Domain: Natural Science — Biochemistry & Molecular Biology
Target concept: Extraction of DNA from strawberries using detergent and alcohol precipitation method

Video generation prompt: In a glass beaker, mix the crushed strawberries with detergent; carefully pour cold alcohol along the side of the beaker to form a layer on top, then gently swirl.

Evaluation guide:
(i) Target concept: Interfacial DNA precipitation driven by polarity-driven solubility shift in a two-phase system.
Minimum mechanism: Strawberry lysate must be aqueous and polar; alcohol must be immiscible, less polar, and cold to suppress thermal motion; DNA must be high-MW and negatively charged to aggregate at the dielectric boundary.
(ii)Storyline: Frame 1–2: Crushed strawberries deposited in static glass beaker (front-facing, fixed viewpoint). Frame 3–4: Detergent dispensed and mixed → homogenate turns uniformly cloudy pink. Frame 5–6: Alcohol poured *along beaker wall* → transparent upper layer forms *without mixing*, establishing sharp interface. Frame 7–10: Gentle rotational swirl begins → white fibrous precipitate emerges *only at interface*, grows continuously, and remains morphologically intact; entire sequence must remain in same shot, same lighting, same beaker position, with interface region fully visible and unoccluded.

Manual:
Experimental Procedure
1. Place crushed strawberries (red-pink, pulpy, no whole berries) into a transparent glass beaker.
2. Add liquid detergent and stir gently to mix—forming a cloudy pink homogenate.
3. Carefully pour cold alcohol along the inner wall of the beaker to form a distinct transparent upper layer over the cloudy pink mixture.
4. Gently swirl the beaker to encourage DNA precipitation at the interface.
Observation of Experimental Phenomena
A sharp, stable interface forms between the lower cloudy pink layer and upper transparent layer; white, stringy, cohesive DNA fibers precipitate exclusively at this interface during/after swirling—neither dissolving nor dispersing into either layer.
Summary of Experimental Principles
Detergent lyses cell and nuclear membranes to release DNA; cold alcohol reduces DNA solubility and dehydrates it, causing precipitation at the aqueous-alcohol interface where polarity shifts abruptly.

Prompt Grounding rubric:
level_1: No strawberry material is shown; no glass beaker is present; neither detergent nor alcohol appears; no crushing, mixing, or pouring action takes place; the scene has nothing to do with extracting DNA from fruit.
level_2: A glass beaker holds a red-pink fruit-like substance, but there is no visible crushing step; no detergent container or liquid is shown being added; no alcohol is poured; the two liquids never form a layered structure.
level_3: Crushed strawberry pulp (red-pink, chunky) sits in a glass beaker; detergent is visibly poured in and mixed through the pulp; cold alcohol is poured in and forms a distinct upper layer (not necessarily along the wall); some swirling motion is shown afterward.
level_4: All three steps appear in the right order and clearly: crushed strawberries in the beaker, detergent added and mixed in, then cold alcohol poured specifically along the inside wall of the beaker to sit as a clear layer on top, followed by a gentle swirl (rotational, not turbulent); every object matches what is expected and sits where it should.
level_5: The visuals match the prompt closely: red-pink pulpy crushed strawberries (no whole berries), a clear glass beaker, a visible detergent bottle or stream during the addition, clear cold alcohol poured continuously along the beaker wall (not dropped or splashed in), an immediate, sharp boundary forming between the cloudy pink layer below and the clear layer above, followed only by a slow, gentle rotational swirl (no vigorous mixing that would break the boundary); no unrelated objects, cuts, or repositioning appear.

Scientific and Causal Correctness rubric:
level_1: Nothing biologically plausible happens: the two layers never separate; the alcohol looks colored or syrupy instead of clear and thin; the strawberry material stays in solid chunks; no cloudiness or precipitate ever appears.
level_2: Two layers do form, but with the wrong look: the top layer is cloudy or milky instead of clear, or the bottom layer is clear instead of cloudy pink; the boundary between them is blurry or fully mixed; no white fibrous material appears at the boundary or in the top layer.
level_3: Two distinct liquid layers form — a cloudy pink lower layer (strawberry-detergent mixture) and a clear upper layer (alcohol); white fibrous DNA material appears at or near the boundary, but its shape is unclear (e.g., a shapeless clump rather than visible strands), or it only shows up after vigorous shaking rather than a gentle swirl.
level_4: The expected sequence plays out clearly: detergent breaks down the strawberry cells into a cloudy pink mixture; cold alcohol added on top creates a clear layer with a sharp boundary; DNA then precipitates specifically at that boundary as visible white, stringy fibers that do not dissolve back into either layer; the fibers appear during or right after the gentle swirl, not before the alcohol is added and not only after rough shaking.
level_5: No scientific detail is off: the lower layer stays evenly cloudy pink with no settling out or clearing; the upper layer stays clear and still except for the gentle swirl-induced surface motion; the white DNA fibers appear only once the alcohol has made contact, sit only at the boundary, keep a continuous thread-like shape (not grainy or clumped), hold together while swirling, and never dissolve, sink, or float away into either layer.

Spatiotemporal Consistency rubric:
level_1: The beaker vanishes and reappears rather than staying in view; the alcohol stream shows up in the frame with no bottle or source visibly pouring it; there is a hard jump cut between the crushing step and the pouring step; the frame's brightness or color balance changes abruptly with no transition; the strawberry pulp appears already inside the beaker without ever being shown getting there.
level_2: The beaker rotates by more than 90 degrees between shots with no visible cause; the detergent bottle disappears right after pouring instead of being set down or moved away naturally; the alcohol stream looks disconnected from the bottle tip pouring it; the two-layer boundary appears instantly rather than forming as the alcohol is poured in; the swirling motion starts before the alcohol has had time to settle into a layer.
level_3: Only a small, easy-to-miss cut is present, if any, between the mixing and pouring steps; the beaker holds a steady position and tilt with at most slight camera wobble during the swirl; every object stays fully visible and where it should be; nothing in the scene deforms or casts a shadow that does not match the rest of the shot.
level_4: Everything from the 3-point description holds, and in addition: the beaker stays centered and still on the surface; the detergent bottle enters from one side and pours cleanly into the beaker; the alcohol bottle enters and pours an unbroken stream along the beaker wall; the layer boundary forms right after the pour finishes with no gap; the swirl only begins once the pour has ended and continues smoothly, without the boundary flickering, jumping, or getting hidden from view.
level_5: Everything from the 4-point description holds, and in addition: the whole sequence plays as one continuous take with no cuts; the beaker holds its position in frame without any visible drift; every motion (the pouring streams, the swirling rotation) looks smooth and physically believable from one frame to the next, without visibly skipping, freezing, or doubling up on itself; there is no sudden lighting change, no shadow that looks wrong for the setup, and no jump in perspective; the boundary between the layers stays fully visible and unobstructed for the entire sequence.