What makes the sun rise and set?

The sun doesn't actually move. Rather, the earth's rotation (at approximately 24 hours per revolution) makes the sun appear to "rise" and "set" as your position on the earth turns in relation to the sun.
when one part of the Earth is facing towards the sun it would eventually become dark. this is because now your part of the world is beginning to face away from the sun then eventually again it would begin to face the sun a gain. you may think the sun is moving however we are acutually rotating around the sun.