Domain: Healthcare — Nutrition & Dietetics
Target concept: Chlorophyll is soluble in alcohol: when spinach leaves are soaked in alcohol, the alcohol turns green.

Video generation prompt: Fresh spinach leaves were placed in a beaker, and alcohol was added until the leaves were completely submerged. The beaker was then placed in a water bath and gently heated. After heating, the beaker was removed and the liquid was filtered to obtain the extract. Only clear instruments, sequential procedures, and correct operational steps are presented.

Evaluation guide:
(i) Target concept: Solvent-based pigment extraction via thermal-assisted dissolution.
Minimum mechanism: Chlorophyll molecules must be released from thylakoid membranes in leaf cells and solvated by ethanol/isopropanol; this requires both solvent contact and thermal energy to disrupt cellular integrity and increase solubility kinetics; thus green color must emerge only in the alcohol phase (never in the water bath's water) and should develop progressively as heating proceeds, whether it first becomes visibly green while the beaker is still in the water bath or only once it is removed for filtration.
(ii)Storyline: [Phase 1: Setup] Fresh green spinach leaves placed in beaker → alcohol poured until fully submerged (liquid level above leaves). [Phase 2: Activation] Beaker lowered into water bath → sustained gentle heating (visible steam/ripples) → duration sufficient for pigment release (implied by color onset). [Phase 3: Isolation] Beaker lifted out intact → liquid decanted/poured into filter funnel → green liquid passes through filter into clear receiving container. [Phase 4: Confirmation] Final shot: clear green filtrate in container; pale leaves remain in beaker or are discarded. Perspective: Fixed overhead or 45° frontal view throughout; all key objects (leaves, beaker, water bath, filter, filtrate) remain fully visible and in-frame during their respective phases; no occlusion of critical state changes (e.g., color shift must occur within visible field).

Manual:
Experimental Procedure
1. Fresh spinach leaves placed in a clear beaker.
2. Alcohol added until leaves fully submerged.
3. Beaker placed in water bath and gently heated.
4. Beaker removed and liquid filtered into a clean container.
Observation of Experimental Phenomena
Alcohol turns green after heating; spinach leaves become pale; filtrate is clear green liquid.
Summary of Experimental Principles
Chlorophyll is soluble in alcohol: when spinach leaves are soaked in alcohol and heated, chlorophyll dissolves into the alcohol, turning it green.

Prompt Grounding rubric:
level_1: Fewer than three of the five setup elements (fresh spinach leaves, beaker, alcohol, water bath, filtration apparatus) are ever shown, or what is shown is clearly wrong: e.g., the beaker stays empty, the leaves sit outside any container, or alcohol is never poured in at all.
level_2: At least three of the five elements appear, but their placement or order is wrong: e.g., the leaves are added after the beaker already looks full of alcohol, the beaker is never set into a water bath before a filtration step occurs, or filtration is shown before the beaker has ever been near a heat source.
level_3: All five elements (leaves, beaker, alcohol, water bath, filtration setup) appear and are correctly associated with each other, and the water-bath heating step comes before filtration, but one clear setup flaw remains, such as the leaves being only partly covered by alcohol, or a filter funnel that is not clearly positioned to catch the liquid draining from the beaker. (This score concerns object presence, placement, and ordering only; whether the liquid changes color is judged separately and does not affect this score.)
level_4: All five elements appear, are correctly associated, and are shown in the correct order with no step skipped: leaves placed in the beaker, alcohol added until the leaves are fully submerged, the beaker set into a visibly heated water bath, the beaker removed, and the liquid filtered into a separate clean container. Whether or not the liquid's color changes has no bearing on this score.
level_5: All five elements appear in the exact order described in the prompt with unambiguous continuity: the leaves are fully submerged in alcohol before heating begins, the beaker stays visibly centered in the water bath for the whole heating stage, the same beaker is lifted out intact, and the filtrate is collected into a distinct clear container, with no duplicated beakers, no extra unexplained equipment, and no missing transition between any two steps.

