Domain: Humanities and Social Sciences — Archaeology
Target concept: Shells or limestone fragments preserved intact in alkaline soils, but eroded in acidic environments.

Video generation prompt: Place two identical fragments of shell or limestone into two separate containers, one containing an acidic soil slurry and the other containing a basic soil slurry. After stirring, position them side by side and observe over time.

Evaluation guide:
(i) Target concept: Differential chemical stability of calcium carbonate minerals (CaCO₃) in pH-dependent aqueous environments.
Minimum mechanism: Acidic conditions (pH < 6) provide H⁺ ions that react with CO₃²⁻ to form soluble CO₂ and Ca²⁺, causing surface dissolution (visible as bubbling/effervescence and gradual surface roughening); alkaline conditions (pH > 8) suppress H⁺ activity, preventing dissolution and enabling preservation.
(ii)Storyline: [Frame 0–2] Two identical shell fragments placed into two visibly distinct slurries (acidic: amber-tinted, basic: bluish-tinted) inside matching containers; [Frame 3–4] Simultaneous stirring induces turbid vortexes in both slurries, with visible gas bubbles rising from the acidic-slurry fragment; [Frame 5–6] Stirring ceases, slurries begin settling, fragments fully visible and stationary; [Frame 7–10] Surface of the acidic-slurry fragment develops visible roughening and a chalky, matte dulling where its surface used to be glossy, while the basic-slurry fragment retains its original luster and sharp edge definition; all observed from a fixed frontal viewpoint with no occlusion, no lighting shift, and no camera motion.

Manual:
Experimental Procedure
1. Place one shell fragment into container A with acidic soil slurry; place identical shell fragment into container B with basic soil slurry.
2. Stir both slurries simultaneously for equal duration, then stop.
3. Position containers side-by-side under fixed viewpoint.
Observation of Experimental Phenomena
Fragment in acidic slurry shows visible gas bubbles (effervescence) during and shortly after stirring, followed by progressive surface roughening and matte dulling; fragment in basic slurry shows no bubbling and remains geometrically intact with sharp edges and a uniform glossy surface.
Summary of Experimental Principles
Shells or limestone fragments preserved intact in alkaline soils, but eroded in acidic environments.

Prompt Grounding rubric:
level_1: Neither shell/limestone fragment appears anywhere in the scene; there are not two separate containers; no acidic or basic slurry is shown; the two containers never appear together in the same shot; no stirring action occurs; there is no setup for comparing the two fragments over time.
level_2: One fragment and one container are visible, but only one slurry type appears, or the second fragment or container is missing; the fragments are not each placed into their own separate container; the two containers never appear together in a way that lets a viewer compare them directly -- for example they are shown one after another, stacked, or with one hidden behind the other.
level_3: Two visually identical fragments appear, each inside its own container; the two slurries look clearly different from each other, either by color/tint or by a clear label identifying which is acidic and which is basic; the two containers appear together in the same frame so they can be compared; both containers are visibly stirred before the observation period begins.
level_4: Everything from the 3-point level still holds, plus: the fragments match each other in size, shape, and appearance; the two containers are the same type and held at the same orientation; the acidic and basic slurries are distinguishable only by color or an explicit label, with no other confusing cue such as a pH strip or extra prop in frame; stirring happens for both containers at the same time and clearly stops before the observation phase; nothing extraneous appears on screen.
level_5: Everything from the 4-point level still holds, plus: both fragments look completely unweathered and intact right at the start, with no pre-existing pitting or discoloration; the containers are transparent enough to show the slurry's opacity and the fragment inside, but not so reflective or distorted that the fragment is hard to make out; the slurry colors follow an intuitive convention -- a warmer tone for acidic, a cooler tone for basic -- without any on-screen text or label that contradicts this convention.

Scientific and Causal Correctness rubric:
level_1: No visible difference in surface condition develops between the two fragments; both look identical the whole time, or both show the same change (e.g., both develop rough patches, or neither changes at all); there's no visible connection between which slurry a fragment sits in and how its surface ends up looking.
level_2: One fragment changes while the other does not, but the pattern is backwards or unclear -- for example the fragment in the basic (bluish) slurry is the one that visibly roughens, bubbles, or loses its shine, while the fragment in the acidic (amber) slurry stays smooth and glossy; or a difference appears but neither slurry can be told apart by color or tint, so it's unclear which fragment received which treatment.
level_3: The fragment in the acidic slurry shows a visible sign of chemical attack -- effervescence/bubbling during or shortly after stirring, visible surface roughening, or a chalky/matte patch replacing its original shine -- while the fragment in the basic slurry keeps its smooth, glossy, intact surface throughout; the difference is clearly visible on screen and lines up with which container is acidic versus basic; there is no reversed or contradictory pattern, such as bubbling appearing in the basic-slurry container.
level_4: Everything described at the 3-point level still applies, and: whatever visible reaction appears in the acidic slurry -- bubbling, roughening, or dulling -- stays confined to the fragment's surface, without the fragment crumbling apart or fully dissolving; the fragment in the basic slurry keeps its original shape, sharp edges, and continuous surface; any bubbling is clearly tied to the acidic-slurry fragment and appears at a time consistent with an ongoing reaction -- during or just after stirring -- rather than as an unrelated one-off flicker; the visible change in the acidic-slurry fragment begins after stirring and continues or persists through the observation period.
level_5: Everything described at the 4-point level still applies, and: the acidic-slurry fragment's surface change (bubbling, roughening, or matte dulling) is clearly and consistently visible with no ambiguity about which fragment it belongs to; the basic-slurry fragment's edges, contours, and surface shine look essentially unchanged from the start of the video to the end; the cause-and-effect is unmistakable to a viewer -- the acidic slurry produces a visible surface reaction, the basic slurry produces none -- with no moment where the pattern reverses or becomes unclear.

Spatiotemporal Consistency rubric:
level_1: A fragment appears to jump to a new position or size between frames; a container's position, scale, or orientation suddenly changes with no transition; the overall lighting suddenly changes; a fragment flickers or disappears partway through with no visible cause; the slurry's level or cloudiness changes with nothing shown to cause it; the camera viewpoint suddenly rotates or pans.
level_2: A fragment is visible, then is simply gone from its container for a stretch, then is visible again, with no motion connecting these states; a container's rim visibly warps or bends; a slurry surface looks turbulent in one moment and glassy-still the next with no settling motion shown in between; a shadow appears to switch sides without the light source moving; the stirring or settling motion looks noticeably jerky or stutters.
level_3: Both fragments stay visible in their own containers throughout, with no unexplained gaps; the two containers keep the same position and orientation relative to each other; the slurry surfaces move naturally -- gentle settling and clearing after stirring -- rather than snapping instantly from turbulent to still; the light falling on both slurries and fragments looks unchanged as the scene progresses; neither container's rim ever appears to cut into or clip a fragment.
level_4: All of the 3-point criteria continue to hold, and additionally: fragment motion looks physically reasonable -- a fragment may settle slightly after stirring, but it never floats or bounces unnaturally; each slurry's surface curve where it meets the container wall looks consistent rather than flattening or changing shape at random; nothing passes in front of the containers to block the view, such as a hand suddenly entering frame or a flare washing out a fragment; the background behind the containers stays static.
level_5: All of the 4-point criteria continue to hold, and additionally: motion looks smooth throughout, without sudden speed-ups or freezes; each fragment's edges stay clear rather than smearing or blurring while anything moves; the way light reflects off the slurry surfaces looks consistent rather than flickering; the containers' transparency looks steady rather than changing on its own; the two containers never appear to shift relative to each other in a way that would suggest the camera itself moved.