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.
More Physics in Daily Life questions
- In a warm office that already reads 26 C, which change can make people feel cooler without lowering the thermostat?
- Why might 26 C feel acceptable in a breezy naturally ventilated summer building but too warm in a sealed winter office?
- On a warm humid day, why can the same 27 C room feel much worse once you start sweating?
- Why can moving air make a 27 C room feel cooler without changing the thermometer?
- Which hidden factor can make a desk beside a cold window feel chilly even when the thermostat across the room still reads 22 C?
- In the same 22 C room, why might someone who just climbed stairs feel warm while someone sitting in a T-shirt feels chilly?