When a 1L bottle is shaken, the blue and white beads mix within the liquid. When allowed to settle, the the beads separate, white at the top and blue at the bottom. However, shortly the two separated colored beads slowly come together until they meet in the center of the liquid, white on top of blue.
Shake the bottle so that the contents are well mixed. Set the bottle down and watch the various layers of liquid and beads form in the bottle.