Domain: Natural Science — Cell & Developmental Biology
Target concept: After lysing the cell culture, centrifugation results in a pellet of cellular debris, with the clarified supernatant remaining above.

Video generation prompt: A microcentrifuge tube containing cell culture lysate was removed from a benchtop centrifuge immediately after a complete high-speed spin and held upright, motionless, in hand.

Evaluation guide:
(i) Target concept: The state of a cell lysate inside a microcentrifuge tube immediately after a completed benchtop centrifugation run, once mechanical separation of debris from soluble material has finished.
Minimum mechanism: The centrifugal force applied during the spin must have already sedimented the denser cellular debris into a compact pellet at the tube's conical bottom, leaving the less dense soluble material as a comparatively clear supernatant above it; because the spin is complete before the tube is removed, this pellet and the clearer fluid above it are already present and stable at the moment the tube is lifted out and held still; nothing further needs to separate on screen.
(ii)Storyline: [Frame 0] Tube sits in the centrifuge rotor with the rotor already stopped and the lid open; [Frame 1-3] a hand reaches in, grasps the tube, and lifts it straight up out of the rotor cavity; [Frame 4-10] the tube is held upright and motionless, revealing a denser mass settled at its conical bottom and a comparatively clear fluid layer above it, with the boundary between the two staying fixed as the tube is held still; no shaking, no re-mixing of the settled mass back into the fluid above; viewpoint stays fixed, frontal or slightly oblique, showing the tube's full length so the bottom mass and the fluid above it are both visible; lighting stays directional and steady enough to make out the boundary between them.

Manual:
Experimental Procedure
1. Centrifuge a lysed cell culture at high speed for the standard time needed to complete pelleting (a full clarifying spin, not a brief pulse).
2. Remove the microcentrifuge tube from the benchtop centrifuge once the rotor has fully stopped, and hold it upright, motionless.
Observation of Experimental Phenomena
A compact, opaque mass of cellular debris sits at the tube's conical bottom, with a visible boundary separating it from the comparatively clear fluid above — the fluid above the boundary looks noticeably less cloudy than the original lysate did before spinning.
Summary of Experimental Principles
Centrifuging a cell lysate applies centrifugal force that sediments the denser cellular debris into a compact pellet at the bottom of the tube's conical tip, while the less dense, soluble components stay suspended in the clarified supernatant fluid above it; because the spin has already run to completion, this separation is already fully formed by the time the tube is removed and held upright.

Prompt Grounding rubric:
level_1: No microcentrifuge tube is visible anywhere in the shot; or no benchtop centrifuge appears in the scene at all (no tabletop unit visible before, during, or immediately after the tube is shown); or the tube is held at a visibly non-vertical angle for the whole clip; or the tube appears completely empty with no fluid inside.
level_2: A microcentrifuge tube is present and mostly upright, but it is never shown near or coming out of a benchtop centrifuge (e.g., it simply sits on a bench with no centrifuge in view at any point); or the tube rests in a stand/rack or on the bench rather than being held in a hand; or the container is the wrong type (e.g., a large test tube or a screw-cap vial instead of a small conical microcentrifuge tube); or the tube tilts more than about 15 degrees from vertical at some point in the clip.
level_3: A single conical-bottom microcentrifuge tube (roughly 0.5-2 mL, translucent or frosted plastic) is held upright in a hand and is clearly linked to a benchtop centrifuge: either being lifted directly out of an open rotor chamber or held immediately beside one with its lid open; the tube stays steady in the hand, without being shaken, inverted, or set down and picked back up; nothing else in the shot (extra containers, unrelated tools) contradicts this simple removal-and-hold action.
level_4: Everything above holds, and in addition: the tube is shown coming straight out of the centrifuge with no intervening step (no pipetting, labeling, or vortexing) before it is held upright and still; the centrifuge itself reads as a compact benchtop model with a hinged lid and a horizontal rotor visible when open (not a large floor-standing or refrigerated unit); the tube's size looks correctly scaled to the hand holding it, spanning roughly a third to half the length of an adult hand.
level_5: Everything above holds, and in addition: a human hand grips the tube by its upper cylindrical wall, with fingers clearly visible around the tube and not covering the cap or the conical tip; the centrifuge's rotor is fully stopped (no motion blur or spinning visible), and its lid sits fully open, consistent with the tube having already been safely removed after the run finished; the fluid column inside the tube, from its conical base to its cap, is left unobstructed by fingers or labels so its full length is visible.

