The Earth, Moon, and Sun unit begins as students take on the role of student astronomers, tasked with advising an astrophotographer who needs to take photographs of the Moon for a fictional magazine called About Space. The astrophotographer can only take pictures of specific features on the Moon at certain times, and this serves as the anchor phenomenon for the unit. In order to provide advice about when to take photographs of the Moon as well as how to take photographs of a lunar eclipse, students will need to investigate where the Moon’s light comes from, what causes the characteristic changes in the appearance of the Moon that we observe, and what conditions are required to view phenomena, such as particular moon phases and lunar eclipses. As students conduct these investigations, they will use a hands-on Moon Sphere Model, the digital Earth, Moon, and Sun Simulation, and the Earth, Moon, and Sun Modeling Tool to gather and represent information about the movement of and light patterns on the Moon. The Sim allows students to explore and manipulate the movement and relative positions of Earth and the Moon, observing these changing arrangements in space from various solar-system perspectives that are otherwise very difficult to imagine. The Modeling Tool allows students to explain what they find in the Sim. Through developing hypotheses and engaging in argumentation, students will come to an understanding about the phases of the Moon and its orbital positions, which they will then apply to their advice to the astrophotographer. By the end of the unit, students will be able to explain the mechanisms behind patterns of light and dark on the Moon, moon phases, and lunar eclipses.