Dry Quick Sand

[Xtremehkr]

Newly developed dry quicksand

Beware of playing in any sandboxes you might find in the laboratory of Dr. Detlef Lohse.

Traditional deathtrap quicksand is a slurry of sand, water and clay. The water keeps the sand from sticking together to support weight, and a person who steps in slowly sinks.

Now Dr. Lohse, a professor of applied physics, and his colleagues at the University of Twente in the Netherlands show that it is possible to vanish into a pile of completely dry sand as well. Worse, their sand looks the same as the normal, weight-supporting variety.

In the current issue of the journal Nature, the researchers describe their experiment. They puffed air through fine-grained sand, shuffling the grains of sand into a more precarious arrangement - something like a house of cards. Even after the air was turned off and the sand settled, the packing density of the grains was an airy 41 percent, down from 60 percent initially.

The researchers suspended a Ping-Pong ball, weighed down with bits of bronze, so that it just touched the surface of the sand. They then burned the string holding the doomed ball. The fluffy sand was incapable of supporting the ball, which immediately and quickly sank without a splash.

A tenth of a second later, the backwash of sand closing up behind the sinking ball caused a thin narrow jet of sand to shoot several inches into the air, like a desperate distress call. Heavier balls sank deeper into the sand, and the jets occurred only for those weighing more than an ounce.

Dr. Lohse said the findings could explain reports of travelers' being swallowed up in the desert.

"The U.S. Army is very interested in this," he said, "because these days, the U.S. Army tends to go to desert states."

Better than landmines?

 

[DavidLeblond]

"Traditional deathtrap quicksand" also doesn't exist, according to the Mythbusters.

 

[Xtremehkr]

Odd that they should refer to it in the article.

 

[Counterfit]

The thing with normal quicksand is, you can swim in it. So it's not much of a death trap (unless you're carrying 50 lbs. of gear like the average soldier)

 

[Sparky's]

"Traditional deathtrap quicksand" also doesn't exist, according to the Mythbusters.

I thought I was the only one who watched that.

what I'm amazed with is the little tiny numbers on the top of the photos, 700ms (milliseconds) for the damn thing to disappear, and what's with the little jet of sand blown straight up?

 

[aus_dave]

Ping pong balls everywhere should be very worried .

 

[Sun Baked]

I wonder if they can puff a big enough hole full of sand to swallow a vehicle.

Imagine a pond sized hole making a Humvee vanish without a trace.

 

[Peyote]

I wonder if they can puff a big enough hole full of sand to swallow a vehicle.

Imagine a pond sized hole making a Humvee vanish without a trace.

I don't think it would work quite as well....Humvees aren't exactly shaped like a smooth sphere if you get my drift. I imagine the process would be significantly slower.



Edit: Also, don't forget that a ping pong ball can't compact the sand beneath is like a large brick shapes vehicle. Most of the sand under a sphere gets pushed to the side easily. Under a large vehicle, however, I imagine that a lot of the sand would compress beneath it, limiting the effect.

 

[Hoef]

Another fine invention from the Netherlands!

 

[Sun Baked]

I don't think it would work quite as well....Humvees aren't exactly shaped like a smooth sphere if you get my drift. I imagine the process would be significantly slower.



Edit: Also, don't forget that a ping pong ball can't compact the sand beneath is like a large brick shapes vehicle. Most of the sand under a sphere gets pushed to the side easily. Under a large vehicle, however, I imagine that a lot of the sand would compress beneath it, limiting the effect.

You don't have to sink a Humvee, just stop it (and the rest of the convoy) long enough to force people to get out and take time to remove it.

Since you also have these locations on GPS and can most likely signal the trap is sprung -- it's much easier to target them with GPS guided bombs/missles.

 

[wdlove]

I can remember enjoying the use of quick sand in Tarzan and some other Jungle Jim Movies when I was a boy. They came on as Saturday afternoon movie features. I think they actually did use the dry quick sand at least once. A great way to catch the bad guys.

 

[the_mole1314]

I thought I was the only one who watched that.

what I'm amazed with is the little tiny numbers on the top of the photos, 700ms (milliseconds) for the damn thing to disappear, and what's with the little jet of sand blown straight up?

I just downloaded that one off bit-torrent!

 

[Peyote]

You don't have to sink a Humvee, just stop it (and the rest of the convoy) long enough to force people to get out and take time to remove it.

Since you also have these locations on GPS and can most likely signal the trap is sprung -- it's much easier to target them with GPS guided bombs/missles.

Never said you needed to sink it to do anything....I'm just talking about the sheer physics of sinking one. Even if you wanted to bog one down, there are more efficient ways

 

[Simon Liquid]

"Traditional deathtrap quicksand" also doesn't exist, according to the Mythbusters.

Yeah, well I don't believe Rodents of Unusual Size exist eithe*CHULNGK*

 

[ddtlm]

Sun Baked:

I wonder if they can puff a big enough hole full of sand to swallow a vehicle.

Deep sand will compact under its own wieght, so the fluffy stuff would only exist on top.

 

[virividox]

creating these traps would be time consuming tho, not very practical if your in a war

 

[Mechcozmo]

Quicksand (normal kind) is so dense, that you would sink up to your chest and then stop. You would float. Now, just roll onto your back and slowly move out.

That's the abbreviated version from "Worst Case Scenario Survival Handbook"

A good read...

 

[wdlove]

Quicksand (normal kind) is so dense, that you would sink up to your chest and then stop. You would float. Now, just roll onto your back and slowly move out.

That's the abbreviated version from "Worst Case Scenario Survival Handbook"

A good read...

That reminded me of rip tides that occur with approaching Hurricanes here in New England. It is a current below the surface that will pull a swimmer out to sea. Even an expert swimmer can't fight against the rip tide. The only safety net is to swim at parallel to the shore till you escape the rip tide. A rip tide tends to be a narrow band. Then the swimmer can easily return to shore