Domain: Engineering — Materials Science & Engineering
Target concept: Comparison of Dry and Wet Fiber Tensile Behavior

Video generation prompt: Two identical human hairs are clamped side by side; the left one is dry, while the right one is wet. Identical weights are simultaneously attached to both hairs to apply tension.

Evaluation guide:
(i) Target concept: Moisture-induced plasticization of keratin reduces tensile stiffness in biological fibers.
Minimum mechanism: Water molecules disrupt hydrogen bonds between keratin chains, increasing free volume and enabling greater conformational mobility under stress, leading to higher elongation at identical load.
(ii)Storyline: Frame 0–1: Static shot showing two parallel, vertically clamped human hairs: left dry (matte, uniform scatter), right wet (localized surface shine, slightly darker tone). Frame 2–3: Identical weights descend synchronously and attach to bottom ends. Frame 4–9: Both hairs elongate vertically under load; right hair extends further along its full length while maintaining continuity and alignment; elongation difference is stable and progressive; no secondary artifacts (dripping, bending, snapping) occur. Perspective: Fixed frontal close-up, shallow depth-of-field isolating hairs and weights; consistent neutral lighting; no camera motion or zoom.

Manual:
Experimental Procedure
1. Place two identical human hairs side-by-side in vertical orientation.
2. Clamp both hairs securely at the top using identical clamping devices.
3. Attach identical weights to the free bottom ends of both hairs simultaneously.
4. Ensure left hair remains dry; right hair is fully saturated with water prior to loading.
Observation of Experimental Phenomena
The wet (right) hair elongates visibly more than the dry (left) hair under identical tensile load; no snapping or irregular deformation occurs in either hair.
Summary of Experimental Principles
Water plasticizes keratin fibers, reducing intermolecular hydrogen bonding and increasing chain mobility—resulting in lower tensile modulus and higher strain at failure for wet hair compared to dry hair.

Prompt Grounding rubric:
level_1: Fewer than two hairs are shown, or no clamping apparatus is visible, or no weight is attached to either hair, or the two weights look different in size or shape, or there is no visual sign at all (moisture, sheen, color, texture) that one hair is meant to be wet and the other dry.
level_2: Two hairs are shown side by side, each clamped at the top with a matching weight hanging from its bottom end, but neither hair shows any visible cue of wetness or dryness (both look identical in sheen and color), or the two hairs overlap or are misaligned so their full lengths cannot both be seen.
level_3: Two human hairs are clamped side by side and hang vertically, each with a matching weight attached at its free end; the right hair shows at least one clear wet cue (surface shine, darker or more translucent tone, or visible moisture) and the left hair shows at least one clear dry cue (matte, uniform light-scattering surface); both hairs are visible along their entire length with no occlusion.
level_4: All conditions for score 3 are met, AND the wet cue appears only on the right hair and the dry cue appears only on the left hair with no cross-contamination; the two clamps match each other in shape and orientation, the two weights are visually identical, and both hairs stay parallel to each other for the whole clip with no extra objects or on-screen labels cluttering the setup.
level_5: All conditions for score 4 are met, AND the wet sheen covers the entire visible length of the right hair rather than only a spot near the tip or clamp, and the matte dry appearance covers the entire visible length of the left hair; both hairs sit against the same background under the same lighting and focus, with no motion blur hiding the wet/dry cues and no frame where the wet/dry appearance flickers or reverses.

Scientific and Causal Correctness rubric:
level_1: Both hairs fail to show the expected physical relationship: the dry (left) hair elongates as much as or more than the wet (right) hair under the identical weight, or neither hair shows any elongation at all despite the attached weights, or one hair snaps or breaks apart while the other does not.
level_2: The wet (right) hair does elongate more than the dry (left) hair, but the effect is barely visible or inconsistent: e.g., the gap between the two hairs appears only briefly and then disappears, or one hair stretches while the other stays perfectly rigid with zero visible give (an unrealistic all-or-nothing response) rather than both hairs stretching by different amounts.
level_3: Both hairs visibly and continuously elongate under the load, and the wet (right) hair's elongation is clearly and consistently greater than the dry (left) hair's elongation for the whole loading sequence; neither hair snaps, frays, or breaks apart.
level_4: All conditions for score 3 are met, AND the wet hair's greater elongation is attributable only to its wetness: the dry hair shows no pre-existing kink, bend, or slack that would exaggerate the gap, and the wet hair shows no dripping or pooling water suggesting gross saturation rather than fiber-level softening; both hairs stay intact and aligned throughout.
level_5: All conditions for score 4 are met, AND each hair's elongation increases smoothly along its length with no localized bulging or sudden thinning, the wet hair keeps its shine and translucency and the dry hair keeps its matte look for the entire loading sequence, and the elongation gap between the two hairs never shrinks or reverses at any point in the clip.

Spatiotemporal Consistency rubric:
level_1: A hair, clamp, or weight vanishes and reappears in the same shot with no physical motion connecting the two states (e.g., a weight is at the bottom of a hair in one frame and off-screen in the next with no visible drop), or the shot cuts abruptly to a different camera angle mid-sequence, or the overall scene brightness jumps sharply between one frame and the next with no in-scene cause.
level_2: A hair is hidden behind another object for more than a single frame and reappears in a different position or shape than before it was hidden, or a hair develops an unnatural hinge-like bend partway down its length instead of a smooth curve, or a weight's descent is visibly non-continuous, falling in one frame and already at rest in the next with no intermediate motion.
level_3: Both hairs, both clamps, and both weights stay continuously visible and in the same relative arrangement throughout; each hair's outline is a single smooth curve at every frame with no kinks or sudden angle changes; any small frame-to-frame wobble in a hair's position is minor and self-corrects rather than accumulating into a visible drift.
level_4: All conditions for score 3 are met, AND each hair elongates smoothly and monotonically as its weight descends with no pause-then-jump in the stretching motion; the shine on the wet hair moves in step with the wet hair's own motion rather than sliding independently of it; neither hair shows flicker, strobing, or a sudden change in sharpness between frames.
level_5: All conditions for score 4 are met, AND the two weights descend at the same rate along parallel vertical paths with no side-to-side drift, both hairs stay in sharp focus against a static, unchanging background for the entire clip, and neither hair's silhouette shows any warping, doubling, or ghosting artifact at any frame transition.