When wet, loose sand is rapidly stirred, quicksand occurs. When water cannot escape from the sand, it forms a liquefied soil that loses strength and cannot sustain weight. The process can be speeded up by small stones or roots that penetrate the surface of the sand.
The term "quicksand" comes from the English word "quick" (as in quick-sand) plus the French word "saud" (safe), because this material is dangerous only if you stay long enough for it to trap you. If you reach deep enough into the sand, you will be all right.
Loose sands often occur in areas where the groundwater level is high and the soil is permeable. Quickly draining soils may cause people to wander into areas where they might not otherwise go. For example, an excavator driving over dry creek beds may fall into a pit of quicksand. High groundwater levels may also cause problems for roads and bridges. Burying portions of these structures causes stress on the remaining structure which may lead to failure.
Quicksands are found in many places around the world. In North America, the most common type of quicksand is glacial silt. This material is rich in nutrients and easy to work with, but it can also bury vehicles quickly.
The quicksand phenomenon happens when sand particles are saturated by an upward flow of an aqueous solution and the mineral particles lose touch microscopically. As a result, the tension of the soil weight matches the water pressure value, rendering the soil's effective tension null. When a person walks into such sand, their weight will cause them to sink up to their knees or hips. Then they must stop moving or else they will be dragged down by the force of the water.
When this occurs in a riverbank, it is called quicksand. The term "quick" comes from the fact that the victim sinks very quickly into the sand. They cannot get out again unless someone helps them.
People have been sinking into riversbanks since ancient times. It is said that Hercules used his strength to pull himself out of a bog in Europe. In America, Indians would walk across hot places in the sun where there was much quicksand because it was good for their skin. In more recent times, people have died in large numbers due to being caught between two floods of the River Jordan in Jerusalem. This has made news around the world because it shows how dangerous quicksand can be.
Modern researchers have shown that this effect is caused by the absorption of water by the sand which makes the soil less stable.
Quicksand is often made up of sand, clay, and salt that has been waterlogged, typically near river deltas. The ground appears to be solid, but as you tread on it, the sand starts to liquefy. The water and sand eventually separate, leaving a layer of densely packed wet sand that can trap it. As more people travel through the area, they add more water and salt, which further slows down the process of dissolution.
In addition to being near rivers, the soil must contain a high percentage of sand or else the quicksand will not form. Areas with lots of clay are not likely to produce quicksand because the water and salt do not have enough time to penetrate the surface to dissolve any silicon-based compounds.
The most common type of quicksand in the United States is called devil's trap because of the difficulty in escaping if you get stuck. Devil's traps are usually found in areas where there is plenty of sunlight and no shade so the soil can dry out. They used to be common along railroad tracks but now they're seen mostly off-road.
Railroads used to use large quantities of wood to build their tracks, which would eventually decay and disappear under the right conditions. When this happened, it created holes in the ground filled with quick-sand that was perfect for trapping unsuspecting travelers' feet. This is how many highway accidents happen each year: people walking in front of speeding trains who cannot escape in time.
Quicksand is a fine sand, clay, and saltwater combination. The bottom is then firmly packed sand with water floating on top. " It's the difficulty of getting water into this really closely packed sand that makes pulling your foot out tough." - webmaster2022
If you check the nests of birds that build their own structures, such as bluebirds and robins, you will often find that they keep falling out. They do this to test how well the structure will hold them while they search for a place to live near their parents' home range. If the nest falls apart when they try to pull it out, then they will go look for another place to build their own nest.
If you watch birds long enough, you will see that some species (like crows) will always build their own nest, while others (like robins) will only build their own nest if they can't find an existing one. In fact, most birds that inhabit human-made environments like to build their own nests. They use any available material like grass or twigs but usually include feathers from their own bodies in their construction.
However, not all nests are built equal.