Domain: Natural Science — Chemistry
Target concept: Under heating conditions, Benedict's reagent reacts with a glucose solution.

Video generation prompt: Two transparent test tubes containing equal amounts of Benedict's reagent: the one on the left contains a glucose solution, and the one on the right contains water; both are placed in a boiling water bath and heated.

Evaluation guide:
(i) Target concept: Visual confirmation of selective colorimetric reaction indicating presence of reducing sugar.
Minimum mechanism: Benedict"s reagent must be alkaline copper(II) citrate complex; glucose must reduce Cu²⁺ to Cu⁺ under heat, forming insoluble Cu₂O; water provides inert control with no reduction capacity; thermal energy must be sufficient to drive reaction kinetics.
(ii)Storyline: Frame 1–2: Two empty transparent tubes placed side-by-side. Frame 3–4: Benedict"s reagent added to both (identical volume, same pour motion). Frame 5: Glucose solution added to left; water added to right (both liquids are clear and colorless at this point, visually indistinguishable from one another until the reagent reacts under heat). Frame 6: Tubes lowered together into boiling water bath (steam visible, water visibly bubbling). Frame 7–10: Left tube progressively transitions from blue → green → yellow → brick-red precipitate settling at bottom; right tube retains uniform, transparent blue with no sediment or hue shift. Viewpoint: Static frontal shot, centered on both tubes, full-tube visibility maintained throughout; no zoom, no pan, no rotation.

Manual:
Experimental Procedure
1. Place two identical transparent test tubes side-by-side.
2. Add equal volumes of Benedict"s reagent to both tubes.
3. Add glucose solution to left tube; add distilled water to right tube.
4. Simultaneously place both tubes into a boiling water bath and heat for several seconds.
Observation of Experimental Phenomena
Left tube develops brick-red precipitate; right tube remains clear blue.
Summary of Experimental Principles
Under heating, Benedict"s reagent oxidizes reducing sugars like glucose, forming insoluble copper(I) oxide (brick-red); water causes no reaction, so reagent stays blue.

Prompt Grounding rubric:
level_1: No two test tubes are visible, or only one tube is present; the tubes are not transparent; Benedict's reagent is absent from either tube; the glucose solution or the water is missing; no boiling water bath appears; or no heating action is shown at all.
level_2: Two transparent test tubes are present side by side, but at least one setup element is incomplete: Benedict's reagent is missing from one tube, the glucose solution or the water is missing, no boiling water bath appears, or the tubes are never actually placed into the bath.
level_3: Two transparent test tubes stand side by side, each holding an equal amount of Benedict's reagent; the left tube additionally holds the glucose solution and the right tube holds water; both tubes are lowered into a visibly boiling water bath (steam or bubbling water present); every object and placement matches the posted prompt.
level_4: Everything described at the 3-point level holds, and both tubes stay continuously visible in their original left/right positions for the entire clip: neither tube is lifted out of the bath, hidden behind another object, or swapped in position.
level_5: Everything described at the 4-point level holds, and the side-by-side arrangement never wavers: no tilt, camera move, or perspective change ever makes it ambiguous which tube holds the glucose solution and which holds water, and both tubes remain together in the bath for the entire sequence with no cut interrupting their joint presence.

Scientific and Causal Correctness rubric:
level_1: Neither tube shows any color change; or both tubes end up the same color (e.g., both stay blue, or both turn brick-red); or the color change happens before the tubes enter the hot bath; or it is the water tube, not the glucose tube, that changes color.
level_2: Only one tube changes color, but the wrong one: for example the water tube turns brick-red while the glucose tube stays blue; or both tubes turn some other color together (green, purple); or the color change appears instantly with no gradual shift as heating proceeds.
level_3: The glucose tube (left) shifts from clear blue to a brick-red precipitate; the water tube (right) stays clear blue; the shift happens only during or after the tubes enter the hot bath; the brick-red color does not fade or revert once it appears.
level_4: Everything described at the 3-point level holds, and the brick-red material in the glucose tube is visibly settled solid at the bottom of the tube, not just a red tint suspended in blue liquid; the water tube stays fully clear and uniformly blue with no cloudiness.
level_5: Everything described at the 4-point level holds, and the contrast is unmistakable: the glucose tube shows a dense layer of settled red precipitate under clear liquid, while the water tube shows unchanged transparent blue liquid with no haze, particles, or blurred boundary anywhere in the tube.

Spatiotemporal Consistency rubric:
level_1: Major visual breaks: one or both tubes jump to a new position or size between shots; the boiling water bath appears and disappears between frames; a tube vanishes for a stretch and then reappears; the scene's lighting swings abruptly between bright and dark with no source or cause shown; or a tube's color flips suddenly with no heating motion shown beforehand.
level_2: Noticeable but less severe breaks: one tube is hidden behind steam or the frame edge for a long stretch without resolving back into view; the bubbling/steam motion freezes while a tube keeps changing color; or a tube tilts or rotates with no hand or physical action causing it.
level_3: Both tubes hold steady position, size, and orientation; neither tube vanishes; the boiling bath keeps bubbling and giving off steam continuously; the sequence plays as one smooth, physically plausible take with no visible cuts or jumps.
level_4: Everything described at the 3-point level holds, and the left/right arrangement of the two tubes never gets scrambled: the glucose tube stays identifiably on the left and the water tube on the right throughout, with no camera distortion stretching or shrinking one tube relative to the other.
level_5: Everything described at the 4-point level holds, and the two tubes enter the bath close enough in time that a viewer would call it simultaneous (within roughly the same second, not one tube dipped in seconds before the other); once heating starts, the glucose tube's color progresses at a pace the water tube's unchanging state never seems disconnected from.