Domain: Natural Science — Physics
Target concept: Mass-spring oscillator released from different initial displacements

Video generation prompt: Place two identical vertical spring-mass systems side by side on the experimental table. Pull the mass block on the left downward more than the one on the right, then release them simultaneously from rest and record their motion.

Evaluation guide:
(i) Target concept: Initial displacement determines oscillation amplitude in undamped simple harmonic motion of identical mass-spring systems.
Minimum mechanism: Linear elastic restoring force (F = -kx), Newtonian inertia (F = ma), and absence of significant dissipative forces (e.g., air resistance, internal friction) sufficient to preserve amplitude distinction over observable timeframe.
(ii)Storyline: Frame 0–1: Two static, side-by-side vertical spring-mass systems visible; left mass visibly lower than right; springs visibly stretched. Frame 2: Simultaneous release, no motion yet. Frame 3–5: Both masses begin upward acceleration; left mass moves faster initially due to greater restoring force. Frame 6–10: Left mass reaches higher peak height and deeper trough than right; both cross equilibrium at same instants; motion remains purely vertical and synchronous; fixed frontal viewpoint ensures unobstructed side-by-side comparison throughout.

Manual:
Experimental Procedure
1. Place two identical vertical spring-mass systems side-by-side on a flat experimental table.
2. Pull the mass block of the left system downward farther than that of the right system.
3. Release both mass blocks simultaneously from rest.
Observation of Experimental Phenomena
The left mass block undergoes larger-amplitude vertical oscillation than the right mass block; both oscillate with same frequency and remain in phase; no lateral motion or detachment occurs.
Summary of Experimental Principles
For an ideal mass-spring system under simple harmonic motion, amplitude is determined solely by initial displacement; frequency and period depend only on mass and spring constant — hence identical systems exhibit same frequency but different amplitudes when released from different initial displacements.

Prompt Grounding rubric:
level_1: Two vertical spring-mass systems are not both present, or they are not set up beside each other on the same tabletop, or one or both mass blocks are missing from the springs, or no downward pull of the left mass is shown before release, or the two masses are not released simultaneously from rest.
level_2: Two vertical spring-mass systems appear beside each other on the same tabletop, but at least one of the following is missing: both mass blocks are clearly attached to their springs; the left mass is pulled down farther than the right mass before release; both masses are let go from rest at the same moment (neither one starts moving early); no visible pre-release drift in either system.
level_3: Two identical vertical spring-mass systems sit side by side on the same tabletop; both mass blocks are visibly attached to their springs; the left mass is displaced downward farther than the right mass before release; both masses are released from rest together, with no motion visible in either system before that moment.
level_4: Everything required at the 3-point level holds, and in addition both systems keep a strictly vertical orientation throughout: neither spring tilts or sways sideways, and neither mass block swings side to side; the camera holds a fixed frontal framing so both systems stay fully visible with nothing blocking either mass block or spring.
level_5: Everything required at the 4-point level holds, and in addition both mass blocks start moving in the same video frame once released; each spring stays attached to its mass block and to the fixed support above it for the whole clip; no frame in the clip freezes, drops, or otherwise breaks the continuity of either system's motion.

Scientific and Causal Correctness rubric:
level_1: The motion breaks basic spring-mass physics for this setup: e.g., a mass block moves without any visible stretch or compression of its spring, a spring detaches or bends sideways instead of stretching along its axis, the oscillations keep growing instead of staying bounded, or the left mass ends up with an equal or smaller swing than the right mass despite starting with the larger pull-down.
level_2: Both systems oscillate, but a basic expectation for this setup fails: e.g., the left and right masses visibly complete their up-down cycles at different speeds even though the springs and masses are identical, one system shows no repeating up-down pattern at all, or the left mass's larger swing is not yet visible within the first oscillation cycle.
level_3: Both mass blocks move up and down periodically after release; the left mass block's swing is visibly larger than the right mass block's within the first oscillation cycle; the two masses appear to complete each up-down cycle in about the same amount of time; the motion of each mass is driven only by its own spring, with no added push or pull after release.
level_4: Everything required at the 3-point level holds, and in addition the two masses pass through their resting (equilibrium) height at matching moments during the first cycle, with neither system visibly leading or lagging the other there; the left mass never becomes the smaller-swinging one at any point; if the swings shrink over time, both systems shrink at a visually similar rate rather than one damping out much faster than the other.
level_5: Everything required at the 4-point level holds, and in addition the left mass keeps swinging noticeably farther than the right mass across at least two more oscillation cycles, rather than the two swings converging toward the same size; the two masses continue crossing their resting height together, with no growing lag between the systems; neither mass block picks up visible sideways rocking that would draw energy away from its vertical swing.

Spatiotemporal Consistency rubric:
level_1: Severe continuity break: a mass block or spring jumps to a new position between frames without passing through the positions in between; a spring's length changes with no corresponding movement of its mass block; one entire spring-mass system blinks out of the shot for a moment and then comes back; the tabletop scene abruptly brightens or darkens with no lamp, switch, or shadow-casting object visible to explain it; the tabletop visibly warps, ripples, or shifts position for no physical reason; or the camera cuts to a different framing partway through the clip.
level_2: A noticeable but less severe break: one mass block freezes in place for a couple of frames while the other keeps moving; a spring's coils briefly separate from the mass block or from the fixed support above without reattaching smoothly; or the tabletop or background shifts sideways between frames by more than roughly a tenth of the frame's width, as though the camera were nudged.
level_3: Both mass blocks and both springs move smoothly from frame to frame with no jumps, freezes, or momentary disappearances; each spring's coils stay attached to its mass block and to the fixed support throughout; the tabletop and background stay in place; nothing about either system's motion looks discontinuous.
level_4: Everything required at the 3-point level holds, and in addition each mass block's up/down speed changes gradually rather than in sudden jumps, matching how a released spring naturally speeds up and slows down; the shadow each mass block casts on the tabletop shifts smoothly and continuously as the mass moves, rather than jumping to a new position or side; neither system's motion visibly gets ahead of or falls behind the other by a growing amount.
level_5: Everything required at the 4-point level holds, and in addition any motion blur on a mass block points along that mass's actual direction of travel rather than a mismatched direction; the two systems appear to sit at the same distance from the camera throughout, with neither one drifting closer or farther; and the two masses' oscillation peaks and equilibrium crossings stay lined up closely enough in time that a viewer would call the two systems' motion simultaneous rather than one trailing the other.