Dry quicksand
Encyclopedia
Dry quicksand is loose sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

 whose bulk density
Bulk density
Bulk density is a property of powders, granules and other "divided" solids, especially used in reference to mineral components , chemical substances, ingredients, foodstuff or any other masses of corpuscular or particulate matter. It is defined as the mass of many particles of the material...

 is reduced by blowing air through it and which yields easily to weight or pressure. It acts similarly to normal quicksand
Quicksand
Quicksand is a colloid hydrogel consisting of fine granular matter , clay, and water.Water circulation underground can focus in an area with the optimal mixture of fine sands and other materials such as clay. The water moves up and then down slowly in a convection-like manner throughout a column...

, but it does not contain any water and does not operate on the same principle. Dry quicksand is an example of a granular material
Granular material
A granular material is a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact . The constituents that compose granular material must be large enough such that they are not subject to thermal motion fluctuations...

.

Until recently, the existence of dry quicksand was doubted, and the reports of humans and complete caravans being lost in dry quicksand were considered to be folklore
Folklore
Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...

.

Scientific research

Writing in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

, physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

 Detlef Lohse and coworkers of University of Twente in Enschede
Enschede
Enschede , also known as Eanske in the local dialect of Twents, is a municipality and a city in the eastern Netherlands in the province of Overijssel and in the Twente region...

, Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 allowed air to flow through very fine sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

 (typical grain diameter was about 40 micrometers
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

) in a container with a perforated base. They then turned the air stream off before the start of the experiment and allowed the sand to settle: the packing fraction of this sand was only 41% (compared to 55–60% for untreated sand).

Lohse found that a weighted table tennis
Table tennis
Table tennis, also known as ping-pong, is a sport in which two or four players hit a lightweight, hollow ball back and forth using table tennis rackets. The game takes place on a hard table divided by a net...

 ball (radius 2 cm, mass 133 g), when released from just above the surface of the sand, would sink to about five diameters. Lohse also observed a "straight jet of sand [shooting] violently into the air after about 100 ms". Objects are known to make a splash
Splash (fluid mechanics)
In fluid mechanics, a splash is a sudden disturbance to the otherwise quiescent free surface of a liquid . The disturbance is typically caused by a solid object suddenly hitting the surface, although splashes can occur in which moving liquid supplies the energy...

 when they hit sand, but this type of jet had never been described before.

Lohse concluded that
In nature
Nature
Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...

, dry quicksands may evolve from the sedimentation
Sedimentation
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration...

 of very fine sand after it has been blown into the air and, if large enough, might be a threat to humans. Indeed, reports that travellers and whole vehicle
Vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

s have been swallowed instantly may even turn out to be credible in the light of our results.


During the planning of the Project Apollo
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...

 moon missions, dry quicksand on the moon was considered as a potential danger to the missions. The successful landings of the unmanned Surveyor
Surveyor program
The Surveyor Program was a NASA program that, from 1966 through 1968, sent seven robotic spacecraft to the surface of the Moon. Its primary goal was to demonstrate the feasibility of soft landings on the Moon...

 probes a few years earlier and their observations of a solid, rocky surface largely discounted this possibility, however. The large plates at the end of legs of the Apollo Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...

 were designed to reduce this danger, but the astronaut
Astronaut
An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft....

s did not encounter dry quicksand.

In popular culture

Dry quicksand was occasionally featured in literature. The 1966 movie African Gold (released abroad as Ride the High Wind) shows an actress being trapped in dry quicksand. Mindwarp (1990) also has an actress wandering into dry quicksand before being rescued. The movie 12 to the Moon (1960) shows a crew member being lost in moon dust similar to dry quicksand. In the film Lawrence of Arabia
Lawrence of Arabia (film)
Lawrence of Arabia is a 1962 British film based on the life of T. E. Lawrence. It was directed by David Lean and produced by Sam Spiegel through his British company, Horizon Pictures, with the screenplay by Robert Bolt and Michael Wilson. The film stars Peter O'Toole in the title role. It is widely...

, a servant of T. E. Lawrence "drowns" in dry quicksand (this was never claimed to have happened in real life). The plot of the Arthur C. Clarke
Arthur C. Clarke
Sir Arthur Charles Clarke, CBE, FRAS was a British science fiction author, inventor, and futurist, famous for his short stories and novels, among them 2001: A Space Odyssey, and as a host and commentator in the British television series Mysterious World. For many years, Robert A. Heinlein,...

 novel A Fall of Moondust
A Fall of Moondust
A Fall of Moondust is a hard science fiction novel by Arthur C. Clarke, first published in 1961. It was nominated for a Hugo Award for Best Novel, and was the first science fiction novel selected to become a Reader's Digest Condensed Book....

