Concrete is poured into moulds and vibrated to let the trapped air escape and so to compact it. Before hot chocolate is poured into its form, vibration technology is used to deaerate the liquid. The objectionable air pockets disappear when the vibration stirs up the material and the friction between the individual particles of the material is decreased. The material becomes loose and flows off properly. 

Even bulk materials like sand, cement, lime, coal, cereals, etc. which are stored in silos or other containers have to be set to motion to overcome the powerful adhesive forces, reduce the friction between the individual particles, and thus to support the outflow. Furthermore the motion of material is necessary for conveying of the bulk materials on conveyor troughs and sieving on reciprocating screens.

This motion is created by so-called external vibrators, which are attached to vibrating equipments, chute of silos, or conveying throughs.