The Impromptu Teaching Model was designed by the University of Central Arkansas for use by preservice teachers in laboratory teaching experiences. Two teaching exercises, microteaching and reflective teaching, form the basis for impromptu teaching. Microteaching provides teachers with the opportunity to master various technical skills of the active phase of teaching. Reflective teaching provides opportunities for teachers to consider why they were successful in meeting the objectives of a particular task, and to encourage analysis and inquiry into teaching strategies. By combining elements of both exercises, impromptu teaching provides a clinical teaching experience involving extemporaneous teaching in the preservice teacher's major area, and an opportunity to compare teaching strategies and planning procedures. (JD)