Domain: Healthcare — Digestive Physiology
Target concept: pH Detection of Pancreatic Juice (Paper Strip Method)

Video generation prompt: Place a small amount of pancreatic fluid into a clean test tube. Briefly immerse the pH indicator paper into the liquid, then remove it and compare it with a standard pH color chart. Clearly demonstrate the handling of the test tube, the indicator paper, and the color chart, with well-organized steps and close-up views of the procedure.

Evaluation guide:
(i) Target concept: Visual verification of pancreatic juice alkalinity via pH indicator paper colorimetry.
Minimum mechanism: Indicator dye must be chemically responsive to [H⁺], pancreatic juice must be physiologically alkaline, and color chart must encode pH scale with validated alkaline-range hues (blue/green dominant).
(ii)Storyline: Frame 1: Static shot of upright test tube with clear liquid → Frame 2: Hand enters, dips paper vertically into tube (full tip submersion visible) → Frame 3: Paper withdrawn, held vertically with uniform wetness → Frame 4: Paper and chart brought into same focal plane, aligned side-by-side, motionless → Frame 5: Final freeze showing paper color identical to single chart band labeled pH 8.0 or 8.5; all transitions require continuous motion, fixed viewpoint, and no occlusion of critical surfaces (paper tip, chart band, liquid meniscus).

Manual:
Experimental Procedure
1. Place clean test tube containing clear pancreatic juice.
2. Briefly immerse pH indicator paper into liquid, then remove.
3. Hold wet paper beside standard pH color chart for direct comparison.
Observation of Experimental Phenomena
pH indicator paper turns blue-green or blue after immersion, matching the pH 8.0–8.5 band on the chart.
Summary of Experimental Principles
Pancreatic juice is alkaline (pH 7.5–8.8); pH indicator paper contains dyes that undergo reversible color change in response to H⁺ concentration, enabling visual pH estimation via calibrated color chart.

Prompt Grounding rubric:
level_1: The test tube, the pH indicator paper, and the color chart are not all shown at some point in the clip (one or more never appears); or the paper is never dipped into the tube's liquid; or the wet paper and the chart are never shown together on screen for comparison.
level_2: Only one of the three core props (test tube, pH indicator paper, or color chart) is clearly shown and recognizable; some partial action occurs (e.g., the paper is held near the tube, or the chart is displayed alone), but the dip-then-compare sequence never completes, such as dry paper resting beside the tube with no contact, or the chart appearing with no paper ever brought beside it.
level_3: All three props appear on screen: a test tube holding clear liquid, a strip of pH indicator paper, and a printed multi-band pH color chart. The paper is visibly dipped into the tube's liquid and withdrawn, and the wet paper is then held next to the chart in the same shot for comparison. The sequence proceeds in order: tube shown, paper dipped, paper withdrawn, paper held beside chart.
level_4: Everything in the 3-point description holds, and in addition: the paper stays flat and uncurled while held against the chart, the liquid in the tube is visibly clear rather than cloudy or opaque, the chart shows at least five separately labeled color bands spanning a pH range (for example, pH 5 through 9), and the wet paper displays one even color rather than streaks or blotches.
level_5: Everything in the 4-point description holds, and in addition: the paper's wetted area is fully soaked with no dry white margin left at the tip, the paper's color reads clearly as one specific chart band without visibly blending into a neighboring band, the tube, paper, and chart are each the same single prop from first appearance to last (none is swapped for a different tube, paper, or chart partway through the clip), and no extra props (gloves, droppers, printed labels) intrude into the shot.

Scientific and Causal Correctness rubric:
level_1: The paper shows no visible color change after being dipped (it stays white or keeps its dry, unreacted tint); or its color change lands in the acidic (pH below 6) or neutral (pH 7) part of the chart; or the chart itself has its colors in the wrong pH order (for example, showing red at pH 9); or the paper is compared against a chart that isn't a pH scale at all (e.g., a plain litmus chart or a glucose-test chart).
level_2: The paper develops color after immersion, but the hue falls outside the alkaline pH 7.5–8.8 range expected for pancreatic juice; or the chart's pH labels are correct but its color order is reversed (e.g., blue placed at the low-pH end); or the wet paper is held next to the chart before it was ever dipped in the liquid; or the paper's color lands exactly one band away from the correct alkaline reading (e.g., the paper reads as the green pH-7 band immediately next to the correct blue pH-8 band, rather than matching it).
level_3: After immersion, the paper's color corresponds to somewhere in the pH 7.5–8.8 band on the chart (blue, blue-green, or greenish-blue); the chart's bands run in the standard alkaline order of increasing pH (yellow, green, blue, violet); the sequence of immersion, color developing, and side-by-side comparison plays out in that order with no contradiction (e.g., the paper isn't shown already dry before the comparison).
level_4: Everything in the 3-point description holds, and in addition: the paper's color sits within a single band rather than blending across two bands, the chart's pH numbers increase in the same direction as its colors (no reversed or skipped values), the paper stays its dry, unreacted color until it actually touches the liquid and only then develops its alkaline hue, and the developed color doesn't fade or bleed while the paper is held up for comparison.
level_5: Everything in the 4-point description holds, and in addition: the paper's final color specifically matches the chart's pH 8.0–8.5 band rather than a neighboring band such as pH 7.5 or pH 9.0; the chart carries separate labels for pH 8.0 and pH 8.5 with a distinct band between them, so this specific match is unambiguous; and the chart is never consulted before the paper has been dipped (the immersion-then-comparison order is never reversed).

Spatiotemporal Consistency rubric:
level_1: The paper appears already inside the test tube with no hand motion shown bringing it there; or the color chart vanishes from the shot and reappears later; or the liquid's level or clarity in the tube changes abruptly between frames with no pouring or draining shown; or the shot cuts from bright to dim lighting with no visible transition; or the paper visibly tears or warps with no physical cause shown.
level_2: At least one of the following occurs: the paper spins more than a quarter turn in the hand with no matching wrist motion; the chart jumps sideways by more than its own width from one frame to the next; the test tube tips over by more than 30 degrees with no supporting hand movement shown; the paper goes from bone-dry to fully soaked within a single frame with no dipping motion shown; or the hand's shadow on the tube disappears in one frame and reappears in the next with no explanation.
level_3: The test tube, the paper, and the chart each keep a believable, unbroken presence through holding, dipping, withdrawal, and comparison: none jumps to a new spot or is swapped for a different object; the shadow cast by the hand on the tube, and later on the chart, stays cast from one consistent apparent direction across the dipping and comparison shots (it doesn't jump to the opposite side or vanish); the paper's entry into the liquid and its withdrawal read as one continuous motion rather than a jump cut; the tube stays cylindrical and the paper stays a flat rectangle throughout, with no warping.
level_4: Everything in the 3-point description holds, and in addition: the hand's dipping and withdrawal motions are smooth with no stutter or sudden jump, the paper doesn't flap, curl, or sag unexpectedly while being held up to the chart, the chart stays flat and facing the camera during the comparison rather than tilting or twisting out of plane, and the liquid in the tube sits still (no sloshing, dripping, or splashing) while the paper-versus-chart comparison is being shown.
level_5: Everything in the 4-point description holds, and in addition: the camera holds one fixed framing for the entire clip with no pan, tilt, or zoom; the hand never fully blocks the paper or the chart during the moment they're held up for comparison; the liquid's surface stays calm and unbroken throughout; and there is no flicker, blur, or trailing double-image on the paper or chart as they're held side by side.