The Barus Effect

A dyed solution of POLYOX (polyethylene oxide - it is the stuff used as the lubricant on the strip found in all modern razors) is extruded from a 50 ml syringe. On exit, a marked swelling in the liquid stream several times the diameter of the orifice is observed. The effect is referred to as the Barus Effect but it also goes by several other names including the Merrington Effect, Die Swell, and Extrudate Swell. Polyox is an example of a highly viscoelastic non-Newtonian fluid. The Barus effect is common