The Sun doesn't actually *change* during the day. It's a massive ball of hot gas that shines constantly. What changes is our *perspective* of the Sun.

Here's a breakdown:

* Earth's Rotation: The Earth spins on its axis, completing one rotation roughly every 24 hours. This rotation is what causes day and night.

* Sun's Position: As the Earth rotates, different parts of the planet face the Sun. When your location faces the Sun, it's daytime. When your location faces away from the Sun, it's nighttime.

* Apparent Movement: From our perspective on Earth, it *appears* like the Sun is moving across the sky. This is an illusion caused by the Earth's rotation.

So, the Sun itself doesn't change during the day. It's our planet's movement that creates the illusion of the Sun "rising" and "setting".