Domain: Natural Science — Biophysics
Target concept: Hemolysis and Crenation of Red Blood Cells in Hypotonic and Hypertonic Saline Solutions

Video generation prompt: Under the optical microscope, two adjacent drops of red blood cells are placed: one drop in distilled water, and the other in a hypertonic solution with a light blue color, and the process is recorded without any interference.

Evaluation guide:
(i) Target concept: Osmotic response of mammalian red blood cells to solute concentration gradients across semi-permeable membranes.
Minimum mechanism: Cells must be anucleate, biconcave, and lack cell walls; membrane must be selectively permeable to water but impermeable to NaCl; hypertonic solution must contain non-penetrating solute (e.g., NaCl) to drive water efflux; distilled water must be truly hypotonic (no solutes) to drive water influx.
(ii)Storyline: Frame 0–2s: Two static, adjacent, sharply bordered drops visible: left transparent/colorless, right uniformly light blue; both contain intact, discoid red blood cells. Frame 3–6s: In left drop, cells progressively lose biconcavity, swell, and rupture (membranes disappear, hemoglobin diffuses); in right drop, cells uniformly shrink, develop angular protrusions, and retain compact, spiky outlines. Frame 7–10s: Hemolysis completes (left: homogeneous pink haze, no intact cells); crenation completes (right: dense cluster of sharp, star-shaped cells); no cross-contamination, no reversal, no motion outside drops; viewpoint remains fixed, focus stable, lighting invariant.

Manual:
Experimental Procedure
1. Place two adjacent drops on a microscope slide: left drop = distilled water + red blood cells; right drop = hypertonic saline solution (light blue) + red blood cells.
2. Observe under optical microscope at fixed magnification; record continuously for 10 seconds without adjustment or interference.
Observation of Experimental Phenomena
- Left (colorless) drop: red blood cells swell and rupture (hemolysis) — loss of defined borders, ghost cells, diffuse pinkish clouding.
- Right (light blue) drop: red blood cells shrink and develop spiky projections (crenation) — angular, star-like shapes with sharp edges.
Summary of Experimental Principles
- Hemolysis occurs in hypotonic medium (distilled water): water enters cells → membrane rupture.
- Crenation occurs in hypertonic medium (concentrated saline): water exits cells → membrane collapse and spiculation.

Prompt Grounding rubric:
level_1: Under the microscope view, no two adjoining drops appear at all: either only a single drop is shown, or no drops are shown; no red blood cells are visible in any drop; neither a colorless (distilled-water) drop nor a light-blue (hypertonic) drop is present; the scene does not read as a magnified microscope field.
level_2: Two drops appear in the field but are not placed adjacent to each other (e.g., separated by empty slide area or shown in separate shots); or one of the two drops contains no visible red blood cells; or both drops look the same color (either both colorless or both tinted), so the distilled-water drop cannot be told apart from the hypertonic drop; the microscope framing is missing or so tightly cropped that drop boundaries are not visible.
level_3: Two adjoining drops sit together in one continuous microscope field: one drop is colorless and transparent (the distilled-water drop) and the other is tinted light blue (the hypertonic-saline drop); red blood cells are visible inside both drops; nothing foreign to the experiment (hands, on-screen labels, instrument overlays) intrudes into the frame.
level_4: Everything at the 3-point level holds, and in addition the two drops stay right next to each other in the same spot they started in for the entire 10-second clip; the red blood cells inside each drop are individually resolvable as separate round/discoid bodies rather than a blurred mass; the light-blue tint stays confined to the hypertonic drop and never bleeds across the boundary into the colorless drop.
level_5: Everything at the 4-point level holds, and in addition the colorless drop and the light-blue drop stay clearly distinguishable by both hue and transparency in every frame across the full 10 seconds; red blood cells stay inside the drop they started in, with none crossing the boundary or merging with cells from the other drop; no frame is degraded by motion blur, an obstruction, or a focus pull that makes either drop's cells hard to make out.

Scientific and Causal Correctness rubric:
level_1: Neither hemolysis nor crenation appears: the cells in both drops look the same (e.g., all still biconcave and intact, or all burst, or all shrunken) with no morphological difference between the colorless and light-blue drops; whichever change does occur is not tied correctly to the drop it should appear in (e.g., swelling shown in the light-blue drop instead of the colorless one).
level_2: A shape change happens but is assigned to the wrong drop for the underlying osmotic mechanism: cells in the colorless (hypotonic) drop appear shrunken/spiky, or cells in the light-blue (hypertonic) drop appear swollen or burst; or only one of the two drops shows any change at all while the other should also be changing.
level_3: Cells in the colorless drop visibly swell and/or rupture, consistent with water moving into the cells in the hypotonic medium; cells in the light-blue drop visibly shrink and develop irregular, spiky edges, consistent with water leaving the cells in the hypertonic medium; the two behaviors stay separate: swelling/rupture never shows up in the light-blue drop and shrinkage/spiking never shows up in the colorless drop.
level_4: Everything at the 3-point level holds, and in addition every visible cell in the colorless drop follows the swelling-to-rupture path with none staying spiky or shrunken, and every visible cell in the light-blue drop follows the shrinking-to-spiking path with none staying swollen or intact; no cell in either drop sits in a confusing halfway state that could be read as the other drop's behavior.
level_5: Everything at the 4-point level holds, and in addition the colorless drop reaches a state of fully disrupted cells (diffuse pink haze or empty membrane outlines with no surviving intact cell), while the light-blue drop reaches a state of uniformly sharp-edged, star-shaped shrunken cells with no smooth-edged or partially-shrunken cells left; neither drop's progression reverses or stalls partway through.

Spatiotemporal Consistency rubric:
level_1: Severe break in continuity: the two drops swap places or one disappears and reappears between frames; red blood cells or the light-blue tint pop in or out abruptly rather than changing gradually; the lighting on the slide flips abruptly between bright and dark with no visible cause; the microscope view jumps in zoom or focus with no transition; the boundary between the two drops tears open or the drops merge into one without any intervening steps.
level_2: Partial but noticeable breaks: the two drops' positions creep or jump slightly from frame to frame beyond ordinary optical drift; the microscope focus drops out for a portion of the clip; the light-blue tint spreads past its own drop's boundary into the colorless drop, or fades and re-intensifies unpredictably; a visible cut or splice interrupts the swelling or shrinking process partway through.
level_3: The two drops stay in the same fixed side-by-side positions for the entire 10-second clip with no merging or tearing of the boundary between them; the colorless drop's cells progress through swelling toward rupture and the light-blue drop's cells progress through shrinking toward spiking without any frame skipping backward in that progression; both drops and their cell outlines stay sharp enough to follow throughout, and the light-blue-versus-colorless contrast that marks the two drops apart stays legible in every frame rather than washing out.
level_4: Everything at the 3-point level holds, and in addition the swelling-to-rupture change in the colorless drop and the shrinking-to-spiking change in the light-blue drop each move forward smoothly frame to frame with no reversals: a ruptured cell never re-forms an intact membrane, and a spiked cell never rounds back out; the number of cells visible in each drop stays plausible from one frame to the next, with none abruptly multiplying or disappearing apart from the hemolysis/crenation process itself.
level_5: Everything at the 4-point level holds, and in addition the two drops' outlines and their position relative to each other stay visually locked to how they appeared in frame 1, with no perceptible drift over the full 10 seconds; the light-blue tint stays confined to its own drop with a stable, clearly readable edge against the colorless drop in every frame; no flicker, strobing, or doubling ever makes a cell boundary or drop edge momentarily vanish or duplicate.