placed centrally. [2–4s] Agar-Congo red mixture (uniformly red-tinted, viscous gel) is dispensed over sample, spreading contiguously. [4–6s] Coverslip is lowered vertically and lands flat, fully covering agar without tilt or bubbles. [6–10s] Seamless transition to stable microscope view: field is sharply focused, centered on hyphae, showing hyphae with visibly deeper red saturation than the surrounding agar, with no panning, zooming, or repositioning; viewpoint remains fixed and orthogonal to slide plane throughout.

Manual:
Experimental Procedure
1. Place Mucor sample (fuzzy white/grey hyphae) centrally on clean glass slide.
2. Add potato dextrose agar pre-mixed with Congo red dye directly over sample.
3. Gently lower coverslip flat onto agar to avoid air bubbles.
Observation of Experimental Phenomena
Under light microscope: Mucor hyphae appear more deeply and saturated red than the lighter red/pink agar background, because Congo red binds polysaccharides (including chitin) in the fungal cell wall.
Summary of Experimental Principles
Congo red binds ordered polysaccharides in the fungal cell wall, including chitin and beta-glucans — it is not an exclusively chitin-specific dye (calcofluor white and fluorescent WGA are the more selective chitin stains); potato dextrose agar provides nutrient medium and physical support; the deeper red staining on the hyphae relative to the background helps distinguish fungal structures from non-fungal debris.

Prompt Grounding rubric:
level_1: The slide, the Mucor sample, the potato dextrose agar-Congo red mixture, the coverslip, and a microscope-view shot are all absent from the clip.
level_2: Only one of the required items appears (e.g., just a slide or just a coverslip); no Mucor sample is shown; no red-tinted agar mixture is shown; there is no microscope-view segment at all.
level_3: The slide, a fuzzy off-white Mucor sample, a visibly red-tinted potato dextrose agar mixture, and a coverslip are all shown, and the clip also cuts to a microscope-view shot, but the order is wrong (e.g., the coverslip is placed before the agar is added) or the sample is not actually positioned under the agar and coverslip.
level_4: Everything in score 3 is correct and happens in order: sample placed on slide, red-tinted agar applied directly over it, coverslip lowered flat on top, then the microscope view, with only small, non-essential slips (e.g., brief motion blur, a moment of soft focus, or the agar's edge slightly cropped by the frame).
level_5: Everything in score 4 holds, and additionally: the slide sits flat and fully visible; the Mucor sample is a clearly defined fuzzy mass placed centrally; the red-tinted agar evenly covers the sample with no bare patches; the coverslip lies flat with no trapped air bubbles or visible tilt; the microscope view is sharp, steady, and centered on the hyphae; nothing is out of order and no extra object intrudes on the shot.

Scientific and Causal Correctness rubric:
level_1: No color difference is visible anywhere in the shot: the agar looks colorless, the hyphae look unstained, or the red dye is shown pooling apart from the sample rather than mixed into agar that touches it.
level_2: Red dye is visible but sits as a separate droplet beside the sample rather than mixed through the agar; or the agar has a red tint but the hyphae appear as a shapeless blob rather than recognizable filaments; there is no visible interaction between the dye and the fungal material.
level_3: The agar has an even red tint and the Mucor hyphae are recognizable as filaments under the microscope, but the hyphae are about the same shade of red as the surrounding agar; there is no extra staining visible on the fungal structures themselves.
level_4: The hyphae show a noticeably deeper or more saturated red than the surrounding agar, indicating the dye has concentrated there, but the effect is incomplete (only part of the visible hyphae look darker, or the background shows uneven, patchy redness that muddies the contrast).
level_5: Under the microscope, the Mucor hyphae stand out with a clearly deeper, more saturated red than the lighter red/pink agar around them, continuously along the visible length of the hyphae rather than in scattered patches; no non-fungal specks or debris in the field show the same deep staining, so the extra color reads as specific to the fungal structures rather than a general pooling of dye.

Spatiotemporal Consistency rubric:
level_1: The coverslip appears already in place with no lowering motion shown; the red-tinted agar appears fully spread with no dispensing motion; the shot cuts straight to the microscope view with a lighting mismatch from the prior shot; or the slide cracks, the coverslip shatters, or the agar flows/spreads in a way that defies gravity.
level_2: At least two clear continuity breaks occur: e.g., the coverslip is shown tilted and then suddenly flat with nothing shown in between; the agar looks solid and then abruptly looks liquid; the microscope view has a different zoom level than expected with no visible zooming; the lighting jumps between shots for no reason.
level_3: The slide stays still, the Mucor sample does not move once placed, the agar visibly spreads outward from where it is poured rather than appearing all at once, the coverslip comes down smoothly and settles flat, and the microscope view keeps the same orientation and scale as the setup shot, apart from one small hiccup, such as a brief lighting flicker or the coverslip settling with a slight wobble.
level_4: Everything in score 3 holds, with no object vanishing and reappearing, no cracked or torn materials, no sudden lighting jump, and no motion that defies gravity (the agar does not float or flow upward); the coverslip lowers steadily and lands flat without bouncing; the shift from the wide setup shot to the microscope view reads as one continuous transition rather than a jump cut.
level_5: Everything in score 4 holds, and additionally: the slide stays motionless and flat throughout; the agar's spread reads as a continuous flow rather than a series of jumps; the coverslip's descent is a single smooth downward motion ending fully flat against the slide; the microscope view settles quickly at a fixed zoom with no visible refocusing, no shift in framing, and consistent depth cues from start to finish.