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Heat of formation is one of a variety of properties used to assess and compare the energy content of high explosives 1 (1). We present a series of introductory and advanced experiments in which heats of formation are predicted from calculation. These experiments can be used to introduce students to commercially available computational chemistry and molecular modeling programs. They also help reinforce several concepts in thermodynamics and computational chemistry. In the initial experiment several compounds are arranged such that students are provided structures with increasing levels of complexity so that they may master the drawing programs in a stepwise manner. Ab initio quantum mechanical (QM) calculations are used to model simple compounds. However, as structural complexity increases, students quickly learn time and expense are considerations in the use of such calculations. In the second experiment students are shown how to set up and use semiempirical calculations, the Austin Model 1 (AM1), the Modified Neglect of Differential Overlap (MNDO) Model, and the Parametric Model 3 (PM3), to estimate the heats of formation for a series of energetic compounds, including some that are used as high explosives. In the third experiment, selected results from computational studies are compared with those predicted using an older, but still useful, group additivity method (2, 3). Both approaches are compared to experimental values. Explosive compounds selected for study range from the very simple (e.g., methane) to the moderately complex (HMX and octanitrocubane). Although the PM3 model proves reasonably accurate for most of the compounds studied, it is not suitable for highly strained compounds such as cubane and octanitrocubane. This deficiency is used in the fourth experiment to introduce a more rigorous theoretical treatment in which density functional theory (DFT) is coupled with an isodesmic reaction approach to calculate the heat of formation of octanitrocubane. The structures of several explosives are presented in Figure 1.