Why Your Christmas Lights Always Get Tangled, According to Science

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iStock

A Christmas tree isn't a Christmas tree without those pretty colored lights, right? OK, no problem. You stored them in a box marked "Xmas lights" 11 months ago. You know where the box is. Now you just have to open the box, grab the lights, and—

That's where it gets tricky. Unless you're very lucky, or extremely well organized, the lights are likely all tangled up; soon you're down on your hands and knees, struggling to untangle a spaghetti-like jumble. (And it's not just you: A couple of years ago, the British grocery chain Tesco hired temporary "Christmas light untanglers" for the holiday season.) But why are Christmas lights so prone to tangling in the first place—and can anything be done about it?

IT'S KNOT AN EASY PROBLEM TO SOLVE

There are really two separate problems, explains Colin Adams, a mathematician at Williams College in Williamstown, Massachusetts and the author of The Knot Book, an introduction to the mathematical theory of knots. First, the cord on which the lights are attached is prone to tangling—just as headphone and earbud cords are (or, in the past, telephone handset cords).

Several years ago, physicists Dorian Raymer and Douglas Smith, then at the University of California, San Diego, did a study to see just how easily cords can get tangled. They put bits of string of various lengths in a cube-shaped box, and then mechanically rotated the box so that the strings tumbled around, like socks in a dryer, repeating the experiment more than 3400 times. The first knots appeared within seconds. More than 120 different types of knots spontaneously formed during the experiment. They also found—perhaps not surprisingly—that the longer the string, the more likely it was to become knotted (few knots formed in strings shorter than 18 inches, they noted). As the length of the string increased, the probability of a knot forming approached 100 percent.

The material that the string (or cord) is made of is important too; a more flexible cord is more likely to tangle than a less flexible one. And while the length of the cord matters, so does its diameter: In general, long cords get tangled more easily than short ones, but a cord with a large diameter will be less flexible, which reduces the risk of knotting. In other words, it's the ratio of length to diameter that really matters. That's why a garden hose can get tangled—it's relatively stiff, but it's also very long compared to its diameter.

But that's not the end of the story. If a cord has a metal wire inside it—as traditional Christmas lights do—then it can acquire a sort of "natural curvature," Jay Miller, a senior research scientist at the Connecticut-based United Technologies Research Center, tells Mental Floss. That means that a wire that's been wrapped around a cylindrical spool, for example, will tend to retain that shape.

"Christmas lights are typically spooled for shipping or packing, which bends metal wire past its 'plastic limit,' giving it natural curvature approximately the size of the spool it was wound around," Miller says. Christmas lights can be even harder to straighten than other wound materials because they often contain a pair of intertwined wires, giving them an intrinsic twist.

And then there's the additional problem of the lights. "Christmas lights are doubly difficult, once things get tangled, because there are all of these little projections—the lights—sticking out of them," Adams tells Mental Floss. "The lights get in the way of each other, and it makes it very difficult to pull one strand through another. That means once you're tangled, it's much harder to disentangle."

IS THERE ANY HOPE FOR A TANGLE-FREE CHRISTMAS?

What, then, can be done? One option would be for manufacturers to make the cord out of a stiff yet elastic material—something that would more readily "bounce back" from the curvature that was imparted to it while in storage. A nickel-titanium alloy known as Nitinol might be a candidate, says Miller—but it's too expensive to be a practical choice. And anyway, the choice of material probably makes little difference as long as the lights still protrude from the cord. Perhaps the biggest breakthrough in recent years has been the proliferation of LED "rope lights" that don't employ traditional bulbs at all; rather, they use LEDs embedded within the rope-like cord itself. Of course, these can still get tangled up in the manner of a garden hose, but without those pesky protrusions, they're easier to untangle.

A simpler solution, says Adams, is to coil the lights very carefully when putting them away, ideally using something like twist-ties to keep them in place. (Martha Stewart has proposed something similar, using sheets of cardboard instead of twist-ties.)

Meanwhile, the mathematicians have some advice if you find yourself confronted with a hopelessly tangled, jumbled cord: Find one of the "free" ends, and work from there.

"Eventually," Adams assures us, "you will succeed."

9 Facial Reconstructions of Famous Historical Figures

A facial reconstruction of King Richard III unveiled by the Richard III Society in 2013
A facial reconstruction of King Richard III unveiled by the Richard III Society in 2013
Dan Kitwood/Getty Images

Why look at a painting of a historical figure when you can come face to face with one? Forensic facial reconstruction using scans of skeletal remains allows researchers to create 3D models of the face through a combination of science, history, and artistic interpretation. The results may be somewhat subjective, but they’re fascinating anyway. Here are nine facial reconstructions of famous people.

1. Richard III

In 2012, King Richard III’s skeleton was found below a parking lot in Leicester, England, where in 1485 he was hurriedly buried after dying in battle. A reconstruction (above) shows a young man, only 32 years old, with a gentle, approachable face. It’s a far cry from the child-murdering villain portrayed by Shakespeare and other writers. One thing they said does seem accurate, however: The skeleton had a curved spine from scoliosis, suggesting that Richard’s humpback may have been real.

