Domain: Natural Science — Physics
Target concept: Thermal effect of infrared radiation (temperature measured by a thermometer)

Video generation prompt: Take two identical mercury thermometers. Coat the bulb of thermometer A with black paint, while leaving thermometer B uncoated. Place them under an infrared lamp and observe their readings after one minute.

Evaluation guide:
(i) Target concept: Differential infrared absorption due to surface color determines rate of temperature increase in identical thermal sensors.
Minimum mechanism: Black pigment must increase broadband IR absorptivity (vs. bare glass/metal) → faster heat transfer to mercury → greater volumetric expansion → higher column rise; mercury must remain liquid-phase and confined; no convection or external airflow interference.
(ii)Storyline: Frame 1: Two identical mercury thermometers placed adjacent, bulbs aligned horizontally, infrared lamp centered above. Frame 2–3: Lamp activates — uniform glow appears over both bulbs. Frame 4–7: Mercury columns begin rising; column in black-coated bulb advances earlier and farther. Frame 8–10: Both columns stabilize; final height of A > B is clearly visible and sustained. Perspective: Fixed frontal view, eye-level to bulb plane, no occlusion, full visibility of bulbs, columns, and lamp base.

Manual:
Experimental Procedure
1. Place two identical mercury thermometers side-by-side.
2. Coat bulb of left thermometer (A) with black paint; leave right thermometer (B) bulb uncoated.
3. Position infrared lamp directly above both bulbs.
4. Observe mercury column heights after illumination.
Observation of Experimental Phenomena
Mercury column in thermometer A rises higher than in thermometer B.
Summary of Experimental Principles
Black surfaces absorb more infrared radiation → greater thermal energy transfer → higher temperature rise measured by mercury expansion.

Prompt Grounding rubric:
level_1: No thermometers visible; or only one thermometer present; or infrared lamp absent; or black paint absent on any thermometer bulb; or thermometers not placed side-by-side under same lamp.
level_2: Two thermometers present and side-by-side, and infrared lamp present, but at least one of the following is missing: (a) thermometer A has black paint on bulb, (b) thermometer B has no paint on bulb, (c) both bulbs are visibly under the lamp"s illumination zone.
level_3: Two identical mercury thermometers placed side-by-side under an infrared lamp; thermometer A bulb is coated with black paint; thermometer B bulb is uncoated; all objects are visually present and correctly typed (no substitution with digital thermometer, alcohol thermometer, or non-mercury type).
level_4: All conditions for score 3 satisfied, AND both thermometers remain stationary throughout video; no repositioning, tilting, or occlusion occurs; lamp remains fixed and continuously illuminates both bulbs simultaneously during entire visible duration.
level_5: All conditions for score 4 satisfied, AND both thermometers are identically oriented (same tilt angle, same vertical alignment), same model/shape/size visually confirmed, and black paint appears only on thermometer A bulb (not on stem, glass, or scale), with no paint residue or smudging on thermometer B bulb.

Scientific and Causal Correctness rubric:
level_1: No temperature reading change visible on either thermometer; or both thermometers show identical reading change; or reading increases on uncoated thermometer while decreasing on black-coated one; or black coating appears on thermometer B instead of A.
level_2: Thermometer readings change, but direction or assignment violates causality: e.g., thermometer A (black-coated) shows smaller or equal rise compared to thermometer B (uncoated); or only one thermometer displays a visible reading change while the other remains static or unreadable.
level_3: Thermometer A (black-coated) shows a higher mercury column height than thermometer B (uncoated) at end of observation; both columns are continuous, liquid-phase mercury, and rise is visually discernible (i.e., column top position differs and is stable at final frame).
level_4: All conditions for score 3 satisfied, AND mercury column rise in thermometer A begins no later than rise in thermometer B; no reversal or drop in either column during observation; both columns remain fully contained within glass tube (no overflow, burst, or leakage).
level_5: All conditions for score 4 satisfied, AND mercury column in thermometer A is visibly taller than in thermometer B by a clearly non-identical amount (i.e., difference is unambiguous and sustained across final 3+ frames); no flickering, pixelation, or artificial animation of mercury level; rise is smooth and monotonic in both, with A consistently leading B from onset.

Spatiotemporal Consistency rubric:
level_1: Thermometers teleport between frames; lamp flickers on/off discontinuously; mercury columns jump vertically without intermediate states; bulb positions shift abruptly relative to lamp; or one thermometer disappears/reappears mid-video.
level_2: At least one major spatiotemporal break: e.g., lamp changes intensity or position between frames; mercury column moves in jerky, non-fluid motion; thermometers rotate or tilt inconsistently; shadows cast by lamp shift direction or vanish without cause.
level_3: No teleportation, no structural break (e.g., intact glass tubes, no cracks), no abrupt light/shadow inversion; both thermometers maintain fixed relative positions; lamp emits steady, uniform illumination over both bulbs; mercury motion is continuous (no frame-skipping jumps).
level_4: All conditions for score 3 satisfied, AND lighting remains spatially consistent: shadows fall in same direction and proportion throughout; no lens distortion (e.g., curved tube walls or skewed scale); no inter-frame misalignment of thermometer stems or bulbs.
level_5: All conditions for score 4 satisfied, AND no temporal artifact: zero frame duplication, zero ghosting, zero motion blur that obscures mercury meniscus or scale markings; lamp glow exhibits natural falloff (brightest at center, softer edges), with identical falloff symmetry on both bulbs; no parallax shift between thermometer positions across frames.