This document is a science mini unit by The Constant Kindergartener that explains why there is day and night. It describes that day and night occur because as the Earth spins on its axis, different parts of the planet face toward and away from the sun, experiencing light or darkness. The mini unit includes activities and worksheets for students to label where it is day and night, illustrate how the Earth spins to create the cycle, and reflect on favorite day and night activities.