Two classroom studies, one conducted in the spring of 1985 and the second in the spring of 1986, showed that many high school students do not differentiate between heat and temperature; instead, they have a single concept that contains some of the features of heat and some of the features of temperature. Because the distinction between these two phenomena is essential to an understanding of other thermal phenomena in both physical and biological systems, researchers developed Microcomputer-Based Laboratories (MBL) to facilitate students' differentiation of heat and temperature. Lessons focusing on the quantitative relationships between the amount of heat, mass and temperature change, heat storage capacity, cooling curves, and latent heat were developed in two formats, computer-based and traditional. In the computer-based lessons, students use the computer as a laboratory tool to record heat and temperature data and to display them as graphs and tables. Results indicate that the MBL can help students understand more clearly the quantification of heat and distinguish between heat and temperature. The MBL allows students to collect data more quickly and with greater precision, and it frees them from performing calculations and drawing graphs. Students need plenty of time to experiment with and discuss thermal phenomena. Lesson plans are included for the topics of: (1) heat and temperature; (2) heat storage capacity; and (3) latent heat. Eighteen tables analyze the results of interviews and tests. Tests and interviews from both the 1985 and 1986 studies are presented in 17 appendices. (CW)