Honestly as a kid I thought that quicksand would be a way bigger problem in life considering how many TV shows and movies I saw that used it.
But basically, what is it, how is it formed, how common is it, that kind of stuff. I live on the US East coast so (to my knowledge) I’ve never encountered it
In: Planetary Science
Oh boy, I really had to set aside everything I learned as a CivE major to ELI5 this one.
Imagine a swimming pool covered in beach balls. They’re all floating there, and the surface looks solid. Except, it’s not – the beach balls have a weight, which is pushing downwards, while the water is pushing upwards due to buoyancy. Everything is in perfect balance… until you decide to step on it. In that case, since the beach balls and water balance each other, there’s nothing to balance your weight, and so you sink. That’s basically quicksand – sand that has become saturated with water and cannot withstand any external load.
Note that quicksand is not a type of sand, rather a *state* of sand. Given enough water, any sand can become “quick”.
It’s basically a sand/water mix that makes it low density. It’s not like tv/movies. You do sink, but it would take hours at a minimum for your body to become submerged. It’s not nearly as dangerous as it’s usually depicted, but at the same time it’s something you shouldn’t fuck around with.
Picture a really deep hole. Now fill that hole with sand. Now pour gallons of water on that sand.
When you step on that hole, your foot falls in a little bit because there is no sturdy ground around you. The sand next to your foot fills in, “submerging” your foot in the sand. This wet sand is sticky due to cohesion and adhesion, so it clings to itself. If you have one foot it one foot out, you will be able to retract your submerged foot no problem. If two feet are in you have an issue. When you try to lift your left foot out, you put all your weight on your right foot, making it seep into the quicksand further. The further in your foot is, the more sand is around and on top of it meaning it will take even more force to pull it out. More force to pull it out means more force on your other foot…. im sure you see the pattern
EDIT: spelling jesus christ
Quicksand is a concept, a state, not an actual thing.
When sand is just sitting there, its sand. You step on it, it doesn’t move, doesn’t compress. Quick sand is a state of sand where water can creeped up into the sand and now the sand has a ‘lubricant’ between its grains, water. This makes is much easier for the sand to move out of the way. It changes all the properties of plain sand. It doesn’t suck you in, it it just very difficult to get out of and movement will often cause you to sink more since your density will be just a little higher than sand+water.
A water spring under a sand area can cause this to happen. Water bubbles up, but not enough to make a pond. Top 1″ is still sand, but under that, its a slurry of sand and water.
You can make your own quick sand with just a bucket and a water pump. Mythbusters did a quicksand episode. Google it.
Quicksand is caused by a phenomenon called “liquefaction”. Liquefaction is a fancy term for when sand is mixed with water AND agitated, it acts more like water than sand.
Think about when you are walking on a beach near the water. The sand (even though it is wet) is solid and you leave some footprints but you can walk across the sand. Think about when you put sand in a bucket and then fill the bucket with water. The sand at the bottom is pretty solid and acts like wet sand.
Now think about when you’re at the beach in the water, the sand at the bottom is still reasonably solid. But if you wiggle your feet around you will sink. You’re sinking because when you agitate the sand in the water you are standing in, the agitated sand acts like water and flows away.
Think about the sand + bucket situation. If you just push your finger down on the sand, it will resist, but if you wiggle your finger it will push deeper in the sand at the bottom of the water.
“Quicksand” occurs in nature when you have a sandy area with an underground spring bubbling up through the sand. The sand is always in a state of agitation because the water bubbling up through the sand, so if you step into it, you can sink.
It’s something that aint exactly water, and it aint exactly earth.
Come on you knew someone had to say it. But the correct answer was already said: deep mud, but with sand instead of dirt so it doesn’t even look like mud, and has even stronger cohesion.
To add, apparently nobody has died directly from quicksand – that’s just a Hollywood trope.
What can happen is you can get caught, then potentially die from exposure, or more likely by drowning from a rising tide.
https://www.quora.com/How-many-people-die-worldwide-on-a-yearly-basis-because-of-quicksand#:~:text=None.,happens%20in%20old%20Hollywood%20movies.
I was walking on a beach years ago as a teen. I jumped off of a retaining wall onto the sand next to an area where shallow water was on top of the sand. I was surprised when I sunk into the sand up to mid-thigh. Unlike movie quicksand, I had no real difficulty extracting myself.
[removed]
It’s basically just wet sand saturated with water, so mud, but not dirt mud, but sand mud. If you walk on it you sink up to a degree but you can’t sink too far down. Cartoons would have you believe you just sink entirely and are swallowed up but really you just stop sinking after a while because when you’ve displaced your body weight in quick sand you just stop sinking, just like water, but quicksand is much more dense than water, so instead of sinking up to your neck before you stop sinking you only go up to your knees or pelvis.
Latest Answers