Domain: Healthcare — Digestive Physiology
Target concept: Amylase Activity Assay (Starch-Iodine Method)

Video generation prompt: Prepare test tubes containing starch solution. Add pancreatic amylase to one test tube and use the other as a control. Incubate both test tubes at body temperature for a short period, then add iodine solution to each test tube in sequence. Demonstrate clear test tube labeling, liquid transfer using a pipette, gentle mixing, and the chronological order of procedures. Do not describe the experimental results.

Evaluation guide:
Target Concept: The amylase activity assay is a *procedural benchmark* in digestive physiology that validates enzymatic function via controlled substrate (starch) exposure, physiological temperature incubation, and endpoint detection (iodine). Minimum mechanistic assumptions: (1) Pancreatic amylase hydrolyzes starch into maltose/dextrins; (2) Intact starch forms blue-black complex with iodine; (3) Hydrolyzed starch loses this capacity, but *this outcome is excluded from demonstration*. Phased Storyline: [Phase 1: Setup] Two identical tubes labeled ‘Control’ and ‘+Amylase’, establishing experimental identity. [Phase 2: Intervention] Amylase added *only* to right tube, creating asymmetry. [Phase 3: Incubation] Both tubes exposed identically to 37°C, enforcing physiological relevance. [Phase 4: Detection Trigger] Iodine added *sequentially* (Control first, then +Amylase), preserving causal order. [Phase 5: Homogenization] Gentle mixing *after each* addition, ensuring uniform reagent contact. Visibility Constraints: Camera must maintain full-tube framing (top cap to base), side-on angle to show label legibility and liquid level; lighting must eliminate glare on glass; operator’s hands must remain in-frame with natural articulation, with no occlusion of labels, pipette tip, or tube openings.

Manual:
I. Basic Demonstration Information
Demonstration Title: Amylase Activity Assay (Starch-Iodine Method) Demonstration
Subject: Healthcare - Digestive Physiology - Enzyme Kinetics
Demonstration Purpose: To visually demonstrate the standardized procedural sequence for assessing pancreatic amylase activity using starch hydrolysis and iodine detection — emphasizing correct test tube labeling, precise liquid transfer with pipette, controlled incubation at body temperature, sequential iodine addition, and gentle mixing — without depicting or interpreting enzymatic reaction outcomes.

II. Demonstration Carrier/Equipment
Core Carrier: Two identical 15 mL glass test tubes; 1% w/v starch solution (clear, colorless, room-temp); pancreatic amylase solution (clear, colorless, refrigerated stock); Lugol’s iodine solution (amber-brown, in dropper bottle); calibrated adjustable pipette (0.1–1.0 mL range) with sterile tips; 37°C water bath (with visible temperature display or thermal indicator); waterproof labeling tape and permanent marker.

III. Demonstration Content Description
Layout: Tubes placed side-by-side on clean bench under even lighting. Label left tube ‘Control’, right tube ‘+Pancreatic Amylase’ — labels centered, horizontal, legible.
State Control: Starch solution pre-poured to 5 mL in each tube before demonstration begins. No color change, turbidity, or precipitation observed in either tube pre-incubation.
Chronological Sequence:
1. Label both tubes visibly and simultaneously.
2. Using pipette, aspirate 0.5 mL amylase solution and dispense *only* into right tube.
3. Place both tubes into 37°C water bath for ≥3 seconds (full submersion or uniform hand-hold at 37°C posture).
4. Remove tubes; add 2 drops iodine to Control tube first, then gently mix 3 seconds with wrist circular motion.
5. Add 2 drops iodine to +Amylase tube second, then gently mix 3 seconds identically.

IV. Observation of Core Phenomena
Label Clarity: Both labels fully visible, non-overlapping, font ≥12 pt, black ink on white tape.
Pipette Use: Visible aspiration (meniscus rise), controlled dispensing (tip inside tube, no splash), tip ejection after use.
Incubation Fidelity: Thermal context confirmed (water bath display reads ‘37°C’ OR hand posture mimics physiological warmth retention).
Iodine Addition Sequence: Strict left-to-right (Control → +Amylase) with ≥1 s inter-stimulus interval; droplets fall vertically into liquid center.
Mixing Motion: Identical gentle circular wrist motion (2–3 rps, 3 s duration) for both tubes; no splashing, bubbling, or overflow.
Visual Verification Baseline: All steps occur in fixed camera frame; no cutaways, zooms, or overlays; human operator’s hands fully visible and anatomically plausible throughout.

V. Demonstration Precautions
- Do NOT show starch-iodine color development (blue-black vs. yellow/brown) or interpret results.
- Do NOT omit or compress chronological order — each step must be discretely observable.
- Avoid reflections/glare obscuring labels or liquid levels.
- Pipette must never contact tube walls or liquid surface before dispensing.
- Incubation must involve both tubes equally — no selective treatment.

