What Exactly is Quicksand?

Quicksand is a staple hazard of adventure movies, TV shows and video games. Whenever a minor character needs to be killed off quickly, the hero needs someone to rescue, or danger needs to be introduced without calling the villain in, quicksand is there to fulfill the task and swallow an explorer whole. Conveniently, there’s always a pool of pasty goo sitting around somewhere, usually perfectly circular and somewhat hidden from the characters’ view. This shouldn’t come as a shock, but real quicksand isn’t exactly how Hollywood makes it out to be.

Quicksand is what happens when regular old sand or grainy soil gets mixed with water under the right conditions. Normally, sand/soil can support weight on top of it because the friction between the grains helps distribute the load across a large area. If enough water seeps up from an underground source and gets under and around each grain, though, the friction gets compromised and the soil and water become a suspension where the grains are floating around in the water. The ground loses a lot of its ability to support weight, and takes on a consistency somewhat like wet concrete. If you step on it, you’ll start to sink, though not necessarily to your doom.

Despite its frequency in fiction, complete submersion and death in quicksand doesn’t happen in real life. Objects sink only to the level at which their weight is equal to the weight of the displaced sand/water mix, and then the object floats due to its buoyancy. The average person is only going to sink to his or her waist, elbows or armpits, depending on what they’re wearing and carrying. People who die in quicksand don’t die because they sank all the way in, but because they weren’t able to get out quickly enough and were exposed to the elements — low temperatures, incoming tide, etc.

Because quicksand needs underground water to form, riverbanks, beaches, sand washes, alluvial fans, swamps, marshes, and areas with natural springs are the most common spots to find it. It can, and does, develop almost everywhere in the U.S., but the hotspots are the marshes and coasts of the Southeast, and the canyons of Utah, Arizona, and New Mexico.

I'm Stuck in Quicksand Right Now. How Do I Escape?

It’s less difficult to get out than you might think. First, don’t struggle. Remember, you won’t sink all the way in, just to your hips or so if you’re not carrying a pack or wearing heavy gear. Flailing, however, makes you sink deeper by making the quicksand more fluid.

Now, to pull yourself out, start by leaning backwards. Yes, you’re putting more of your upper body in the sand, but it will spread your weight out a little more and improve your buoyancy. You’re basically going to backstroke yourself out from here. Kick your legs slowly to loosen the sand around them and then try to gently bring them up towards the surface. Once your legs and midsection are at or on the surface, gently and slowly paddle with your arms with short strokes along the surface of the quicksand - don’t submerge your hands or arms all the way and get them stuck.

Once you’ve paddled to the edge of more solid ground, pull yourself out. Depending on what type of soil the quicksand is made of and what type of shoes you’ve got on, you might have a hard time pulling your feet completely free because of the quicksand’s suctioning effects. Try and grab a stick and pry your shoes off, but don’t squirm too much or stick your hands in to pull them off.

Quicksand’s Evil Twin

There’s another type of quicksand that’s a little bit scarier than the regular stuff and can cause a person to sink completely — and very quickly. Fortunately, no one has ever confirmed a natural occurrence of it. It’s called dry quicksand and scientists only know it from conditions they created in the lab. Dry quicksand forms when grains of sand form a very loose structure that can barely hold its own weight, let alone yours. In the lab, it’s made by blowing air through the sand, but could be caused naturally by the gradual buildup of sand blown around in the air. Hypothetically, desert winds could create a patch of dry quicksand on the down-wind side of a dune.

While scientists haven’t confirmed dry quicksand in the wild, they don’t discount the possibility that it’s out there. It was a concern during the planning of the Apollo moon missions, and astronomers were worried that the battering of the moon by asteroids and meteorites might have ground some of its surface to a deep, loose layer of debris, soil and dust that would swallow the lunar module whole. To support the craft in the event of these conditions, NASA added large plates to the ends of its legs to help distribute weight.

We'll be answering 20 big questions like this one today. We'll plan more days like this, so if you have something you're dying to know, leave us a comment or tweet @mental_floss with the hashtag #bigquestions.

Cameron Spencer, Getty Images
Big Questions
How Do Aerial Skiers Perfect Their Jumps?
Cameron Spencer, Getty Images
Cameron Spencer, Getty Images

If you've ever watched an aerial skier in action, you know that some of the maneuvers these athletes pull off are downright jaw-dropping—and you've probably seen more than a few of these skiers land on their rear ends at some point. The jumps are incredible, but they're also so technical that one seemingly insignificant motion can drop a skier on his or her tail.