Scientific and Causal Correctness rubric:
level_1: The alcohol never turns green (it stays colorless or turns brown/yellow/black instead), or the spinach leaves still look fully green and unfaded at the end of the sequence; or a green color shows up somewhere it should not, such as in the water bath's own water or on a dry surface never touched by alcohol.
level_2: A green color does appear, but tied to the wrong cause or location: e.g., only the wet surface of the leaves looks green with nothing appearing to leave the leaves and enter the surrounding liquid, or the alcohol turns green even though the leaves were never actually submerged in it, or the liquid is already green before any heating has started.
level_3: The alcohol in the beaker visibly turns green during or after the water-bath heating, and only the alcohol turns green (not the water bath's water), but the cause-and-effect timing is loose: for example, it's unclear whether the color built up gradually as heating proceeded or appeared all at once at some indeterminate point during or after heating, or the leaves still look just as vividly green at the end as at the start, with no visible fading.
level_4: The alcohol turns progressively greener while the beaker sits in the heated water bath, and the leaves are visibly paler by the time heating ends, showing a believable transfer of color from leaves to liquid; the green stays confined to the alcohol (never the water bath's water or a dry surface), and the filtered liquid keeps its green color.
level_5: The green color builds up gradually in the alcohol as heating proceeds (becoming visible either while the beaker is still in the water bath or only once it is lifted out for filtration, either timing is acceptable), and by the end of the sequence the spinach leaves look convincingly decolorized (pale or yellow-green, not still vivid green), the filtered liquid is an evenly green, clear filtrate with no leaf fragments or cloudiness, and no green color appears anywhere except in the alcohol that has contacted the heated leaves.

Spatiotemporal Consistency rubric:
level_1: The spinach leaves or the beaker change position or state abruptly between shots with no motion shown to explain it (e.g., the leaves are suddenly floating in alcohol with no submersion action ever shown, the beaker instantly appears already sitting inside the water bath with no placement shown, or the scene cuts straight from an empty filter funnel to a container already full of filtrate with no pouring shown in between), or the lighting on the scene abruptly shifts between bright and dark (or vice versa) between shots with no visible cause.
level_2: Several transitions skip the motion that should connect them: e.g., alcohol is shown already filling the beaker with no pour visible, steam rises over the water bath with no heat source ever shown warming it, or the beaker is shown already lifted out of the water bath with no hand or tool visibly doing the lifting.
level_3: One clear break interrupts an otherwise continuous sequence (e.g., the beaker appears already seated in the water bath without the placement motion being shown, the filtrate appears in its receiving container without the pouring motion being visible, or the lighting/shadow tone drifts slightly and inconsistently across shots without an abrupt bright-to-dark flip and without any object teleporting or breaking apart structurally), while the alcohol's liquid level and clarity inside the beaker otherwise stay consistent from one shot to the next, with no unexplained rise, drop, or clouding.
level_4: Every action shows continuous, physically plausible motion: the leaves are lowered into the beaker, alcohol is poured in with a visibly rising liquid level, the beaker is lowered into and later lifted out of the water bath by a visible hand or tool motion, and the liquid flows steadily through the filter into the receiving container, with the filter funnel remaining aligned directly over the receiving container throughout the filtration step and the water bath's steam rising continuously for as long as the beaker stays submerged, with no unexplained gap in either, and with the lighting and shadow direction staying stable throughout with no jumps or flicker.
level_5: The entire sequence plays out with unbroken visual continuity from first frame to last: no jump cuts, no object popping in or out of frame, the beaker stays in the same position within the water bath throughout heating, the filter funnel stays aligned over the receiving container throughout filtration, and the liquid's level rises and falls smoothly during every pour, with the alcohol inside the beaker showing no unexplained flicker, clouding, or level jump beyond the gradual color change caused by heating and pigment release, and with the lighting on the scene remaining completely constant in direction and intensity from first frame to last.