Maybe you have just heard that a paint’s viscosity, or resistance to flow, stems from a thixotropic agent Malaysia mixed with it. You start to read at least what thixotropy is in a nutshell when you notice a quicksand as an example of natural thixotropy. You remember the movies where characters get trapped and risk drowning completely in it.
The question you ask yourself is: can a quicksand really submerge a human being in full? Even more intriguing, what makes it tick that it can sink objects like a ship?
To start with, a quicksand isn’t a monstrous force of nature that hates everything so much that anything it catches, it will tightly grip and drown the object into oblivion. In reality, a quicksand is just sand or another grainy soil that behaves like a viscous liquid when it is saturated by water. Because the trapped water cannot escape from the sand, it creates liquified soil, which can no longer support weight.
A quicksand is a good example of how thixotropy works in the form of shear thinning. Long story short, a fluid is in a solid state when idle, but if stressed, it quickly liquifies. After that, it will return to its formerly solid state when it is no longer disturbed for some time.
Flowing underground water and earthquakes are the two causes of quicksand. In the first case, the force of gravity is opposed by the upwards flow of the water, reducing the buoyancy of sand. In the second, the force of the shaking ground increases a shallow groundwater’s pressure, liquifying sand and silt deposits. When a building, car or other objects sink into or fall over that ground, it is because the surface loses the strength to support weight.
Vibrations can quicken the creation of a quicksand as this, along with the water barrier, reduces the friction between sand particles and thus liquifying them.
The short answer is no. Why? Because you are less dense than a quicksand.
Though people can sink in one, they will only be floating on it rather than drowning. At best, the deepest depth they may be submerged is no more than beyond the waist unless something is probably pulling them down. Still, the quicksand does not behave like one in a movie at all. Your body density is 1 gram per millimeter, while the quicksand is 2 grams per milliliter. Even in your uncontrolled panic, you will only reach halfway there and may sink no further. This is also combined by not only the density of your legs, but because you have lungs, this is buoyant enough to stay relatively afloat.
You can, however, still drown in water if the quicksand is close to a river or a coastal area where the tide can come and drag you in.
If you fall in a position other than on your legs, you may suffocate from your compromised breathing, depending on how you fall into the quicksand. Falling headfirst is definitely a no-go. Besides, hypothermia can also be your enemy when half of your sunken body cannot regulate your body temperature, especially since the quicksand is wet or if this happens to you in a desert at night.
Lastly, crush syndrome can be a risk if you are stuck in quicksand for too long. The longer the pressure is extended on the skeletal muscles, the more likely your circulatory system will break into chaos. Your muscles and nerves can be damaged by compression, which also releases compounds that damage your kidneys.
Trying to lift one foot off a quicksand is the equivalent of lifting a car, so just trying to escape this way will not do. If there is no help or it is on the way, the best method you can employ is to relax and slowly bring yourself to the surface. You could also lean back so your body’s weight is distributed over a wider area, then use your legs to move to the surface. If there is a branch or other objects to hold onto, do not yank.
If you panic and trash around in the quicksand, you will more easily sink further into it, which is dangerous if the mentioned hazards like hypothermia and tides exist in the area. Once you are out of the surface minus your legs, sit down and slowly work them free.