Quicksand, also known as sinking sand, is a colloid consisting of fine granular material (such as sand, silt or clay) and water. It forms in saturated loose sand when the sand is suddenly agitated. When water in the sand cannot escape, it creates a liquefied soil that loses strength and cannot support weight. Quicksand can form in standing water or in upward flowing water (as from an artesian spring). In the case of upward flowing water, forces oppose the force of gravity and suspend the soil particles.
Quicksand and a warning sign about it at a gravel quarry in England
The saturated sediment may appear quite solid until a sudden change in pressure or shock initiates liquefaction. This causes the sand to form a suspension and lose strength. The cushioning of water gives quicksand, and other liquefied sediments, a spongy, fluid-like texture. Objects in liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced soil/water mix and the submerged object floats due to its buoyancy.
Soil liquefaction may occur in partially saturated soil when it is shaken by an earthquake or similar forces. The movement combined with an increase in pore pressure (of groundwater) leads to the loss of particle cohesion, causing buildings or other objects on that surface to sink.
A group of hikers encountering quicksand on the banks of the Paria River, Utah
Quicksand warning sign near Lower King Bridge, Western Australia
Quicksand is a shear thinningnon-Newtonian fluid: when undisturbed, it often appears to be solid ("gel" form), but a less than 1% change in the stress on the quicksand will cause a sudden decrease in its viscosity ("sol" form). After an initial disturbance—such as a person attempting to walk on it—the water and sand in the quicksand separate and dense regions of sand sediment form; it is because of the formation of these high volume fraction regions that the viscosity of the quicksand seems to decrease suddenly. Someone stepping on it will start to sink. To move within the quicksand, a person or object must apply sufficient pressure on the compacted sand to re-introduce enough water to liquefy it. The forces required to do this are quite large: to remove a foot from quicksand at a speed of 1 cm/s would require the same amount of force as that needed to lift a car.[1]
It is impossible for a human to sink entirely into quicksand,[2] due to the higher density of the fluid. Quicksand has a density of about 2 grams per cubic centimeter, whereas the density of the human body is only about 1 gram per cubic centimeter. At that level of density, sinking beyond about waist height in quicksand is impossible. Even objects with a higher density than quicksand will float on it if stationary. Aluminium, for example, has a density of about 2.7 grams per cubic centimeter, but a piece of aluminium will float on top of quicksand until motion causes the sand to liquefy.[3]
Continued or panicked movement, however, may cause a person to sink further in the quicksand. Since this increasingly impairs movement, it can lead to a situation where other factors such as weather exposure (i.e. sun stroke), dehydration, hypothermia, drowning in a rising tide or predatory animals may harm a trapped person.[4]
Quicksand may be escaped by slow movement of the legs in order to increase viscosity of the fluid, and rotation of the body so as to float in the supine position (lying horizontally with the face and torso facing up).[3]
Examples
Patches of quicksand found on the Maine coast are known as "honeypots".[5][6]
In popular culture
Quicksand is a trope of adventure fiction, particularly in film, where it is typically and unrealistically depicted with a suction effect that causes people or animals that walk into it to sink until fully submerged and risk drowning. This has led to the common misconception that humans can be completely immersed and drown in quicksand; however, this is physically impossible.[7] According to a 2010 article by Slate, this gimmick had its heyday in the 1960s, when almost 3% of all films showed characters sinking in clay, mud, or sand.[8]
^Khaldoun, A., E. Eiser, G. H. Wegdam, and Daniel Bonn. 2005. "Rheology: Liquefaction of quicksand under stress." Nature 437 (29 Sept.): 635. doi:10.1038/437635a
^"Will Quicksand Really Kill You?". The Science Explorer. Retrieved 2020-04-08.
^ abBakalar, Nicholas (September 28, 2005). "Quicksand Science: Why It Traps, How to Escape". National Geographic News. Retrieved October 9, 2011.
