On the Gemini IV mission, NASA sent out Ed White as the first American astronaut to attempt a spacewalk. After thoroughly enjoying his trip outside the capsule, White returned…but the hatch wouldn’t close properly. It was a real chore for the astronauts to wrench the hatch closed. In assessing what happened, NASA engineers wondered: Had the hatch undergone “cold welding?”
As Derek from Veritasium explains in the video below, “In space, if two metals come into contact, they can actually fuse together without the need for heat or melting of either piece.” As he promptly continues, this is not what happened to the hatch on Gemini IV. But it has happened on space missions, and it’s a real problem for metals we send into space.
Watch this video for a detailed explanation of how cold welding works, why it happens less than we might fear, and how it has actually occurred in space.
Sharing trivia with friends has never been easier in our age of social media, but there’s still something charming about sending something through the mail. Amazing Animal Facts—previously a book and now a box of cards—allows you to send info-packed notes to your friends and family. The postcards feature animal-related facts along with illustrations by Sweden-based artist Maja Säfström.
The box set, which includes 50 cards, has five categories to choose from: sea, forest, field, jungle, and sky. Each card is dedicated to a different animal and comes with one to five different facts about the species. (For example, did you know that blue whales have belly buttons?) As a fun twist, all the cards are in black and white, so you can customize and color them to your liking. Once you finish coloring and adding a personal note, you can apply a stamp and pop it in the mail.
In this installment of Ingredients, chemist George Zaidan digs into a key ingredient of many citrus-scented air fresheners: Limonene. In addition to being a killer band name, Limonene is found in citrus peels, and it happens to react with ozone to create formaldehyde.
Before we go nuts on this formaldehyde thing, it’s important to be clear that the amount of formaldehyde is low, and likely not an issue unless you’re going vastly overboard with ozone generators (like some “air cleaners”) and a lot of citrus-scented products. But it’s fascinating to explore how the chemical interplay between two otherwise innocuous consumer products—citrus-scented air fresheners and ozone-producing “air cleaners”—can create a really nasty substance.
For five minutes of useful chemistry advice, tune in:
Oreo cookies are full of mysteries, not the least of which is the design of the wafer itself. But for many of us who’ve sat on either side of a cream-filled Oreo and twisted to see who got more of the delicious insides, another question has prevailed: What strategy, if any, can one apply to the game? We now have an answer, and it only took three Princeton University aerospace engineers to figure it out.
As Gizmodo reports, John Cannarella, Dan Quinn, and Joshua Spechler were graduate students in 2014 when they first started to consider the question surrounding the world’s most famous sandwich cookie. They did a bit of research and, when they found that no one had tackled the question, set to work hunting for an answer.
“It’s interesting from an engineering standpoint since the cookie is similar to many modern composites: a strong brittle layer (the wafer) for strength coupled with a weaker ductile layer (the cream) for toughness,” Cannarella told Quartz. “Shatterproof glass and batteries are other good examples of material systems that are mechanically analogous to Oreos.”
Sure, yeah, OK. But it’s also really important for winning playground face-offs in the ’90s.
To get a better sense of the physics at play, the team analyzed the cookie, putting it through rigorous experiments involving both robotic testers and real-life participants. They went through thousands of Oreos and, in the end, made a discovery that will help you win your cookie war every time: In any given box of Oreos, the cream ends up on the same side for every single cookie.
In other words, if you’re headed into battle, test a cookie from the box ahead of time. If you pull one out, twist it, and the cream is on side closest to the back of the box, that will be true for every cookie, in every row.
While Nabisco isn’t forthcoming about the cookie-making process, Quartz notes that a 2010 episode of How It’s Made has an illuminating look at the process behind Newman-O’s, which in turn helps to shed some light on the manufacturing methodology of Oreos. To assemble the sandwich cookies, a machine applies a dollop of cream onto one cookie and then finishes it with another. The physicists guess that the first wafer probably has a better hold on the cream (though there’s no way to be sure) and that ends up being the victory cookie in the twist game.
And there you have it. Go forth and share a cookie. Oh and we’re not necessarily saying you should employ the test cookie method to win, that would be cheating. We’re just the messengers here.
Scientists found that men wearing white t-shirts with a large black letter “T” printed on the front were 12% more attractive to women. The t-shirt creates the illusion of broadened shoulders and a slim waist, a male body shape women typically find attractive.
As much as 7% of the population has experienced waking from sleep and being totally paralyzed but aware as mind and body become out of sync in REM cycles.
As a recurring feature, our team combs the Web and shares some amazing Amazon deals we’ve turned up. Here’s what caught our eye today, October 29.
Mental Floss has affiliate relationships with certain retailers, including Amazon, and may receive a small percentage of any sale. But we only get commission on items you buy and don’t return, so we’re only happy if you’re happy. Good luck deal hunting!
When most people talk about international borders, they’re being somewhat metaphorical. Rare is the person who’s actually traveled the full border between two countries and has a real idea of how they are separated by geography and political history. You may have crossed through one border checkpoint, but you may not have climbed the middle-of-nowhere mountain that forms the border a few hundred miles away.
In light of the political discussion around border walls, The Intercept and Field of Vision created a timelapse of some 200,000 images showing each of the 1954 miles of the U.S.-Mexico border, stretching from the Pacific Ocean to the Gulf of Mexico. All the images were downloaded from Google Maps according to the geographic coordinates of the international boundary line. Some of the images show urban stretches, with only roads and fences to separate one city from the other across the border; other parts are simply a stretch of flat desert; and still other parts of the border contain very real geographical obstacles like mountains and rivers.
“The southern border is a space that has been almost entirely reduced to metaphor. It is not even a geography. Part of my intention with this film is to insist on that geography,” writes data artist Josh Begley on The Intercept. He wrote the code that downloaded and stitched together all 200,000 images. “By focusing on the physical landscape, I hope viewers might gain a sense of the enormity of it all, and perhaps imagine what it would mean to be a political subject of that terrain.”
The whole thing is almost seven minutes long and pretty dizzying, both in the metaphorical and physiological sense. You can watch it here.
In 1965, Compax Corporation’s ad agency hired Jim Henson’s company to make three TV ads. Compax sold a line of pre-shrunk cotton fabric called Pak-Nit RX, designed to resist shrinking in clothes dryers and stretching outside of them.
Henson and his partner Jerry Juhl ginned up three ads, including the tale of “Shrinkel and Stretchel” (loosely based on Hansel and Gretel). In the spot, the young duo encounter a witch (Taminella Grinderfall, voiced by Juhl), who puts them in an oven. Due to their aforementioned heat-resistance, they’re unscathed. This attempted murder leads to an extended discussion of the positive properties of the brand.
So gather around, kids, and watch the eerie tale of two shrinkage-resistant Muppets!
The world’s first horror movie doesn’t seem particularly scary these days, but in 1896, Le Manoir du Diable (released in the U.S. as The Haunted Castle) had the most cutting-edge special effects of its day. Made by famed French filmmaker Georges Méliès, whose films include the influential A Trip to the Moon, the short revolves around a bat that turns into the demon Mephistopheles.
The soundtrack sounds like a weird little lullaby, somewhat taking away from the horror of it all—it actually makes pretty good work music, if I’m being honest. But there are some fun 19th century special effects, some of the first ever to appear on film. People appear and disappear in clouds of smoke, and bats suddenly take human forms! On the less frightening side, there are quite a few men in funny hats, and the demon pokes people in the butt—which is what really makes the film come together. (After all, nothing says “Happy Halloween!” like a pitchfork to the rear end.)
