Domain: Healthcare — Nutrition & Dietetics
Target concept: The Effect of Selenium on Antioxidant Activity (Simulation)

Video generation prompt: Prepare three test tubes, each containing an equal volume of hydrogen peroxide solution. Add a lipid oxidation indicator to each test tube. The first test tube receives no selenium, the second test tube is supplemented with a low concentration selenium solution, and the third test tube is supplemented with a higher concentration selenium solution. Gently mix all test tubes and place them side by side for comparison.

Evaluation guide:
(i) Target concept: Selenium-dependent modulation of H2O2-induced lipid oxidation rate, quantified via chromogenic indicator kinetics.
Minimum mechanism: The lipid oxidation indicator must be redox-sensitive and produce a stable, concentration-dependent color upon oxidation by hydrogen peroxide; the selenium species added directly to Tubes 2 and 3 (e.g., sodium selenite) must act as a direct, non-enzymatic GPx-mimetic catalyst (cycling between oxidation states to decompose H2O2 chemically without requiring any enzyme or protein to be present in the tube), thereby delaying indicator color development in a dose-responsive manner: more selenium added, slower and lighter the resulting color.
(ii)Storyline: Frame 1–2: Static wide shot showing three aligned, empty test tubes. Frame 3–4: Equal-volume liquid (H2O2 + indicator) dispensed into each tube; identical fill level, same color baseline. Frame 5–6: Dropper approaches Tube 1 → stops short, withdraws (no contact); same dropper delivers to Tube 2 (one entry); same dropper delivers to Tube 3 (second entry, visibly distinct). Frame 7–9: All three tubes undergo identical gentle swirling motion; simultaneous, same amplitude/duration. Frame 10: Final static shot; three tubes side-by-side, color gradient clearly visible (Tube 1 darkest, Tube 3 lightest), no motion, no occlusion, fixed viewpoint.

Manual:
Experimental Procedure
1. Place three identical test tubes side-by-side. Fill each with equal volume of hydrogen peroxide solution + lipid oxidation indicator.
2. Add no selenium to Tube 1; add low-concentration selenium solution to Tube 2; add high-concentration selenium solution to Tube 3.
3. Gently mix all three tubes identically.
Observation of Experimental Phenomena
Tube 1 (no selenium) develops darkest color; Tube 2 (low selenium) develops intermediate color; Tube 3 (high selenium) develops lightest color.
Summary of Experimental Principles
Selenium enhances antioxidant activity: higher selenium concentration inhibits lipid oxidation more effectively, slowing color development of the oxidation indicator.

Prompt Grounding rubric:
level_1: None of the posted_prompt's core elements appear together: no three test tubes (or fewer than three containers), no hydrogen-peroxide-plus-indicator liquid visible in any tube, no selenium added to any tube, or the tubes are not lined up side by side for comparison.
level_2: Three tubes stand side by side, but the setup breaks down somewhere: the liquid volumes look clearly unequal across the tubes, the indicator's color is missing from the liquid, or the three selenium conditions are never visually distinguished; no dropper ever approaches any tube, or the same addition (or none at all) happens to all three.
level_3: Three test tubes stand side by side, each holding a visibly equal volume of pale liquid (hydrogen peroxide plus indicator); Tube 1 receives no addition, Tube 2 receives one visible dropper delivery, and Tube 3 receives a second, visibly larger or repeated dropper delivery; the tubes stay in their fixed side-by-side arrangement throughout these additions.
level_4: Beyond level 3, the same dropper is used for both Tube 2 and Tube 3, held the same way each time; Tube 1 is never approached by the dropper at all; all three tubes are then swirled or inverted gently in the same manner after their additions; and no gloves, labels, or clutter block the view of the tube arrangement.
level_5: Beyond level 4, Tube 1's total isolation from any dropper is unambiguous across every frame; Tube 2 receives exactly one discrete addition; Tube 3's addition is visibly distinct from Tube 2's: a longer pour, a bigger rise in liquid level, or two separate additions rather than one; the post-addition swirling runs identically and without interruption across all three tubes; and the tubes keep the same unlabeled look and spacing from the first frame to the last.

Scientific and Causal Correctness rubric:
level_1: No tube shows any color development over time, or all three tubes end up the same color, or a tube's color changes before any addition or mixing has occurred, or the trend runs backward, for instance Tube 3 (the highest selenium dose) darkens fastest while Tube 1 (no selenium) stays palest.
level_2: Some color change appears, but it violates the expected dose-response: a tube darkens before its swirling is finished, Tube 1 develops color no faster than Tube 2 or Tube 3, all three tubes converge on one final shade, or the three change together with no differentiation between them.
level_3: After mixing, all three tubes darken at different rates that track the amount of selenium added: Tube 1 (no selenium) reaches the deepest color (e.g., deep amber-brown), Tube 2 (low selenium) reaches a middling shade, and Tube 3 (high selenium) stays palest (e.g., faint yellow or nearly colorless); the three shades stay visibly distinct through the final frame.
level_4: Beyond level 3, the ordering Tube 1 ≥ Tube 2 ≥ Tube 3 in darkness holds at every point in time after mixing with no crossovers; no tube ever lightens after having darkened; color development only begins once swirling is finished and then proceeds without pausing; and no flashing or artificial-looking color jump breaks the visual continuity.
level_5: Beyond level 4, the three tubes' color trajectories stay smooth with no abrupt jumps in hue or saturation between frames; Tube 1 stays the darkest tube throughout; Tube 3 stays the palest throughout; Tube 2's shade sits strictly between the two at every frame, never matching either; and no shadow or stray light source makes any tube look artificially darker or lighter than its actual color.

Spatiotemporal Consistency rubric:
level_1: Severe continuity break: a tube's position or size jumps between frames, a tube vanishes and then reappears, the whole arrangement rotates or resizes with no visible cause, the background shifts abruptly, the lighting flashes or strobes, or the swirling motion looks physically impossible, e.g., a tube snapping to a new tilt with no travel in between.
level_2: Moderate break: the tubes stay side by side but at least one looks a different height or width from frame to frame; the dropper appears or disappears with no visible approach or withdrawal; the swirling starts or stops with no easing in or out; or the liquid surface looks unnaturally stiff or overly shimmery for a water-based solution.
level_3: All three tubes keep the same spacing, position, and size across the whole sequence; the dropper travels smoothly into and back out of whichever tube it visits; the swirling motion looks gentle and matches in style across all three tubes; and the lighting and the shadows the tubes cast stay steady in direction and strength across the sequence.
level_4: Beyond level 3, no tube appears to drift sideways relative to the others; the liquid's surface bulges and settles naturally during swirling rather than staying flat and rigid; nothing blocks more than roughly 10% of any tube's visible area at any point; and the sequence shows no frozen frames, jump cuts, or repeated frames.
level_5: Beyond level 4, the spacing between neighboring tubes looks visually constant across every frame rather than drifting; the dropper tip stays a steady distance from the tube opening while dispensing, without bobbing; the swirling motion builds up and eases off naturally rather than starting or stopping instantly; the liquid's surface catches the light the same way in all three tubes; and none of the tubes, the dropper, or the liquid boundary appears to bend, stretch, or warp.