Popular beliefs

Cracking your knuckles has consequences, but not the ones you think

You’ve heard it before: Don’t swim after eating. You’ll lose most of your body heat through your head. Swallow a piece of gum, and it’ll stay in your body for years. Many of these common beliefs that parents or teachers have told you repeatedly over the decades are simply not true. Here are 10 everyday myths that science has set straight, and the real stories behind them.

The myth of carrots providing a better sense of vision in the dark became especially popular during World War II, when the British government promoted this idea to help explain the success of its pilots while keeping its new airborne radar technology a secret. It was just a myth, although there was a scientific explanation to back it up.

Carrots are rich in beta-carotene, which your body converts into vitamin A, an important nutrient for healthy vision. If someone is deficient in vitamin A, eating more of it can improve their eyesight. But for people who already get enough of the vitamin, extra carrots won't suddenly make it easier to see at night.

You hear footsteps in the middle of the night and find a family member quietly wandering through the house while asleep. Your first instinct is to wake them up, but remember you’ve been told it’s dangerous. That’s just a myth, so go ahead and wake them.

The person may be startled, confused, or briefly disoriented, but there’s no evidence that being awakened causes physical injury. The bigger concern is that someone suddenly pulled from sleep may react unpredictably or accidentally lash out because they don’t understand what’s happening. For that reason, sleep specialists usually recommend gently guiding the person back to bed if it’s safe to do so, rather than abruptly shaking them awake, but there’s no intricate danger to waking a sleepwalker.

Almost everyone has heard the sharp popping sound of someone cracking their knuckles, followed by another person saying, "Keep doing that, and you’ll get arthritis."

Researchers have been looking into that claim for decades, and the evidence simply doesn’t support it. The popping sound comes from tiny gas bubbles forming and collapsing inside the fluid that lubricates your joints, not from bones grinding together. Multiple studies comparing habitual knuckle crackers with people who never crack their knuckles have found no higher risk of developing arthritis. Some research has suggested that frequent knuckle cracking may slightly reduce grip strength or cause temporary swelling in a few people, but it has not been shown to damage the joints. So while the sound may bother the people around you, it isn’t likely to lead to arthritis.

Most of us have heard someone say, "Imagine what you could do if you used the other 90 percent of your brain." The truth is that modern brain imaging has shown that virtually every part of the brain has a purpose.

Even when you’re resting, different regions are constantly working together to control movement, memory, breathing, emotions, vision, and countless other functions. While not every area is active at the same moment, there is no large section of the brain sitting permanently unused. Scientists aren’t exactly sure where or how this myth started, but your brain is one of the busiest organs in your body. Even while you’re asleep, it’s hard at work keeping you alive and processing the day’s experiences.

If a child accidentally swallowed a piece of gum, some adult would inevitably claim it would sit in the stomach for the next seven years.

The warning, even if a myth, contains a small grain of truth. The gum base isn’t fully broken down by the digestive system the way other foods are. But that doesn’t mean it stays behind. Instead, it moves through your digestive tract along with everything else you eat and is naturally eliminated within a few days. So while swallowing pieces of gum isn’t something doctors recommend making a habit of, there’s no need to worry if it happens by accident.

After lunch at the lake or a backyard barbecue, the adults would insist everyone, especially the kids, stay out of the water for at least an hour. The idea was that digestion would pull blood away from your arms and legs, causing severe muscle cramps that could make you drown.

Medical research, however, has found no evidence that eating before swimming creates that kind of danger. While vigorous exercise immediately after a very large meal might make some people feel uncomfortable or sluggish, a normal swim after eating is generally considered safe for healthy individuals. The "wait an hour" rule probably prevented plenty of cannonballs during nap time over the years, but it wasn’t based on scientific evidence.

If you ever left the house on a cold winter morning without a hat, chances are someone reminded you to wear one since "most of your body heat escapes through your head." The belief became widespread after military studies conducted in the 1950s observed significant heat loss from uncovered heads. What they didn’t notice was that the subjects were bundled up everywhere else. Naturally, their only exposed body part lost the most heat.

