Domain: Natural Science — Physics
Target concept: Different Flame Emission Spectra from Alkaline Earth Metal Salts (Barium)

Video generation prompt: In the laboratory, a metal wire loop is dipped into barium salt powder in a ceramic dish, and then the metal wire loop is inserted into the same Bunsen flame.

Evaluation guide:
(i) Target concept: Flame emission spectroscopy of barium ions requires thermal excitation in oxidizing flame environment to produce atomic emission at characteristic green wavelengths.
Minimum mechanism: Barium salt must be in solid particulate form, transferred to wire loop via direct contact, introduced into hot oxidizing flame region (not reducing zone), and emit green light *only* during thermal excitation — no persistence, no phosphorescence, no chemical combustion color.
(ii)Storyline: Frame 1–2: Static shot showing ceramic dish with visible white/grey barium salt powder and adjacent Bunsen burner with stable blue flame. Frame 3–4: Metal wire loop moves downward into dish and makes clear contact with powder surface. Frame 5–6: Loop lifts, visibly coated with powder, and moves horizontally/vertically into flame core. Frame 7–9: Green emission appears *instantly* and *only* around loop in flame; flame baseline remains unchanged elsewhere. Frame 10: Loop withdraws; green extinguishes immediately; flame returns to baseline blue. Perspective: Fixed frontal view, eye-level, centered on dish-flame axis; no camera motion; all objects fully in frame and in focus throughout.

Manual:
Experimental Procedure
1. A clean metal wire loop is dipped into barium chloride or barium nitrate powder in a ceramic dish.
2. The powder-coated loop is immediately inserted into the non-luminous (blue) zone of a steady Bunsen flame.
Observation of Experimental Phenomena
A vivid, transient emerald-green flame emission appears exclusively where the wire loop resides within the flame; the green vanishes instantly upon loop removal; the flame baseline remains blue when unoccupied.
Summary of Experimental Principles
Barium ions, when thermally excited in a flame, emit photons predominantly at ~524 nm and ~514 nm wavelengths, producing a characteristic green color — a signature of alkaline earth metal flame test spectroscopy.

Prompt Grounding rubric:
level_1: None of the required elements appear: no metal wire loop, no ceramic dish, no barium powder, and no Bunsen burner or flame are shown at any point, and neither the dipping action nor the flame-insertion action occurs.
level_2: Only one or two of the four elements (wire loop, ceramic dish with powder, Bunsen burner, flame) appear; the loop never visibly contacts the powder in the dish, or never reaches the flame; the dip-then-insert order is missing or reversed (e.g., the loop enters the flame before it ever visits the dish).
level_3: The wire loop, ceramic dish, barium powder, and Bunsen flame are all visible; the loop dips into the dish and then moves into the flame in that order; but the powder is not clearly deposited on the loop after dipping, or the loop's path into the flame is not a continuous, purposeful motion (e.g., it hovers at the flame's edge without clearly entering the flame body).
level_4: The loop, dish, powder, and flame are all present with plausible appearance (dish shallow and matte, powder fine and light-colored, flame a steady blue cone); the loop visibly picks up powder from the dish and carries it in one continuous motion into the flame; the dish and burner do not shift position relative to one another from the start of the clip to the end.
level_5: All conditions of the 4-point level hold, and in addition: the powder visibly clings to the lower third of the loop right after dipping; the loop is oriented so its wire ring faces the camera as it enters the flame; the flame's blue cone keeps one continuous, connected outline rather than appearing to split into separate patches; the loop, dish, and burner keep the same shape and material appearance from beginning to end, with no part of them turning transparent or changing into a different material.

Scientific and Causal Correctness rubric:
level_1: The flame never turns green at any point; it stays a uniform blue or yellow throughout, even while the loop sits inside it, with no visible link between inserting the powder-coated loop and any color change.
level_2: The flame does change color, but not as a barium test should: the new color is red, orange, violet, or magenta rather than green; or green does appear but starts before the loop reaches the flame, lingers after the loop is pulled out, or shows up only as an isolated speck away from the loop rather than around it.
level_3: Green appears in the flame only while the loop is inside it, concentrated around the loop's position; but the green looks washed out (pale mint) or is heavily mixed with the flame's ordinary yellow/orange, or it flickers on and off in a way unrelated to whether the loop is actually still in the flame.
level_4: Whenever the loop is in the flame, green is clearly the dominant color surrounding it, replacing the blue/yellow tone in that region with no strong contamination from other hues; the green stays on the whole time the loop remains immersed and disappears once the loop leaves; away from the loop, the flame keeps its ordinary blue color.
level_5: All conditions of the 4-point level hold, and in addition: the green stays confined to a small region right around the loop rather than spreading through the whole flame; the shade is a vivid, medium-brightness green (not pale mint, not a neon glow), matching what a barium flame test should produce; the green becomes visible soon (within roughly half a second) after the loop enters the flame and fades out soon after it is withdrawn, rather than lingering for several seconds or appearing only after a long delay.

Spatiotemporal Consistency rubric:
level_1: The wire loop, dish, or flame jump from one position or state to another between shots with no motion shown in between (e.g., the loop is suddenly inside the flame with no visible travel from the dish); the flame vanishes and reappears; the dish or burner changes position; the room's lighting flips abruptly (e.g., bright to dark or vice versa) between frames, or the direction of the light swings wildly from one frame to the next.
level_2: The loop's path from dish to flame shows a visible skip (its position jumps rather than moving smoothly); the flame flickers so violently that its cone briefly breaks into disconnected patches; the dish or burner visibly slides or rotates by more than about 10% of its own width between two consecutive frames; a shadow cast by the loop or dish suddenly shows up on the opposite side of the object with no change in the light source.
level_3: The loop's movement from dish to flame is mostly smooth apart from a small stutter or brief wobble; the flame dims slightly for an instant with no clear connection to the loop's motion; a shadow looks slightly softer or harder than expected for one moment; the dish's rim appears to bend or warp very briefly.
level_4: The loop travels from dish to flame along one continuous, steady path with no visible jumps in speed; the flame keeps its usual shape and structure (blue base plus a brighter zone) throughout; the dish and burner stay perfectly still and rigid; the shadows cast by the loop and dish stay on the same side and keep the same softness from start to finish; nothing about the loop, dish, or flame appears to pass through or get incorrectly cut off by another object.
level_5: All conditions of the 4-point level hold, and in addition: the loop's edges stay sharp and well-defined even while it is moving quickly, without a blur that looks mismatched to its speed; the flame keeps flickering the way a real flame does rather than looking frozen or artificially smoothed; the outlines of the loop, dish, and burner line up consistently between frames with no visible doubled edges or drift; the overall brightness and color of the room lighting stay the same throughout, with no sudden glint or tint change.