Domain: Natural Science — Chemistry
Target concept: Boc-Protected Amine vs Free Amine in the Ninhydrin Color Reaction

Video generation prompt: Two small glass vials are placed side by side: the one on the left contains the free amine with a blue cap, and the one on the right contains the Boc-protected amine with a red cap. The chemist adds ninhydrin to both and heats them in a water bath.

Evaluation guide:
(i) Target concept: Differential ninhydrin reactivity based on amine proton availability.
Minimum mechanism: Free primary amine must be present and unblocked to condense with ninhydrin and undergo oxidative decarboxylation to yield the colored triketohydrindeneamine product; Boc protection sterically and electronically blocks nucleophilic attack at nitrogen, preventing adduct formation.
(ii)Storyline: Frame 0–2: Static wide shot showing two identically sized glass vials side-by-side, left with unambiguous blue cap, right with unambiguous red cap; fixed viewpoint, front-lit, full vial bodies visible. Frame 3–4: Close-up hand action adding clear liquid (ninhydrin) separately to each vial; liquid contact visible at meniscus. Frame 5–6: Both vials lifted and placed together into a visible water bath (rim and heated water surface evident). Frame 7–9: Stable shot holding both vials in bath; left vial solution transitions from colorless to saturated purple/blue; right vial solution retains original color and clarity: no hue shift, no precipitation, no turbidity. All transitions are continuous, causally linked to heating, and constrained to solution volume; no off-screen inference required.

Manual:
Experimental Procedure
1. Place two identical glass vials side-by-side: left vial capped with blue cap (free amine), right vial capped with red cap (Boc-protected amine).
2. Add ninhydrin solution to both vials.
3. Place both vials into a water bath and heat uniformly.
Observation of Experimental Phenomena
- Left vial (blue cap) develops a distinct purple/blue color.
- Right vial (red cap) remains colorless.
Summary of Experimental Principles
Free amines react with ninhydrin to form Ruhemann’s purple (a blue-purple chromophore); Boc-protected amines lack a free -NH2 group and therefore do not undergo this reaction.

Prompt Grounding rubric:
level_1: Fewer than two glass vials appear, or the two vials are not placed side by side; the left vial lacks a clearly blue cap or the right vial lacks a clearly red cap; no ninhydrin is added to either vial; no water-bath heating step is shown at all.
level_2: Two vials appear but not clearly side by side, or the cap colors are wrong (e.g., both blue, both red, or swapped so red is on the left); ninhydrin is added to only one of the two vials, or heating in a water bath happens to only one vial or not at all.
level_3: Two vials sit side by side: blue cap on the left, red cap on the right; ninhydrin is visibly added to both vials; both vials are placed into a shared water bath. All three actions occur, though their order or the exact moment of reagent contact may be unclear.
level_4: Everything in score 3 holds true, and in addition: ninhydrin is shown contacting the liquid inside each vial in turn, the blue and red caps stay identifiable as the scene proceeds, and both vials appear together in the same water bath at the same time, matching the prompt's setup with no swapped identities.
level_5: Everything in score 4 holds true, and in addition: the blue and red cap colors stay clearly readable in every shot with no fading or blocking; the two vials keep their left/right seating in the bath without drifting apart or trading places; the ninhydrin-adding and bath-placement actions are each shown as one continuous, visible motion rather than an implied cut.

Scientific and Causal Correctness rubric:
level_1: Neither vial shows any color change; or both vials change color the same way; or a color appears before the vials are placed in the water bath or before ninhydrin is even added.
level_2: One vial changes color, but it's the wrong one for its chemistry: the red-cap (Boc-protected) vial turns purple/blue, or the blue-cap (free-amine) vial stays colorless; or the left vial's color appears out of step with the heating (e.g., before the right vial despite both being heated together).
level_3: The blue-cap (free-amine) vial visibly develops a purple/blue color once heating begins; the red-cap (Boc-protected) vial stays colorless or keeps its original hue; the color only shows up after heating starts and only in the blue-cap vial; the causal chain of free amine + ninhydrin + heat producing color is visible, even if the timing or contrast is soft.
level_4: Everything in score 3 holds true, and in addition: the red-cap vial's lack of color is unambiguous (no faint tinting or hue drift); the blue-cap vial's color is a clear, recognizable purple/blue rather than brown, gray, or yellow, and appears within the solution itself rather than as a cap or meniscus artifact; the color only starts developing once heating is underway, not during the ninhydrin addition.
level_5: Everything in score 4 holds true, and in addition: the blue-cap vial's purple color becomes rich and evenly saturated through the whole liquid volume; the red-cap vial keeps exactly the same color, clarity, and brightness from before heating to after; nothing in the lighting (reflections, glare) makes either vial appear to change color; the contrast between the two vials is obvious at a glance with no ambiguous in-between shade.

Spatiotemporal Consistency rubric:
level_1: One of the vials disappears or swaps sides between shots; a cap changes color (blue becomes red or vice versa) with no explanation; the water bath appears or vanishes between shots; the camera view suddenly cuts to a different angle mid-action; the lighting flips abruptly (e.g., bright to dim) between shots with no visible cause.
level_2: Both vials stay on screen but visibly jump or slide to a new spot between shots; a cap's color washes out or flickers; the ninhydrin liquid vanishes mid-pour and then reappears; the water bath's surface warps or ripples in an unnatural way.
level_3: Both vials remain in their original left/right spots and stand upright for the whole clip; neither vial, cap, nor the water bath blinks out of existence or changes shape; the pouring of ninhydrin and the lowering of vials into the bath happen as one smooth, uncut motion; the overall brightness and shadow direction in the shot stay the same from start to finish.
level_4: Everything in score 3 holds true, and in addition: the liquid surface inside each vial rises and settles naturally as ninhydrin is added, with no floating droplets or upside-down meniscus; if steam or ripples appear over the bath, they show up under both vials at the same time; the dropper or pipette never appears to pass through a vial's glass wall.
level_5: Everything in score 4 holds true, and in addition: each vial's cylindrical body and cap keep their solid, undistorted shape in every shot, with no bending or warping; reflections and highlights on the glass and liquid shift believably as the view or lighting changes; any steam shown drifts upward and thins out naturally; the footage plays smoothly with no frozen, repeated, or stuttering frames anywhere in the clip.