The Kaye Effect

The Kaye Effect is a strange property of complex liquids which was first described by the British engineer Alan Kaye in 1963.

While pouring one viscous mixture of an organic liquid onto a surface, the surface suddenly spouted an upcoming jet of liquid which merged with the downgoing one.

This phenomenon has since been discovered to be common in all thixotropic liquids (liquids which thin under shear stress). Common household liquids with this property are liquid hand soaps, shampoos and non-drip paint. The effect usually goes unnoticed, however, because it seldom lasts more than about 300 milliseconds.