Domain: Engineering — Mechanical Engineering
Target concept: Commonly Used Materials for Components

Video generation prompt: Acrylic plates and phenolic resin plates with equal thickness and area are sequentially placed on a high-temperature heating stage (200°C), kept for 5 seconds, and then removed to observe the morphological changes of the specimens.

Evaluation guide:
(i) Target concept: Differential thermal deformation response of thermoplastic vs. thermoset polymers under transient high-temperature exposure.
Minimum mechanism: Acrylic must be thermoplastic (reversible softening above Tg), phenolic must be thermoset (crosslinked, irreversible, dimensionally stable), and heating stage must sustain sufficient surface temperature for thermal conduction to exceed acrylic"s Tg within 5 s while remaining below phenolic"s decomposition threshold.
(ii)Storyline: Frame 1–2: Empty heating stage visible. Frame 3–4: Acrylic plate placed centrally; full surface contact established. Frame 5–8: Plate remains motionless in contact (no visible change during heating). Frame 9: Acrylic removed. Frame 10–11: Phenolic plate placed centrally; full surface contact established. Frame 12–15: Plate remains motionless in contact. Frame 16: Phenolic removed. Frame 17–20: Both plates positioned adjacent in fixed lateral orientation, filling same horizontal plane, under consistent frontal lighting, enabling direct visual contrast of post-heating morphology.

Manual:
Experimental Procedure
1. Place acrylic plate flat on 200°C heating stage.
2. Wait 5 seconds (plate remains in contact).
3. Remove acrylic plate.
4. Place phenolic resin plate flat on same heating stage.
5. Wait 5 seconds (plate remains in contact).
6. Remove phenolic resin plate.
7. Position both plates side-by-side for direct comparison.
Observation of Experimental Phenomena
Acrylic plate shows visible warping or edge curling; phenolic resin plate remains flat and unchanged in shape and surface integrity.
Summary of Experimental Principles
Acrylic (PMMA) has low heat deflection temperature (~105°C) and softens rapidly at 200°C; phenolic resin is a thermoset polymer with high thermal stability and dimensional retention up to ~200°C.

Prompt Grounding rubric:
level_1: No acrylic plate or phenolic resin plate appears; no heating stage visible; no sequential placement of two plates; no removal action shown; no side-by-side comparison setup.
level_2: At least one plate (acrylic or phenolic) appears, and a heated surface is present, but plates are not both present simultaneously in the same scene; placement sequence is missing or reversed; removal action is absent or misattributed to only one plate.
level_3: Both acrylic and phenolic resin plates appear in the same scene, placed sequentially on a heating stage; removal action occurs after placement; plates are visibly distinct in appearance (e.g., differing transparency or surface texture); side-by-side spatial arrangement is established before or after removal.
level_4: All PG elements correct: two distinct plates (acrylic and phenolic resin), sequential placement on heating stage, 5-second stillness implied by unbroken contact, synchronized removal, and side-by-side post-removal positioning, with no object duplication, omission, or substitution (e.g., no wood, metal, or PVC used instead).
level_5: Perfect PG fidelity: acrylic and phenolic resin plates are unambiguously identifiable by visual type (acrylic = transparent/rigid/glossy; phenolic = opaque/tan-brown/matte), placed one after the other on a clearly defined high-temperature heating stage; removal occurs as a single coordinated action; side-by-side comparison is maintained continuously from pre-placement through post-removal without camera cut, repositioning, or replacement.

Scientific and Causal Correctness rubric:
level_1: No thermal deformation observed in either plate; both plates remain geometrically identical before and after heating; no difference in state, shape, or surface integrity is shown.
level_2: Only one plate shows any change (e.g., warping or discoloration), but the change contradicts subject knowledge (e.g., acrylic remains flat while phenolic bends); or change appears before heating or during placement, violating causal order.
level_3: Both plates show morphological changes after removal, but the nature of change is inconsistent with material properties: e.g., both warp identically, or acrylic shows charring while phenolic shows no change, failing to reflect known differential thermal stability.
level_4: Morphological changes are present and differ between plates: acrylic plate shows visible warping/buckling/edge curling; phenolic resin plate remains flat or shows only minor surface darkening (no charring, melting, or flow); all changes appear only after removal, not during heating contact.
level_5: Acrylic plate exhibits clear, localized warping or edge lifting (no melting, dripping, or transparency loss); phenolic resin plate shows zero warping and retains original flat geometry and surface integrity (no blistering, cracking, or softening); change appears exclusively after removal, with no deformation during heating contact, fully consistent with acrylic’s low HDT (~105°C) vs. phenolic’s high thermal stability (>150°C at 200°C for 5 s).

Spatiotemporal Consistency rubric:
level_1: Objects teleport (e.g., plates appear/disappear mid-frame), heating stage flickers or changes size/shape abruptly, lighting shifts discontinuously, or plates undergo impossible motion (e.g., instant rotation without motion blur).
level_2: One plate exhibits discontinuous motion (e.g., jumps during placement), shadow direction flips between frames, or background structure breaks (e.g., stage edge vanishes then reappears); at least two major spatiotemporal violations present.
level_3: Minor motion stutter or brief inter-frame jitter occurs, but all objects maintain consistent relative positions; lighting and shadows remain stable; no object duplication or erasure; no structural distortion of plates or stage.
level_4: All motion is continuous and physically plausible: placement and removal involve smooth translation without acceleration artifacts; plates retain rigid-body integrity throughout; lighting, shadow, and perspective remain fixed and coherent across entire sequence.
level_5: Zero spatiotemporal artifact: rigid plates move with natural inertia and micro-adjustment; contact with stage shows consistent pressure-induced slight compression (subtle but visible flattening at edges on first frame of contact); no inter-frame aliasing, ghosting, or depth inconsistency; viewpoint remains absolutely fixed (no pan, tilt, zoom, or parallax shift).