Domain: Natural Science — Physics
Target concept: Place an inflated balloon in direct contact with an ice cube, ensuring that the balloon deflates slowly within 10 seconds and decreases in volume, in contrast to a balloon in direct contact with hot water.

Video generation prompt: Place two identical inflated balloons side by side. Position one balloon in direct contact with an ice cube and the other in direct contact with a container of hot water, so each balloon's surface touches its temperature source. Keep both balloons stationary. During the experiment, display the temperature comparison device and the balloons for approximately 2 minutes, and record a time-lapse video.

Evaluation guide:
(i) Target concept: Thermal contraction of trapped gas due to a temperature gradient.
Minimum mechanism: The balloon membrane must be elastic and gas-tight; each balloon must be in direct contact with its temperature source (the ice cube or the hot water container) so heat conducts efficiently through the membrane into the trapped gas rather than through still air alone; the temperature differential must be large enough, and the contact close enough, to produce a measurable volume change within the roughly two-minute observation window; no external force or leakage should affect either balloon.
(ii)Storyline: Frame 0–1: Two identical inflated balloons appear side by side, each resting directly against its ice cube or hot water container, temperature device active with contrasting readings. Frame 2–3: The balloon touching the ice begins a smooth, gradual contour reduction; the balloon touching the hot water retains its shape. Frame 4–5: The size disparity between the balloons keeps increasing; the temperature readings stay stable and distinct. Perspective: Fixed frontal view, full-frame composition, no camera motion, all key objects simultaneously visible and unoccluded throughout.

Manual:
Experimental Procedure
1. Place two identical inflated balloons side by side on a flat surface.
2. Rest an ice cube directly against (touching) the left balloon.
3. Rest a container of hot water directly against (touching) the right balloon.
4. Position a temperature comparison device (e.g., dual-display thermometer) visibly between or beside them, showing two distinct readings.
5. Keep all objects stationary and record continuously for about two minutes.
Observation of Experimental Phenomena
The balloon touching the ice cube visibly decreases in volume (shrinks) over the course of the recording, while the balloon touching the hot water container holds its size or expands slightly; the temperature device shows a lower value on the ice side and a higher value on the hot-water side.
Summary of Experimental Principles
Gas volume contracts when cooled (Charles's Law); air inside the balloon touching the ice loses kinetic energy, decreasing pressure and causing gradual deflation; air inside the balloon touching the hot water gains kinetic energy, maintaining or increasing internal pressure.

Prompt Grounding rubric:
level_1: Two identical inflated balloons aren't shown, or the ice cube and hot water container are missing, or the balloons aren't placed side by side, or one balloon is inflating while the other stays flat or unchanged, or there is no temperature comparison device in view at all.
level_2: The two balloons are side by side, but only one temperature source is present (ice cube or hot water, not both), or the temperature device is visible but doesn't display two distinct readings, or the balloons visibly drift, roll, or sway rather than staying put.
level_3: Two identical inflated balloons sit side by side; an ice cube touches one balloon and a container of hot water touches the other; both balloons stay stationary throughout; the temperature comparison device is visible and shows two distinct readings, one low and one high — all the objects and actions named in the prompt are present.
level_4: Everything at the 3-point level holds, and in addition the ice is clearly recognizable as an opaque solid cube and the hot water as a liquid with a visible surface (steam or subtle surface motion optional), the temperature device shows an unambiguous contrast between its two readings (one side low, one side high), and the balloons stay fully in frame and in the same relative spots without shifting or being blocked from view.
level_5: Everything at the 4-point level holds, and in addition the ice cube and hot water container sit at roughly the same height as the balloons' middles so the contact reads clearly, the temperature device sits centered or symmetrically between the two balloons, both balloons start out matching in shape and size, and there is no ambiguity at any frame about which object is which or whether they are touching and stationary.

Scientific and Causal Correctness rubric:
level_1: Neither balloon changes volume; or both shrink by the same amount; or the balloon touching the ice inflates instead of shrinking; or the balloon touching the hot water shrinks instead of holding steady; or the order of events runs backward, with the hot-side balloon shrinking before the ice-side one does.
level_2: Only one balloon's volume ever changes; or a volume change happens but doesn't track which temperature source it's next to (e.g. the ice-side balloon stays full size while the hot-side one shrinks); or both balloons change volume in the same direction; or the temperature readings contradict which source is which (the ice side reads a higher number than the hot side).
level_3: The balloon touching the ice cube visibly shrinks while the balloon touching the hot water holds its size or grows slightly; the temperature device reads lower on the ice side and higher on the hot-water side; the link between which balloon sits where and which one shrinks is visually clear.
level_4: Everything at the 3-point level holds, and in addition the ice-side balloon's shrinkage is steady and doesn't reverse or puff back up partway through, the hot-side balloon never gets visibly smaller than it started, and the two temperature readings stay stable and clearly different from each other the whole time.
level_5: Everything at the 4-point level holds, and in addition the visible size gap between the two balloons is larger by the end of the roughly two-minute recording than it was at the start, even if the rate of shrinkage isn't perfectly even moment to moment, and the ice-side balloon's shrinking never shows an implausible jump, flicker, or sudden partial re-inflation that would contradict simple gas cooling.

Spatiotemporal Consistency rubric:
level_1: A balloon jumps to a new position or shape between frames with no transition, the ice cube or the hot water container blinks out of view and reappears, the temperature device suddenly relocates, the lighting swings drastically (a flash, or shadows vanishing/appearing all at once), or a balloon's surface tears or bends in a way rigid or flexible materials couldn't.
level_2: A balloon's outline flickers or stutters briefly, the ice cube or hot water container is blocked from view for more than about a third of the recording, the temperature device wobbles or rotates on its own, the shadows fall in a direction that doesn't match a fixed light source, or a balloon briefly drifts out of frame and comes back.
level_3: Both balloons, the ice cube, and the hot water container all stay visible and in their same relative spots the whole time; the temperature device stays in the same place and orientation; the lighting stays even enough that no new shadow suddenly appears on the balloons or the ice-and-hot-water setup where there wasn't one before; and there is no visible break in the scene's structure or a jump in time.
level_4: Everything at the 3-point level holds, and in addition the shrinking balloon's outline changes gradually and continuously rather than jumping between sizes, neither the ice cube nor the hot water container jitters or twitches in place, and the temperature display's numbers change smoothly without flickering or garbled digits.
level_5: Everything at the 4-point level holds, and in addition there is no visible frame-to-frame misalignment or ghosting in any object, the sense of depth between the balloons/stimuli in front and the background doesn't suddenly jump or flatten out, the pace of the balloon's shrinking looks steady and natural rather than speeding up or slowing down erratically, and every object's rigidity or flexibility looks physically consistent throughout (the balloon behaves like a balloon, the ice cube like a solid, the water like a liquid).