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What Exactly is Quicksand?

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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.

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Big Questions
Can You Really Go Blind Staring at a Solar Eclipse?
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A total solar eclipse will cut a path of totality across the United States on August 21, and eclipse mania is gripping the country. Should the wide-eyed and unprotected hazard a peek at this rare phenomenon?

NASA doesn't advise it. The truth is, a quick glance at a solar eclipse won't leave you blind. But you're not doing your peepers any favors. As NASA explains, even when 99 percent of the sun's surface is covered, the 1 percent that sneaks out around the edges is enough to damage the rod and cone cells in your retinas. As this light and radiation flood into the eye, the retina becomes trapped in a sort of solar cooker that scorches its tissue. And because your retinas don't have any pain receptors, your eyes have no way of warning you to stop.

The good news for astronomy enthusiasts is that there are ways to safely view a solar eclipse. A pair of NASA-approved eclipse glasses will block the retina-frying rays, but sunglasses or any other kind of smoked lenses cannot. (The editors at, an eclipse watchers' fan site, put shades in the "eye suicide" category.) NASA also suggests watching the eclipse indirectly through a pinhole projector, or through binoculars or a telescope fitted with special solar filters.

While it's safe to take a quick, unfiltered peek at the sun in the brief totality of a total solar eclipse, doing so during the partial phases—when the Moon is not completely covering the Sun—is much riskier.


NASA's website tackled this question. Their short answer: that could ruin their lives.

"A student who heeds warnings from teachers and other authorities not to view the eclipse because of the danger to vision, and learns later that other students did see it safely, may feel cheated out of the experience. Having now learned that the authority figure was wrong on one occasion, how is this student going to react when other health-related advice about drugs, alcohol, AIDS, or smoking is given[?]"

This story was originally published in 2012.

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Big Questions
If Beer and Bread Use Almost the Exact Same Ingredients, Why Isn't Bread Alcoholic?
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If beer and bread use almost the exact same ingredients (minus hops) why isn't bread alcoholic?

Josh Velson:

All yeast breads contain some amount of alcohol. Have you ever smelled a rising loaf of bread or, better yet, smelled the air underneath dough that has been covered while rising? It smells really boozy. And that sweet smell that fresh-baked bread has under the yeast and nutty Maillard reaction notes? Alcohol.

However, during the baking process, most of the alcohol in the dough evaporates into the atmosphere. This is basically the same thing that happens to much of the water in the dough as well. And it’s long been known that bread contains residual alcohol—up to 1.9 percent of it. In the 1920s, the American Chemical Society even had a set of experimenters report on it.

Anecdotally, I’ve also accidentally made really boozy bread by letting a white bread dough rise for too long. The end result was that not enough of the alcohol boiled off, and the darned thing tasted like alcohol. You can also taste alcohol in the doughy bits of underbaked white bread, which I categorically do not recommend you try making.

Putting on my industrial biochemistry hat here, many [people] claim that alcohol is only the product of a “starvation process” on yeast once they run out of oxygen. That’s wrong.

The most common brewers and bread yeasts, of the Saccharomyces genus (and some of the Brettanomyces genus, also used to produce beer), will produce alcohol in both a beer wort
and in bread dough immediately, regardless of aeration. This is actually a surprising result, as it runs counter to what is most efficient for the cell (and, incidentally, the simplistic version of yeast biology that is often taught to home brewers). The expectation would be that the cell would perform aerobic respiration (full conversion of sugar and oxygen to carbon dioxide and water) until oxygen runs out, and only then revert to alcoholic fermentation, which runs without oxygen but produces less energy.

Instead, if a Saccharomyces yeast finds itself in a high-sugar environment, regardless of the presence of air it will start producing ethanol, shunting sugar into the anaerobic respiration pathway while still running the aerobic process in parallel. This phenomenon is known as the Crabtree effect, and is speculated to be an adaptation to suppress competing organisms
in the high-sugar environment because ethanol has antiseptic properties that yeasts are tolerant to but competitors are not. It’s a quirk of Saccharomyces biology that you basically only learn about if you spent a long time doing way too much yeast cell culture … like me.

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


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