In the previous tutorials you saw that experimental evidence supports the theory that matter, such as electrons and subatomic particles, exhibit wave behavior. Wave behavior is utilized by the electron microscope, which enables us to look at nanometer-sized details in objects. We must consider this wave behavior as we try to understand why atoms have only certain allowed energies. The next steps are to learn how to interpret matter waves, to understand what information they carry, and how we can use that information.