Domain: Engineering — Energy Engineering
Target concept: Renewable Energy (Wind Energy): The higher the wind speed, the brighter the bulb shines.

Video generation prompt: Fix a small wind turbine on the experimental bench and connect its generator output to a miniature bulb via wires. Position a variable-speed fan facing the turbine blades, gradually increasing the fan's airflow speed from low to high, and observe the changes in the brightness of the bulb as the fan speed increases.

Evaluation guide:
(i) Target concept: Electromechanical energy conversion from wind kinetic energy to visible light output via a direct-coupled generator-bulb system.
Minimum mechanism: Fan airflow must exert torque on turbine blades causing rotation; turbine shaft must drive an electromagnetic generator; generated current must flow through closed circuit to heat bulb filament; filament temperature rise must produce increased visible radiance without spectral shift.
(ii)Storyline: Frame 0–1: Static scene: turbine mounted, bulb connected, fan off and adjacent. Frame 2–3: Fan begins slow rotation (blades just blurring), bulb remains dark. Frame 4–6: Fan rotation visibly accelerates (increasing blur/definition), bulb begins glowing faintly (low-intensity uniform emission). Frame 7–9: Fan at highest visible speed (dense motion blur or sharp high-RPM definition), bulb at brightest stable state (intense uniform glow, no saturation). Throughout: fixed viewpoint, no object repositioning, no lighting shifts, no extraneous illumination; brightness change solely attributable to fan-driven turbine motion.

Manual:
Experimental Procedure
1. Fix small wind turbine on experimental bench.
2. Connect turbine output wires to miniature bulb.
3. Position variable-speed fan adjacent to turbine blades, facing them directly.
4. Start fan at lowest speed; gradually increase speed over time.
Observation of Experimental Phenomena
Bulb starts unlit or very dim; brightness increases progressively and continuously as fan speed increases; bulb color remains constant; no flickering or reversal of brightness trend.
Summary of Experimental Principles
Wind energy conversion: kinetic energy of moving air spins turbine blades → mechanical energy → electrical energy via generator → lights bulb; higher wind speed → greater rotational energy → higher voltage/current → brighter bulb.

Prompt Grounding rubric:
level_1: No small wind turbine is visible, no miniature bulb is visible, no variable-speed fan is visible, or none of these three objects appears anywhere in the video.
level_2: At least one of the three core objects (turbine, bulb, fan) is visible, but at least one of the other two is missing, or all three appear yet not together in one continuous scene (e.g., the fan is shown in a separate shot from the turbine/bulb, or the bulb is not on the same bench).
level_3: A small wind turbine fixed on the experimental bench, a miniature bulb connected to the turbine by visible wires, and a variable-speed fan positioned facing the turbine blades are all visible together in one continuous, fixed-viewpoint scene.
level_4: The turbine, bulb, and facing fan described for score 3 are all present together, and further: the turbine's mounting to the bench is visible (base or fasteners shown), the wires between turbine and bulb form an unbroken connection with no dangling ends, the fan is clearly aimed at the turbine blades rather than angled away, and no object enters or leaves the frame partway through the sequence.
level_5: The mounted turbine, connected wires, and aimed fan described for score 4 all hold, and further: the turbine and bulb keep the same fixed spatial relationship throughout with no repositioning or sudden camera refocus, the fan does not drift sideways or rotate away from its facing position, and all three objects keep consistent relative size and orientation without cropping or distortion at any point.

Scientific and Causal Correctness rubric:
level_1: Bulb brightness shows no change over time as the fan speeds up, bulb brightness decreases while fan speed increases, or the bulb is already lit brightly before the fan starts moving.
level_2: Bulb brightness changes, but not consistently with fan speed (for example it dims partway through then brightens again, or flickers unpredictably), or the bulb changes brightness before the fan blades start turning or after the fan has already stopped, or the bulb's color shifts (e.g., from white-yellow to blue-white) instead of just its intensity changing.
level_3: As the fan is shown speeding up (blades turning visibly faster, with increasing motion blur), bulb brightness increases without ever dimming back down; the bulb starts dark or at its dimmest while the fan is off or slow, and brightness only ever increases as fan speed increases.
level_4: The dark start and one-directional brightening described for score 3 both hold, and further: the bulb is fully dark in the earliest frames where the fan is off or barely turning, the brightening happens gradually across the sequence rather than in one sudden flash, the bulb's color stays the same hue throughout (only intensity changes), and no other light source in the scene brightens independently of the fan/turbine action.
level_5: The gradual, hue-stable brightening described for score 4 holds, and further: the bulb reaches its brightest, most saturated glow only in the frames where the fan is at its visibly fastest, densest-blur speed, the brightening keeps pace with the fan's visible speed changes without long stretches where the fan clearly speeds up but the bulb brightness stays flat, and the bulb shows no brightness change at all while the fan is slowing down or stationary.

Spatiotemporal Consistency rubric:
level_1: The turbine, bulb, or fan is missing from a frame and then abruptly shows up in a different spot with no motion connecting the two positions; the bulb switches from off to fully lit (or the reverse) within a single frame with no transition; the fan's blade speed jumps between two very different rates within what should be one continuous spin-up; or the scene's overall brightness pattern flips to an inconsistent state between adjacent frames.
level_2: The turbine's position shifts noticeably between frames without any visible cause, the wire between turbine and bulb appears or disappears rather than staying continuously connected, the fan's rotation visibly skips or stutters as if frames were dropped, or background elements in the scene warp or change shape between frames.
level_3: The turbine, bulb, and fan each stay in the same place on the bench throughout with no jumps between positions; the wire connecting turbine and bulb stays intact and taut in every frame; the fan blades' rotation looks continuous rather than skipping; the bench and background stay stable in shape and position across the sequence.
level_4: The fixed object positions and intact wire described for score 3 both hold, and further: the fan blades show a steady, uniform increase in rotational speed rather than sudden jerks or overshoots, the turbine does not vibrate or wobble away from its mounted position, and the bulb's glow does not flicker or jitter frame to frame even as it brightens.
level_5: The steady fan spin-up and stable turbine mounting described for score 4 hold, and further: the distances between the fan, turbine, and bulb stay visually constant throughout with no drifting closer or farther apart, the wire connecting turbine to bulb keeps a consistent length and shape rather than stretching or reshaping, and there is no camera drift or perspective change that would make the bench or objects appear to shift size across the sequence.