H6C17S1.3 Earth's Rotation-Day and Night

Earth's Rotation-Day and Night

You can see how this works by standing and facing a lamp. Pretend you are Earth and the lamp is the Sun. Now, without pivoting your head turn around slowly in a counterclockwise direction. The lamp seems to move across your vision, then disappear. You rotate until you finally see the lamp again. The lamp didn’t move—you did.

When you rotated, you were like Earth rotating in space, causing different parts of the planet to face the Sun at different times. The rotation of Earth—not movement of the Sun—causes night and day.

Because the Sun only appears to move across the sky, this movement is called apparent motion. Can you think of any other objects you encounter that might display apparent motion?