Abstract: Apparatus and a method for investigating dynamic rheological properties of a viscoelastic medium involves oscillating at least one shear wave generation surface in a container containing the viscoelastic medium such that shear waves generated thereby impinge on two spaced shear wave receiving surfaces, the receiving surfaces being spaced by different distances from the source of shear waves impinging thereon. Transducers are provided for the shear wave receiving surfaces capable of generating output signals dependent on the variations in physical parameters of heating the wave receiving surfaces induced by the oscillating shear wave generation surfaces.