As the thirteenth lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide with relation to internal energy, heat, and temperature. The topics are concerned with collisions, thermometers, friction forces, degrees Centigrade and Fahrenheit, calories, Brownian motion, and state changes. The content is arranged in scrambled form, and the use of matrix transparencies is required for students to control their learning activities. Students are asked to use a magnetic tape playback, instructional tapes, and single concept films at the appropriate place in conjunction with the worksheet. Included are a homework problem set and illustrations for explanation purposes. Related documents are SE 015 963 through SE 015 977. (CC)