Abstract: Method and apparatus is disclosed for mixing two or more materials normally considered difficult to evenly and homogeneously intermix such as, for example, viscous fluids. The apparatus is also effectively usable to entrain a gas in a liquid and for ceramic particle formation. The mixing portion of the apparatus includes a mixing chamber in the form of a narrow gap between two walls movable relative to one another. The mixing chamber has individual inlets thereto at one end thereof for individually introducing the different elements to be mixed therein and an outlet at the opposite end for discharge therefrom of the mixed elements. The mixing chamber is preferably an annular chamber in the form of a truncated cone and defined by spaced apart walls, one of which is movable relative to the other by rotation. The distance between the walls defining the mixing chamber is preferably selectively adjustable.