Domain: Engineering — Food and Bioprocess Engineering
Target concept: Determination of Vitamin E (Phosphomolybdate Colorimetric Method)

Video generation prompt: Take 2 mL of the plant oil extract into a test tube, add 2 drops of ethanol solution of phosphomolydic acid, and heat for 1 minute in a boiling water bath.

Evaluation guide:
(i) Target concept: Heat-induced redox complexation between tocopherol (vitamin E) and phosphomolybdic acid yields a stoichiometric blue chromophore.
Minimum mechanism: Vitamin E must be present in oil phase; phosphomolybdic acid must be ethanol-soluble and reduced by tocopherol; boiling provides activation energy for electron transfer; aqueous-ethanol medium enables complex solubilization and color development.
(ii)Storyline: [Frame 0–2] Static wide shot: labeled plant oil bottle, graduated cylinder showing 2 mL meniscus, empty test tube side-by-side. [Frame 3–4] Cylinder tip contacts test tube rim; oil flows smoothly into tube until meniscus reaches calibration mark. [Frame 5–6] Dropper approaches tube; two identical spherical droplets detach sequentially and enter liquid surface with visible impact ripples. [Frame 7–9] Hand inserts tube vertically into steaming water bath; tube fully submerged; blue color emerges uniformly from bottom upward during immersion and intensifies continuously. [Visibility constraint: test tube interior must remain fully visible at all times, with no hand occlusion, no frosted glass, no glare masking color development.]

Manual:
Experimental Procedure
1. Transfer 2 mL plant oil extract into a clean test tube.
2. Add exactly 2 drops of ethanol solution of phosphomolybdic acid.
3. Immerse test tube fully in boiling water bath and heat for 1 minute.
Observation of Experimental Phenomena
Uniform blue color develops throughout the liquid in the test tube exclusively during heating.
Summary of Experimental Principles
Phosphomolybdic acid reacts with vitamin E under heat to form a stable blue molybdenum-blue complex; intensity correlates with vitamin E concentration.

Prompt Grounding rubric:
level_1: None of the required objects appear: no test tube, no plant oil, no phosphomolybdic-acid-in-ethanol reagent, no boiling water bath; none of the three actions (transferring oil, adding reagent, heating) takes place.
level_2: At least one of the required objects appears (test tube, or oil bottle, or water bath), but none of the three actions is correctly performed; or one action happens but with the wrong object (e.g., liquid poured into a beaker instead of the test tube); the transfer-then-add-then-heat sequence is missing or out of order.
level_3: The test tube, the plant oil container, and the boiling water bath are all present; roughly 2 mL of oil is transferred into the test tube; a liquid reagent is added to it; the tube is heated in the boiling water bath, but something is off, such as the reagent bottle being labeled as something other than phosphomolybdic acid, no visual cue for the 2 mL or 2-drop quantities, or the tube sitting next to the bath without ever being placed into it.
level_4: Everything required for score 3 holds, AND every object matches what the domain calls for (amber oil in a dropper or cylinder, a clear test tube, a reagent bottle that reads 'phosphomolybdic acid in ethanol', a visibly steaming water bath); the three actions happen in the correct order: transfer, then reagent addition, then heating; the 2 mL oil volume and the 2 separate reagent drops are both clearly shown; the tube is fully immersed in the boiling bath during heating.
level_5: Everything required for score 4 holds, AND the reagent bottle's label is legible and reads 'phosphomolybdic acid in ethanol'; the oil is measured with a calibrated 2 mL device rather than eyeballed; the two reagent drops come from the same dropper tip, one after the other, matching in size and path; the test tube stays upright and fully submerged without tilting or being lifted throughout the whole heating period; steam rises steadily and evenly from the water bath the entire time.

Scientific and Causal Correctness rubric:
level_1: No blue (or any other) color ever appears in the test tube; the tube is never placed into the water bath, or heating is never shown; no reagent drops are ever added; the liquid at the end of the video looks the same as the plain oil did at the start.
level_2: A color does appear, but it is not blue (e.g., it turns green, black, or brown instead); or a blue color appears without the tube ever being heated; or the tube is heated but no color change follows; or a blue color is already present before the two reagent drops are added or after the tube is pulled back out of the bath, rather than during heating.
level_3: The color change happens only after heating starts, and it goes from the oil's original pale color to blue; but the blue only covers part of the liquid, fades again before the video ends, or does not fill evenly from top to bottom; or the blue is visible before a full minute of heating would plausibly have passed given the pace shown.
level_4: Blue color fills the entire visible liquid column in the test tube; it only starts appearing once heating is underway, not before or after; once it appears, it stays visibly blue for at least a second after the tube comes out of the bath; no other color (brown at the edges, leftover yellow, a purple cast) competes with the blue; the blue looks the same shade whether viewed near the top, middle, or bottom of the liquid.
level_5: Everything required for score 4 holds, AND the blue starts appearing right as the tube goes into the boiling water and keeps getting deeper/more saturated the longer it stays in the bath; no in-between color (gray, violet, green) is ever seen at any point; the blue stays a consistent, recognizable blue (not drifting toward teal, purple, or gray) for the remainder of the video once fully developed; the color looks equally blue across the top, middle, and bottom of the liquid with no settling, layering, or streaking visible.

Spatiotemporal Consistency rubric:
level_1: The test tube is shown empty of oil in one frame and already holding the 2 mL of oil in the very next frame with no pouring shown; the test tube itself vanishes from the shot or reappears with no continuous motion connecting the two states; the water bath is shown steaming in one frame and with no steam at all in the next with no lid or heat-source change to explain it; the oil's volume inside the test tube changes between frames without any pouring or removal action being shown; the reagent bottle switches its label or appearance between the pouring shot and the dropping shot; the lighting abruptly shifts (e.g., jumping from bright daylight to near darkness) between frames with no cause shown.
level_2: The test tube is shown fully submerged in the water bath in one frame and sitting beside the bath, not yet inserted, in the very next frame, with no insertion motion shown; the two drops of phosphomolybdic acid solution appear to merge into the oil instantly without any drop shape or impact ripple ever being shown; the level of steam rising from the bath surface drops to nothing and then reappears within a couple of frames with no lid or draft to explain it.
level_3: The test tube keeps the same position and tilt from the oil-transfer step through the heating step; once the tube is lowered into the water bath, it stays fully submerged there without being lifted back out mid-heating; the two drops from the dropper are shown landing on the oil's surface one after the other, each producing a small ripple, rather than merging into the oil unseen; the oil and, later, the developing blue liquid keep a solid, unbroken appearance throughout (no warping or flickering).
level_4: Everything required for score 3 holds, AND the test tube stays centered in frame and does not drift sideways at any point; the reagent bottle stays in the same spot next to the test tube throughout; the level of steam over the water bath stays fairly constant rather than surging or vanishing; every motion (pouring the oil, releasing the drops, lowering the tube into the bath) flows smoothly from start to finish without stopping mid-motion; the hand handling the tube never fully blocks the view of the tube's interior during the drop addition or while the color is developing.
level_5: Everything required for score 4 holds, AND the video shows no shaking or trembling of the camera or the test tube from one frame to the next; the steam rising from the water bath flows as a continuous, smooth column rather than sputtering in bursts; the oil's surface stays undisturbed beyond the small ripple from each drop as it lands; the reflections of light on the glass test tube and reagent bottle shift together in a way that matches a single, unmoving light source and viewpoint, rather than appearing to move independently of the glassware.