Domain: Natural Science — Chemistry
Target concept: Reaction of aluminum with hydrochloric acid

Video generation prompt: A small piece of silvery aluminum foil was placed into a test tube containing 5 mL of colorless dilute hydrochloric acid.

Evaluation guide:
(i) Target concept: Visual confirmation of spontaneous redox reaction between elemental aluminum and aqueous H⁺ ions, producing gaseous H₂.
Minimum mechanism: Aluminum must be in direct, sustained contact with dilute aqueous HCl; surface oxide layer must be breached (naturally via Cl⁻ or pre-abraded) to initiate reaction; H₂ gas nucleation requires heterogeneous surface and supersaturation — hence bubbles originate *only* at aluminum–liquid interface and rise buoyantly.
(ii)Storyline: [Frame 0–2] Static shot: upright test tube with colorless liquid at ~mid-height; silvery aluminum foil held above rim → [Frame 3–4] Foil descends and contacts liquid surface → [Frame 5–10] Continuous bubble nucleation at foil surface, immediate detachment, and vertical ascent through liquid; no liquid discoloration, no foil dissolution, no lateral motion of foil; all events occur within single fixed frontal view with stable lighting and no occlusion.

Manual:
Experimental Procedure
1. Place a clean, dry test tube upright on surface.
2. Add 5 mL of colorless dilute hydrochloric acid to the test tube.
3. Drop one small piece of silvery aluminum foil into the acid.
Observation of Experimental Phenomena
- Immediate emergence of continuous, rising gas bubbles from the aluminum foil surface.
- No color change in the liquid.
- Aluminum foil remains intact and silvery throughout observation.
Summary of Experimental Principles
Aluminum reduces H⁺ ions in hydrochloric acid, producing hydrogen gas (2Al + 6HCl → 2AlCl₃ + 3H₂↑); the reaction is exothermic but proceeds visibly at room temperature with observable effervescence.

Prompt Grounding rubric:
level_1: No test tube is visible, or no aluminum foil is visible, or the liquid is not colorless, or the acid container is something other than a test tube, or the aluminum foil is not silvery in color, or the liquid volume looks far above or below roughly one-third of the tube's height (inconsistent with 5 mL in a standard test tube), or more than one piece of foil is shown.
level_2: The test tube and a colorless liquid are both shown, but the aluminum foil is missing entirely, or it is shown resting beside or on top of the test tube rather than being placed into it, or its surface looks dull gray, black, or oxidized rather than silvery, or the liquid itself is visibly tinted, cloudy, or colored.
level_3: The test tube holds a colorless liquid at roughly one-third to one-half fill height, and a single small piece of silvery aluminum foil is shown being lowered into, or resting inside, the liquid; no extra props (droppers, gloves, hands) dominate the frame; the foil, liquid color, and liquid volume all match what the posted_prompt describes.
level_4: Everything required at the 3-point level is shown, and in addition the aluminum foil is entirely submerged with no part propped against the dry upper wall or hanging over the rim, the test tube stays upright and does not shift position, and no part of the foil, liquid, or tube is blocked from view at any point.
level_5: Everything required at the 4-point level is shown, and in addition the foil's entry into the liquid happens within the first few seconds (roughly 3 seconds) of the clip, the camera holds one fixed frontal framing on the test tube for the entire clip with no zoom or repositioning, and the foil, liquid, and tube walls stay clearly distinguishable from one another throughout.

Scientific and Causal Correctness rubric:
level_1: No bubbling is ever seen; or vigorous foaming/fizzing appears before the foil touches the acid; or bubbles appear while the foil is still above the liquid surface; or the acid turns colored, cloudy, or otherwise changes hue; or the foil visibly dissolves away, melts, or turns into a dull non-metallic residue during the clip.
level_2: Bubbling only starts more than about 5 seconds after the foil contacts the acid, or the bubbles that appear stay fixed in place rather than detaching and rising, or bubbles form only at the liquid surface unconnected to the foil, or the foil shows visible pitting or flaking before any bubbling begins.
level_3: A steady stream of small hydrogen-gas bubbles forms on the surface of the submerged foil once it contacts the acid, the bubbles detach and rise through the liquid, the liquid itself stays colorless throughout, and the foil keeps its intact, silvery appearance (no blackening or crumbling).
level_4: Everything required at the 3-point level holds, and in addition the bubbles originate only from the foil surface (not from the tube walls or bottom), the bubbling stays at a gentle, steady rate rather than an explosive froth or thick foam layer, and the foil keeps a recognizable shape and metallic shine for the whole clip.
level_5: Everything required at the 4-point level holds, and in addition the bubbling begins within about a second of the foil becoming fully submerged, the bubble stream continues without stalling or restarting for the remainder of the clip, and the liquid stays clear and undisturbed apart from the flow that the rising bubbles themselves create.

Spatiotemporal Consistency rubric:
level_1: The test tube's position or orientation changes abruptly between frames with no connecting motion; or the aluminum foil instantly changes shape, size, or location; or the liquid surface height or shape jumps without a visible cause; or the scene lighting flips between bright and dark within a single frame; or the test tube's shape becomes distorted.
level_2: The camera angle drifts, pans, or zooms instead of holding still; or the foil rotates or slides sideways with no bubble or physical cause behind it; or bubbles drift sideways across the frame instead of floating upward; or ripples from a burst bubble linger far longer than is physically plausible; or shadows shift direction even though nothing about the room lighting has changed.
level_3: The test tube stays in the same position and orientation for the whole clip; the foil, once placed, does not slide, float up, or sink to a new resting spot; the bubbles that form travel upward through the liquid; the liquid surface stays calm except where a bubble is actively breaking through it; and the direction and brightness of light and shadow on the tube stay the same from the first frame to the last.
level_4: Everything required at the 3-point level holds, and in addition there is no flicker, strobing, ghosting, or motion blur that hides the outline of the tube or foil, the tube's cylindrical shape never looks flattened or bent from odd perspective warping, and a bubble's position changes smoothly from frame to frame rather than jumping partway up the tube with nothing shown in between.
level_5: Everything required at the 4-point level holds, and in addition the bubbles rise in generally straight, parallel paths rather than crossing or scattering erratically, the foil does not visibly drift or reposition once it has settled in the liquid, and the curve of the liquid surface where it meets the tube wall looks the same in every frame, indicating a steady, unmoving camera.