Why do shadows change size during the day?
Show answer & explanation
Answer: Sun's angle changes with time
Sun's angle changes with time ✓ — Correct! As Earth rotates, the Sun appears to move across the sky, changing its angle. When the Sun is low (morning/evening), light hits objects at a shallow angle, casting long shadows. At noon, the Sun is high overhead, creating short shadows directly below. The shadow is longest at sunrise/sunset and shortest at noon. This is why ancient people used sundials to tell time!
Atmosphere bends light more — Wrong. Atmospheric refraction has minimal effect on shadow length. Shadows change size because the Sun's angle relative to objects changes as Earth rotates, not from light bending in the atmosphere.
Objects expand in heat — Wrong. Objects don't expand enough to noticeably change shadow size. Shadows change because the Sun's position in the sky changes throughout the day, altering the angle at which light hits objects.