Why Your Christmas Lights Always Get Tangled, According to Science

iStock
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."

11 Masks That Will Keep You Safe and Stylish

Design Safe/Designer Face Covers/Its All Goods
Design Safe/Designer Face Covers/Its All Goods

Face masks are going to be the norm for the foreseeable future, and with that in mind, designers and manufacturers have answered the call by providing options that are tailored for different lifestyles and fashion tastes. Almost every mask below is on sale, so you can find one that fits your needs without overspending.

1. Multicolor 5-pack of Polyester Face Masks; $22 (56 percent off)

Home Essentials

This set of five polyester masks offers the protection you need in a range of colors, so you can coordinate with whatever outfit you're wearing.

Buy it: The Mental Floss Shop

2. 3D Comfort Masks 5-Pack; $20 (25 percent off)

Brio

The breathable, stretchy fabric in these 3D masks makes them a comfortable option for daily use.

Buy it: The Mental Floss Shop

3. Reusable Face Masks 2-pack; $15 (50 percent off)

Triple Grade

This cotton mask pack is washable and comfortable. Use the two as a matching set with your best friend or significant other, or keep the spare for laundry day.

Buy it: The Mental Floss Shop

4. Active Masks 3-pack; $23 (14 percent off)

RipleyRader

Don’t let masks get in the way of staying active. These double-layer cotton masks are breathable but still protect against those airborne particles.

Buy it: The Mental Floss Shop

5. Washable Protective Cotton Face Masks 2-pack; $13 (35 percent off)

Its All Good

Avoid the accidental nose-out look with this cotton mask that stays snug to your face.

Buy it: The Mental Floss Shop

6. Washable 3D Masks 12-pack; $24 (44 percent off)

Elicto

With this 12-pack of protective masks, you can keep a few back-ups in your car and hand the rest out to friends and family who need them.

Buy it: The Mental Floss Shop

7. Reusable Dust-Proof Mask with 5 Filters; $22 (45 percent off)

Triple Grade

This dust-proof mask can filter out 95 percent of germs and other particles, making it a great option for anyone working around smoke and debris all day, or even if you're just outside mowing the lawn.

Buy it: The Mental Floss Shop

8. Reusable Fun Face Cover / Neck Gaiter (Flamingo); $20

Designer Face Covers

Channel some tropical energy with this flamingo fabric neck gaiter. The style of this covering resembles a bandana, which could save your ears and head from soreness from elastic loops. Other designs include a Bauhaus-inspired mask and this retro look.

Buy it: The Mental Floss Shop

9. Seamless Bandana Mask; $8 (52 percent off)

Eargasm Earplugs

This seamless gaiter-style mask can be worn properly for protection and fashioned up into a headband once you're in the car or a safe space. Plus, having your hair out of your face will help you avoid touching your eyes, nose, and mouth before washing your hands.

Buy it: The Mental Floss Shop

10. Two-Ply "Love" Face Masks 2-Pack; $18 (40 percent off)

Design Safe

These statement masks allow you to have a voice, even if your mouth is covered.

Buy it: The Mental Floss Shop

11. Neoprene/Fleece Neck and Face Mask (Purple); $10 (66 percent off)

Its All Good

This mask will definitely come in handy once winter rolls around. It features a fleece neck, face, and ear covering to keep your mask secure and your face warm.

Buy it: The Mental Floss Shop

Prices subject to change.

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links. If you haven't received your voucher or have a question about your order, contact the Mental Floss shop here.

How Henrietta Lacks Became the Mother of Modern Medicine

A historical marker in Clover, Virginia, honors Henrietta Lacks.
A historical marker in Clover, Virginia, honors Henrietta Lacks.

On February 8, 1951, a surgeon at Johns Hopkins Hospital in Baltimore, Maryland, shaved a piece of cancerous tissue from the cervix of a 30-year-old woman. She had signed an “operation permit,” allowing him to place radium into her cervix to treat her cancer, but nobody had explained their plans to her. And no one foresaw that Henrietta Lacks, a Black woman with a sixth-grade education and five children, would become the mother of modern medicine.

