The 23 “Science Facts” Everyone Still Believes That Are Actually Complete Nonsense

Many widely held science “facts” are actually outdated myths or outright falsehoods that persist thanks to repetition, media oversimplification, and our own cognitive biases. Despite overwhelming scientific evidence debunking these misconceptions, they continue to spread in classrooms, everyday conversations, and pop culture. From misunderstandings about the human brain to myths about animal behavior and the laws of physics, these beliefs linger stubbornly. Their persistence shows why scientific literacy and critical thinking are more important than ever. Let’s set the record straight on 23 “facts” everyone thinks they know—but are actually complete nonsense.

1. We Only Use 10% of Our Brains

A vibrant brain scan reveals intricate patterns of neural activity, showcasing the fascinating complexity explored in neuroscience. | Photo by Anna Shvets on Pexels

The claim that we use only 10% of our brains is pure fiction. Modern neuroimaging reveals that nearly every part of the brain is active, even during basic activities like talking or walking. This myth endures because it tempts us with the idea of hidden potential, but science says otherwise.
In reality, even small areas of brain damage can cause profound deficits, highlighting how essential the entire brain is. For more, see this review in Scientific American.

2. Lightning Never Strikes the Same Place Twice

A dramatic bolt of lightning illuminates the night sky as it strikes near the towering Empire State Building and surrounding skyscrapers. | Photo by pikist.com

Despite the saying, lightning frequently strikes the same spot, especially when that spot is a tall building or structure. The Empire State Building, for example, is struck by lightning more than 20 times annually. Physical features, not randomness, determine where lightning hits.

According to the National Weather Service, this myth persists because people imagine lightning as unpredictable—when it actually follows the laws of physics.

3. Goldfish Have 3-Second Memories

A curious goldfish glides through crystal-clear water, showcasing surprising intelligence and debunking the myth of short fish memory. | Photo by imsogabriel Stock on Pexels

The idea that goldfish can only remember things for three seconds is a myth. Scientific research has shown that goldfish are capable of remembering information for months. They can even be trained to recognize sounds and feeding times, demonstrating surprising cognitive abilities.

This misconception sticks around because it fits the stereotype of small, “simple” animals. For more details on goldfish memory, see the BBC.

4. Humans Have Five Senses

A detailed illustration shows the human brain surrounded by sensory organs, highlighting the connection between senses and perception. | Photo by cottonbro studio on Pexels

The belief that humans have just five senses—sight, hearing, touch, taste, and smell—is a classic oversimplification. In reality, our bodies are equipped with many more senses, including balance (vestibular sense), temperature (thermoception), and body position (proprioception).

Neuroscientists now recognize anywhere from 9 to 21 distinct senses, depending on the definitions used. This myth lingers due to how senses are traditionally taught in schools. For more, see Encyclopedia Britannica.

5. Different Parts of the Tongue Detect Different Tastes

A detailed tongue map highlights different taste buds as a person samples flavors during a lively taste testing session. | Photo by renovatingyourmind.com

The famous “tongue map” suggesting sweet, salty, sour, and bitter tastes are detected only in certain areas of the tongue is simply incorrect. Modern research shows that taste buds for all flavors are spread across the entire tongue.

This myth continues because of misinterpreted early research and misleading textbook diagrams. For scientific evidence, see this study in Cell.

6. Hair and Fingernails Continue to Grow After Death

Close-up of fingernails and hair strands emerging from decomposing skin, highlighting the natural process of postmortem changes. | Photo by piqsels.com

It’s a common myth that hair and fingernails keep growing after death. In reality, growth stops because cell division ceases soon after death. Instead, as the skin dehydrates and retracts, hair and nails appear longer, creating a convincing illusion.

This misconception is fueled by the changes seen during decomposition. For clarification, see the American Academy of Dermatology.

7. Bats Are Blind

A group of bats soars through the night sky, guided by echolocation and their remarkable night vision. | Photo by flickr.com

Despite the common saying, bats are not blind. Many bat species have excellent night vision and use echolocation as an additional navigation tool. According to the U.S. Geological Survey, bats can see well in low light and depend on both their eyes and ears.

