Leaders in science education have actively promoted inquiry science since the 1960s and continue to do so today. The US National Science Education Standards recommend that science instruction and learning should be well grounded in inquiry. In spite of these efforts, however, little has changed in the way science is taught. Teacher-talk and textbooks are still the primary providers of science information for students. The objective of this paper is to: (a) define inquiry as a strategy for teaching science, (b) review the history of inquiry science teaching, and (c) present the Physics by Inquiry model for in-servicing middle school science teachers in order to provide assistance for teachers to successfully implement an inquiry approach to teaching science.