Henrietta was born Loretta Pleasant on August 1, 1920, in Roanoke, Virginia. Somehow, her name became Henrietta. After her mother died in 1924, Henrietta was sent to Clover, Virginia, to live with her grandfather, Tommy Lacks. Her cousin David “Day” Lacks lived in the same house.

Seventeen years later, after having two children together, Henrietta and Day married and then moved close to Baltimore so that Day could work at Bethlehem Steel while Henrietta took care of their growing family. She was big-hearted, fun-loving, and pretty, and though only 5 feet tall, she dressed and walked with a flare.

Immortal Cells

But on January 29, 1951, four months after the birth of her fifth child, Henrietta went to the dreaded hospital. Most Black people living in the Baltimore area did not trust Johns Hopkins. It was segregated, so they were certain they would not receive the same quality of care as white people, and, worse, they would be used for medical experiments. There were rumors that surgeons routinely performed hysterectomies on Black women who came in with any type of abdominal or pelvic pain. Henrietta was not one to complain, but, according to the 2010 book The Immortal Life of Henrietta Lacks by Rebecca Skloot, she could no longer bear the painful “knot on her womb.”

The tissue taken from her cervix 10 days later was given to Dr. George Gey, director of tissue culture research at Hopkins [PDF]. He believed that if he could find a continually dividing line of malignant human cells, all originating from the same sample, he could find the cause of cancer—and its cure. His assistant placed tiny squares of the specimen into test tubes, then labeled each tube with the first two letters of the unwitting donor’s first and last names: HeLa.

Oregon State University via Flickr // CC BY-SA 2.0

Soon, Henrietta’s cells began to divide. And, unlike the other cells they had sampled, they did not die. Gey started giving the immortal cells to colleagues, saying they had come from a woman named Helen Lane.

Within two years, HeLa cells had been put into mass production, commercialized, and distributed worldwide, becoming central to the development of vaccines and many medical advances. By 2017, HeLa cells had been studied in 142 countries and had made possible research that led to two Nobel Prizes, 17,000 patents, and 110,000 scientific papers, thereby establishing Henrietta’s role as the mother of modern medicine.

Henrietta had died on October 4, 1951. No one had told Henrietta, or her husband Day, that the cells still existed. No one had mentioned the myriad hopes and plans for HeLa cells. No one had asked permission to take them or use them.

HeLa Revealed

In 1971, an article in the journal Obstetrics & Gynecology reexamined the origin of the HeLa cells and reported that cervical adenocarcinoma had led to the death of the cell donor, Henrietta Lacks. Her name was now public knowledge.

Two years later, in a casual conversation with a friend, Henrietta’s family learned about the cells. The Lackses were shocked: Henrietta was alive through her cells.

A scanning electron micrograph of just-divided HeLa cellsNational Institutes of Health, Wikimedia Commons // Public Domain

Then, a Rolling Stone article created an uproar in the scientific community by disclosing that the woman behind the cells was Black. Once again, the Lacks family was stunned. The article revealed that significant amounts of money were being made from the cells—while Henrietta's husband and children could not afford decent medical care and while her body lay in an unmarked grave.

More reports were written about Henrietta’s cells. Intimate details from her medical record were exposed in a 1986 book called A Conspiracy of Cells: One Woman’s Immortal Legacy and The Medical Scandal It Caused. Medical professionals came to draw blood from her children. The BBC made a movie, The Way of All Flesh. And, as Skloot reports, a con man claimed he could get money for the family from Johns Hopkins.

Meanwhile, and throughout subsequent decades, the Lacks family's focus has been to try to figure out what it means to them that her cells are alive. They have received none of the billions of dollars the cells have garnered for biomedical companies, cell banks, and researchers. But Henrietta’s family can be heartened that through the Henrietta Lacks Foundation, founded by Skloot in 2009, the mother of modern medicine continues to demonstrate her big-heartedness.

The foundation’s mission is to “provide financial assistance to individuals in need, and their families, who have made important contributions to scientific research without personally benefiting from those contributions, particularly those used in research without their knowledge or consent." Moreover, it gives the countless people who have benefited from their contributions a way to show their appreciation to them. To date, members of the Lacks family and others have received more than 50 monetary grants.