This myth endures mainly because of the misleading phrase “blind as a bat.”

8. The Great Wall of China Is Visible from Space

The Great Wall of China snakes across the landscape, as seen from space through the visor of an observing astronaut. | Photo by wikimedia.org

The belief that the Great Wall of China is visible from space is a myth. Astronauts have reported that it’s not visible from the Moon and is barely discernible from low Earth orbit without aid. According to NASA, many other human-made objects are actually more noticeable from space.

This misconception lingers because it sounds like an impressive and memorable “fact.”

9. Sugar Causes Hyperactivity in Children

A group of children bursts with energy and laughter, surrounded by colorful sweets and half-eaten treats. | Photo by therewasabrightflashoflight.blogspot.com

Despite popular belief, scientific studies consistently show no causal link between sugar intake and hyperactivity in children. Double-blind research summarized by the Mayo Clinic found no measurable effect.

This myth persists due to the placebo effect and confirmation bias—parents often associate sugary events like parties with energetic behavior, overlooking other factors like excitement or environment. Sugar is not the culprit for children’s bursts of energy.

10. Vaccines Cause Autism

A scientist in a lab coat examines vaccine samples, highlighting ongoing medical research into autism and immunization safety. | Photo by Martin Lopez on Pexels

There is no scientific evidence that vaccines cause autism. Extensive research, including numerous large-scale epidemiological studies, has thoroughly debunked this claim. The infamous study that first suggested a link was retracted for serious ethical breaches and data falsification.

The CDC clearly states there is no connection between vaccines and autism. Yet, this myth persists, fueled by misinformation, fear, and the powerful force of cognitive biases.

11. Antibiotics Kill Viruses

Colorful illustrations of viruses and bacteria highlight the difference, as a pill bottle of antibiotics lies nearby unused. | Photo by Edward Jenner on Pexels

Antibiotics are only effective against bacteria, not viruses. Taking antibiotics for viral infections like the common cold or flu won’t help and actually promotes antibiotic resistance—a serious global health concern.

The World Health Organization explains that misuse and misunderstanding of medical terminology fuel this persistent myth. For more details, visit the World Health Organization.

12. Humans Swallow Eight Spiders a Year in Their Sleep

A curious spider perches near a sleeping person, bringing to life the eerie urban legend whispered before bedtime. | Photo by abhishek goel on Pexels

The idea that people swallow eight spiders a year while sleeping is a fabricated myth with no scientific basis. Spiders are unlikely to crawl into a sleeping human’s mouth because the vibrations from breathing and movement actually deter them.

According to Scientific American, this myth was probably invented to demonstrate how easily misinformation can spread.

13. Seasons Are Caused by Earth’s Distance from the Sun

Earth’s tilted axis is shown orbiting the sun, illustrating how the changing angle creates the seasons. | Photo by collegesidekick.com

It’s a common misconception that seasons are determined by how close Earth is to the sun. In reality, Earth’s axial tilt is responsible for seasonal changes. When one hemisphere tilts toward the sun, it experiences summer; the opposite hemisphere gets winter.

NASA clearly explains this phenomenon in detail (NASA Space Place). The myth persists because of simplified lessons in early education.

14. Cracking Knuckles Causes Arthritis

A close-up of hands mid-knuckle crack, highlighting the common habit and its connection to hand health and arthritis myths. | Photo by opas.org.br

Cracking your knuckles does not cause arthritis, according to multiple studies. The familiar popping noise is actually the sound of gas bubbles rapidly collapsing in the synovial fluid of your joints—not a sign of harm or damage.

While frequent knuckle cracking may lead to minor hand swelling or reduced grip strength, it doesn’t increase your arthritis risk. This myth persists because the noise seems alarming. For more, see Harvard Medical School.

15. Ostriches Bury Their Heads in the Sand

An ostrich stands in a sandy landscape with its head buried, playfully illustrating the enduring animal myth. | Photo by Magda Ehlers on Pexels

Ostriches do not bury their heads in the sand to hide from danger. Instead, they may lower their heads to turn their eggs or scan for predators, which can look like they’re burying them.

