Abstract: A method and apparatus for effecting rapid thermal cycling of samples, by producing a high-velocity air flow through a closed loop flow path, and energizing an electrical heater within the closed loop flow path to heat the air flowing therethrough to a desired temperature. A sample holder is introduced into the closed loop flow path for exposing the sample holder to the high-velocity heated air flowing therethrough for rapidly heating the sample. The sample is rapidly cooled to a desired temperature by de-energizing the electrical heater, and opening an air outlet from the closed loop flow path, while continuing to produce the high-velocity air flow therethrough.