Domain: Natural Science — Physics
Target concept: Dispersion of Light (Prism Spectroscopy)

Video generation prompt: A triangular glass prism is placed in a beam of sunlight, allowing the light to pass through it. Observe what happens to the light as it exits the prism, noting the appearance, distribution, and order of any colors that result.

Evaluation guide:
(i) Target concept: Optical dispersion of polychromatic white light via differential refraction in a dielectric prism.
Minimum mechanism: A transparent, non-uniformly shaped (triangular) dielectric medium must be placed in the path of collimated or quasi-collimated white light; refraction at two non-parallel interfaces causes angular separation proportional to wavelength.
(ii)Storyline: Frame 1–2: Static shot showing intact triangular glass prism on surface, ambient daylight present. Frame 3–4: Directional sunbeam enters first prism face (visible as luminous column). Frame 5–7: Light exits second prism face and transforms into a linear, spatially extended colored band. Frame 8–10: Band remains stable, fully resolved, with seven contiguous hues in strict ROYGBIV order; no occlusion, no motion blur, no viewpoint shift. All events occur within a single fixed camera view; prism and projection plane remain coplanar and mutually visible throughout.

Manual:
Experimental Procedure
1. Place a transparent triangular glass prism on a stable surface in direct sunlight.
2. Orient the prism so sunlight enters one face and exits through another.
3. Observe the light exiting the prism onto a white surface or in air.
Observation of Experimental Phenomena
A continuous, linear band of seven distinct colors appears where the light exits the prism: red, orange, yellow, green, blue, indigo, violet — always in that fixed order from longest to shortest wavelength.
Summary of Experimental Principles
White light is composed of multiple wavelengths; when passing through a prism, different wavelengths refract by different amounts due to dispersion, separating into the visible spectrum.

Prompt Grounding rubric:
level_1: No prism appears in the shot, or the prism is not illuminated by any beam of light, or no colored band of light is produced anywhere in the scene: for example, a photo of the prism sitting in shade with nothing exiting it.
level_2: The prism is present and lit by a beam of light, but either no beam is visibly entering the prism, or a colored band appears somewhere in the frame without any visible connection to light exiting the prism (e.g., floating separately, or already present before the beam starts), or a colored band appears while the prism itself has left the frame.
level_3: The prism is present and visibly lit by a directional beam entering one face; a band containing at least three different colors appears where light exits another face, roughly aligned with that exit path.
level_4: The prism is present and lit by a directional beam; a single, unbroken, roughly linear multi-colored band emerges from the prism's exit face and stays aligned with it as the only visible source of color in the shot; no ambient rainbow, colored light fixture, or screen effect elsewhere could explain the band.
level_5: The prism is present and lit by a directional beam; a single unbroken, linear, multi-colored band emerges only from the prism's exit face and stays spatially attached to that exit point for the full shot, with nothing else in the frame (no second light source, prism, or on-screen graphic) that could account for the band.

Scientific and Causal Correctness rubric:
level_1: The colored band has no causal connection to the prism: for example, colors appear before the beam ever reaches the prism, the band persists unchanged after the beam is blocked or the prism is removed, or the colors look like a flat rainbow graphic rather than light emerging from the exit face.
level_2: The band emerges from the prism's exit face, but shows too few distinguishable hues (fewer than three), or includes non-spectral colors (such as pink, white, brown, or black patches) mixed in with the spectral ones, or the hues run in a scrambled or reversed order with no optical basis (e.g., violet sits beside red rather than at the opposite end of the band from it).
level_3: The band shows at least five distinguishable hues running in roughly red-to-violet order along its length, with no non-spectral colors mixed in, and the band only appears once light is actually passing through the prism.
level_4: The band shows exactly seven distinguishable hues (red, orange, yellow, green, blue, indigo, violet) arranged in that order along the band with no non-spectral color mixed in, and the ordering is consistent with wavelength-dependent refraction: red sits nearest the beam's original, undeviated direction, and violet sits farthest from it.
level_5: The band shows exactly seven distinguishable hues in strict red-orange-yellow-green-blue-indigo-violet order with no gap, repeat, or non-spectral color anywhere along its length; the ordering correctly reflects that violet is refracted the most and red the least; and the band is present throughout the entire time the beam passes through the prism, consistent with it disappearing if the beam or prism were removed.

Spatiotemporal Consistency rubric:
level_1: The prism jumps to a different position or orientation between frames with no visible movement causing it, or the colored band appears or vanishes instantly rather than building up, or the beam of light snaps from one direction to another with no transition, or the prism's shape changes between frames (an edge disappears or a face warps).
level_2: The prism shifts or rotates slightly between frames without any smooth motion connecting the two positions, or the band's length or position changes in sudden steps rather than continuously, or the beam switches on and off rather than staying lit, or the shadow the prism casts points in a direction the beam couldn't actually produce.
level_3: The prism stays in the same place and shape throughout the shot; the beam holds a consistent direction and brightness; the colored band builds up steadily from the exit face rather than snapping into existence or relocating; no part of the prism or the band vanishes and reappears somewhere else.
level_4: Everything at the level below holds, and the beam's brightness and direction stay steady rather than drifting, and the band's edges stay aligned with the prism's exit face from frame to frame with no visible skipping or misalignment of the band relative to the prism.
level_5: Everything at the level below holds, and the prism remains completely still with a consistent shape throughout, and the band forms smoothly and continuously from the exit face without any visible flicker, wobble, or doubled image, and the band's position tracks the prism consistently for the entire shot with no drift or warp in perspective.