17 Simple Things That Scientists Can’t Explain

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With the unprecedented scientific advancements of today that have explained many complex mysteries, one might expect even the simplest questions to have clear scientific answers. Yet, these 17 ordinary things that scientists don’t actually understand highlight the irony.


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Why we itch feels like it should be straightforward, but it’s anything but. From the itch triggered by a fly landing on your skin to the one from a mosquito’s bite, the reasons behind that annoying sensation and the compulsion to scratch are complex and not fully understood. 

Is it a defense mechanism, an evolutionary thing, or something else entirely? Scientists are still scratching their heads over this one.


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Why do we laugh? It’s a universal human experience, yet science is still trying to figure out the exact reason behind our chuckles and guffaws. Theories range from laughter being a way to bond socially, helping our ancestors survive as a group, to the idea that humor arises from the unexpected flip between what we expect and reality. 

So, next time you find yourself laughing at a joke, remember, you’re part of a big, unsolved mystery that’s been tickling scientists’ brains for ages.



Why do we need to sleep? It’s something we all do, but the reason behind it is still a bit of a head-scratcher for scientists. While sleeping makes us vulnerable (not ideal in the wild), not getting enough of it is even worse for our health. 

The brain seems to do some housekeeping during our snooze, cleaning out toxins and making connections. But as to the how and why we drift off into dreamland? That’s still up for debate. 


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Aging is the ultimate universal experience, yet it’s one of life’s greatest puzzles. Free radicals, telomere shortening, and a combination of other factors play roles, but no single cause has been pinpointed as the key to why we age. 

With each discovery, it seems we’re only touching the surface of a deep and complex process that encompasses our biology’s every aspect. It’s a reminder that, despite advances in science, the march of time holds secrets we’re still far from fully understanding.

Tornado Formation

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Tornadoes, those fearsome winds that can lay waste to everything in their path, are still not fully explained by science. We know they arise from the clash of cold, dry air with warm, humid air, especially in places like Tornado Alley in the U.S. 

Yet, not every thunderstorm in these conditions spawns a tornado, and scientists are still trying to piece together why. Even with some theories gaining traction, like temperature changes around mesocyclones, the complete picture of tornado formation remains elusive.



Ever caught a yawn from someone, even if you weren’t tired? Yawning is a bit of a puzzle. It feels like it’s as much a part of our lives as breathing, yet scientists can’t pin down why we do it or why it’s so contagious. 

Some think it’s our body’s way of pumping more oxygen to the brain when we’re tired, but that doesn’t explain why it spreads like wildfire in a group. Animals do it too, possibly as a form of social bonding or mirror behavior. 


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Why do we dream? This question has puzzled thinkers from ancient philosophers to modern neuroscientists. Dreams, especially those during REM sleep, are as intriguing as they are mysterious. 

Theories suggest dreams might help us process emotions or solve problems, but solid evidence is yet to be found. Could our dreams be just random noise in our brain’s processing, or do they serve a deeper purpose? As we close our eyes each night and drift into this other realm, we’re stepping into one of humanity’s oldest unsolved mysteries.

The Homing Instinct of Animals


Animals’ ability to find their way back to their birthplaces with pinpoint accuracy is a marvel of nature. Whether it’s Antarctic fur seals returning to the exact spot of their birth or Pacific salmon navigating vast oceans to spawn in their natal streams, the mechanisms behind these incredible journeys are not fully known. 



Why do cats purr? It’s a sound that signifies coziness and contentment, but it’s more than simply your furry friend feeling good. Cats also purr when scared or hurt. The big mystery is why only some cats can purr, and big ones like lions can’t. 

Scientists think it might be a comfort thing or even a way for cats to heal themselves, as the vibration helps with tissue growth. Yes, your fluffy friend might be purring away not just for cuddles but to keep those bones strong. Who knew these little furballs were so complex?


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Crying is a uniquely human thing, tied up with our emotions in ways we don’t fully understand. Sure, tears can clear out the eyes, but why do we cry when we’re sad or overwhelmed? 

It might be our body’s built-in way of showing vulnerability, sparking empathy in others, or a form of non-verbal communication that screams, “I’m feeling something big here!” 


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Tylenol is widely used for a range of pains, including headaches and muscle aches. Despite its common use, the exact mechanism of how it works remains unclear. 

It’s believed to involve inhibition of pain enzymes, interaction with the body’s cannabinoid system, or modulation of serotonin signaling in the brain—possibly a combination of these actions. Still, the specific details of its function are still under investigation.

Ice Skating


Everyone enjoys ice skating, but this fun winter activity turns out to be more of a puzzle than we thought. The old idea that pressure from the skate melts the ice just doesn’t cut it anymore. 

Researchers are exploring the properties of ice itself to understand what makes it so slippery, particularly for activities like skating. They’re investigating if the structure of ice’s top layer, possibly due to looser molecular bonds or imperfections, plays a role in facilitating the glide of skates. Makes you appreciate those winter laps a bit more, doesn’t it?


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Turbulence affects everything from airplane flights to the weather, yet it remains one of physics’ unsolved puzzles. Despite its importance in both natural phenomena and engineered systems, we lack a complete understanding of how turbulent flow develops or can be predicted. 

The challenge of solving the Navier-Stokes equations—a set of formulas that describe fluid movement—highlights the complexity of turbulence. This mystery also has real-world implications for engineering and science, making its solution one of the holy grails of physics.



Hiccups: annoying, spontaneous, and surprisingly mysterious. Despite their common occurrence, the exact why and how of hiccups remain elusive. They might be evolutionary leftovers or a way for infants to burp out excess air, but definitive answers are scarce. 

The Static Electricity and the Balloon

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That classic balloon-rubbing hair trick is actually a scientific head-scratcher. Why does your hair stand on end, and what’s with the static? 

The old electron-transfer theory is losing ground, and the latest thinking involves more than just material differences, perhaps even the transfer of other molecules upon contact. It’s a shockingly (pun intended) complex interaction for such a simple experiment.


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Bicycles, the eco-friendly transport option many of us rely on, hold a secret to their stability that has baffled scientists. This stability goes beyond merely rotating wheels; the bigger question is why bicycles remain upright and don’t fall over while moving. 

Theories range from gyroscopic effects to dynamic steering, but no one has nailed it down yet. As we pedal away, science is still trying to catch up, turning our two-wheeled commutes into another scientific mystery.

Sand’s Softness

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The softness of beach sand, as relaxing as it is puzzling, defies a simple explanation. The texture varies with grain size and moisture content, creating a mystery that science has yet to solve. 

While compacted layers feel harder, the perfect softness on top has scientists digging deep for answers. It turns out, even the simplest pleasures, like sand between your toes, come with complex scientific inquiries.

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Kate Smith, a self-proclaimed word nerd who relishes the power of language to inform, entertain, and inspire. Kate's passion for sharing knowledge and sparking meaningful conversations fuels her every word.