In reality, your head loses heat at about the same rate as any other uncovered area of skin, depending on its size. A warm hat is still a smart idea on a cold day, but only because it covers exposed skin, not because your head has some special ability to leak away most of your body heat.

Many tongue illustrations show the tongue divided into neat sections, with one area for sweet foods, another for salty flavors, and others for sour and bitter. The famous "taste map" came from a misunderstanding of research published in the early 1900s.

While some parts of the tongue may be slightly more sensitive to certain flavors than others, taste buds across nearly the entire tongue can detect sweet, salty, sour, bitter, and umami, the savory taste found in foods like mushrooms, cheese, and broth. The old diagram appeared in textbooks for decades, making it one of the most successful scientific misconceptions ever taught in classrooms. Today, we know the tongue is much more versatile than that simple map suggested.

If you grew up in the age of bulky television sets, you may remember a parent telling you to back away from the screen before you damaged your eyes. That warning became especially common in the 1960s when early television models were found to emit unusually high levels of radiation because of a manufacturing defect. Those sets were quickly recalled, but the myth lingered long after the problem disappeared.

Modern televisions don’t pose that risk. Sitting very close to the screen may leave your eyes feeling tired or dry after a while, but it doesn’t cause permanent damage to your vision. Even if screen time is not recommended for children up until 7 years old, the screen itself isn’t likely to be the cause of poor eyesight.

Everyone learned about the five senses at some point: sight, hearing, smell, taste, and touch. That lesson dates back more than 2,000 years to the ancient Greek philosopher Aristotle.

However, modern science paints a much more intricate picture. In addition to the five traditional senses, your body constantly relies on other senses that work without you even noticing them. These include your sense of balance, your awareness of where your arms and legs are without looking, your ability to feel pain, temperature, and more. Depending on how they’re classified, scientists recognize anywhere between 10 and 20 different senses.

WORDPLAY PARADOX

Double Take: Explore the Two-Faced World of Contronyms

Image: Glen Carrie

The English language is a fascinating tapestry woven with countless quirks and nuances. Among its many delights are contronyms, words that have two contradictory meanings.

These linguistic anomalies add a delightful twist to communication, and they often require context to avoid misunderstandings. Read on as we go through a list of contronyms, explore their duality, and uncover their origins.

Image: Abby Savage

Let’s kick off this list with a word that evokes images of both separation and unity at the same time. On one hand, it can mean to adhere firmly to something, as in "to cleave to tradition."

In the context of adherence, it is all about sticking together like peanut butter and jelly.

But here is the twist, this word can also mean to split apart, as in "to cleave through the dense underwood." A lumberjack wielding an axe is ready to "cleave through a mighty oak."

How did this linguistic paradox come to be? Well, "cleave" originates from two separate Old English words, "cleofian" meaning "to adhere" and "cleofan" meaning "to split." Over time, these two divergent meanings merged into one delightful linguistic enigma.

Image: Tingey Injury Law Firm

Now, here’s a word that will keep you on your toes. Depending on the context, it can either mean to approve or to penalize. How’s that for a linguistic rollercoaster?

Originating from the Latin word "sanction," meaning "law" or "decree," sanction has managed to maintain its dual personality throughout its journey into the English language. When used for approval, "sanction" is like a stamp of authority, giving the green light to proceed. For example, "The committee voted to sanction the new project, signaling their full support."

However, it can morph into its alter ego, meaning punishment or penalty. For example, you might say, "The regulatory body decided to sanction the company for violating environmental regulations."

Image: Duncan Kidd

Prepare to have your cleaning routine turned upside down with the contradictory nature of "dust." This deceptive little word can mean both to remove dust and to sprinkle with fine particles. It’s like a linguistic magic trick, leaving you wondering which way is up.

In the context of cleaning, "dust" means to rid surfaces of pesky particles that accumulate over time. You might say, "I need to dust the shelves before guests arrive for dinner."

But hold on to your feather dusters, because this word can also mean to sprinkle with fine particles and, in that context, you might find yourself saying, "The baker carefully dusted the freshly baked pastries with cocoa powder."

