The Franck-Hertz experiment, (1913, Nobel Prize 1926), with the well defined periodic and equidistant minima and maxima of the collector electrode current, is undoubtedly one of the most impressive experiments to demonstrate and verify the quantum theory. In these demonstrations, it is possible to observe energy transitions produced by collisions between electrons and atoms. At first these collisions take place elastically without significant transfer of energy. As the accelerating voltage is increased, non elastic collisions take place. This energy transfer reappears with progressively increasing accelerating voltage. Description KA6041 Franck-Hertz Oven, (Hg)Heating oven consists of a steel cabinet, heated by a solid element, and the temperature is controlled by a thermostat located on the side. The front panel carries ceramic insulated connecting sockets for the tube. The collector electrode is connected to a BNC jack for connection to the F-H operating unit. The symbolic designation of the tube is marked on the front panel in bold lines, while the circuit is delineated in thinner lines. The oven possesses two glass windows through which the tube and heating element can be viewed. The cover plate accommodates a thermometer for monitoring the temperature.