Thumbnail: Sometimes matter behaves as a particle and sometimes a wave. Quantum physics is the study of this phenomena. Imag used with permission (Public domain; Maschen).
Paul Peter Urone (Professor Emeritus at California State University, Sacramento) and Roger Hinrichs (State University of New York, College at Oswego) with Contributing Authors: Kim Dirks (University of Auckland) and Manjula Sharma (University of Sydney). This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).