In this activity, students determine the amount of heat energy released from a burning peanut and relate this experiment to a microcalorimeter. They will explore how light energy can cause a change in temperature and relate what they find in this activity to how a microcalorimeter works to produce a spectrum of light from an incoming source. Students will discover that, because it can measure very tiny temperature changes, this device will allow for the collection of spectra with extremely high-energy resolution, which will allow the measurement of chemical shifts due to different chemical bonding states, and the precise identification of incident photons.