What is quicksand made out of

If you wait long enough, the sand particles settle and the buoyancy of the mixture will cause you to rise up to the top. As proof, the beads in the experiment did in fact float, and never became more than half submerged in sand. Although each bead measured only four millimetres in diameter, Bonn says that the findings still apply to people, as they have the same density. The results from the study appear this week in Nature 1.

Nature , Download references. You can also search for this author in PubMed Google Scholar. How quicksand works. What is quicksand? Reprints and Permissions. Khamsi, R. Quicksand can't suck you under. Nature Download citation. When they shook it only a little, the bead stayed floating on top.

But when they shook the container a bit harder, the ball descended to the bottom. But if quicksand becomes less viscous as you struggle, why is it so difficult to escape? The reason, explain the study's authors, is that after its initial liquefaction, quicksand's apparent viscosity thickness or flow resistance increases. The increase is due to the formation of sand sediment, which has a very high viscosity.

It's the difficulty of moving this dense sand that causes the problem. Water has to be introduced into the sand sediment to loosen it, and this requires considerable amounts of force. The authors estimate that the force needed for someone to pull their foot out of quicksand at a speed of a centimeter a second would be the equivalent of that required to lift a medium-size car. If you do step into quicksand, says study co-author Daniel Bonn, you'll only sink in a little deeper than your waist.

So how do you get out? Don't ask your friends to tug on you; they're likely to pull you "into two pieces if [they] try hard to pull [you] out," said Bonn, a physics professor at the Van der Waals-Zeeman Institute at the University of Amsterdam. This creates a space between the legs and the quicksand through which water can flow down to dilate [loosen] the sand," he explained.

A person will gradually begin to sink in quicksand, and movement will make the victim sink faster. This may be the origin of the advice to "never struggle if you're caught in quicksand. But no amount of struggling will send you in over your head. Bonn suggests that it isn't struggling that can get you into trouble, but getting caught in quicksand near the sea, which is generally where quicksand is found.

All rights reserved. Floating in Quicksand Quicksand has a density of about 2 grams per milliliter. However, your movements will cause you to dig yourself deeper into it. In this article, you will learn just how quicksand forms, where it's found and how you can escape its clutches if you find yourself hip-deep in it. Next, we'll find out how the ground shaking beneath your feet can lead to sand slipping beneath your weight.

So head to the next page -- quick. Quicksand is an interesting natural phenomenon -- it is actually solid ground that has been liquefied by a saturation of water. The " quick " refers to how easily the sand shifts when in this semiliquid state. Quicksand is not a unique type of soil; it is usually just sand or another type of grainy soil.

Quicksand is nothing more than a soupy mixture of sand and water. Quicksand is created when water saturates an area of loose sand and the ordinary sand is agitated. When the water trapped in the batch of sand can't escape, it creates liquefied soil that can no longer support weight. There are two ways in which sand can become agitated enough to create quicksand:.

Vibration tends to enhance the quickness, so what is reasonably solid initially may become soft and then quick, according to Dr. The vibration plus the water barrier reduces the friction between the sand particles and causes the sand to behave like a liquid. To understand quicksand, you have to understand the process of liquefaction.

When soil liquefies, as with quicksand, it loses strength and behaves like a viscous liquid rather than a solid, according to the Utah Geological Survey. Liquefaction can cause buildings to sink significantly during earthquakes. While quicksand can occur in almost any location where water is present, there are certain locations where it's more prevalent.

Places where quicksand is most likely to occur include:. The next time you're at the beach , notice the difference in the sand as you stand on different parts of the beach that have varying levels of moisture. The vibration and resulting solid flow have been known to engulf people, cars, and buildings.

Technically speaking, quicksand is a non-Newtonian fluid. What this means it can change its ability to flow viscosity in response to stress. Undisturbed quicksand appears solid, but it's really a gel. Stepping on it initially lowers the viscosity, so you sink. If you stop after the first step, the sand particles beneath you get compressed by your weight.

The sand around you also settles into place. Continued movement like thrashing around from panic keeps the mixture more like a liquid , so you sink further. However, the average human has a density of about 1 gram per milliliter, while the average quicksand density is about 2 grams per milliliter.

You'll only sink halfway, no matter how badly you freak out. Disturbing quicksand makes it flow like a liquid, but gravity acts against you. The trick to escaping the trap is to move slowly and try to float. Strong forces stiffen quicksand, making it more like a solid than a liquid, so pulling and jerking only make a bad situation worse. A quick Google search reveals most writers don't have personal experience with quicksand or consult water rescue experts.

Quicksand can kill! It's true you don't sink in quicksand until you're submerged. Humans and animals typically float in water, so if you are standing upright, the furthest you'll sink in the quicksand is waist-deep. If the quicksand is near a river or coastal area, you can still drown the old-fashioned way when the tide comes in, but you won't suffocate with a mouthful of sand or mud. Dry quicksand presents its own special risks. There are reports of people, vehicles, and entire caravans sinking into it and being lost.

Whether this has actually occurred is unknown, but modern science considers it possible. In the movies, escape from quicksand often comes in the form of an outstretched hand, underwater vine, or overhanging branch. The truth is, pulling a person even yourself out of quicksand won't result in freedom.