Observe and explain how shadow length and direction change over the course of a day due to Earth's rotation, and use shadow data as evidence.
As Earth rotates, the sun's apparent position in the sky changes throughout the day, which changes the shadows that objects cast. In the early morning and late afternoon, when the sun is low near the horizon, shadows are long. Around midday, when the sun is highest in the sky, shadows are shortest. Shadows also swing direction over the day, generally moving from one side toward the other as the sun appears to cross the sky.
Tracking a shadow's length and direction over a day is real evidence of Earth's rotation; the sun itself is not moving across the sky, but Earth's spin makes it appear to, and the shadow record proves the pattern is steady and predictable, not random.
Mastery looks like: They can predict and explain how shadow length and direction change over a day, connecting the pattern to Earth's rotation.
Common stumbles: Thinking the sun is physically moving across the sky rather than Earth rotating; expecting shadows to be the same length all day.