Prompt Grounding rubric:
level_1: No test tubes visible; no labeling, no pipette, no liquid transfer, no incubation setup, no iodine addition; scene unrelated to starch-enzyme assay (e.g., random lab objects, no digestive physiology context).
level_2: At least one test tube is present and labeled, but the labels are illegible or mismatched (e.g., 'A'/'B' instead of '+Amylase'/'Control'); the pipette is absent or misused (e.g., used as a stirrer); no visible incubation step occurs (no warm-water dwell or thermal cue); iodine is added before incubation or to both tubes at once with no sequence; the order of steps is fully scrambled.
level_3: Two clearly labeled test tubes are present ('Control' and '+Amylase') with legible, correctly positioned labels; the pipette is used to transfer liquid into one tube only, or is used without a visible aspirate/dispense action; incubation is implied by a brief pause near a warm surface with no clear thermal cue; iodine is added to both tubes but not in a clear one-after-the-other sequence.
level_4: Two transparent test tubes holding a clear, colorless starch solution are each durably and clearly labeled 'Control' and '+Pancreatic Amylase'; the pipette is used correctly, with a visible draw from the amylase vial and a precise dispense into one tube only; incubation is shown as a 3-5 second dwell in or near a visibly warm water bath; iodine solution is added one tube at a time (first Control, then +Amylase) with a gap of at least a second between the two additions; all core steps appear in the correct order.
level_5: All of score 4, plus: the labels are cleanly printed in bold, high-contrast lettering large enough to read clearly on screen, and are affixed at the same height on both tubes; the pipette shows a visible volume marking and a smooth draw-dispense-eject motion; the incubation happens in a bath that is clearly warm (e.g., visible steam, a warm-colored indicator, or a marked temperature display) with both tubes treated identically; iodine is added with a fresh tip for each tube, followed by a few seconds of gentle mixing motion after each addition; the six steps (label, add starch to both, add amylase to one, incubate both, add iodine to Control, add iodine to +Amylase) each play out with a clear, visible pause between them so they read as distinct events.

Scientific and Causal Correctness rubric:
level_1: The experiment shows no genuine single-variable design at all: amylase is added to both tubes or to neither, or the two tubes are otherwise treated identically with no distinguishing variable, so there is no way the depicted setup could actually test amylase activity.
level_2: The single-variable logic is broken in a major way: iodine or the incubation step is applied to only one of the two tubes instead of both, or the 'Control' and '+Amylase' tubes are visibly exposed to different incubation conditions (e.g., different warmth or different dwell time) beyond the amylase itself, introducing a second uncontrolled variable.
level_3: Only one tube receives amylase and both tubes otherwise get the same starch volume, iodine treatment, and mixing, but the incubation step is shown with an implausible thermal cue (e.g., the tubes sit in ice water or a visibly boiling bath) rather than something that reads as body-temperature warmth, undercutting the premise of testing a body-temperature enzyme.
level_4: Only the '+Amylase' tube receives enzyme; both tubes get the same starch volume, the same dwell time in a bath or hand-hold that plausibly reads as body-temperature warmth (not icy or boiling), and the same iodine volume and mixing treatment: a genuine single-variable test of amylase activity, even though the resulting color is never shown.
level_5: All of score 4, plus every non-enzyme variable (starch volume, incubation exposure, iodine volume, mixing technique and duration) is visibly matched between the two tubes so precisely that a viewer could recognize this as a properly controlled amylase-activity experiment from the setup alone, with nothing in the depicted procedure hinting at or requiring the excluded color outcome.

Spatiotemporal Consistency rubric:
level_1: A test tube is hidden from view for a moment and then shown suddenly full again with no visible transition, a hand adding a reagent disappears mid-pour and reappears elsewhere, a tube's orientation snaps to a different angle with no motion shown getting there, or the lighting on the bench changes drastically from one moment to the next.
level_2: There is a visible jump cut between steps, a hand's motion looks jerky at the start or end of a pour, the water bath's surface ripples in a way that doesn't match anything touching it, or a tube visibly wobbles hard during a phase when it should be sitting still.
level_3: Both tubes stay in the same position relative to each other throughout; hand motion during each addition looks like one continuous motion rather than a series of jumps; the tubes stay upright and still during incubation; the water bath's surface shows only small, steady ripples rather than sudden disturbances.
level_4: The camera viewpoint doesn't pan, tilt, or zoom at any point; no hand or object fully blocks the view of either tube's contents during an addition or during heating; both tubes keep the same orientation across every phase of the procedure; neither tube's liquid surface flickers or strobes at any point.
level_5: All of score 4, plus: the lighting stays even across the whole clip with no glare appearing or vanishing on the glass or labels, any shadow cast by the hand or pipette points the same way throughout, the liquid inside each tube stays level and undisturbed until the corresponding action begins, and the camera holds one fixed framing and angle for the entire clip so the tubes' apparent alignment and spacing never shift.