Domain: Healthcare — Basic Immunology
Target concept: Immune Complex Detection (PEG Precipitation Method)

Video generation prompt: Prepare labeled tubes, add the patient's serum and specific antigen solution, gently mix, then slowly add polyethylene glycol solution dropwise. Gently invert to mix and allow to stand for a short period.

Evaluation guide:
(i) Target concept: Immune complex detection via PEG-induced precipitation in vitro.
Minimum mechanism: Serum contains IgG antibodies; specific antigen is added to form antigen-antibody complexes; PEG dehydrates and aggregates complexes into insoluble pellets that sediment under gravity; sedimentation requires time, mixing, and absence of agitation.
(ii)Storyline: Frame 1–2: Labeled tube appears empty → serum added (amber liquid) → antigen added (clear liquid). Frame 3: Gentle mixing (liquid swirls, no separation). Frame 4: PEG added dropwise (clear droplets enter, no splashing). Frame 5: Tube inverted 180° smoothly (liquid flows upward, then settles). Frame 6: Tube held upright and motionless → pellet appears at bottom over next frames; upper phase clears progressively. Perspective: Fixed frontal view, shallow depth, all actions occur within single continuous shot or seamless cuts preserving spatial coherence.

Manual:
Experimental Procedure
1. Prepare labeled tube.
2. Add patient serum and specific antigen solution into tube.
3. Gently mix.
4. Slowly add polyethylene glycol (PEG) solution dropwise.
5. Gently invert tube to mix.
6. Allow tube to stand still for short period.
Observation of Experimental Phenomena
A white or off-white pellet forms at the bottom of the tube; upper liquid phase becomes clear.
Summary of Experimental Principles
Immune complexes in serum bind antigen and precipitate when PEG reduces solubility; PEG-mediated precipitation is detected via visible pellet formation.

Prompt Grounding rubric:
level_1: No labeled tubes visible; no serum, antigen, or PEG solution present; no mixing or standing action shown; none of the four core objects (labeled tube, serum, antigen solution, PEG solution) appear.
level_2: At least one labeled tube appears, and at least one liquid container is present, but no identifiable serum, antigen, or PEG solution is distinguishable by color/labeling; no dropwise addition or inversion motion occurs; sequence of steps is absent or reversed.
level_3: Labeled tube(s) present; patient serum and specific antigen solution both visibly added into the same tube (two distinct liquids, different colors or labels); PEG solution is introduced (visibly distinct liquid, e.g., clear vs. colored); dropwise addition motion is shown (visible falling droplets entering tube); inversion motion occurs after addition; standing period is implied by stillness.
level_4: All elements in score 3 are present AND correctly ordered: (1) labeled tube prepared, (2) serum added, (3) antigen solution added, (4) PEG added dropwise, (5) gentle inversion, (6) stillness for standing, with no missing step, no extra unrelated action, and all objects consistently positioned side-by-side or within same fixed viewpoint throughout.
level_5: All elements in score 4 are present AND every object retains consistent visual identity (e.g., serum remains amber/brown, antigen remains clear/color-coded, PEG remains clear/water-like), all actions occur without interruption or spatial discontinuity (no jump cuts, no object teleportation), and inversion motion shows full 180° rotation with continuous fluid sway inside tube during motion.

Scientific and Causal Correctness rubric:
level_1: No immune complex precipitation phenomenon observed; no turbidity, cloudiness, or pellet formation appears at bottom of tube; liquid remains uniformly transparent before and after standing; no causal link between PEG addition and visible change.
level_2: Turbidity or cloudiness appears, but not localized at tube bottom; no pellet formation; change occurs before PEG addition or without inversion/standing; serum and antigen solutions are mixed but show no interaction; PEG addition produces no observable effect.
level_3: After standing, a visible white or off-white pellet forms at the bottom of the tube; upper liquid phase becomes clearer; pellet appears only after PEG addition + inversion + standing, i.e., pellet appearance coincides temporally with post-standing frame and does not exist in pre-PEG frames.
level_4: All elements in score 3 are present AND pellet is exclusively in the tube containing both serum and antigen (not in control tubes if shown); no pellet forms in tubes missing either serum or antigen; turbidity transition from uniform suspension to settled pellet is visually evident; no false-positive pellet (e.g., air bubble, debris, or undissolved solid unrelated to immune complexes).
level_5: All elements in score 4 are present AND pellet morphology is consistent with immune complex precipitation: compact, granular, non-flocculent, non-adherent to tube walls; upper phase is sharply defined and optically clear (no haze); no dissolution, dispersion, or re-suspension during standing; pellet remains stationary and centered at bottom throughout stillness period.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: tube disappears/reappears; liquid jumps between containers; sudden lighting shift or shadow reversal; inversion motion shows discontinuous rotation (e.g., starts mid-turn, skips 90°); standing period shows flickering or frame drops.
level_2: Moderate rupture: tube changes position/orientation between shots without motion continuity; PEG droplet appears fully formed mid-air without descent path; inversion shows jerky motion with >1 visible pause or direction reversal; standing stillness includes unintended micro-motion or camera shake.
level_3: All objects maintain fixed relative positions; tube remains upright and stable during standing; PEG droplets follow continuous downward trajectory into tube; inversion shows smooth arc motion without reversal or pause; no lighting/shadow discontinuity across time; no object deformation or stretching.
level_4: All elements in score 3 are present AND camera viewpoint remains strictly fixed (no pan/tilt/zoom); tube base stays anchored in same screen region; liquid surface remains level during inversion and settles horizontally during standing; no parallax shift between foreground/background objects.
level_5: All elements in score 4 are present AND motion trajectories are physically plausible: droplet fall accelerates naturally; inversion rotation speed is uniform; liquid inside tube sways continuously with inertia during inversion and settles smoothly without oscillation; no inter-frame strobing or motion blur that obscures object boundaries.