Have you ever wondered how the human hand can split a block of wood or concrete without damaging itself? Physicists Michael Feld, Ronald McNair, and Stephen Wilk, also wondered about the same thing. But they were not just physicists; they were also karate enthusiasts. Feld was a brown belt, while McNair was a fifth-degree black belt. In 1979, the trio published a paper about this curiosity, and the answer that they found was, well, found in physics.

As it turns out, there’s no trick—the perfect karate strike is nothing more than a precise application of Newton’s laws.

Feld, McNair, and Wilk placed wood and concrete in a hydraulic press to determine the amount of stress (force) needed to crack the underside of the objects. A wood plank can bend by about one centimeter before it breaks, which requires a force of 500 newtons. Concrete blocks only need to be deflected one millimeter before breaking, but since the material is less bendable than wood, that displacement requires 2,500 to 3,000 newtons. And because some energy is lost upon collision, the fist needs to exert even more force than that in order to actually break the blocks.

Thankfully, the human hand is capable of generating a very high degree of force in a very short period of time. The impact from a typical strike lasts only about five milliseconds. Through a combination of theory and experiment, the team discovered that within this brief flash of time, “the hand of the karateka, or practitioner of karate, can…exert a force of more than 3,000 newtons, a wallop of 675 pounds.” The team’s model indicates that the hand must reach a speed of 6.1 meters per second to break wood and 10.6 meters per second to break concrete. “Such speeds agree with our observation that beginners can break wood but not concrete,” they write. “A hand velocity of 6.1 meters per second is within range of the beginner, but a velocity of 10.6 meters per second calls for training and practice.”

Good to know!

(Image Credit: Pixabay)

Well, I didn't expect this to actually exist, but here we are. Would you buy a scent bottle of your favorite anime girl’s feet? I …honestly wouldn’t, but hey, if there’s a line dedicated to anime girl feet scents, then there must be people out there who would buy them, right? If you’re curious as to what the hell these scents are, watch sydsnap and Shibuya Kaho as they try 50+ of these ‘special scents.’

Have you wondered why flamingos frequently stand on one leg? According to zoologist  Dr Paul Rose, flamingos are more stable on one leg than they are on two. How is that possible? Apparently, the ligaments and tendons in a flamingo’s legs can be locked in position, and that reduces any muscular effort to stay in one place. Standing on one leg is basically an energy-saving activity for these winged creatures:  

“If you’re a flamingo, you’re going to want to sleep on one leg as you can activate this locking mechanism and just stay there. Sleeping on two legs would mean constantly maintaining your balance.”

Interestingly, they aren’t the only animals to engage in this behaviour. Ducks, geese, swans and flamingos are birds of a feather, using similar locking mechanisms in their legs to stay perfectly balanced.

“So many birds stand on one leg. It just so happens that because flamingos have such long legs, we see it more,” says Rose.

“Yet we can even see this behaviour in humans to some extent if they’re in a queue: people will rest more weight on one leg than the other.”

Image via Science Focus

Computer-generated images and videos are getting harder to detect, to the point that we can’t tell whether these deepfakes are fake at all! While there isn’t a trick we can use to easily discern if these resources are fake or not, a new AI tool was able to spot the difference between real images and deepfakes. The AI looks at the light reflected in the eyes, as the Next Web details: 

The system was created by computer scientists from the University at Buffalo. In tests on portrait-style photos, the tool was 94% effective at detecting Deepfake images.

The system exposes the fakes by analyzing the corneas, which have a mirror-like surface that generates reflective patterns when illuminated by light.

In a photo of a real face taken by a camera, the reflection on the two eyes will be similar because they’re seeing the same thing. But Deepfake images synthesized by GANs typically fail to accurately capture this resemblance.

Instead, they often exhibit inconsistencies, such as different geometric shapes or mismatched locations of the reflections.

The AI system searches for these discrepancies by mapping out a face and analyzing the light reflected in each eyeball.

It generates a score that serves as a similarity metric. The smaller the score, the more likely the face is a Deepfake.

Image via the Next Web 

A yellowed painting of the Last Supper was hiding in plain sight, so to speak, as it hung unnoticed on a church wall in Ledbury. England. The 12- by- 5-foot canvas came close to being discarded, but was saved and analyzed by experts. According to experts, the artwork was actually created in Titian’s workshop, as the Smithsonian details: 

Staff at the St. Michael and All Angels Church initially asked art historian and conservator Ronald Moore to restore a 19th-century copy of Leonardo da Vinci’s Last Supper. But when Moore approached the painting, which hangs above the church’s altar, he found himself drawn to the less prominently displayed canvas.

