This study investigates whether graduate courses for in-service physics teacher professional development that combine the conceptual history of physics, physics content, and physics education research readings will result in the teachers using the history of science for their own classroom instruction. In a study conducted in the USA, teachers who took such courses reported that their instruction in the history of science resulted in their better understanding of student learning, and a better ability to include the history of physics in their teaching. Ten teachers were selected from the pool of teachers who had participated in the professional development to determine how the self-reported use of the history of science translated into the teachers' classroom practice. The research questions addressed whether or not the teachers used the history of science in their practice, and if so, how and what obstacles the teachers perceived in using the history of science. The investigation found that all ten teachers used the history of science in their physics classes to better understand their students' conceptions in physics, to teach about theory change, and to increase student interest. Eight also used history to better communicate physics concepts. All discussed impediments they perceive to more use of history with their students. The professional development described may serve as a model for changing science teachers' practice with respect to teaching with the history of science.