Thread: Quicksand

Okay, any geologists attend the site?

Having a debate, a friendly one, involving quicksand. We have all been brought up believing that quicksand exists, and in some places around where I live, we have quicksand on beaches and are quite dangerous. But there are some questions as to whether quick sand is even real.


Is quicksand a real phenomenon?

(I think we might be talking, about the quicksand found in movies) - that doesn't exist right?

Mythbusters busted the quicksand myth in 2004. What they actually found is that quicksand, a mixture of fine sugar sand and water, is very buoyant, and will float you.

Cool, thanks.

I stepped in a sink hole in Florida...I took one step..solid....another solid...and another .I was up to my thighs in like 4 seconds....let's just say...my husband was looking for his golf ball, and I found it and he wasn't looking at me. Our partner pulled me out of that crap! *L*.......all I know is it was scary!

Originally Posted by AlexG

Mythbusters busted the quicksand myth in 2004. What they actually found is that quicksand, a mixture of fine sugar sand and water, is very buoyant, and will float you.

I didn't know that Sir AlexG!! Mahalo for the information!

True quicksand is more boyant than pure water. However, there is another factor involved. Quick sand is not just a mixture of sand suspended in water, it also a column of water moving upward through earth. How "quick " the quick sand is depends on the rate and volume of the water flow.
Here is the story: I was working nights in hospital. suddenly in the middle of the night water is coming right through the concret basement walls, as it would if you covered tap with a handkerchief and turned on the water. Water would come right through the cloth. So we called in all the maintanece supervisors etc. One of them opens an access door above where we think there must be a leak. We see nothing but a green lawn and the 3x4 concrete door way pavement. Then he stepped on that little concrete pad. Suddenly he was hanging from the accessdoor by the key that was still in the lock. He did not sink, he fell. It was like he had tried to step on a cloud.
What had happened was that the settling of the building had caused a nine inch main to shear off where it went into the foundation, 16feet below ground level. It was the main that supplied the fire control "stand pipe".

Originally Posted by Sealeaf

True quicksand is more boyant than pure water. However, there is another factor involved. Quick sand is not just a mixture of sand suspended in water, it also a column of water moving upward through earth. How "quick " the quick sand is depends on the rate and volume of the water flow.
Here is the story: I was working nights in hospital. suddenly in the middle of the night water is coming right through the concret basement walls, as it would if you covered tap with a handkerchief and turned on the water. Water would come right through the cloth. So we called in all the maintanece supervisors etc. One of them opens an access door above where we think there must be a leak. We see nothing but a green lawn and the 3x4 concrete door way pavement. Then he stepped on that little concrete pad. Suddenly he was hanging from the accessdoor by the key that was still in the lock. He did not sink, he fell. It was like he had tried to step on a cloud.
What had happened was that the settling of the building had caused a nine inch main to shear off where it went into the foundation, 16feet below ground level. It was the main that supplied the fire control "stand pipe".

Was he ok?

As pointed out in myth busters, most die from quicksand after being stuck there.

About twenty years ago, myself and three other strangers rescued an older man trapped in a sand and mud mixture near a popular fishing spot for salmon. He'd walked out at low tide, hit a soft spot and was buried nearly up to his waist yelling for help. The four of us gingerly approached. He was tired, said he was a bit cold and quite stuck. All of us knew the tide was about to turn and cover the place with ten feet or more of 50 degree water. One of us went back to pull a rope and some old rug out from the back of a pickup. Another of us left to call the authorities and ask for a boat just in case. The old man ended up leaving his waders in the mud but we were able to pull him out using the rug near him to grip and help support him as he wallowed out of the hole. A couple cops showed up about a half hour later and shared some blankets just as we all got back to our trucks and were trying to laugh it off sharing a thermos of hot coffee.

I'm a heck of a lot more careful now and carry a walking stick along with my fishing pole. Now I'd probably be that old man...lol.

Originally Posted by Geometrogenesis

Is quicksand a real phenomenon?

Yes. But as others have noted, it is not a composition of sands but the phenomenon of sand being suspended in a plume of rising water (hence the term 'quicksand.') What happens is this:

1) You step in it. Since it is effectively water with sand in it you sink immediately up to your chin (or whatever level you normally float at.)
2) Attempts to get out don't work since there is nothing to grab onto, and anything you pull into the plume with you is just blown back up by the plume.
3) The longer you stay there the more sand settles on your back/feet/shoulders - basically anything that blocks the water from the plume. Sand is heavier than water so you sink further and further.

Originally Posted by billvon

Originally Posted by Geometrogenesis

Is quicksand a real phenomenon?

Yes. But as others have noted, it is not a composition of sands but the phenomenon of sand being suspended in a plume of rising water (hence the term 'quicksand.') What happens is this:

1) You step in it. Since it is effectively water with sand in it you sink immediately up to your chin (or whatever level you normally float at.)
2) Attempts to get out don't work since there is nothing to grab onto, and anything you pull into the plume with you is just blown back up by the plume.
3) The longer you stay there the more sand settles on your back/feet/shoulders - basically anything that blocks the water from the plume. Sand is heavier than water so you sink further and further.

Thank goodness Charlie was there to pull me out.....cause I don't FLOAT I SINK!

Yes he was fine there were about eight people right behind him and we pulled him back into the building.