Image: Unsplash+

If you thought bolts were just for locking doors, think again. "Bolt" is another word that defies expectations meaning both to secure tightly and to make a swift gateway. It’s like having a trusty tool and a daring escape plan all rolled into one.

In the context of securing, "bolt" is all about fastening something firmly in place. In this case, an example would be, "Be sure to bolt the gate shut to keep the livestock from wandering off."

But don’t get too comfortable because "bolt" also means to dash away at lightning speed, leaving others in the dust. You might use it in a sentence like, "When the alarm sounded, the thief made a desperate attempt to bolt from the scene."

Image: Unsplash+

In the world of gardening, the word "seed" is a vital component of growth. But did you know it can also mean the opposite? That’s right, "seed" can both mean to sow seeds for planting and to remove seeds from fruits or vegetables. It’s like playing chef and gardener at the same time!

When used in the context of planting, "seed" is all about laying the groundwork for future growth. An example of this meaning could be: "It’s time to seed the garden with tomatoes and cucumbers for a summer full of fresh produce."

At the same time, "seed" can also mean to remove seeds, like when preparing a delicious meal. In a sentence, it could go: "After slicing the peppers, be sure to seed them to reduce the heat."

Image: Unsplash+

When it comes to giving something a makeover, the word "trim" seems straightforward enough. But in the world of contronyms, nothing is as it seems. "Trim" can mean both adding decorative elements and removing excess material. It’s like being both an interior designer and a tailor, all in one fell swoop.

In the context of adding, "trim" means embellishing or decorating something to enhance its appearance. You can "add a lace trim to a dress" or "adorn a tree with colorful trimmings."

On the other hand, "trim" can also mean removing excess material or parts of something to improve efficiency or aesthetics. You can "trim back overgrown bushes," or "trim any excess of fat from the meat."

Image: Diego González

When you think of a screen, you might envision a movie theater or a computer monitor. But did you know that "screen" can also mean both to display and to conceal?

According to the first definition, "screen" is to showcase or present something for everyone to see. For example, "The art gallery screened a documentary highlighting the artist’s creative process."

As for the second definition, "screen" also refers to shielding or hiding from view. In this case, you can use it in a sentence like, "The curtains were drawn to screen the room from the harsh afternoon sun."

Image: Quinten de Graaf

In the world of business, you have probably overlooked a project. But you have probably overlooked a detail that unleashed hell too, isn’t that so? "Overlook" is a fascinating contronym as it can mean both to supervise and to neglect.

In the context of supervising, "overlook" is a synonym for "monitoring", that is, it means to watch something over with care and attention. For example, "As the project manager, it’s my job to overlook the progress of the team."

However, it can also be a synonym for failing to pay attention, quite ironic, isn’t it? In this context, overlooking something might end in unintended consequences, like, "Don’t overlook the details, or you might miss an important opportunity."

Image: Osman Rana

In the natural world, "weather" stands as a true anomaly. It’s a word that plays with our perceptions, veering between resilience and erosion. Like a cliff facing the relentless pounding of waves, "weather" embodies both strength and vulnerability.

When the tempests rage and the skies darken, "weather" becomes a symbol of resilience. In the face of adversity, we say a person or thing can "weather the storm," emerging stronger on the other side.

Yet, there’s another facet to this polysemic word. "Weather" can also mean the slow erosion of time’s touch. In this sense, to "weather" is to bear witness to the ceaseless march of time, where even the mightiest structures yield to its embrace.

Image: David Marcos

In the dance of presence and absence, the word "left" takes center stage, twirling between what remains and what has departed. It’s like having one foot in the past and one foot in the present, never quite sure where you stand.

Amidst the flow of comings and goings, "left" refers to what remains or is still available after others have departed. You might say, "I’ll take the last slice of pizza since no one else is left to claim it."

However, "left" can also mean having departed or gone away, leaving behind an empty space or a sense of loss. You might use it in a sentence like, "She felt a pang of sadness as she realized her friends had all left the party without saying goodbye."