[en] Experimental results are given of thermal explosions in a copper-water system. Measurements are presented relative to transient temperature, pressure, and reactive force with scanning frequencies up to 20 kHz. Results are described of particle size analysis and of thermal explosion debris surface measurements. Photos taken with a high-speed camera (up to 8000 f/s) as well as pictures from the scanning electron microscope and from metallographic studies complete the experimental material. A mechanism of thermal explosion is assumed by which 'jets', observed experimentally, of small particles from the bulk mass of the hot material trigger the phenomenon. Sudden phase transformations and combined internal stresses lead to copper fragmentation followed by a vapour explosion. (author)