it is said that when someone tries hard to escape quicksand, they will sink deeper into it. how is that so? how does quicksand work?
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Fun fact: You can never completely drown in quicksand,because quicksand is denser than human body.So one would only sink upto waist level before they start to float.
As for sinking deeper part, it happens because when you flail around in quicksand,you displaced mud from around yourself,creating empty space which makes it easier for a body to sink in. As learnt from discovery channel,to escape quicksand,you must free your arms outside then try to pull your body straight up using the arms.
I watched a video a while back where an older couple got stuck in quicksand in Thailand. Totally terrifying. The man had one leg knee-deep. When he tried to put the other foot down to push himself out, it just sank–now both feet were knee-deep and he couldn’t do much of anything except flail around. Fortunately a local stopped, got prone on the quicksand and tossed them a rope that he tied to his car and used to pull them out.
This also happens with grain and is an important safety issue that kills people every year. When you try to stand up out of it, the weight you put on one foot will never be enough to free your other foot, but it IS enough to make you sink in further. So eventually you just sink in too far to ever hope to escape by yourself. You would think that you can breathe “through” the grain, but that’s not what kills you— the weight of the grain will press your chest until you can’t inhale. Every exhale creates a place for grain to fall into and increases the effort required for the next breathe. Suffocating is the easy way out or maybe there’s an auger running at the bottom that makes it quick…
The amount of effort required to free you increases shockingly fast over just a few feet of depth— if you just wrapped a rope around someone buried chest deep and pulled you would likely just tear them apart.
The concept is like ketchup. The more you shear it (ie, stir it), the less viscous it gets. (To a point). So, if you stay still, it will remain viscous and support your weight. But if you thrash about, it will become less viscous, and you will sink. Like how if you upend a ketchup bottle, the ketchup will stay put, but if you shake it, the ketchup flows out.
In the case of ketchup, this is called being thixatropic.
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