What causes day and night?

• A. The Moon's orbit around the Earth.
• B. The rotation of the Earth on its axis.
• C. The tilt of the Earth's axis.
• D. The Sun's changing position.

Answer: (B)

Day and night come from Earth spinning on its axis. As the planet rotates, different parts of its surface move into and out of the Sun’s light. When your location faces the Sun, you have daylight; when that part of Earth rotates away, it becomes night. The Sun appears to travel across the sky from east to west because the Earth is turning in that direction. The tilt of Earth’s axis changes how long days last and causes seasons, but it isn’t what creates day and night by itself. The rotation of Earth brings the Sun into view and then takes it away.