What is Quicksand?

The thought of quicksand often inspires fear in people, since many believe that being caught in it will quickly result in drowning. This is actually not the case. People are lighter than quicksand, and if they do not struggle, they will quickly rise to the top. This substance is just ordinary sand, but it can cause a person to sink because it has become oversaturated with water.

Quicksand can occur anywhere in the world but is most likely to occur near a water source, like a creek, river, ocean or lake. When the sand gets a little exposure to water, it actually becomes more finely packed. A little bit of water increases friction in the sand, causing it to bind closely together. This is why people tend to use water when building sand castles, as the water helps maintain the shapes.

However, too much water causes the sand particles to lose friction. The sand slips apart rapidly when weight is put onto it, as a person stepping on a patch might do. The term, therefore, applies to sand that quickly allows a person to sink into it.

Portrayals of quicksand are highly exaggerated, however. People only tend to drown in quicksand if they flail their arms and legs about. This makes them sink because they are literally helping the sand split apart. On the other hand, the person who does not panic, and who puts his hands and legs slightly apart, moving as slowly as possibly, will not sink. As in water, people are naturally buoyant in quicksand.

Further, quicksand is not a bottomless pit that will suck a person down to the earth’s core. In fact, some quicksand is only about 2 to 4 feet (about 0.61 - 1.22 m) deep, although this depth can cause some difficulty when a person tries to get out. It’s often much easier to get into quicksand (or water) than to get out of it because the density creates a vacuum-like effect. Again, the key is moving very slowly in order to get out.

Sometimes, quicksand causes problems when it forms under buildings, which have far greater mass than a single person. In times of flooding over sand, theoretically, regular sand could become quicksand, and cause the mass of a building to sink. This sinking might also cause structural instability in the building and precipitate collapse, particularly in instances of earthquakes.

However, individuals don't need to fear quicksand if they remember “quick sand, slow movement.” Even a person falling headfirst into it is likely to float to the surface quite rapidly if he or she does not struggle.