Domain: Engineering — Instrument and Meter Engineering
Target concept: Analog Ammeter

Video generation prompt: Connect the analog ammeter (range 0-5A, division value 0.1A) in series with the DC circuit, which includes a dry cell, a sliding rheostat, and a small bulb. Slowly adjust the sliding rheostat to decrease the resistance, and focus the lens on the ammeter pointer and the small bulb.

Evaluation guide:
(i) Target concept: Series current measurement using analog ammeter under variable resistance in a simple DC circuit.
Minimum mechanism: Closed-loop DC path exists; ammeter internal coil interacts with current to produce torque on pointer; rheostat slider motion alters effective resistance; bulb resistance is constant and positive; dry cell provides stable EMF.
(ii)Storyline: Frame opens on static setup showing all four objects in correct series configuration. Rheostat slider begins moving leftward (lower-resistance direction). Simultaneously, ammeter pointer starts sweeping rightward from near-zero position; small bulb filament begins glowing with increasing intensity. Throughout, camera maintains fixed viewpoint centered on ammeter face and bulb, keeping both sharply focused. No cuts, pans, or focus shifts occur. Motion of slider, pointer, and brightness change proceed continuously and synchronously until video ends.

Manual:
Experimental Procedure
1. Connect analog ammeter (0–5A, 0.1A divisions) in series with dry cell, sliding rheostat, and small bulb to form closed DC circuit.
2. Adjust rheostat slider to decrease resistance gradually.
3. Keep camera focused on ammeter pointer and small bulb simultaneously.
Observation of Experimental Phenomena
- Ammeter pointer deflects rightward continuously as slider moves toward lower-resistance end.
- Small bulb illumination increases steadily and visibly.
Summary of Experimental Principles
- Analog ammeter measures current via magnetic deflection; must be connected in series.
- Decreasing rheostat resistance increases circuit current (I = V/R), raising both ammeter reading and bulb power (P = I²R_bulb).

Prompt Grounding rubric:
level_1: None of the four circuit elements (analog ammeter, dry cell, sliding rheostat, small bulb) appear on screen; no series wiring is shown; the rheostat slider is never moved; the ammeter pointer and the bulb are never both in the shot.
level_2: One or two of the four elements appear, but they are not wired into a single loop; the rheostat slider does not move; the ammeter pointer and the bulb are not both visible and in focus at the same time.
level_3: All four elements are visible and wired into one series loop (current enters and exits the ammeter through opposite terminals rather than a side tap); the rheostat slider is seen moving along its track; the ammeter pointer and the bulb are both in frame and in focus at some point in the video.
level_4: All score 3 conditions hold, and the ammeter's dial is legible, showing a 0-5A scale with tick marks at 0.1A intervals; the dry cell is a cylindrical battery with its + and - ends marked; the rheostat is the sliding-wire type with exposed resistance wire and a movable rider, not a rotary dial; the bulb's filament visibly glows when current flows.
level_5: All score 4 conditions hold, and within one unbroken shot (no cuts, zooms, or refocusing) the ammeter pointer sweeps from a low reading toward a higher one while the rheostat slider moves toward the lower-resistance end of its track and the bulb's glow brightens at the same time; the camera keeps both the ammeter face and the bulb in view and in focus throughout.

Scientific and Causal Correctness rubric:
level_1: Moving the rheostat slider produces no effect on the ammeter or the bulb — the pointer stays put while the slider moves, or the bulb stays unlit no matter where the slider sits.
level_2: The pointer moves, but in the wrong direction for the slider's motion (e.g., it swings toward zero as the slider moves toward the lower-resistance end); or the bulb dims as the slider moves toward lower resistance instead of brightening.
level_3: As the rheostat slider moves toward the lower-resistance end of its track, the ammeter pointer swings toward a higher reading and the bulb's brightness increases at the same time, matching the expected effect of rising current as circuit resistance drops.
level_4: All score 3 conditions hold, and the pointer only begins moving once the slider starts moving, without anticipating it; the bulb's brightening tracks the pointer's swing without a noticeable lag (brightening begins within about the same moment the pointer starts moving, not several moments later); at no point does the bulb glow while the pointer sits at zero, or vice versa.
level_5: All score 4 conditions hold, and the pointer settles on a final reading clearly above zero and below the top of the scale; the bulb's glow is steady rather than flickering; nothing on screen implies an impossible state, such as the bulb lit while the pointer reads zero or the pointer moving while the slider sits motionless.

Spatiotemporal Consistency rubric:
level_1: The ammeter, bulb, rheostat, or dry cell abruptly appears or disappears between frames; the rheostat slider jumps to a new position with no motion in between; the scene's brightness or color shifts suddenly with no change in the bulb; the pointer snaps to a new angle with no sweep visible; the picture jumps between sharp and blurry as though the lens refocused mid-shot.
level_2: The pointer's swing is choppy, skipping between angles rather than sweeping continuously; the slider advances in visible jumps rather than gliding along its track; the bulb switches from off to fully lit with no in-between brightness; the camera's focus shifts back and forth between the ammeter and the bulb instead of holding both sharp together.
level_3: The ammeter, bulb, rheostat, and dry cell each stay in the same place in the frame relative to one another; the pointer's motion shows a slight blur consistent with real movement; the slider glides steadily along its track; the bulb's brightness change is gradual rather than stepped; nothing in the shot warps, stretches, or loses its shape.
level_4: All score 3 conditions hold, and the ammeter and bulb stay in the same relative position within the frame throughout, with no repositioning mid-shot; the camera does not pan, tilt, or zoom; the edges of the devices and their cast shadows line up consistently from one frame to the next.
level_5: All score 4 conditions hold, and the pointer sweeps in one continuous motion without hesitating or reversing; the slider travels in a single steady direction along its straight track; the bulb's brightness ramps up smoothly rather than in visible steps; no frame appears frozen, duplicated, or strobing at any point.