Particle size distribution influences the physical and chemical properties of solids. Therefore this criterion is of highest importance in the context of science and quality control. Only if the size distribution remains constant, a steady product quality can be guaranteed, as the following examples show: the strength of concrete depends on the particle size of the cement the taste of chocolate is influenced by the fineness of the cocoa the flow characteristics and solubility of washing powders depend on the fineness and particle shape of the basic materials