Domain: Engineering — Nuclear Engineering
Target concept: Gamma Radiation and Nuclear Protection

Video generation prompt: The gamma radiation shielding experimental setup (including a cobalt-60 gamma source, gamma detector, and lead plate holder) was used to place 5 mm, 10 mm, and 15 mm lead plates sequentially between the source and the detector, and the change in detector count rate was observed.

Evaluation guide:
(i) Target concept: Exponential attenuation of gamma photons in dense matter
Minimum mechanism: Photons interact probabilistically with lead nuclei via Compton scattering and photoelectric absorption; probability of interaction increases with thickness, causing monotonic, non-linear reduction in transmitted flux
(ii)Storyline: Frame 1–2: Static wide shot showing aligned source–holder–detector triad, all objects fully visible and labeled. Frame 3–4: Hand or manipulator places 5 mm plate into holder (plate fully seated, no gap). Frame 5–6: Detector display stabilizes showing first count rate (e.g., “420”). Frame 7–8: 5 mm plate retracted, 10 mm plate inserted identically. Frame 9–10: Detector updates to second lower value (e.g., “180”). Frame 11–12: 10 mm retracted, 15 mm inserted. Frame 13–14: Detector updates to third lowest value (e.g., “65”). All actions occur from fixed frontal perspective; no camera movement; detector display always fully in frame and legible; occlusion strictly follows physical layering (thicker plate always fully covers thinner plate"s position)

Manual:
Experimental Procedure
1. Position cobalt-60 source, gamma detector, and lead plate holder in straight line.
2. Insert 5 mm lead plate into holder between source and detector.
3. Record detector count rate.
4. Replace with 10 mm lead plate; record count rate.
5. Replace with 15 mm lead plate; record count rate.
Observation of Experimental Phenomena
Detector count rate decreases progressively: highest with 5 mm plate, lower with 10 mm, lowest with 15 mm plate.
Summary of Experimental Principles
Gamma radiation intensity attenuates exponentially with absorber thickness; lead’s high atomic number and density make it effective for shielding; thicker lead reduces photon transmission, lowering detected count rate.

Prompt Grounding rubric:
level_1: None of the four required elements (the cobalt-60 source, the gamma detector, the plate holder, and the lead plates) are shown, or none of the plates (5 mm, 10 mm, 15 mm) is ever placed between source and detector.
level_2: The source, detector, and holder are all present, but the video never shows three distinct plate thicknesses being placed one after another; only one thickness recurs, or several plates appear in the holder at the same time instead of one at a time.
level_3: The cobalt-60 source, gamma detector, and plate holder are all present and recognizable; three separate lead plates are inserted one at a time between the source and detector; the plates are visually distinguishable from one another (e.g., by edge thickness or by labels), but nothing on screen indicates which value (5, 10, or 15 mm) belongs to which plate.
level_4: All three apparatus pieces are present, and none of them shifts position throughout the sequence; the plates are inserted strictly in the order 5 mm, then 10 mm, then 15 mm, with each one fully seated in the holder and held there for a pause before the next replaces it; no plate is skipped, repeated, or shown out of order; nothing unrelated crosses the source-holder-detector line.
level_5: All conditions of the 4-point level hold, and in addition each plate carries its own visible identifying mark (e.g., an engraved or printed '5', '10', or '15' facing the camera, or a visibly stepped edge profile that grows thicker with each swap), and that mark stays legible and unobstructed for the whole time that plate is in place.

Scientific and Causal Correctness rubric:
level_1: The detector's displayed count rate does not change across the three placements, or it rises when a thicker plate is added, or the display stays frozen or blank throughout, showing no link between plate thickness and the reading.
level_2: The count rate does change with each plate swap, but not consistently (for example it drops for the 5 mm plate, then rises for the 10 mm plate), or the three displayed values are not in decreasing order (e.g., the 5 mm reading is lower than the 10 mm reading).
level_3: The displayed count rate is strictly lower after the 10 mm plate than after the 5 mm plate, and strictly lower again after the 15 mm plate than after the 10 mm plate; all three readings are distinct, plausible numbers; but the video doesn't clearly tie each reading to the moment its plate finishes being inserted (e.g., the display is hard to read or the value changes at an unclear time).
level_4: All conditions of the 3-point level hold, and in addition each new count-rate value appears on the display right after its plate is fully inserted and then holds steady during a pause before the next swap, with no flicker or reset in between; the three readings are clearly in decreasing order with no extra in-between values shown.
level_5: All conditions of the 4-point level hold, and in addition the size of the drop is visibly bigger between the first two placements (5 mm to 10 mm) than between the last two (10 mm to 15 mm): for example the needle swings further, or the displayed value falls by a noticeably larger amount, going from 5 mm to 10 mm than from 10 mm to 15 mm, showing the expected tapering-off attenuation pattern without requiring the exact digits to be read precisely.

Spatiotemporal Consistency rubric:
level_1: The source, detector, or holder jump from one position to another between frames with no motion shown; a lead plate appears or disappears without being carried into place; the detector display resets or jumps to a new value with no visible cause; the holder or detector appears to split apart or detach; or the lighting abruptly changes (e.g., a flash, strobing, or the whole scene going dark) with no visible cause.
level_2: The objects stay roughly in place, but a plate seems to pass straight through the source or detector instead of sliding into the holder from the side; a plate is suddenly in the holder with no insertion motion shown at all; the display updates with no pause or settling time; a shadow cast by the holder shows up on the opposite side of the object from one frame to the next with no change in the light.
level_3: The source, detector, and holder all stay in place throughout; each plate slides smoothly along the source-detector line into the holder; the display updates once per plate, with the new number settling in rather than snapping into place instantly; no plate, the holder, or the detector visibly stretches, warps, or passes through another object.
level_4: All conditions of the 3-point level hold, and in addition each plate's insertion motion is smooth from start to finish, with no sudden speed-up, stop-and-start, or skipped frames; the display's new reading appears right as the plate finishes sliding in, not noticeably before or after; the shadow the plate casts on the holder grows a little longer as thicker plates are used, matching what a thicker plate should do.
level_5: All conditions of the 4-point level hold, and in addition, when the 10 mm plate replaces the 5 mm plate it fully covers the same slot with no visible gap or overlap, and likewise for the 15 mm plate replacing the 10 mm; the holder fully occludes the gap behind each plate, with no visible sliver of background or of the source/detector showing through, at any frame.