Given that the skiers can fly up to 60 feet in the air and come down on a 37-degree grade, it seems like just going out and trying a new trick would be a good way to break your neck. That's why you'll need one unexpected piece of equipment if you want to start training for aerials: a towel.

Instead of perfecting their flips and twists over the snow, aerial skiers try out their new maneuvers on ramps that launch them over huge swimming pools. The U.S. national team has facilities in Park City, Utah and Lake Placid, New York that include specially designed pools to help competitors perfect their next big moves. The pools have highly aerated patches of bubbles in their centers that decrease the surface tension to make the water a bit softer for the skiers' landings.

If you're an aspiring aerial skier, expect to get fairly wet. New skiers have to make a minimum of 200 successful jumps into water before they even get their first crack at the snow, and these jumps have to get a thumbs up from coaches in order for the skier to move on.

This sort of meticulous preparation doesn't end once you hit the big-time, either. American Ashley Caldwell, one of the most decorated athletes in the sport, is competing in her third Olympics in Pyeongchang, but failed to advance past the qualifiers on February 15, as she wasn't able to land either one of the two triple-flipping jumps she attempted. Still, it's this very sort of risk-taking that has brought her to the top of her game, and caused friction with more than one of her past coaches.

"Why win with less when you can win with more?" Caldwell said of her competition mentality. “I don’t want to go out there and show the world my easiest trick. I want to show the world my best trick, me putting everything on the line to be the best.”

You can check out some of Team USA's moves in the video below:

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Big Questions
Is There Really Such Thing As 'Muscle Memory'?

Is there really such a thing as 'muscle memory'? For example, in the sense of your fingers remembering where the keys of the keyboard are?

C Stuart Hardwick:

Yes and no. There is no literal memory in the muscles, but the thing people call “muscle memory” exists, though the name is a misnomer.

A better name might be “subconscious memory,” as the information is stored in the brain, but is most readily accessible—or only accessible—by non-conscious means.

What “non-conscious” refers to here is the brain’s enormous capacity to train up what might almost be called “subroutines,” that exist outside our conscious experience. I like the term for this that at least one researcher in the field uses: “zombie agency.”

Zombie agents are non-conscious, or sub-conscious (in the literal, not the Freudian sense) that can do essentially everything you can do except make value judgments. So, for example, you don’t consciously know how to control your muscles in order to walk —in all likelihood, you wouldn’t know where to begin—but your zombie agents do, and they’ll take you wherever you want to go, dodging curbs and puppies, and “waking you” when appropriate to decide which babies to stop and kiss.

Zombie agents can be rather startling things. When you suddenly become aware that you’ve driven halfway across town in the direction of the office instead of going to the shoe store Saturday morning, you have zombie agents to thank. You “wake” as if from slumber, and with the frightening realization that you’ve been flying down the highway at prodigious speed while your mind was on other things. You feel as if you’ve been asleep, and in a way you have—but a very funny kind of sleep in which it is only the uppermost layer of abstract reason that is disassociated from the rest of conscious experience. Your zombie agents have been driving to work, responding to traffic, adjusting the radio, noting the check engine light, all the things you think of as “you, driving the car,” except the big one: deciding where to go. That part was on automatic pilot (which is another good way to think of this).

This is at the advanced end of the spectrum. Typing your friend’s phone number using “muscle memory” is at the other, but it’s the same phenomenon.

We didn’t evolve to remember phone numbers, so we aren’t very good at it. In fact, we are so bad at it, we invent all sorts of mnemonic devices (memory aids) to help us [in] relating numbers to words or spacial memory, either of which are closer to the hunting and gathering we are evolved for. The illusion of “muscle memory” arises because we are supremely well adapted to manual manipulation and tool-making. We don’t need to invent a memory aid to help us remember what we do with our hands, we only have to practice.

So the conscious mind says “dial Tabby’s number,” and our fingers—or more correctly, the zombie agent which learned that task—do it. Similarly, after sufficient training, we can do the same thing with tasks like “play a major fifth,” "drive to work,” or “pull an Airbus A380 up for a go-around.”

It feels like muscle memory because the conscious mind—the part you experience as being you—is acting like a coach driver, steering the efforts of a team of zombie agents, all harnesses to collective action. But it isn’t muscle memory, it's just memory—though it may be stored (or at least some of it) in the deeper, motor cortex parts of the brain.

This post originally appeared on Quora. Click here to view.


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