Domain: Natural Science — Physics
Target concept: Standing in front of a plane mirror and raising the left hand, the image in the mirror raises the right hand with the same height and shape as the object, which is a distinctive visual characteristic.

Video generation prompt: A person stands upright in front of a vertical plane mirror. He slowly raises his left hand to shoulder height. Apart from the movement of the arm, the rest of his body remains stationary. The scene focuses on the action of raising the hand and the corresponding reaction of the image in the mirror.

Evaluation guide:
(i) Target concept: Lateral inversion in plane mirror reflection.
Minimum mechanism: Mirror must be vertical and planar; observer and object must be in same plane perpendicular to mirror; light propagation must follow rectilinear reflection with angle-of-incidence = angle-of-reflection; image formation requires optical coherence without distortion or parallax error.
(ii)Storyline: [Start] Person standing still, full front view, mirror centered behind; [Trigger] Left hand begins upward motion from side; [Causal transition 1] Light from left hand reflects off mirror surface; [Causal transition 2] Reflected rays converge to form virtual image behind mirror plane; [Effect] Image’s right hand rises synchronously; [Constraint] Camera viewpoint is fixed, frontal, and wide enough to capture person and full mirror image simultaneously without cropping; [Visibility] Both person’s left hand and image’s right hand must remain fully visible and unoccluded throughout motion; [End] Both hands hold steady at shoulder height with image maintaining precise lateral reversal.

Manual:
Experimental Procedure
1. A person stands upright, facing forward, centered in front of a vertical plane mirror.
2. The person keeps entire body still except for the left arm, which slowly raises from resting position at side to shoulder height.
3. The motion lasts ~10 seconds; camera holds fixed frontal viewpoint showing both person and mirror image side-by-side.
Observation of Experimental Phenomena
The mirror image simultaneously raises its right hand to the same height as the person’s left hand; the image’s hand matches the person’s hand in shape, orientation, and timing; no other body part in the image moves.
Summary of Experimental Principles
A plane mirror produces a laterally inverted, same-size, upright virtual image; when an object raises its left hand, the image appears to raise its right hand — a direct consequence of reflection symmetry across the mirror plane.

Prompt Grounding rubric:
level_1: No person is visible, or no vertical mirror is visible, or the person never raises a hand, or the person and their mirror image never appear together in the same shot, or the person appears to be facing away from or at a sharp angle to the mirror rather than standing in front of it.
level_2: A person and a mirror both appear, but the hand-raising action is missing or unclear, or the mirror shows no image of the person at all, or the person stands at enough of an angle that a front-on view isn't clear, or it isn't possible to tell which hand starts moving first.
level_3: The person stands upright, facing a vertical mirror; a hand rises smoothly from the side up to about shoulder height; the mirror shows a reflection of the person at the same time; the raised hand is identifiable as the person's left hand; person, mirror, and reflection are all visible together in one continuous shot.
level_4: Everything required for score 3 holds, and additionally: it is clearly the left hand that rises (e.g., visible from its position relative to the body's midline or from a worn item like a watch or bracelet on that wrist); the reflection also shows a hand rising in the mirror at the same time; the person and their reflection stay adjacent within the frame with stable, consistent composition throughout.
level_5: Everything required for score 4 holds, and additionally: the left hand starts fully at rest at the person's side before any motion begins; the reflected hand's rise visibly tracks the timing of the real hand's rise, moment for moment; the person and reflection never overlap, duplicate, or become misaligned; the whole sequence plays without a cut, from hand-at-rest, through the raise, to holding still at shoulder height.

Scientific and Causal Correctness rubric:
level_1: The reflection shows no relationship to the person's action at all. For example, the reflection also raises its left hand rather than its right, or the reflected hand moves before the real hand does, or the reflection stays completely still while the person's hand rises, or the reflection appears upside-down or sideways.
level_2: The person raises the left hand, but the reflection raises what is clearly still identifiable as its left hand rather than its right; or the reflected hand rises to a visibly different height than the real hand (e.g., overhead or at waist level); or the reflected hand has a noticeably different shape or pose (e.g., a fist where the real hand is open); or the reflection appears to float beside the person rather than inside the mirror.
level_3: As the person raises the left hand, the reflection's hand, on the side that would be its right hand given the mirror reversal, rises as well; the reflected hand reaches roughly the same height on screen as the real hand; nothing about the reflection contradicts the basic left-right reversal expected of a mirror image.
level_4: Everything required for score 3 holds, and additionally: the reflected hand's rise keeps pace with the real hand's rise without any visible lag or getting ahead of it; the reflected hand matches the real hand's shape and finger/joint posture throughout the motion; the reflected hand appears to originate from inside the mirror (behind its surface), not from in front of or floating past the mirror's frame.
level_5: Everything required for score 4 holds, and additionally: it is clearly the reflection's right-hand side that rises (for instance, a ring, watch, or sleeve detail visible on that wrist sits on the side consistent with a mirrored right hand, or the thumb points the way a mirror-reversed right hand's thumb would); the reflection shows no stretching or size mismatch relative to the person; the start and stop of the reflected hand's motion line up with the real hand's start and stop; the person's and reflection's shoulders stay level with each other throughout.

Spatiotemporal Consistency rubric:
level_1: The person or their reflection vanishes and reappears between shots; the mirror flickers, disappears, or suddenly changes size or tilt; the shadows in the scene disappear and then reappear with no cause; the person's or reflection's body warps, melts, or breaks apart in an impossible way.
level_2: The person's or reflection's hand motion shows visible jumps rather than a smooth path (more than a couple of noticeable skips); the reflection appears to sit at the same depth as the person rather than behind the mirror surface; parts of the background shift on their own even though the camera itself is not moving; the hand starts or stops moving instantly, with no gradual speeding up or slowing down.
level_3: The hand's rise is smooth and continuous; the person's body stays completely still except for the rising arm; the mirror stays stable and fully visible the whole time; nothing about the person, mirror, or reflection breaks apart, flickers, or vanishes; the shadows and overall room lighting look the same from the start of the clip to the end.
level_4: Everything required for score 3 holds, and additionally: no part of the person's body besides the raised arm shows any detectable movement; the reflection stays mirrored evenly around the person's midline without drifting left or right relative to them; the reflection stays fully contained within the mirror's edges with no spillover outside it; the spatial relationship between the person and reflection never shifts unexpectedly from one moment to the next.
level_5: Everything required for score 4 holds, and additionally: the motion looks physically natural, with no floating limbs, no sliding feet, and no unexplained knee or torso movement while the person is meant to be still; the mirror's frame and the wall or background around it stay rigid and undistorted; the person and reflection keep the same relative horizontal and vertical position throughout, with no drifting apart; aside from the raised arm, the pose stays completely steady.