2. Bach

J.S. Bach’s bust has sat on innumerable pianos for centuries, but he only posed for one portrait in his lifetime. So this reconstruction of his face—which was taken from a bronze cast of his skull—offers an interesting glimpse into the man beneath the 18th century wig. You get the same thick neck, underbite, and stern brow you see in the painting, but the reconstruction’s friendly, confused stare lacks the soul of the real man … and his music, for that matter.

3. Shakespeare

Apparently, no one knows anything about Shakespeare for sure—his hair color, his sexual orientation, how he spelled his name, whether he liked his wife, etc. Some people aren’t even sure whether he wrote his plays or not. So this rendering, taken from a death mask found in Germany, is bound to be controversial. But if it is Shakespeare, it’s pretty intriguing. It shows a man who suffered from cancer and had a sad, soulful face.

4. Dante

Maybe it’s because The Divine Comedy dealt with the ugliness of sin that Dante Alighieri is usually depicted as unattractive, with a pointy chin, buggy eyes, and enormous hooked nose. But a reconstruction done from measurements of the skull taken in 1921—the only time the remains have been out of the crypt—reveals a much more attractive Dante. The face has a rounder chin, pleasant eyes, and smaller nose than previously thought. It’s a face with character.

5. King Henri IV

The mummified head of France’s King Henri IV was lost after the French Revolution until a few years ago, when it showed up in a tax collector’s attic. In his day, Henri was beloved by everyone except the Catholic fundamentalists who murdered him in 1610. The hard-living king looks a bit old for his 56 years, but there’s a twinkle in his eyes. What the model cannot show, however, was how much the king stank—apparently he smelled of ”garlic, feet and armpits.”

6. Cleopatra’s Sister

Cleopatra hated her half-sister Arsinoe IV so much she had her dragged out of the temple of Artemis and murdered. In 2013, researchers said they had discovered what may be Arisone’s body, based on the shape of the tomb, carbon dating, and other factors. The resulting facial reconstruction shows a petite teenager of European and African blood. And yeah, maybe this is closer to what Arsinoe would look like if she were trapped in The Sims, but since Cleopatra’s remains are long gone, this may be the closest we get to knowing what she looked like.

7. King Tut

King Tutankhamun, whose famous sarcophagus has traveled far more than the “boy king” did in his 19-year lifetime, had buckteeth, a receding chin, and a slim nose, according to 3D renderings of his mummy. His weird skull shape is just within range of normal and was probably genetic—his father, Akhenaten, had a similarly shaped head. Tut’s body also had a broken leg, indicating he may have died from falling off a horse or chariot.

8. Copernicus

Nicolaus Copernicus, who challenged the belief that the sun revolved around the earth, died in 1543 at age 70. When his body was found in 2006 in a Polish church and confirmed by matching DNA to strands of his hair left in a book, the Polish police used their forensic laboratory to make this portrait. They made sure to include Copernicus’s broken nose and the scar above his left eye. Who knew that the Father of Astronomy looked so much like the actor James Cromwell?

9. Santa Claus

The remains of St. Nicholas, i.e. Santa Claus, have been in a church in Bari, Italy, since they were stolen from Turkey in 1087. This reproduction, taken from measurements of his skull, reveal that St. Nicholas had a small body—he was only 5’6”—and a huge, masculine head, with a square jaw and strong muscles in the neck. He also had a broken nose, like someone had beaten him up. This is consistent with accounts of St. Nicholas from the time: It turns out that Santa Claus had quite a temper.

A version of this list was first published in 2013.

Bombshell, Victoria’s Secret’s Bestselling Fragrance, Also Happens to Repel Mosquitoes

Dids, Pexels
Dids, Pexels

People love Bombshell, the best-selling fragrance at Victoria’s Secret, for its summery blend of fruity and floral notes. Not everyone is a huge fan, though: As Quartz reports, the perfume is surprisingly good at warding off mosquitoes. In fact, it’s almost as effective as DEET insect repellent, according to the results of a 2014 experiment by researchers at New Mexico State University.

Researchers took 10 products that are commercially available and tested their ability to repel two different species of mosquitoes: the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus), both of which are known to transmit diseases like dengue fever, chikungunya, and yellow fever. In doing so, volunteers subjected their own flesh to the test by placing their hands on either side of a Y-shaped tube containing the blood-sucking critters. One hand was covered in a synthetic rubber glove, while the other hand was sprayed with one of the products but otherwise left bare. Researchers recorded which tunnel the mosquitoes flew to, and how long they avoided the other end.

Three of the products contained DEET, while four products didn’t. In addition, there were two fragrances (including Bombshell) and one vitamin B1 skin patch. The DEET products were the most effective, but Bombshell proved to be nearly as good, keeping mosquitoes at bay for roughly two hours.

“There was some previous literature that said fruity, floral scents attracted mosquitoes, and to not wear those,” Stacy Rodriquez, one of the study’s authors, said in a statement. “It was interesting to see that the mosquitoes weren’t actually attracted to the person that was wearing the Victoria’s Secret perfume—they were repelled by it.”

This isn’t the first time a perfume has had an unintended effect on the natural world. It turns out that tigers are obsessed with Calvin Klein’s Obsession for Men cologne, partly because it contains a synthetic version of civetone, a pheromone that's secreted by glands located near a civet’s anus. This substance was once used to create musky fragrances, but nowadays the scent is mostly reproduced in a lab. Still, the fake stuff must be pretty convincing, because big cats go crazy when they catch a whiff of it.

[h/t Quartz]

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