BIG QUESTIONS

How Do 3D Glasses Work?

Stereoscopy—the illusion of depth created by showing a separate image to each eye—is at least as old as photography itself. In the last few years, however, stereoscopic 3D movies have come back in a big way. Theaters show you 3D movies by projecting two i

What Makes Something an Antique?

Every time you watch Antiques Roadshow, you probably wonder: Just how do we know what items are antiques?

Where Did Hard Hats Come From?

Historically, dockworkers covered their hats with tar and let that harden to offer some protection against falling objects. But hard hats as we know them today developed slowly.Wikipedia credits writer Franz Kafka with designing the first industrial hard

Why Do We Say “Pardon My French” When We Curse?

My dad always used to preface the dropping of an F-bomb or a tangent of creative profanity with a request that listeners “pardon his French.”

What's Up With "10-4" And Other Radio Lingo?

Reader and frequent question-asker Nate J. wrote in wondering why we say things like "10-4" and "Roger" on walkie-talkies and other two-way radios.

Why Is the Sound of Nails on a Chalkboard So Unpleasant?

The act of scraping nails down a chalkboard creates a sound so awful that most people have an instantaneous reaction: A shiver runs up the spine, and they slap their hands over their ears. Anything to block out that noise! But why do unpleasant sounds af

What is Rubella?

Rubella Virus. Wikimedia CommonsAlmost everyone is familiar with the measles and mumps, but the 'R' in the MMR vaccine might not ring a bell. Here's the lowdown.Discovery and SymptomsRubella is a disease caused by a virus of the same name. It can be sprea

Why Is Cranberry Juice Good For UTIs?

A mental_floss staffer who shall remain nameless asks, “Why is cranberry juice good for treating UTIs? I will not tell you why this question had been on my mind.”Bacterial infections in the urinary tract and its organs are pretty common, especially in adu

Why Is Abruptly Quitting Something Called "Going Cold Turkey"?

Around this time of year, we’re all loosening our belts and getting ready to gorge ourselves on hot, gravy-laden turkey. So we couldn’t help but wonder about things at the opposite end of the temperature spectrum: the “cold turkey” invoked when people up

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Why Are Blueprints Blue?

Photo Courtesy of the Free Library of PhiladelphiaTechnical drawings of architectural or engineering designs always seem to consist of white images and text on blue paper. Why?

How Do Tongue Twisters Twist The Tongue?

Try and say “she sells sea shells by the sea shore” three times very fast. The first time might go alright, but on the second or third go-round, chances are the words start to degrade as you’re saying them, falling apart in your mouth like a crumbling Jen

Is It True That T. Rex Could Only See Things That Were Moving?

I rewatched Jurassic Park a few weeks ago and, from the story to the special effects, it still holds up. But I’ve been nagged by one thing that’s stuck with me from the first time I saw the movie...

Why Do We Crave Chocolate?

If you’re like most people, you simply can’t pass up the opportunity to partake in a piece of chocolate (or five).

How & Why Do Leaves Change Color?

Despite their astonishing record of losses when dealing with lumberjacks and beavers, trees are pretty tough customers. Their trunks, branches, roots and twigs are all more than capable of enduring a winter's worth of freezing temperatures, snow, sleet an

Why Did the U.S. Abandon the Gold Standard?

Some have called for a return to the gold standard. What does the phrase actually mean, and how would it affect the economy?

Does Eating Celery Really Result in Negative Calories?

Snake oil salesmen all over the web would have you believe that, for a few easy payments, they'll reveal to you a diet focused on “negative calorie” foods.

Was Manhattan Really Bought for $24?

One of the most persistent myths in American history is that European explorers really got one over on the Native Americans by purchasing the entire island of Manhattan—where property has averaged $1000+ per square foot over the last few years—for a measl

Are Carrots Really That Good For Your Eyes?

When I was a kid, my parents often tried to sell me on the idea that carrots were good for my eyes—and if I wanted to avoid vision correction in the future, I would eat them now. But after I was fitted for my first pair of glasses in fourth grade, they dr

Why Do We Have Fingerprints?

Though fingerprints are handy for identifying perps, biologically, scientists still aren't quite sure what our fingerprints are for. But as they test different hypotheses, they're getting closer to the answer—and learning some pretty cool stuff in the pro

Why Are First-Year Students Called Freshmen?

Image credit: Duke.eduThere was a time when almost every university student was a sophomore. Well, a sophister, to be exact, but that’s where the word “sophomore” originated. A sophist was a wise man (derived from the Greek word sophos), so when Henry VI

Why Are Bottles of Champagne Smashed On New Ships?

Before a ship slides from its berth into the water, it must first get hit on—by a bottle of booze, usually champagne. Here’s the lowdown on the history and physics of smashing some bubbly and launching a ship

Why Is it so Hard for Pandas to Get Pregnant?

In the wild, giant panda mating occurs just as nature specials would have you believe. There’s intense competition for each female, and the dominant male will mate with her several times to ensure success. And that strategy works: Wild female pandas gener

Did Blowing into Nintendo Cartridges Really Help?

When I was a kid with a Nintendo Entertainment System (NES), sometimes my games wouldn't load. But I, like all kids, knew the secret: take out the game cartridge, blow on the contacts, and put it back in. And it seemed to work. (When it failed, I'd ju

Naked and Nude: What's the Difference?

Technically speaking, naked implies that a person is unprotected or vulnerable. It also describes something that is unadorned or without embellishment, as in the oft-mentioned naked truth. Nude, on the other hand, means one thing: unclothed.Think of it

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