“I could see it was a bit special, but I didn’t know how special,” the scholar tells the Telegraph. “It’s about ten feet off the ground, so you can’t see it unless you stand on a ladder.”

After studying the work for some 11,000 hours, writes Lianne Kolirin for CNN, Moore and researcher Patricia Kenny found a number of telling clues, including Titian’s signature, a virtuosic underdrawing of the artist himself and a 1775 letter penned by collector John Skippe that references his purchase of a Titian painting. One of Skippe’s descendants donated the Last Supper scene to the Ledbury church in 1909.

“It’s so big and nobody’s taken any notice of it for 110 years,” Moore says to the Telegraph. “Anything coming from Titian’s workshop is very important indeed.”

Image via the Smithsonian 

What was the story behind the well-known (and well-used) Bluetooth logo? At first glance, it just seems like a fancy or creative way to use ‘B’ as a logo. However, the story behind Bluetooth's name and logo is actually interesting! The name ‘bluetooth’ belongs to a Viking-era king with a bad tooth, and the logo the engineers that developed Bluetooth used is hiding a secret message: 

Engineers Sven Mattisson Jim Kardach were working on the technology in the late 1990s when they realised it needed a catchy name to make it stand out from the confusing plethora of wireless tech being developed at the time. And the concept of 'Bluetooth' was, like all the best ideas, devised over a beer.

According to France24, the two men began discussing history while drowning their sorrows after a disappointing pitch. They "talked at length" about Vikings, including the king of Denmark, Harald "Bluetooth" Gormsson – a name said to refer to his dead tooth. 

The king is most famous for uniting Norway and Denmark, a parallel which delighted Mattisson and Kardach who were "seeking to unite the PC and cellular industries with a short-range wireless link" (which is, of course, exactly the same as bringing warring nations together).

But it isn't just the name that has a surprising history – the Bluetooth logo is also hiding a secret. It turns out the design actually contains two letters, rather than just a slightly insect-like B. What you're actually looking at is a superimposition of the Nordic runes for the letters H and B (below), for 'Harald Bluetooth'.

Image via CreativeBloq

A long, soaking bath is nice, but it often seems not worth the trouble, since you can't immerse your whole body in that short tub. (The other reason is the prospect of having to clean it, but that's another subject.) Why are our bathtubs too small?

In order to fully understand the reason why bathtubs aren't comfortably human-sized, it's important to consider how the world was different when plumbing first made its way into our homes. "Indoor plumbing came into the United States in the late 1880s," Jeremy Cressman, a veteran of the residential and commercial bath industry who currently serves as the vice president of sales and marketing at BLANCO America, tells Mental Floss. In the late 19th century it was difficult to make large bathtubs because of the expense involved—though cost wasn't the only thing governing typical tub size. People were a little smaller, too. And baths tended to be made with cast iron, so they were heavy and difficult to move. (Contemporary bathtubs are often made from fiber-reinforced plastic.)

Ahem, although indoor plumbing "came into the United States in the late 1880s," it took at least a century to become almost universal. It's much harder to run water lines than it is to string wire along poles. But to answer the question of why your tub is so short, you have to run through the history of American bathtubs, which you can read at Mental Floss.

(Image credit: Doug Coldwell)

In the early part of the 20th century, soda fountains were all the rage. In addition to a place to get tasty refreshments while shopping, a store's soda fountain was a novelty and a meeting place. Carbonated drinks were mixed up fresh behind the counter, and all kinds of innovative recipes were promoted. But soda pop and ice cream floats weren't as popular in cold weather, so soda fountains came up with creative hot drinks. Oh sure, there was coffee, tea, and hot cocoa, but also soup and proprietary recipes with ingredients like eggs and clam juice.   

The popularity of hot drinks didn’t happen on its own. Trade magazines and books not only published recipes, which they often called formulas, for everything from hot pineapple juice to hot malted orange, but they also offered promotional ideas and sales tips. An issue of The Soda Fountain, for example, suggested staging a “Hot Soda Pageant This Winter.” The editors proposed selecting different drinks each month and promoting them with window displays. One month would promote hot milk and egg drinks; another bouillons, broths, and soups; another coffee, tea, and chocolate drinks; another hot fruit drinks. During malted-milk-drinks months, they recommended a “peaceful scene with cows grazing, milkmaids, great pails of foaming milk and happy, healthy youngsters in the foreground.”