quicksand, this, article, about, geological, feature, other, uses, disambiguation, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, . This article is about the geological feature For other uses see Quicksand disambiguation This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Quicksand news newspapers books scholar JSTOR April 2022 Learn how and when to remove this template message Quicksand also known as sinking sand is a colloid consisting of fine granular material such as sand silt or clay and water It forms in saturated loose sand when the sand is suddenly agitated When water in the sand cannot escape it creates a liquefied soil that loses strength and cannot support weight Quicksand can form in standing water or in upward flowing water as from an artesian spring In the case of upward flowing water forces oppose the force of gravity and suspend the soil particles Quicksand and a warning sign about it at a gravel quarry in England Quicksand on the Thames The saturated sediment may appear quite solid until a sudden change in pressure or shock initiates liquefaction This causes the sand to form a suspension and lose strength The cushioning of water gives quicksand and other liquefied sediments a spongy fluid like texture Objects in liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced soil water mix and the submerged object floats due to its buoyancy Soil liquefaction may occur in partially saturated soil when it is shaken by an earthquake or similar forces The movement combined with an increase in pore pressure of groundwater leads to the loss of particle cohesion causing buildings or other objects on that surface to sink Contents 1 Properties 2 Examples 3 In popular culture 4 See also 5 References 6 External linksProperties Edit A group of hikers encountering quicksand on the banks of the Paria River Utah Quicksand warning sign near Lower King Bridge Western Australia Quicksand is a shear thinning non Newtonian fluid when undisturbed it often appears to be solid gel form but a less than 1 change in the stress on the quicksand will cause a sudden decrease in its viscosity sol form After an initial disturbance such as a person attempting to walk on it the water and sand in the quicksand separate and dense regions of sand sediment form it is because of the formation of these high volume fraction regions that the viscosity of the quicksand seems to decrease suddenly Someone stepping on it will start to sink To move within the quicksand a person or object must apply sufficient pressure on the compacted sand to re introduce enough water to liquefy it The forces required to do this are quite large to remove a foot from quicksand at a speed of 1 cm s would require the same amount of force as that needed to lift a car 1 It is impossible for a human to sink entirely into quicksand 2 due to the higher density of the fluid Quicksand has a density of about 2 grams per cubic centimeter whereas the density of the human body is only about 1 gram per cubic centimeter At that level of density sinking beyond about waist height in quicksand is impossible Even objects with a higher density than quicksand will float on it if stationary Aluminium for example has a density of about 2 7 grams per cubic centimeter but a piece of aluminium will float on top of quicksand until motion causes the sand to liquefy 3 Continued or panicked movement however may cause a person to sink further in the quicksand Since this increasingly impairs movement it can lead to a situation where other factors such as weather exposure i e sun stroke dehydration hypothermia drowning in a rising tide or predatory animals may harm a trapped person 4 Quicksand may be escaped by slow movement of the legs in order to increase viscosity of the fluid and rotation of the body so as to float in the supine position lying horizontally with the face and torso facing up 3 Examples EditPatches of quicksand found on the Maine coast are known as honeypots 5 6 In popular culture EditQuicksand is a trope of adventure fiction particularly in film where it is typically and unrealistically depicted with a suction effect that causes people or animals that walk into it to sink until fully submerged and risk drowning This has led to the common misconception that humans can be completely immersed and drown in quicksand however this is physically impossible 7 According to a 2010 article by Slate this gimmick had its heyday in the 1960s when almost 3 of all films showed characters sinking in clay mud or sand 8 See also EditBulldust Dry quicksand Grain entrapment Quick condition Sapric Tar pit ThixotropyReferences Edit Khaldoun A E Eiser G H Wegdam and Daniel Bonn 2005 Rheology Liquefaction of quicksand under stress Nature 437 29 Sept 635 doi 10 1038 437635a Will Quicksand Really Kill You The Science Explorer Retrieved 2020 04 08 a b Bakalar Nicholas September 28 2005 Quicksand Science Why It Traps How to Escape National Geographic News Retrieved October 9 2011 Discovery Channel MythBusters Season 2 Killer Quicksand October 20 2004 What to do in Maine The Woks of Life 20 October 2020 Retrieved 20 July 2022 Beagan Jessica Fall 2003 286 West Kennebec Road Columbia A Journal of Literature and Art 38 47 50 JSTOR 41808253 Reaney Patricia 29 September 2005 Quicksand myth exposed www abc net au Reuters Retrieved 2020 04 08 Engber Daniel 23 August 2010 Terra Infirma The rise and fall of quicksand Slate Retrieved 23 August 2010 External links Edit Wikimedia Commons has media related to Quicksand Wikiquote has quotations related to Quicksand Look up quicksand in Wiktionary the free dictionary How quicksand works at HowStuffWorks What is quicksand Scientific American Video showing quicksand in a sandpit at YouTube Retrieved from https en wikipedia org w index php title Quicksand amp oldid 1149179565, wikipedia, wiki, book, books, library,
