Domain: Natural Science — Physics
Target concept: Mixture of Water and Alcohol

Video generation prompt: Two test tubes with 150 ml graduations are placed side by side on the table. The left test tube contains 50 ml of water, and the right test tube contains 50 ml of alcohol. All the water from the left test tube is added to the right test tube, and the volume level of the resulting mixture is observed.

Evaluation guide:
(i) Target concept: Volume contraction in ideal/non-ideal liquid mixtures due to intermolecular packing efficiency.
Minimum mechanism: Both components must be miscible, molecularly small, polar (H-bond capable), and non-reactive; no phase separation, gas evolution, or temperature-driven expansion/contraction dominates.
(ii)Storyline: Frame 0–2: Static wide shot: two upright, side-by-side test tubes on table, each filled to 50 ml with colorless liquid; graduations fully visible. Frame 3–6: Continuous pour: liquid flows smoothly from left tube into right tube with no spillage, meniscus in right tube rises steadily but sublinearly. Frame 7–9: Stable post-mix state: right tube holds homogeneous, colorless, transparent liquid; meniscus settles below 100 ml mark with clear, unobstructed view of graduation interval; left tube is empty and upright. Perspective: Fixed frontal camera angle, eye-level with 50 ml mark, no panning/zooming; full tube height and graduation range always in frame; no hand/tool occlusion of critical regions (meniscus, 90–100 ml zone).

Manual:
Experimental Procedure
1. Place two identical clear test tubes with 150 ml graduation markings side-by-side on a flat table.
2. Fill left tube with 50 ml water (colorless, transparent).
3. Fill right tube with 50 ml alcohol (colorless, transparent).
4. Pour entire contents of left tube into right tube.
5. Observe final volume level of mixture in right tube.
Observation of Experimental Phenomena
The final volume of the water-alcohol mixture is less than 100 ml — visibly below the 100 ml graduation mark.
Summary of Experimental Principles
Water and alcohol molecules form intermolecular hydrogen bonds, allowing smaller molecules to occupy spaces between larger ones — resulting in volume contraction upon mixing.

Prompt Grounding rubric:
level_1: No test tubes are visible; or only one test tube is shown; or neither tube contains any liquid; or the two tubes are not placed side by side on the table; or the pouring action from one tube into the other never happens; or the clip ends without showing any liquid level in the receiving tube after the pour.
level_2: Two 150 ml graduated test tubes stand side by side, but at least one required element is missing: the left tube's liquid is not identifiable as water (wrong tube, wrong color, or no liquid), the right tube's liquid is not identifiable as alcohol, the starting 50 ml quantity in either tube is not indicated by its meniscus position, the pour is not directed from the left tube into the right tube, or no post-pour liquid level is ever shown in the right tube.
level_3: Two clear, upright 150 ml graduated test tubes sit side by side on the table; the left tube holds a colorless liquid (water) filled to its 50 ml line; the right tube holds a colorless liquid (alcohol) filled to its 50 ml line; the water is poured from the left tube into the right tube; afterward the right tube shows a liquid level with its meniscus visible against the graduation scale.
level_4: Everything required for score 3 holds, and in addition: the water and alcohol look visually indistinguishable from each other (both colorless and transparent) before pouring; the 150 ml graduation lines on both tubes stay sharp and legible throughout; the pour begins with the left tube tipping and ends with all of its liquid inside the right tube, with none spilled onto the table; and the final meniscus in the right tube settles at one single, clear height against the graduation scale (not split, doubled, or hidden).
level_5: Everything required for score 4 holds, and in addition: the meniscus in the right tube is never blocked by hands, tools, glare, or condensation at any stage - before pouring, mid-pour, and after settling; both tubes stay upright and in the same spot on the table throughout; the transferred water leaves no droplets clinging inside the left tube or splashed outside the right tube; and the final meniscus is held on screen steadily enough that a viewer could confidently name a single graduation value.

Scientific and Causal Correctness rubric:
level_1: The final mixture level sits at or above the tube's 100 ml line; or the two liquids are shown in different colors (e.g., tinted water or tinted alcohol); or the graduation scale appears inconsistent between the two tubes; or no change in liquid level is observable after the water is poured in.
level_2: The water and alcohol are correctly shown as colorless and transparent, but the final mixture level cannot be judged - it is not shown, is obstructed, or sits right at the 100 ml line with no visible gap in either direction; or the pour is reversed (alcohol poured into water) or shown flowing both ways.
level_3: The water and alcohol stay colorless and transparent throughout; the pour runs from the water tube into the alcohol tube; the final mixture level sits visibly below the 100 ml line, with a clear, unambiguous gap between the meniscus and that line; the mixture remains a single clear phase with no cloudiness, layering, or color change.
level_4: Everything required for score 3 holds, and in addition: no bubbles, foam, or brief cloudiness appear during or right after pouring; the meniscus keeps its normal concave curve before and after mixing rather than flattening or bulging; no fogging, steam, or condensation forms on the tube walls that would suggest a temperature-driven rather than mixing-driven change in level.
level_5: Everything required for score 4 holds, and in addition: the final level reads clearly within the 90-99 ml range on the graduation scale (noticeably short of the 100 ml line rather than merely a hair's width below it, and not dropping to about 85 ml or lower, which would overstate the contraction), matching the modest volume contraction expected when equal volumes of water and ethanol are combined; the liquid surface settles and stays quiet, with no lingering swirl or rocking after the pour ends.

Spatiotemporal Consistency rubric:
level_1: Either test tube jumps to a new position or vanishes and reappears between frames; the liquid volume in a tube changes abruptly with no pour visible to explain it; the room's lighting swings between bright and dark from one frame to the next with no cause; or a tube flips from upright to tilted, or back, with no hand or pouring motion shown.
level_2: Both tubes stay in frame and upright, but at least one of the following mars the sequence: the pouring stream jumps or skips partway through instead of flowing continuously; the meniscus in the right tube flickers or changes shape erratically frame to frame; the 150 ml graduation lines warp or shear out of their straight, evenly spaced pattern; or objects on the table behind the tubes drift sideways relative to the tubes themselves.
level_3: Both tubes stay fixed in the same spot and orientation on the table for the whole clip; the pour runs as one continuous stream from the left tube into the right tube without stopping and restarting; the rising meniscus in the right tube moves smoothly and comes to rest without bouncing; the graduation markings stay straight and evenly spaced on both tubes in every frame; and the light falling on the tubes and the shadows they cast keep the same direction and brightness from the first frame to the last.
level_4: Everything required for score 3 holds, and in addition: the meniscus lines up with the same graduation mark regardless of viewing angle across frames, with no apparent drift from camera parallax; the tubes' cylindrical outlines stay straight rather than bowing in and out; the liquid boundary and graduation lines stay sharp rather than smeared by motion blur or ghosting; and both tube bases stay flush on the tabletop without lifting, sliding, or rocking.
level_5: Everything required for score 4 holds, and in addition: the pour itself looks fluid rather than stepping or freezing at any instant; the background behind the tubes stays in matching focus with the tubes throughout, with no mismatched blur pulling one out of focus while the other stays sharp; any reflections or glare on the tube glass hold a fixed position and brightness rather than sliding or flaring; and no hand, tool, or other object ever blocks the tubes' bodies or graduation scales at any point in the clip.