How Quicksand Works

Most people understand the dangers of quicksand, but how many actually know how it works? The science of quicksand is based on the principle of hydrocolloid gels. A colloid is any system where particles of two different substances are mixed together to create a new substance. A hydrocolloid is such a system of particles that also includes water in the mixture. The colloid that creates quicksand is usually made up of clay and either silt or sand. When salt water is added to create a hydrocolloid, this mixture becomes what we know as quicksand.

How quicksand works: The science behind quicksand

Oddly enough, when the hydrocolloid gel is left untouched, it can be rather solid. It is only when some type of pressure is placed on top of the hydrocolloid gel that it becomes more of a liquefied surface. This means that the quicksand will separate and become more liquid when someone steps on it. This sudden separation is what causes people to sink into the quicksand so quickly. After the initial liquefaction, salt within the hydrocolloid starts to create pockets of higher density material again. This process of recombining the colloid is called flocculation and it is what gives quicksand its thick consistency again.

How quicksand works: How it traps people and animals

Once the quicksand has recombined around a person or animal who has fallen in, the liquid substance has become so thick that it can be difficult to get out of. The good news is that a person's body has less mass than the sand surrounding it, so the quicksand itself cannot pull a person under the surface by itself. What leads to sinking and asphyxiation is the struggling and thrashing about that most people do when they first fall into a pit of quicksand. This displaces the liquid in the quicksand and the person ends up surrounding himself with the thicker sand and clay mixture.

How quicksand works: Surviving if you fall in

To survive a fall into quicksand, remain calm and try not to make any unnecessary movements. You should be able to swim back slowly out of the liquid quicksand in a similar manner to swimming in a pool. Obviously, it will take more time to swim out of a thick pile of quicksand than a pool of water, so stay patient and do not panic. However, you should still work at a fairly rapid pace because many quicksand pits are located near bodies of water. If you are near a river or ocean, you may be in trouble when the tide comes in and the water level rises. Many quicksand deaths are not caused by the quicksand itself, but by drowning caused by nearby water overflowing.