Domain: Engineering — Energy Engineering
Target concept: Combustion and Flame Temperature

Video generation prompt: A candle and a 99% alcohol burner are placed side by side in the same scene. Both the candle and the alcohol burner are ignited, and the flames are captured using an infrared thermal camera to compare the temperature distribution and core temperatures of the two flames.

Evaluation guide:
(i) Target concept: Comparative thermal radiance of laminar diffusion flames from two fuels under identical ambient conditions.
Minimum mechanism: Fuel must be vaporized at the flame base; combustion occurs in diffusion-controlled regime; thermal camera must resolve spatial temperature gradients without saturation or clipping; both flames must be steady-state and unconfined.
(ii)Storyline: Frame 1–2: Static wide shot showing unignited candle and alcohol burner side-by-side on shared surface. Frame 3–4: Ignition event visible at both wick and burner port (simultaneous spark/flame contact). Frame 5–10: Stable dual-flame thermal view: candle flame extends vertically with graded warmth; alcohol flame remains compact with intense central hotspot; both flames persist without extinction, occlusion, or drift; viewpoint remains fixed; thermal rendering remains consistent.

Manual:
Experimental Procedure
1. Place a standard paraffin candle and a 99% alcohol burner side-by-side on a non-flammable surface.
2. Ignite both simultaneously using a common ignition source.
3. Capture the burning flames using an infrared thermal camera in real time.
Observation of Experimental Phenomena
- Candle flame shows an elongated, teardrop-shaped thermal profile with a cooler, dimmer base near the wick, a moderately warm luminous interior/tip, and its hottest zone forming a thin outer mantle where the flame's edge meets the surrounding air.
- Alcohol flame shows a shorter, broader, more symmetrical thermal profile with a cooler outer edge and an intensely hot, compact core, reflecting cleaner, more complete, low-soot combustion.
- Thermal camera output clearly distinguishes two separate flame regions with different core intensities and spatial extents.
Summary of Experimental Principles
- Combustion efficiency and flame temperature depend on fuel volatility, stoichiometry, and heat release rate.
- The visible contrast between the two flames comes mainly from combustion completeness and flame geometry rather than from a large difference in theoretical adiabatic temperature: loss-free adiabatic flame temperatures for ethanol and for paraffin-type hydrocarbons are both roughly in the 1900-2000°C range. The much lower real, measured open-flame temperatures seen here reflect radiative and convective heat loss; the alcohol flame's cleaner, soot-free combustion concentrates its heat into a small, intensely hot core, while the candle's sootier combustion spreads heat over a taller flame with a cooler interior and a hotter outer mantle.

Prompt Grounding rubric:
level_1: Neither the candle nor the alcohol burner is visible, or only one of the two flame sources appears; neither flame is lit; or the footage is shown only in ordinary visible light with no thermal/infrared imaging at all.
level_2: Both the candle and the alcohol burner appear in the scene, but at least one is never ignited; or the two flames are not shown side by side (e.g., one is stacked behind the other, overlapping, or largely hidden from view); or the view alternates between thermal imaging and plain visible-light footage instead of staying in thermal imaging.
level_3: The candle and the 99% alcohol burner are both present, sitting side by side, both lit, and shown together in one continuous thermal-camera view; however, the wick or the burner's flame base is partly hidden from view at some point, or the two flame sources are not quite level with each other (one sits noticeably forward, back, higher, or lower than the other).
level_4: Everything required at the 3-point level holds, and additionally both flames stay completely visible for the whole recording with no occlusion; neither flame flickers out or needs re-lighting; the candle and the burner sit level and directly side by side with no perspective distortion making one appear closer or farther; the thermal-camera view is maintained continuously with no cut to ordinary visible-light footage.
level_5: Everything required at the 4-point level holds, and additionally: both flames sit on the same level surface with no height difference between their supports; no hand, tool, label, or other object ever enters the frame; and the thermal image keeps the candle flame and the alcohol flame as two clearly separate regions, with no blurring or blending of their heat signatures into one another.

Scientific and Causal Correctness rubric:
level_1: The candle and alcohol flames show no meaningful thermal contrast (e.g., both render as a single uniform color in the thermal image); or the relative brightness is inverted so the alcohol flame reads as cooler than the candle flame; or the flame colors in the thermal view do not correspond to any plausible heat distribution (e.g., the candle flame rendered as uniformly cold).
level_2: One or both flames show an implausible heat pattern: for instance, the candle's thermal image is a single uniform hot blob with no cooler region near the wick base; or the alcohol flame's visible yellow/orange light dominates the thermal readout instead of showing a compact hot core; or heat appears only at the wick or burner opening with no warm region extending upward into the flame body.
level_3: Both flames show at least two distinguishable temperature regions each: the candle flame has a visibly cooler base/interior with a hotter zone at its outer edge, and the alcohol flame has a visibly cooler outer region with a hotter, more concentrated core; however, one of the two flames shows only a single uniform temperature region rather than this two-zone contrast.
level_4: Everything required at the 3-point level holds, and additionally the candle flame shows three distinguishable zones (a cooler, dimmer region near the wick base, a moderately warm luminous interior/tip, and a hottest thin outer-edge mantle where the flame meets the surrounding air), while the alcohol flame shows two zones, a cooler outer edge and a hottest compact core; at no point does the candle's interior/tip appear hotter than its own outer mantle, and at no point does the alcohol flame's outer edge appear hotter than its core.
level_5: Everything required at the 4-point level holds, and additionally: the candle flame's thermal shape is tall and narrow with a smooth gradient from base to tip; the alcohol flame's thermal shape is shorter, wider, and more rounded or symmetrical; no heat bridge or bloom artifact connects the two separate thermal shapes; and the alcohol flame stays visibly shorter than the candle flame throughout, consistent with its faster, more complete combustion.

Spatiotemporal Consistency rubric:
level_1: The candle, the burner, or a flame vanishes and reappears, or suddenly relocates to a different spot in the frame; the recording jump-cuts between clearly different moments with no continuous motion bridging them; the thermal image suddenly switches to a completely different brightness scale or color palette mid-recording with no cause (e.g., the whole scene flashes from normal contrast to solid white or black).
level_2: A flame's position drifts sideways or up/down between frames with no continuous motion connecting the two positions; a jump of roughly more than one-tenth of the frame's height counts as this kind of break; the candle holder or the alcohol burner's body changes size or shape between frames; the thermal color palette assigned to the scene shifts partway through the recording (e.g., what was rendered orange is suddenly rendered blue) with no real temperature change to justify it.
level_3: The candle flame and the alcohol flame flicker at visibly inconsistent, uncorrelated rates (e.g., one flutters rapidly while the other stays nearly still) without this being explained by any visible draft or disturbance; the background surface shows a faint repeating pattern shift between frames; the thermal overlay's brightness or opacity noticeably varies from frame to frame even though the actual flames appear steady.
level_4: Everything required at the 3-point level holds, and additionally the candle and the alcohol burner keep the same spacing and alignment relative to each other and to a fixed background reference (such as the bench edge) throughout, with no drift in either flame's base position; each flame's outline changes shape only gradually, with no sudden jump in size or shape; the thermal color assigned to a given temperature stays the same from one frame to the next, with no sudden palette swap.
level_5: Everything required at the 4-point level holds, and additionally: neither flame region shows streaking or smearing inconsistent with a steady thermal-camera view of a mostly stationary flame; the background behind the two flames does not shift sideways relative to the flames between frames; and no lens artifact (flare, color fringing, or dark corners) appears, disappears, or changes strength across the recording.