The Smithsonian explains that this myth likely comes from misinterpreting these natural behaviors. Ostriches rely on running, not hiding, for self-defense.

16. Water Conducts Electricity

A stream of water flows over exposed electrical wires, dramatically illustrating the dangers of water’s powerful conductivity. | Photo by pixnio.com

It’s a common misconception that water itself is a good conductor of electricity. In reality, pure water is a poor conductor; it’s the dissolved salts and minerals in most water that allow electricity to flow.

This myth persists because mixing water and electricity is genuinely dangerous in daily life, but it’s the impurities—not the water itself—that pose the risk. The U.S. Geological Survey explains this important distinction.

17. Humans Evolved from Monkeys

A timeline of primate silhouettes evolves from early ancestors to modern humans, illustrating the journey of human evolution. | Photo by pressbooks.nebraska.edu

The idea that humans evolved directly from monkeys is incorrect. Instead, humans and modern monkeys share a distant common ancestor. The evolutionary path is a branching tree, with different primate species diverging over millions of years.

This myth persists because evolution is often oversimplified in popular culture and education. For a clearer picture of our origins, visit the Smithsonian National Museum of Natural History.

18. Blood in Veins Is Blue

A close-up of veins beneath the skin, their bluish hue illustrating how blood’s color shifts with light perception. | Photo by courses.lumenlearning.com

Blood is never blue; it is always some shade of red. Oxygen-rich blood is bright red, while deoxygenated blood appears darker. The blue appearance of veins beneath the skin is simply a trick of light penetration and reflection.

This persistent myth is fueled by misleading illustrations and the way veins look under the skin. For the scientific explanation, see the Cleveland Clinic.

19. Alcohol Kills Brain Cells

A detailed illustration shows alcohol molecules interacting with vibrant brain cells, highlighting the impact of drinking on neural pathways. | Photo by youtube.com

Moderate alcohol consumption does not kill brain cells. While excessive drinking can damage dendrites—the connections between neurons—and impair communication, the notion that casual drinking “kills” brain cells is a myth.

This misunderstanding likely arose from studies on severe alcohol abuse. For most people, typical social drinking does not destroy brain cells, as clarified by the National Institute on Alcohol Abuse and Alcoholism.

20. If You Touch a Baby Bird, Its Mother Will Abandon It

A cozy bird nest cradles hungry baby birds, evoking ancient nature myths about new life and renewal. | Photo by Mohan Nannapaneni on Pexels

Most birds will not abandon their chicks if touched by humans. Birds generally have a poor sense of smell and will continue caring for their young even after brief human contact.

The Cornell Lab of Ornithology notes that this myth may actually help prevent unnecessary or harmful human interference with wildlife.

21. Gum Stays in Your Stomach for Seven Years

A curious child stares at a piece of chewing gum, pondering the classic myth about gum staying in your stomach forever. | Photo by cottonbro studio on Pexels

Although chewing gum is mostly indigestible, it does not remain in your stomach for seven years. Instead, it passes through the digestive system and is excreted like most other substances.

The Mayo Clinic explains that this myth persists mainly as a cautionary tale for kids, rather than any real danger.

22. Daddy Longlegs Are the Most Venomous Spiders

A delicate daddy longlegs spider perches on a leaf, its long legs poised despite the myths about its venom. | Photo by Charles Haacker on Pexels

Daddy longlegs, also known as harvestmen, are not actually spiders and they do not possess venom harmful to humans. In fact, their mouthparts aren’t even capable of biting people.

The University of California, Riverside explains that this myth likely stems from confusion with cellar spiders, which are also harmless to humans.

23. Shaving Makes Hair Grow Back Thicker

A close-up of a razor gliding over skin, debunking the common myth that shaving increases hair growth. | Photo by opentextbc.ca

Shaving does not make hair grow back thicker, darker, or faster. The blunt edge left by razors can make new growth seem coarser or more noticeable, but this is simply a visual illusion—not a biological change.

The Mayo Clinic confirms that shaving has no effect on hair’s actual texture or growth rate.

Remember, questioning what we think we know is a crucial part of scientific literacy. Always look for reputable sources and keep challenging persistent myths!