Domain: Engineering — Agricultural Engineering
Target concept: Compared with wheat seedlings without root hairs, those with root hairs turned red more quickly when immersed in red ink, showing a noticeable visual difference.

Video generation prompt: Place two similar wheat seedlings side by side, one with intact root hairs and the other without root hairs. Immerse the roots of both seedlings simultaneously into containers containing red ink solution. Keep the seedlings upright and stationary. Observe the movement of the ink along the stems within a short period.

Evaluation guide:
(i) Target concept: Root hairs enhance absorption rate of aqueous solutions in plant roots.
Minimum mechanism: Red ink must behave as a passive water-soluble tracer moving via xylem under transpiration-driven flow; differential uptake requires functional root hair surface area and intact vascular continuity.
(ii)Storyline: Frame opens on static side-by-side setup → roots dip into red ink simultaneously → ink begins ascending in both stems → ascent progresses continuously → leading edge of red color becomes visibly farther up the stem of the root-hair-intact seedling → difference in ascent extent remains stable until end of clip. Perspective: Fixed frontal view, eye-level or slightly elevated, full root-to-stem visibility; no occlusion; lighting reveals texture and color contrast without glare or loss of detail.

Manual:
Experimental Procedure
1. Place two similar wheat seedlings side-by-side in same frame.
2. Ensure one seedling has intact root hairs; the other has root hairs removed.
3. Immerse roots of both seedlings simultaneously into separate containers of red ink.
4. Keep both seedlings upright and motionless.
Observation of Experimental Phenomena
Red color ascends higher and faster in the stem of the seedling with root hairs than in the one without root hairs.
Summary of Experimental Principles
Root hairs increase surface area for water and solute uptake; thus, red ink (as a water-soluble dye) is absorbed more rapidly via capillary action and transpiration pull in seedlings with intact root hairs.

Prompt Grounding rubric:
level_1: Fewer than two wheat seedlings appear in the shot, or both seedlings look identical in root-hair coverage (either both hairy or both hairless), or no red-ink container is shown, or the roots are never immersed in ink, or a seedling is shown lying down rather than standing upright, or the two seedlings are never framed together for comparison.
level_2: Two wheat seedlings are shown together, but at least one setup detail is missing or wrong: root hairs are not clearly visible on the intended seedling; the other seedling still shows visible root hairs instead of being hairless; only one ink container is present instead of two separate ones; the two seedlings' roots are immersed into the ink at clearly different times rather than together; or a seedling tips over or is repositioned during the recording.
level_3: Two wheat seedlings of similar size stand side by side in the same shot; one clearly shows root hairs along its root zone and the other clearly does not; each seedling's roots sit in its own container of red ink; both sets of roots enter the ink at essentially the same moment; both seedlings remain upright and still for the observation period.
level_4: Everything true at level 3 holds, and in addition the camera holds one fixed, front-facing view for the whole clip with no pan, tilt, or zoom; the two seedlings appear at a similar size and framing, with neither one tilted, cropped, or blocked from view; the two ink containers look like a matched pair (same shape, similar fill level).
level_5: Everything true at level 4 holds, and in addition each seedling is fully visible from the base of its stem to the tips of its leaves; whether root hairs are present is unmistakable from the texture/density at the root zone; the two containers are identically shaped, filled to the same level, and placed symmetrically on either side of the frame; nothing else enters or leaves the shot, and neither seedling nor container is touched or adjusted once the roots are immersed.

Scientific and Causal Correctness rubric:
level_1: Neither stem ever changes color, or red appears in both stems at exactly the same time and to the same extent, or red shows up only in the leaves or the soil rather than the stem, or red color is visible before the roots ever touch the ink, or the red coloring travels downward from the leaves rather than climbing up from the roots.
level_2: Red color reaches at least one stem, but something is inconsistent with root-hair-driven uptake: both stems redden at the same rate/extent; or the red stays confined to the root zone without climbing the stem; or the hairless seedling's stem reddens ahead of the seedling with root hairs; or the red streak is broken into disconnected patches or fades partway up the stem.
level_3: Both stems show a red streak climbing from the roots upward, but the seedling with visible root hairs shows the red reaching noticeably higher (or getting there sooner) than the hairless seedling, a difference in how far or how fast the color has climbed that is plain to see within the clip.
level_4: Everything true at level 3 holds, and in addition the red streak in both stems climbs steadily without gaps, sudden jumps, or reversals, and once the color starts climbing, the leading edge in the root-hair seedling stays ahead of the leading edge in the hairless seedling at every point checked afterward.
level_5: Everything true at level 4 holds, and in addition the red dye is visible along the exterior of both stems as a continuous vertical streak or line running up the stem's surface, rather than a diffuse blush spreading sideways across the whole stem, and this streak stays a stable red color with no fading, smearing, or patchy dilution in either seedling.

Spatiotemporal Consistency rubric:
level_1: A seedling or ink container suddenly appears or disappears between shots with no cause; the lighting jumps in color or intensity, changing the direction or strength of shadows; a stem visibly bends, stretches, or warps with nothing pushing on it; or the root zone of a seedling separates from its container between frames.
level_2: At least one clear spatiotemporal flaw appears: a seedling's position or angle suddenly jumps; the ink level in a container changes with no visible cause; root hairs appear or disappear mid-clip without anything blocking the view; the lighting flickers or throws inconsistent shadows; or the background shifts or rotates.
level_3: Neither seedling nor container ever teleports; each seedling's roots stay visibly connected to its container and each stem stays intact; there is no sudden lighting or shadow change; no stem bends or warps out of nowhere; every object keeps a consistent spatial relationship and physical form across the clip.
level_4: Everything true at level 3 holds, and in addition any motion that does occur (e.g., a slight natural sway of a seedling) looks smooth and physically plausible, with no floating or sudden stops/starts, and the footage shows no strobing, ghost images, or duplicated frames between shots.
level_5: Everything true at level 4 holds, and in addition the seedlings in the foreground and the background never drift out of alignment with each other as if on separate planes, there is no stray lens flare or color fringing at the seedlings' edges, focus does not drift in and out, and the outline of each seedling and container stays crisp rather than intermittently softening or blurring.