(1961) was based on the perils of working and traveling on a moon surface covered by a deep layer of dry quicksand, based on the actual risks considered during the planning of the Project Apollo
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...

 missions. In Universal Pictures' 1999 The Mummy
The Mummy (1999 film)
The Mummy is a 1999 American adventure film written and directed by Stephen Sommers and starring Brendan Fraser, Rachel Weisz, John Hannah and Kevin J. O'Connor, with Arnold Vosloo in the title role as the reanimated mummy. The film features substantial dialogue in ancient Egyptian language, spoken...

, Captain Winston Havelock's biplane and body disappear into dry quicksand after High Priest/Mummy Imhotep summons a sand storm to make the biplane crash.

In the videogame Xenogears
Xenogears
is a science-fiction console role-playing game developed and published by Square for Sony's PlayStation. It was released on February 11, 1998 in Japan and on October 20, 1998 in North America. The game was never released in PAL territories...

 the continent of Ignas (the country of Aveh) is covered mostly by a large desert, and several plot events revolve around characters' gears or vehicles being buried by dry quicksand.

The Princess Bride
The Princess Bride
The Princess Bride is a 1973 fantasy novel written by William Goldman. It was originally published in the United States by Harcourt Brace, while in the UK it is/was published by Bloomsbury Publishing....

featured dry quicksand (called "Snow Sand" in the book and "Lightning Sand" in the movie) as one of the three terrors of the Fire Swamp. Dry quicksand was also featured in the movies Mad Max: Beyond Thunderdome, and the 2004 Chinese film, Kekexili: Mountain Patrol
Kekexili: Mountain Patrol
Kekexili: Mountain Patrol is a 2004 film by Chinese director Lu Chuan that depicts the struggle between vigilante rangers and bands of poachers in the remote Tibetan region of Kekexili...

. In the 1993 film Pure Luck
Pure Luck
Pure Luck is a 1991 American comedy film starring Martin Short and Danny Glover. It is remake of the popular French comedy film La Chèvre .- Plot :...

Martin Short's character finds himself sinking in dry quicksand in Mexico before being rescued.

In a 1990 episode of Mission: Impossible
Mission: Impossible
Mission: Impossible is an American television series which was created and initially produced by Bruce Geller. It chronicled the missions of a team of secret American government agents known as the Impossible Missions Force . The leader of the team was Jim Phelps, played by Peter Graves, except in...

, "The Sands of Seth", a minister of the Egyptian government heads a cult that meets in an ancient structure with a dry quicksand pit for disposing of undesirable individuals.

Philip J. Fry
Philip J. Fry
Philip J. Fry, known simply as Fry, is a fictional character, the main protagonist of the animated science fiction sitcom Futurama. He is voiced by Billy West using a version of his own voice as he sounded when he was 25.-Character overview:...

 and Leela drive a (stolen replica) lunar rover from an amusement park
Amusement park
thumb|Cinderella Castle in [[Magic Kingdom]], [[Disney World]]Amusement and theme parks are terms for a group of entertainment attractions and rides and other events in a location for the enjoyment of large numbers of people...

 into a pit of dry quicksand in the Futurama
Futurama
Futurama is an American animated science fiction sitcom created by Matt Groening and developed by Groening and David X. Cohen for the Fox Broadcasting Company. The series follows the adventures of a late 20th-century New York City pizza delivery boy, Philip J...

episode "The Series Has Landed".

In Indiana Jones and the Kingdom of the Crystal Skull, the title character gets caught in a dry quicksand pit while trying to escape from Soviet soldiers. While sinking, Indiana humorously tries to explain the difference between dry and regular quicksand.

World 2 (Desert World) of Super Mario Bros. 3
Super Mario Bros. 3
, also referred to as Super Mario 3 and SMB3, is a platform video game developed and published by Nintendo for the Nintendo Entertainment System , and is the third game in the Super Mario series. The game was released in Japan in 1988, in the United States in 1990, and in Europe in 1991...

features many obstacles that resemble dry quicksand.

External links

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