In this clicker case, students are guided through the history of atomic structure, and in the spirit of discovery learning, use data from historical experiments to discern the different models of the atom. In particular, students move from the time of Democritus in the 5th century BCE to the time of Moseley in the early 1900s as they learn how the nuclear model of the atom was developed. Students not only learn about the different models of the atom and how they evolved over time, and about the fundamental particles of matter, but they also engage in higher-order critical thinking. This is accomplished by having the students interpret the data from historical experiments (cathode ray tube, gold foil experiment, etc.) and decide which models of the atom are most appropriate as the interpretable evidence changes over time. This case is designed to be used in a first-semester/first-quarter general chemistry course, and is generally presented to the students in the first two weeks of the course.