Domain: Natural Science — Physics
Target concept: Heavy element

Video generation prompt: An experimental subject holds a spring scale inside an elevator, with a 500g mass suspended below the scale; the elevator accelerates rapidly upward, and changes in the scale reading are observed.

Evaluation guide:
(i) Target concept: Apparent weight increase due to inertial frame acceleration
Minimum mechanism: Elevator must accelerate upward (not just move upward at constant velocity); scale must measure tension force; mass must be rigidly coupled to scale via suspension; reading must reflect increased tension, not arbitrary change.
(ii)Storyline: [Frame 1–3] Static baseline: scale held, mass suspended, elevator stationary → scale shows ~4.9 N / 500g. [Frame 4–7] Acceleration onset: elevator begins upward motion → visible parallax (interior features shift downward), scale reading rises monotonically. [Frame 8–10] Sustained acceleration: reading remains elevated, mass remains tautly suspended, hand maintains firm grip, no relative motion between scale/mass/hand. Perspective: fixed frontal view showing hand, scale, mass, and partial elevator wall/floor for motion reference; no cuts or viewpoint shifts.

Manual:
Experimental Procedure
1. A person holds a spring scale inside an elevator cabin.
2. A 500g mass is suspended from the scale's hook.
3. Elevator accelerates rapidly upward.
Observation of Experimental Phenomena
The spring scale reading increases above its stationary value during upward acceleration.
Summary of Experimental Principles
Newton's Second Law: because the mass hangs from the scale rather than resting on a surface, the elevator's upward acceleration increases the tension needed to accelerate the mass, which stretches the spring further and raises the scale reading.

Prompt Grounding rubric:
level_1: No spring scale present; no 500g mass visible; no human hand holding any device; no elevator interior scene (e.g., missing walls, ceiling, floor, or door frame); no upward motion cue (e.g., no vertical parallax, no acceleration-indicating visual reference).
level_2: Spring scale and 500g mass are both present but not connected (mass not suspended from scale hook); human hand is present but not holding the scale; elevator interior is partially visible (e.g., only one wall shown) but lacks at least two of: ceiling, floor, or door frame; upward motion cue is absent or contradicted (e.g., downward drift, static background).
level_3: Spring scale is held by a human hand; 500g mass is visibly suspended from the scale's hook; elevator interior is fully recognizable (ceiling, floor, at least one side wall, and consistent spatial enclosure); upward motion is indicated by continuous vertical parallax relative to fixed interior features (e.g., wall seams, light fixtures, or floor tiles moving downward in frame).
level_4: All elements of 3-score are present AND the scale reading display is visible (digital or analog face clearly legible), AND the mass is visually consistent with a typical 500g cylindrical or cuboidal lab weight (e.g., metallic, uniform color, no text or label contradicting 500g), AND the same hand keeps its grip in the same position on the scale's handle throughout the sequence.
level_5: All elements of 4-score are present AND the camera holds a single fixed viewpoint on the hand, scale, mass, and elevator interior, with no panning, tilting, or zooming at any point in the sequence, AND no additional person, hand, or object enters or leaves the frame outside of the described setup.

Scientific and Causal Correctness rubric:
level_1: Scale reading remains unchanged during upward motion; or reading decreases during upward motion; or mass detaches, floats, or exhibits free-fall behavior; or scale shows zero load while mass is attached.
level_2: Scale reading changes but in wrong direction (e.g., decreases) OR changes occur without upward motion; OR mass appears weightless (no tension in suspension string/wire) while scale shows non-zero reading; OR reading changes before or after motion onset with no temporal alignment.
level_3: Scale reading increases during upward motion AND the mass remains suspended with visible tension in the suspension element (e.g., taut string/wire, no sagging); AND the increase is sustained for the duration of upward motion (no flickering, resetting, or intermittent display); AND no contradictory phenomena appear (e.g., mass bouncing, scale oscillating wildly, or sudden drop in reading mid-motion).
level_4: All elements of 3-score are present AND the reading increase is visually monotonic (no reversal or dip) during upward motion AND the suspension element remains continuously taut (no slack appearing at any point) AND the scale face orientation stays upright (no rotation or tilting that obscures readability) AND no secondary false indicators appear (e.g., floating labels, animated arrows, or external text overlays).
level_5: All elements of 4-score are present AND the reading increase begins around the same moment that the parallax cues first indicate the elevator is accelerating upward, AND the reading holds at its elevated level for as long as the parallax cues continue to indicate upward acceleration, with no unexplained dip, reset, or return toward baseline before the sequence ends, AND the displayed value is numerically consistent with an elevated reading (e.g., an analog needle deflected past the resting mark, or digital digits reading above the ~4.9 N / 500 g baseline), AND no visual artifact such as glare or a reflection on the display face could be mistaken for an actual reading change.

Spatiotemporal Consistency rubric:
level_1: The 500g mass or the spring scale jumps from one position to a clearly different position without passing through the space in between; the scale or the mass disappears from view and then is back again with no visible cause; the elevator's walls, floor, or ceiling warp, ripple, or dissolve into a different shape between frames; the hand releases its grip on the scale and re-grips it with no visible motion connecting the two moments; the lighting inside the elevator cuts abruptly from bright to dark (or the reverse) with no visible cause; the hand or scale spins through more than a quarter turn between one frame and the next with no visible motion path connecting the two orientations.
level_2: The hand's grip shifts to a different spot on the scale's handle with no visible transition between the two grip positions; the suspension string appears taut in one moment and visibly slack in the next (or the reverse) with no gradual change in between; the downward drift of the wall seams, floor tiles, or light fixture used as parallax cues freezes for several moments and then jumps ahead abruptly; the mass swings out to the side independently of the scale in a way inconsistent with hanging from a single hook.
level_3: The hand keeps continuous contact with the scale's body throughout; the mass stays centered directly beneath the scale's hook; the suspension string stays visibly straight without any sudden snapping taut or going slack; the wall seams, floor tiles, and light fixture used as parallax references keep the same shape and spacing relative to one another from moment to moment; the downward scroll of these interior features that signals the elevator's upward acceleration proceeds at a steady, even pace rather than in visible freezes or jumps.
level_4: All elements of 3-score are present AND the parallax drift of the interior features stays purely vertical, without drifting sideways by a noticeable amount, AND the scale and mass move together as a single rigid unit, with the mass never swinging out away from directly under the hook, AND the point where the hand grips the scale stays visible and is not blocked from view by the mass, the hand's own fingers, or the elevator frame, AND no part of the hand, scale, mass, or string visibly passes through another object's surface.
level_5: All elements of 4-score are present AND the whole acceleration sequence unfolds as one continuous, unbroken motion with no freezing followed by a sudden jump ahead, AND the floor-tile lines and wall seams keep a straight, evenly spaced pattern with no shearing or warping over the whole sequence, AND the suspension string keeps an unbroken, continuous connection between the mass and the scale's hook in every moment shown, AND at no point do the hand, scale, mass, or string visibly merge into or overlap through one another.