What happens to the sun when it gets dark?

The sun doesn't go to sleep! It keeps shining all the time. At night, our side of the Earth turns away from the sun, so it gets dark. In the morning, we turn back to face the sun, and it's light again.

When it gets dark, it means that the part of the Earth you're on is facing away from the sun. The sun is still there, but it is on the other side of the Earth.

During the day, the sun's light shines on the side of the Earth that is facing it, and at night, the side of the Earth that is facing away from the sun is in darkness.

When it gets dark, the sun hasn't gone anywhere and it hasn't stopped shining. The Earth is spinning, like a very slow top, and it turns all the way around once a day. When your side of the Earth faces the sun, it's daytime. As your side turns away, the sun seems to sink below the horizon, and it gets dark. Right then, it's daytime for people on the other side of the world. So it's not the sun that changes, it's the Earth turning that makes day and night.