What makes quicksand “quick” ?
Quicksand is sand that is so saturated with water that the mixture forms a suspension. When the sand and water suspension is subjected to an upward flow, it goes into motion and becomes “quick”. The intergranular pressure between sand grains decreases, causing the frictional forces between them to also decrease. A cushion of water keeps each sand grain from bumping into its neighbors. The result is the sand has little strength available to bear the weight of anything resting on its surface. Although soil scientists at one time believed quicksand to be a separate classification of soil, it is now thought to be ordinary sand, “…buoyed up by a hydrostatic pressure from below,” such as water from underground springs. The sand grains can be large or small, angular or smooth in shape. Quicksand particles don’t necessarily have to be rounded like tiny ball bearings as was previously thought. The primary characteristic of quicksand that sets it apart from ordinary sand is that the water pres
