In a microscopic model of the photoelectric effect it becomes clear that the conservation of energy is exclusively determined by Doppler shift processes, i.e., the whole energy of the pho-ton vanishes by means of Doppler redshifts. Accordingly, if a photon is generated, the energy is won by Doppler blueshifts. This is supposed to be valid for all processes with energy con-servation. An experiment is carried out to make this Doppler energy flow visible by means of interactions with probes. The result of this experiment is that a weak force is measurable in the vicinity of processes with energy conservation. With the aid of a twisted rubber driven low-power device ( ), accelerations of about 10-6 m/s2 are measurable. In the close vicinity of the device, accelerations with values up to 10-3 m/s2 can be concluded. The conse-quences which result from this force are discussed. Keywords: Compton-Effect, Doppler-Effect, energy- momentum conservation, flywheel