Domain: Natural Science — Physics
Target concept: A balloon bursts, releasing colored powder in a radial pattern to simulate supernova ejecta.

Video generation prompt: Suspend a thin latex balloon filled with colored powder from a fine thread, then puncture the balloon with a needle.

Evaluation guide:
(i) Target concept: Isotropic ballistic dispersion of dry particulate matter driven by sudden release of elastic potential energy in a thin confining membrane.
Minimum mechanism: Balloon must be thin-walled and elastic (not rigid or plastic); powder must be dry, free-flowing, and initially at rest; rupture must be localized and instantaneous to trigger symmetric acceleration; ambient air resistance must not dominate early dispersion phase.
(ii)Storyline: Phase 1 (Static setup): suspended thin latex balloon fully inflated, visibly containing dry colored powder, no motion. Phase 2 (Contact): needle tip touches balloon surface at single point, no deformation yet. Phase 3 (Rupture): localized failure at contact point, immediate membrane recoil, powder begins outward acceleration. Phase 4 (Radial expansion): powder streams diverge spherically from rupture origin, maintaining discrete particle identity, with no preferential direction. Phase 5 (Full dispersion): cloud reaches maximum visible extent while retaining radial symmetry and particulate character. Perspective constraint: Fixed frontal or slightly oblique viewpoint showing full balloon silhouette before rupture and unobstructed view of dispersion field; no occlusion of rupture origin or peripheral ejecta.

Manual:
Experimental Procedure
1. Suspend a thin, inflated latex balloon by a fine thread.
2. Fill it with dry, brightly colored powdered pigment (e.g., red, blue, yellow).
3. Puncture the balloon surface with a fine needle at its center.
Observation of Experimental Phenomena
Upon puncture, the balloon ruptures instantly and the colored powder bursts outward in a symmetrical radial pattern from the rupture point, forming a spherical cloud that expands uniformly in all directions.
Summary of Experimental Principles
The rapid release of elastic energy stored in the stretched latex membrane accelerates the enclosed powder outward ballistically; the resulting radial ejecta pattern illustrates isotropic expansion analogous to supernova remnant dynamics.

Prompt Grounding rubric:
level_1: No balloon is visible; no colored powder is visible; no puncturing action occurs; the scene does not depict a suspended latex balloon being punctured with a needle.
level_2: A balloon is present but not recognizable as thin latex (e.g., a foil balloon, a thick rubber ball, or a rigid sphere); the colored powder is absent, or it looks like a liquid or spray rather than dry powder; the puncturing action is replaced by something else (e.g., the balloon is cut with scissors or shown exploding with flame); no powder leaves the balloon at all.
level_3: A thin, inflated latex balloon hangs in the frame; colored powder is visible inside it before puncture; a needle or similarly sharp point touches the balloon's surface; the balloon breaks and powder is seen leaving it afterward. The basic setup and action described in the prompt are all present, even if rough around the edges.
level_4: Everything required for a 3 also holds, and additionally: the balloon stays fully intact and inflated right up until the needle touches it, with no premature sagging or leaking; the powder is clearly confined inside the balloon beforehand rather than partially spilled; the powder's point of exit is clearly the puncture site rather than some other part of the balloon; no stray hands, tools, or props linger in the shot to distract from the puncture and release.
level_5: Everything required for a 4 also holds, and additionally: the balloon's suspension looks passive rather than hand-held, with a visible thread or filament and no hand gripping it at the moment of puncture; the needle's contact with the balloon is unambiguous and confined to one small spot; nothing in the frame (smoke, glare, a hand, a prop) blocks the view of where the powder is coming from as it leaves the balloon.

Scientific and Causal Correctness rubric:
level_1: The powder behaves in a way that contradicts basic mechanics: for example, it appears to move inward toward the balloon, falls straight down as if simply dropped rather than being propelled outward, or clumps together instead of dispersing; there is no visible cause-and-effect between the needle touching the balloon and the powder starting to move.
level_2: The balloon breaks but the powder doesn't spread outward in multiple directions: it stays clumped, spreads only after a delay, or barely moves at all; the powder's color visibly changes as it travels (fading or blending into a different hue); the powder looks wet or sticky rather than a dry, free-flowing dust; the powder starts moving noticeably before or after the puncture rather than right at it.
level_3: The powder visibly leaves the rupture point heading in several different directions at once, starting right after the needle makes contact, and keeps its original color as it travels; the balloon material itself visibly springs back at the moment of rupture; the pattern clearly diverges outward from a single point rather than drifting sideways as one coherent mass.
level_4: Everything required for a 3 also holds, and additionally: the powder keeps moving outward throughout the shot without reversing direction or stalling partway; gravity doesn't visibly dominate the pattern, so the cloud doesn't look lopsided toward the floor or the ceiling; individual powder particles stay visually distinct rather than merging into a smear or a solid-looking blob; the balloon's torn fragments recoil in a way that looks consistent with a thin, stretched rubber membrane rather than a rigid shell.
level_5: Everything required for a 4 also holds, and additionally: the cloud of powder looks balanced across at least four quadrants around the rupture point, with no single side (left, right, up, or down) visibly getting more powder than the others; every visible trajectory appears to start from the same small spot on the balloon's surface; the spread looks like it is being driven by the balloon's release of stored elastic energy rather than by something like a gust of air pushing it sideways.

Spatiotemporal Consistency rubric:
level_1: The balloon's position or the powder's spread jumps discontinuously between frames: for example, the balloon sits in a noticeably different spot from one frame to the next with no motion in between, the powder appears already fully spread out before the needle ever touches the balloon, or the rupture appears to happen at a different spot on the balloon than where the needle made contact; the lighting or shadows shift abruptly and discontinuously between frames with no cause; or the balloon's shape distorts non-physically, such as caving inward and then exploding outward.
level_2: The balloon visibly deflates or leaks gradually rather than rupturing, with powder trickling out instead of a clean puncture-triggered release; the powder appears already in its final, fully dispersed shape without any visible motion getting it there; the suspension thread's attachment point shifts abruptly partway through; the camera cuts or zooms in the middle of the puncture-to-dispersion sequence.
level_3: The thread's attachment point and the balloon's hanging position stay put before the puncture; the powder stays still until the needle makes contact, then starts moving continuously right after, with no jump; the balloon and powder never disappear from the frame and then reappear; the shadows cast by the balloon and the light on the room or background look the same before and after the rupture rather than swapping direction or brightness.
level_4: Everything required for a 3 also holds, and additionally: the balloon's surface visibly dimples or tents slightly right before it gives way; the torn fragments' recoil looks quick and smooth rather than jerky; the powder's movement relative to the background looks like it is genuinely traveling through the same space rather than sliding as a flat overlay; the puncture-to-dispersion sequence plays without any frozen frame, sudden skip, or repeated frame.
level_5: Everything required for a 4 also holds, and additionally: any motion blur on the powder matches how fast it appears to be moving, so a fast-moving cloud isn't rendered perfectly crisp and the barely-moving balloon fragments aren't blurred; the rupture appears to originate from the same exact spot on the balloon throughout the event; the powder never appears to pass behind the intact balloon surface it just escaped from; the room or background behind the balloon stays put and unobstructed for the whole sequence.