Taylor's Experiment 2

When Pine and Gollub ran this experiment they thought that rotating the cylinder would shear the fluid, causing some particles to collide. Those particles would then be displaced when the cylinder was rotated back to its original position. They also thought that the more they rotated the cell, the more likely it was that collisions would occur. But what they found was something unexpected. When they rotated the cell past a certain point, shearing the fluid above a certain threshold, some particles would collide and upon rotating the cell back those particles would be displaced from their original position. But when the cell was rotated below that threshold, the particles moved around for a certain amount of time and then they just stopped.