Domain: Natural Science — Physics
Target concept: Melting

Video generation prompt: A beaker containing crushed ice is placed on a hot plate, a thermometer is inserted into the beaker, and heating is performed slowly while continuously recording the process.

Evaluation guide:
(i) Target concept: Solid-to-liquid phase transition driven by conductive heating, occurring isothermally at the melting point.
Minimum mechanism: Heat transfers from hot plate → beaker base → crushed ice interface → bulk ice; as long as solid ice and liquid water coexist, incoming thermal energy goes into breaking hydrogen bonds (latent heat of fusion) rather than raising temperature, so the thermometer's reading stays essentially flat; once the last ice has melted, further heating raises the liquid water's temperature and the reading resumes climbing.
(ii)Storyline: [Frame 0] Beaker with dry, granular crushed ice sits centered on hot plate; thermometer inserted vertically, bulb buried in ice; scale readable at its starting value. [Frame 1–3] Ice surface develops moisture, grains round slightly, a thin liquid layer forms at the base; the thermometer column holds at its starting value. [Frame 4–7] Liquid layer deepens, ice volume visibly reduces, remaining grains become smaller and fewer; column remains essentially flat while solid ice and liquid water coexist. [Frame 8–10] Last ice grains disappear; liquid fills beaker to the original ice height; column then begins climbing from its plateau value as the now-fully-liquid water keeps absorbing heat. Perspective: Fixed frontal view, full beaker in frame, no occlusion, consistent lighting, no camera motion.

Manual:
Experimental Procedure
1. Place a beaker containing crushed ice on a hot plate.
2. Insert a thermometer into the crushed ice so bulb is fully immersed.
3. Turn on hot plate to low heat and observe continuously for 10 seconds.
Observation of Experimental Phenomena
- Crushed ice gradually shrinks and becomes wetter; liquid water accumulates at beaker bottom.
- Thermometer liquid column holds steady while ice and water coexist, then resumes rising once all the ice has melted.
- No steam, bubbling, or boiling occurs.
Summary of Experimental Principles
Melting is a phase transition from solid to liquid at constant temperature (0°C for pure ice); energy input breaks hydrogen bonds without raising temperature until transition completes.

Prompt Grounding rubric:
level_1: None of the four required elements (beaker, crushed ice, hot plate, thermometer) is present in the video, or the frame contains an entirely different setup.
level_2: One or two of the four required elements (beaker, crushed ice, hot plate, thermometer) appear, but at least one is not visually identifiable as itself (e.g., the thermometer is a plain stick with no bulb or liquid column, the ice is a single solid block rather than crushed pieces, or the hot plate looks like a generic flat surface with no heating element), and no placement relationship among them is shown.
level_3: All four elements are present and identifiable: a cylindrical transparent beaker; crushed ice as granular, opaque white pieces inside the beaker; a hot plate with a visible heating-element cue (e.g., a lit power/heat indicator or coil pattern); and a thermometer with a visible liquid column and scale. The crushed ice sits inside the beaker, the beaker sits on the hot plate, and the thermometer bulb is inserted into the ice; these placements are all correct.
level_4: Everything required at the 3-point level is present, and in addition: the thermometer bulb stays buried inside the crushed ice rather than floating above it or resting against bare beaker glass; the beaker is centered on the hot plate (not offset by more than roughly half the beaker's width); and no hands, tools, labels, or other extraneous objects enter the frame at any point.
level_5: Everything required at the 4-point level holds, and in addition: the crushed ice fills the beaker to a consistent height with no water visibly pooled before heating starts; the thermometer's scale markings are legible; the hot plate's power/heat indicator stays lit continuously, consistent with the manual's low-heat setting (no glow or heat haze is required, since low heat does not produce one); and the beaker, hot plate, and thermometer keep the same relative arrangement throughout the video, with no drifting, tilting, or repositioning of any of the three.

Scientific and Causal Correctness rubric:
level_1: No visible state change occurs (the crushed ice looks fully solid throughout with no wetness, shrinkage, or liquid appearing); or liquid water is present from the very first frame with no visible prior melting, or the thermometer's reading drops below its starting value at any point during heating.
level_2: Only one of the two required phenomena is shown correctly: either the crushed ice visibly melts (surface wetting, grain shrinkage, liquid pooling at the base) while the thermometer reading is shown climbing steadily through the entire melting period with no plateau, or the ice shows no visible melting at all while the thermometer reading changes; or the thermometer reading jumps erratically (repeated unexplained rises and drops) while the ice melts.
level_3: The crushed ice shows progressive, visible melting (softened granular texture, a wet surface, shrinking and disappearing ice pieces, and liquid pooling at the beaker's base), while the thermometer's liquid column holds essentially flat during the period solid ice and liquid water coexist, consistent with heat being absorbed as latent heat of fusion rather than raising the mixture's temperature; the reading does not fall or reverse at any point.
level_4: Everything required at the 3-point level holds, and in addition: the flat thermometer reading during ice-water coexistence shows no unexplained spikes or dips, melting visibly progresses from the ice surface and base inward rather than happening as one instantaneous change, and once the last visible ice piece disappears the thermometer reading begins climbing again rather than staying flat indefinitely or having already been climbing before all ice was gone.
level_5: Everything required at the 4-point level holds, and in addition: the crushed ice shrinks gradually while keeping a granular appearance right up until the last piece disappears; the temperature plateau during coexistence is smooth, with no visible flicker in the reading; the renewed rise after complete melting is gradual rather than an instant jump to a new value; and no condensation, steam, or bubbling appears on or in the beaker, consistent with the low-heat setting staying below boiling.

Spatiotemporal Consistency rubric:
level_1: A severe spatiotemporal break occurs: the beaker jumps to a different position or size between frames, the thermometer is missing from one frame and back in the next with no motion explaining it, the hot plate's heating indicator switches on and off with no consistent pattern, the room's lighting swings between two entirely different states within a single cut (e.g., bright daylight to near darkness with no transition), or the beaker visibly cracks, deforms, or breaks apart.
level_2: A moderate violation occurs: the beaker rocks or rotates by more than roughly 15 degrees, the thermometer visibly bends or slides vertically by more than about a third of its length, the crushed ice appears to slosh or flow like a liquid before any melting has occurred, the hot plate's indicator light pulses on and off irregularly, or the shadow cast by the beaker swaps to the opposite side of the frame between adjacent shots with no corresponding change in the light source.
level_3: The beaker stays visibly still in its original spot on the hot plate; the thermometer's tilt does not change by more than about 5 degrees; individual crushed-ice grains may shift slightly within the pile as it melts but the pile's overall shape and position are retained; the hot plate indicator's brightness changes smoothly rather than snapping on or off; and the light source's apparent direction and color stay the same across the video.
level_4: Everything required at the 3-point level holds, and in addition: there is no ghosting or tearing between frames, no shimmering or flickering at object edges, motion reads as continuous rather than jerky, the background does not shift relative to the beaker and hot plate in a way that suggests an unintended camera move, and the beaker stays upright with no visible tilt beyond about 2 degrees throughout.
level_5: Everything required at the 4-point level holds, and in addition: crushed-ice grains move only in ways consistent with gravity-driven settling or melt-induced slumping, never sliding or rolling in a way that looks artificially propelled; the thermometer's liquid column rises with a smooth, gradually changing speed rather than a constant linear ramp or an instant jump; the hot plate's indicator brightens or dims with an even, centered gradient rather than a patchy or lopsided one; and the beaker, ice, and thermometer never visibly intersect, float apart from their supports, or squash/stretch out of rigid shape.