Projections and coordinates are key advancements in the geographic sciences that allow us to better understand the nature of the Earth and how to describe location. These innovations in describing the Earth are the basis for everything that is done in a GIS framework. Shape of the Earth is a critical starting point because in fact the Earth is not round but rather a more complex shape called a geoid. Coordinate systems are often referenced to a particular model shape of the Earth, but many different formats exist because not all coordinates work equally well in all areas. While projections and coordinates are abstract concepts in themselves, students eventually find them interesting because 1) it causes them to challenge their current ideas of the Earth's shape and 2) it is much easier to visualize these ideas for learning through interactive GIS such as Google Earth.