* Rotation: The Earth spins on its axis, completing a full rotation roughly every 24 hours. This rotation causes day and night. As the Earth rotates, different parts of the planet face the Sun, experiencing daylight. When a specific location on Earth faces away from the Sun, it experiences night.
* Revolution: The Earth orbits the Sun in an elliptical path, taking approximately 365 days to complete one full orbit. This movement, combined with the Earth's tilt, causes the seasons. The tilt of the Earth's axis means that different parts of the planet receive varying amounts of sunlight throughout the year, leading to changes in the length of days and nights.
In short:
The Sun isn't always in the sky because of the Earth's constant movement – spinning on its axis (rotation) and orbiting the Sun (revolution).