Scientific and Causal Correctness rubric:
level_1: The fluid inside the tube looks completely uniform with no denser region anywhere, as if no centrifugation had occurred; or a solid, compact pellet is visible while the tube is also shown being swirled or shaken; or the fluid has an unnatural bright color (e.g., neon blue or green) with nothing in the scene suggesting a dye was added; or the fluid appears to be bubbling or actively circulating despite the tube being held still.
level_2: A denser-looking region is visible, but it sits near the top of the fluid column rather than at the tube's conical bottom; or a bottom region does appear but as a loose, cloud-like haze rather than any kind of settled mass; or the fluid remains just as opaque throughout its whole length as it would look immediately after lysis, with no region reading as clearer than any other.
level_3: A visibly denser, more opaque patch sits at the conical bottom of the tube, and the fluid above it reads as noticeably less cloudy than that bottom patch, even though the edge between the two is blurry or gradual rather than sharply defined and a faint haze still lingers in the upper fluid.
level_4: Everything above holds, and in addition: the denser bottom patch reads as one cohesive mass rather than a diffuse cloud, and it occupies roughly the bottom quarter or less of the fluid column's height; the fluid above it looks close to clear, with at most a faint tint remaining; no bubbles, foam, or visible swirling suggest the bottom mass is being stirred up or disturbed.
level_5: Everything above holds, and in addition: a distinct, visibly sharp boundary line separates the compact bottom mass from the clear fluid above it, and that line follows the curve of the tube's conical taper rather than cutting across it as a flat edge; the fluid above the boundary looks essentially clear rather than merely lighter; no glare, reflection, or lens artifact obscures the view of this boundary at any point in the clip.

Spatiotemporal Consistency rubric:
level_1: Partway through the lifting motion, the tube momentarily blinks out of view and then reappears already resting still in the hand, with the actual lift itself never shown; or the fluid inside jumps from one arrangement to a completely different one between two adjacent frames with no shaking or tilting shown in between; or the tube's rigid conical-cylindrical shape bends, stretches, or warps at any point; or the lighting on the tube and centrifuge shifts abruptly between frames: a cast shadow vanishes and then reappears, or the scene's brightness jumps with no visible cause.
level_2: The tube stays visible the whole time, but the hand holding it changes size or shifts its grip position abruptly between frames rather than smoothly; or the dense patch at the tube's bottom changes size or shape suddenly with no tilting, shaking, or inversion shown to explain it; or the centrifuge visible in the background changes its color, model, or orientation partway through the clip; or a shadow cast by the tube or hand rotates or shifts direction while the tube itself stays still.
level_3: The tube, the hand holding it, and the centrifuge in the background each keep one consistent size, shape, and color from the first frame to the last; the motion of lifting the tube out of the rotor and into the upright hold reads as a single unbroken path with no jump cuts; once the tube is held still, the boundary between the dense bottom patch and the clearer fluid above stays at the same height and shape.
level_4: Everything above holds, and in addition: the hand's grip shifts and its fingers move smoothly and continuously during the lift, slowing naturally into the final still hold rather than snapping into position; the centrifuge's chamber and lid keep the same texture, reflectivity, and apparent viewing angle throughout, consistent with a fixed camera; the tube wall's clarity (how easily the fluid inside can be seen through it) stays constant once the tube is held still, neither becoming noticeably more see-through nor more opaque without cause.
level_5: Everything above holds, and in addition: the tube and hand always render in front of the centrifuge body whenever they overlap it in frame, never behind it; the boundary between the dense bottom patch and the clearer fluid above curves in a way that matches the tube's conical taper rather than appearing as a flat line where the tube wall is curved; every frame shows a distinct moment of the lifting-and-holding motion, with no segment of frames repeating or freezing and no visible jump in the hand's progress from one position to the next.