Theresults Described In This Paper Come from Systematic Investigations of Howstudent Learn Physics. Research Tools Include Classroom Observations, Freeresponse and Multiple-Choice Diagnostics, Videotaped and Transcribed Individualdemonstration Interviews, and Many Other Methods. Due to Space Limitations, Wewill Only Cite the Results of a Few Studies and Provide References Wherefurther Details Can Be Found. an Overview of the Field of Physics Educationresearch Can Be Found In a Recent Issue of Physics Today .