Abstract: This invention is a demonstration device to be used in the teaching of the concept of the Fluid Mosaic Membrane. The Biomembrane Demonstration Apparatus consists of a transparent vessel containing two or three immiscible fluids with sufficient difference in density to support layering. Phospholipid molecules are represented by a spherical head region and two tail-like structures; said molecules are of two types, differing in density such that a lipid bilayer is naturally formed along the interfaces between the immiscible fluids. Protein representing molecules are designed to float within either or both lipid layers. The device may be used as a showpiece or as a working demonstration model.