Many bulk commodities, such as cereal grains loaded into a silo require active mixing during storage. A special pulsated bottom mixer was patented at our university for gentle mixing of granular solids stored in large containers or silos. This work intended to reveal the fundamentals in displacement of single particles mixed by different pulsation orders. A glass-walled simulator (filled with wooden cylinders) was build in order to be able to follow particles inside the simulated mixer. Three pulsating pistons were attached to the bottom of the simulator. Their movements provide the mixing effect. Selected cylinders (some with different densities and friction coefficients) were followed during mixing. Their positions were recorded after certain pulsations. From the measurements the mixing velocity of cylinders was calculated. Examinations were focused on to give restrictions of the mixing: density and friction of the particles in connection with the pulsation. No correlations were found between the mixing velocity and density or friction of the particles. (C) 2004 Elsevier B.V. All rights reserved.