The Kaye Effect

Have you ever seen a stream of liquid, like shampoo or thick detergent, splash onto the floor and then unexpectedly spring back up into the air instead of just falling? This peculiar phenomenon is known in fluid dynamics as the 'Kaye effect'. It occurs when a viscoelastic liquid, like the ones mentioned, falls and creates a thin layer of air beneath the stream. The liquid then glides over this air layer as if it were a lubricant. When the stream hits the pool of liquid on the ground, it bounces off frictionlessly, momentarily jumping into the air like a spring. Although it disappears in just a few seconds and is hard to notice, this phenomenon of liquid spontaneously leaping upwards is one of the most fascinating and beautiful physical occurrences demonstrated by everyday fluid dynamics.