The transient thermal response of a single spherical particle in a cold quiescent gas is considered when the particle is heated by a sequence of well‐characterized radiation pulses. The equations describing particle heating and cooling are formulated and a numerical solution is presented. The sensitivity of particle temperature as a function of heating pulse, particle, and gas properties is illustrated. Measured temperature histories of single particles suspended in an electrodynamic balance and pulse heated with a CO2laser are presented in support of the analysis. The combination of unique state of the art instrumentation with the heat transfer analysis described results in a powerful new method for characterizing thermophysical properties of materials such as heat capacity and absorptivity.