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Created page with "File:lighterstill.jpgright|frame *[http://en.wikipedia.org/wiki/14th_century 14th Century] ==Definitions== *1: sand readily yieldin..."
[[File:lighterstill.jpg]][[File:Get-out-of-Quicksand.jpg|right|frame]]
*[http://en.wikipedia.org/wiki/14th_century 14th Century]
==Definitions==
*1: [[sand]] readily yielding to [[pressure]]; especially : a deep mass of loose sand mixed with [[water]] into which heavy objects readily sink
*2: something that [[entraps]] or [[frustrates]] <lead poor people into consumerist quicksand — Robert Wright>
==Description==
'''Quicksand''' is a colloid [https://en.wikipedia.org/wiki/Hydrogel hydrogel] consisting of fine material (such as sand or silt), [[clay]], and [[water]].
Quicksand 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 upwards [[flowing]] water (as from an [https://en.wikipedia.org/wiki/Artesian_aquifer artesian spring]). In the case of upwards flowing water, seepage forces oppose the force of [[gravity]] and suspend the [[soil]] particles.
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, fluidlike 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]].
[https://en.wikipedia.org/wiki/Soil_liquefaction Liquefaction] is a special case of quicksand. In this case, sudden earthquake forces immediately increase the pore pressure of shallow groundwater. The saturated liquefied soil loses strength, causing buildings or other objects on that surface to sink or fall.
Quicksand itself is harmless: a [[human]] or [[animal]] is unlikely to sink entirely into quicksand at all due to the higher [[density]] of the [[fluid]] (assuming the quicksand is on dry ground and not under [[water]], but even if underwater, sinking is still impractical). Quicksand has a density of about 2 grams per milliliter, while the density of the human body is only about 1 gram per milliliter. At that level of density, sinking in quicksand is impossible. Descending about up to the waist is possible, but not any further. Even objects with a higher density than quicksand will float on it—until they move. Aluminum, for example, has a density of about 2.7 grams per milliliter. But a piece of aluminum will float on top of quicksand until motion causes the sand to liquefy.[2]
Continued or [[panicked]] movement may cause the [[victim]] to sink deeper, leading to [[belief]] that quicksand is [[dangerous]]. Because it increasingly impairs human locomotion, it allows harsher elements such as [[sunlight]], [https://en.wikipedia.org/wiki/Dehydration dehydration], carnivores, omnivores, [https://en.wikipedia.org/wiki/Hypothermia hypothermia] or [[tides]] to harm a trapped person. 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.[https://en.wikipedia.org/wiki/Quicksand]
[[Category: Earth Science]]
*[http://en.wikipedia.org/wiki/14th_century 14th Century]
==Definitions==
*1: [[sand]] readily yielding to [[pressure]]; especially : a deep mass of loose sand mixed with [[water]] into which heavy objects readily sink
*2: something that [[entraps]] or [[frustrates]] <lead poor people into consumerist quicksand — Robert Wright>
==Description==
'''Quicksand''' is a colloid [https://en.wikipedia.org/wiki/Hydrogel hydrogel] consisting of fine material (such as sand or silt), [[clay]], and [[water]].
Quicksand 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 upwards [[flowing]] water (as from an [https://en.wikipedia.org/wiki/Artesian_aquifer artesian spring]). In the case of upwards flowing water, seepage forces oppose the force of [[gravity]] and suspend the [[soil]] particles.
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, fluidlike 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]].
[https://en.wikipedia.org/wiki/Soil_liquefaction Liquefaction] is a special case of quicksand. In this case, sudden earthquake forces immediately increase the pore pressure of shallow groundwater. The saturated liquefied soil loses strength, causing buildings or other objects on that surface to sink or fall.
Quicksand itself is harmless: a [[human]] or [[animal]] is unlikely to sink entirely into quicksand at all due to the higher [[density]] of the [[fluid]] (assuming the quicksand is on dry ground and not under [[water]], but even if underwater, sinking is still impractical). Quicksand has a density of about 2 grams per milliliter, while the density of the human body is only about 1 gram per milliliter. At that level of density, sinking in quicksand is impossible. Descending about up to the waist is possible, but not any further. Even objects with a higher density than quicksand will float on it—until they move. Aluminum, for example, has a density of about 2.7 grams per milliliter. But a piece of aluminum will float on top of quicksand until motion causes the sand to liquefy.[2]
Continued or [[panicked]] movement may cause the [[victim]] to sink deeper, leading to [[belief]] that quicksand is [[dangerous]]. Because it increasingly impairs human locomotion, it allows harsher elements such as [[sunlight]], [https://en.wikipedia.org/wiki/Dehydration dehydration], carnivores, omnivores, [https://en.wikipedia.org/wiki/Hypothermia hypothermia] or [[tides]] to harm a trapped person. 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.[https://en.wikipedia.org/wiki/Quicksand]
[[Category: Earth Science]]