Domain: Healthcare — Basic Immunology
Target concept: Eosinophil Count (Eosinophil Staining)

Video generation prompt: Prepare a blood smear on a slide, and add eosin stain dropwise. Allow it to stand for a moment, then gently rinse with water, blot dry, and examine the slide under an optical microscope. Demonstrate the sequential procedures of the slide, including staining, rinsing, and microscopic observation.

Evaluation guide:
(i) Target concept: Visual demonstration of eosinophil identification via differential staining of blood smear using eosin dye.
Minimum mechanism: Eosin must be a pink-red aqueous solution; blood must be present as a thin film on glass; staining requires direct contact and dwell time before rinsing; eosinophils must express basic proteins that bind eosin selectively to yield pink granules visible under brightfield microscopy.
(ii)Storyline: [Frame 0–1] Clean glass slide enters view, stationary. [Frame 2–3] Blood drop placed near slide edge. [Frame 4–5] Dropper descends and releases single pink-red drop onto blood. [Frame 6–7] Stillness: stain spreads slightly, no motion. [Frame 8–9] Gentle water stream flows across stained area. [Frame 10–11] Absorbent paper touches wet edge and lifts. [Frame 12–13] Slide placed on microscope stage. [Frame 14–15] Eyepiece view fades in, showing field with pink granule-bearing cells exhibiting bilobed nuclei, all from fixed frontal viewpoint with consistent lighting and scale.

Manual:
Experimental Procedure
1. Place a small drop of blood near one end of clean glass slide.
2. Use dropper to add one drop of eosin stain directly onto blood.
3. Wait 1–2 seconds for stain to react.
4. Gently rinse slide with stream of water.
5. Blot dry with absorbent paper.
6. Observe under optical microscope.
Observation of Experimental Phenomena
After staining and rinsing, slide shows pale pink background with discrete, intensely pink, refractile granules inside cells; microscope reveals cells with bilobed nuclei and uniform bright pink cytoplasmic granules.
Summary of Experimental Principles
Eosin is an acidic dye that binds basic components (e.g., eosinophil granules rich in major basic protein), producing characteristic pink-red staining; this enables morphological identification of eosinophils in peripheral blood smears.

Prompt Grounding rubric:
level_1: No blood smear preparation shown; no slide, no dropper, no stain bottle, no microscope visible; no sequential actions related to smear preparation or staining.
level_2: At least one correct object present (e.g., glass slide or dropper), but zero correct core actions (no placement of blood, no dropwise addition of stain, no rinsing, no blotting, no microscope observation); sequence is absent or unrecognizable.
level_3: All three core objects present (glass slide, dropper with liquid, microscope) and at least two of the six core actions shown: (a) blood placed on slide, (b) eosin stain applied dropwise, (c) a brief stillness/standing period after staining, (d) water rinsing, (e) blotting, (f) microscope observation, but at least one action is missing or out-of-order.
level_4: All three core objects present (glass slide, dropper with liquid, microscope); all six core actions appear in correct sequential order: (i) blood placed on slide, (ii) eosin stain added dropwise, (iii) standing period implied by stillness, (iv) gentle water rinse, (v) blotting, (vi) microscope observation, but one non-core flaw exists (e.g., dropper not visibly over slide during dispensing, or microscope not showing eyepiece view).
level_5: All three core objects present (glass slide, dropper containing pink-red liquid, upright optical microscope); all six core actions occur in strict sequence with precise spatial alignment: (i) blood placed near slide edge, (ii) dropper tip positioned directly above slide and releasing single drop onto blood area, (iii) 1–2 second stillness with stain spreading visibly, (iv) water stream directed gently across stained area without splashing or displacement, (v) absorbent paper contacting only wet edge of slide, (vi) microscope eyepiece view showing field with distinct pink-stained cells, all within a single fixed viewpoint.

Scientific and Causal Correctness rubric:
level_1: No biologically plausible color change observed; stain appears blue, green, yellow, or clear; no cellular morphology visible under microscope; blood remains unstained or uniformly discolored.
level_2: Stain color is red or pink but applied to wrong substrate (e.g., on empty slide, on gloved hand, or on unrelated surface); no contrast between background and cells under microscope; no evidence of eosinophil-specific staining pattern.
level_3: Eosin stain appears as pink-red liquid applied dropwise to blood smear; post-rinse, slide shows uneven or partial pink hue; microscope view contains cellular shapes but lacks definitive eosinophil identification features (e.g., no bilobed nuclei + bright pink granules).
level_4: Stain is pink-red liquid applied to blood smear; after rinse and dry, slide shows pale pink background with scattered darker pink granular structures; microscope view shows round/ovoid cells with clearly visible pink granules, but either nuclear lobulation is ambiguous or granule distribution is inconsistent with eosinophils.
level_5: Eosin stain is distinctly pink-red liquid; after rinse and blotting, slide shows uniform pale pink background with discrete, intensely pink, refractile granules localized within cells; microscope view shows multiple cells with bilobed or segmented nuclei AND densely packed, uniform, bright pink granules filling cytoplasm, matching canonical eosinophil morphology under eosin staining.

Spatiotemporal Consistency rubric:
level_1: The slide, dropper, or blood drop instantly jumps to a different position or size with no motion connecting the two states; the eosin drop or rinse water visibly flows backward toward its source; the glass slide cracks apart and then reassembles whole; or scene lighting switches between two unrelated states with no transition.
level_2: At least two of the following occur: the slide's orientation changes between two frames with no visible turning motion; the dropper is shown full of stain and then instantly empty with no drop falling; the rinse water appears as a motionless puddle rather than a flowing stream; or the shot cuts directly from the stain sitting on the slide to the eyepiece view with no rinsing, blotting, or stage-loading shown.
level_3: One continuity break occurs: e.g., a hard cut appears between the water rinse and the blotting step with no connecting hand motion; the eosin drop is shown already resting on the smear with no visible fall from the dropper tip; or the slide's position on the microscope stage differs from its position during blotting with no repositioning motion shown.
level_4: No instant jumps, no reversed drop or rinse motion, and no hard cuts across the six staining steps (placement, staining, standing, rinsing, blotting, microscope observation); the dropper's release, the rinse, and the blotting motion each connect continuously, but one small timing flaw remains, e.g., the rinse stream's angle shifts slightly between frames without cause, or the eyepiece image sharpens in one abrupt jump instead of a gradual focus pull.
level_5: The eosin drop falls continuously under gravity from the dropper tip onto the blood smear; the standing period shows the stain visibly spreading across the smear without any cut; the rinse water flows in one unbroken stream from source to slide and off its edge; the blotting paper makes a single continuous contact-and-lift motion against only the wet edge; the slide moves smoothly onto the microscope stage; and the eyepiece view's focus gradually sharpens from blur while the framing remains fixed throughout.