The task of preparing K-12 teachers to teach science is an important (though often unacknowledged) responsibility of science faculty. In recent years, a steadily increasing number of physics departments have begun to recognize the need to take a more active role in the professional development of K-12 teachers of physics and physical science.  The task of preparing K-12 teachers to teach science is an important (though often unacknowledged) responsibility of science faculty. In recent years, a steadily increasing number of physics departments have begun to recognize the need to take a more active role in the professional development of K-12 teachers of physics and physical science.The task of preparing K-12 teachers to teach science is an important (though often unacknowledged) responsibility of science faculty. In recent years, a steadily increasing number of physics departments have begun to recognize the need to take a more active role in the professional development of K-12 teachers of physics and physical science.However, if these developments are to lead to a long-lasting positive impact, it is necessary to recognize the inadequacy of the preparation usually offered in physics departments and to reflect on the characteristics of instruction that has been shown to be more effective.