Read about the era of "hot sodas," and find recipes for Hot Cherry Egg Bounce, Hot Egg Lime Juice Fizz, and Reeking Smatch at Atlas Obscura.

Once upon a time, we often heard the slogan "M&Ms melt in your mouth; not in your hand!" But we all knew from experience that if you held them in your hand too long, the candy coating would shed color all over your skin, especially on a hot day. The YouTube channel Another Perspective used water to dissolve the candy coating just to see what it would look like. They used different angles and different  rates and directions of water flow to create these effects, which look pretty neat. I'm just glad I don't have to clean up after this. -via Geeks Are Sexy

The idea is that humanity needs an emergency repository of reproductive materials in the event that it becomes extinct on Earth. A facility beneath of the surface of the moon could provide a safe shelter for a restart of the human race, as well as other preserved species from Earth. The New York Post reports on the project proposed by Jekan Thanga and his colleagues:

The so-called “ark,” according to Thanga’s presentation, would then cryogenically preserve various species in the event of global disaster. “We can still save them until the tech advances to then reintroduce these species — in other words, save them for another day,” he said. [...]

The pits also are the perfect size for cell storage, according to Thanga. They go down 80 to 100 meters underground and “provide readymade shelter from the surface of the moon,” which endures “major temperature swings,” as well as threats from meteorites and radiation.

-via Dave Barry | Photo: Jekan Thanga et al.

I feel like I'm suffocating by just watching this video.

This particular deathtrap is located in the Devil's Sinkhole State Natural Area in western Texas. Can the explorers squeeze through the entrance and, more importantly, back out again? Let's find out. What's the worst that could happen?

The best part of this video is the dialog, as the joking cavers give their stuck friends helpful and unhelpful hints. It gets especially good when one caver decides to go in headfirst.

-via Born in Space

O no. Netflix doing the purge?!? pic.twitter.com/XXlHtfgfsy

— chante most (@DOP3Sweet) March 9, 2021

Netflix is testing ways to keep people from using other people's accounts. They are being somewhat soft about it as you can see from the screenshot above. This verification screen comes up randomly for an "unspecified number of users."

"This test is designed to help ensure that people using Netflix accounts are authorized to do so," a Netflix spokesperson told the Hollywood Reporter.

As the photo demonstrates, users are also being given the option to "verify later." At present, according to Netflix, the number of times a user is able to click "Verify Later" before being forced to verify is not set in stone.

While this new verification effort may boot unwanted piggybackers, as presented it fails to stop one key demographic: people intentionally sharing their passwords with friends and family. After all, if you gave your Netflix password to someone, why wouldn't you also share a Netflix verification code?

So far, this is just a test. They may well come up with something more draconian in the future. This test may signal a shift away from the company's previous tendency to encourage password sharing, which it has done to entice new customers. Read more at Gammawire.

Kung Fu Panda hit theaters in 2008, and it may have been the last animated movie I saw in a theater. It was full of overdone tropes and fat jokes, but it was darned funny and exquisitely animated. Screen Junkies goes over all that in this Honest Trailer.

We all know about corsets for women, once a part of everyday life for certain social classes, and now representative of the struggle to appear attractive. But they weren't just for women. Men wore them as well in different places at different times; they just tried to keep their corset use discreet. It wouldn't do to admit that their exceptional bodies needed help to look that way!

The corset has endured hundreds of iterations from its induction into fashion by Catherine de Medici in the 1500s up until its usage diminished as a result of rations for the second World War. But men have been involved in corsets since corsets were invented. One of America’s founding fathers, Thomas Paine, was a corset maker by family trade. According to research, “Stays or corsets were used in the army (especially among the cavalry), for hunting, and for strenuous exercise, not unlike a weight lifter’s belt today”. Purser Thomas Chew, a 30-year career Naval officer, who fought in the War of 1812 wore his corset to sea. But as history has shown, sometimes function becomes fashion…

Messy Nessy Chic has a brief history of men's fashions of the 18th and 19th centuries and how a corset could help them achieve the stylish look of their day.

Arrange two watering cans so that they overflow into each other. Fill them both, then add water to one of them. The excess water will flow into the other, then back again.

I'm not a science person, but video seems fishy to me. If real, wouldn't this be a perpetual motion machine?

-via Laughing Squid