We use 100% of our brain! The 10% myth is false. Brain imaging (fMRI, PET scans) shows that most of the brain is active most of the time. Even during sleep, the brain is active (dreaming, memory consolidation). The brain accounts for about 2% of body weight but consumes about 20% of the body's energy – it would not waste energy on unused tissue. Stroke victims or people with brain injuries show deficits that depend on which region is damaged. This proves that all parts of the brain serve important functions. The myth may have started with psychologist William James (1842-1910), who said that humans have untapped potential, but he did not mean that 90% of the brain is unused. The myth was popularized by self-help books and movies ("Lucy" (2014) uses the myth as a plot device). In reality, we use nearly all of our brain, just not all at once. Different tasks activate different networks. The brain is highly efficient and adaptive. Neuroplasticity allows the brain to reorganize after injury. The myth persists because it is appealing (the idea of hidden potential). Scientists have debunked it many times. The brain is one of the most complex organs in the known universe. It contains about 86 billion neurons, each with thousands of connections. The myth of 10% is a classic example of pseudoscience. Don't believe everything you hear – check the evidence!

Lightning strikes the same place many times! The Empire State Building is struck about 25 times per year. The Willis Tower (formerly Sears Tower) in Chicago is struck about 100 times per year. Lightning rods are designed to be struck repeatedly. The saying is an old proverb meaning that something bad won't happen to you again – but it has no basis in science. Lightning is attracted to the tallest object in an area. If that object remains the tallest, it will continue to be struck. The Eiffel Tower was struck 10 times in one hour during a storm in 1902. A person can be struck multiple times (Roy Sullivan, a park ranger, was struck seven times and survived). The myth persists because it's a common saying. The correct saying should be "Lightning tends to strike the same place repeatedly." The Empire State Building has a lightning rod system that safely conducts the electricity to the ground. About 1,000 lightning strikes occur around the world at any given moment. Lightning is a giant spark of electricity. It can heat the air to 50,000°F (5 times hotter than the sun). The sound of thunder is the rapidly expanding air. Lightning safety: if you hear thunder, you are within striking distance. Go indoors. Do not stand under tall trees. Wait 30 minutes after the last thunder before going outside. The myth "lightning never strikes the same place twice" is a classic example of a popular misconception. Now you know the truth!

A penny would not kill! The terminal velocity of a penny is about 30-50 mph (48-80 km/h). At that speed, it would sting like a pebble but would not penetrate the skin or skull. The myth likely comes from the idea that any falling object can kill if dropped from a great height – this is true for heavy, aerodynamic objects (like a bullet or a metal bolt). However, a penny is light and flat, so air resistance slows it down. The MythBusters TV show tested this using a ballistic gel dummy and found that the penny left a small dent but did not penetrate. They also fired a penny at high speed using a compressed air gun to simulate a vacuum (no air resistance), and it did cause damage. But in real conditions, the penny would not be fatal. The same applies to other light, flat objects (paper, leaves). However, heavier objects (a brick, a metal tool) could kill. The moral: don't drop heavy things from high places! But a penny is safe. This myth is a great example of how our intuition can be wrong. The terminal velocity of an object depends on its mass, shape, and cross-sectional area. The formula for terminal velocity is vt = sqrt(2mg/ρACd). For a penny, the values result in low terminal velocity. So next time someone says a penny could kill, you can correct them!

Humans share a common ancestor with monkeys! The common ancestor of humans and Old World monkeys lived about 25-30 million years ago. The common ancestor of humans and chimpanzees (our closest living relatives) lived about 6-8 million years ago. Humans are apes (great apes), not monkeys. Monkeys have tails; apes (including humans) do not. The phrase "humans evolved from monkeys" is a common misunderstanding of evolution. Evolution does not claim that humans evolved from modern monkeys; it claims that humans and monkeys share a common ancestor. That common ancestor was not a monkey (as we know them) and not a human. It was a primate that gave rise to both lineages. Over millions of years, the two lineages diverged, accumulating different traits. The fossil record shows transitional forms (e.g., Australopithecus, Homo habilis, Homo erectus). Humans are not "more evolved" than monkeys; both lineages have been evolving for the same amount of time. We are just different, not "higher" or "lower." The misconception is often used to attack evolution. Understanding evolution requires understanding common ancestry. The theory of evolution is one of the most robust theories in science. It is supported by evidence from fossils, DNA, and anatomy. Humans share about 98-99% of their DNA with chimpanzees, about 93% with macaques, and about 85% with mice. These similarities are evidence of common ancestry. Now you can correct this common myth!

Sugar does not cause hyperactivity! The myth was popularized by a 1970s book that claimed sugar caused hyperactivity, but later research disproved it. A 1994 meta-analysis of 23 studies found no effect of sugar on behavior. A 1995 study in the Journal of the American Medical Association (JAMA) also found no effect. Parents expect sugar to cause hyperactivity, so they perceive it (confirmation bias). In double-blind studies, parents who were told their child had consumed sugar rated the child as hyperactive – even when the child had received a placebo. Children are often hyperactive at birthday parties, Halloween, and holidays – which also have lots of candy. The excitement of the event (not the sugar) is the cause. Sugar can cause a brief energy spike followed by a crash (sugar rush), but this is not the same as hyperactivity. Artificial food dyes (Red #40, Yellow #5) have been linked to hyperactivity in some children, but sugar has not. The American Academy of Pediatrics (AAP) states that sugar does not cause hyperactivity. The myth persists because it is a convenient explanation for children's behavior. However, sugary foods are unhealthy for other reasons (tooth decay, obesity, poor nutrition). Limit sugar for health reasons, but not because it causes hyperactivity. This myth is a classic example of how popular beliefs can be wrong. Always look for scientific evidence!

Humans have many more senses! The traditional five senses were proposed by Aristotle. Modern science recognizes: sight (vision), hearing (audition), touch (tactition), taste (gustation), smell (olfaction), balance (equilibrioception – sense of gravity and movement), proprioception (sense of body position and movement of limbs), thermoception (sense of temperature), nociception (sense of pain), interoception (sense of internal body state – hunger, thirst, bladder fullness, heartbeat, etc.), and others. Some scientists also include chronoception (sense of time), chemoreception (detection of chemicals in the blood), and magnetoreception (detection of magnetic fields – in some animals, humans may have a weak sense). The number depends on definition. The sense of touch actually includes several: pressure, vibration, stretch, temperature, and pain. The vestibular system (inner ear) detects balance and acceleration. Proprioceptors in muscles and joints tell you where your limbs are without looking. Interoceptors detect hunger, thirst, and the need to urinate. The concept of "five senses" is a useful teaching tool but not scientifically accurate. Humans have a rich sensory experience. Some people have additional senses (e.g., magnetoreception is stronger in some). The idea that we have only five senses is a myth. Now you know the truth!

Bats are not blind! The phrase "blind as a bat" is a myth. Bats have functional eyes and can see. Microbats (insect-eating bats) use echolocation to hunt in the dark, but they also use their eyes. They can see well enough to avoid obstacles. Megabats (fruit bats) have excellent eyesight and do not use echolocation (they navigate by sight and smell). Echolocation is not a substitute for eyes; it is an additional sense. Some bats can even see ultraviolet light. The myth may have arisen because bats are nocturnal and often found in caves. People assumed they could not see. In reality, bats have adapted to low-light conditions. The phrase "blind as a bat" is a common saying, but it is not scientifically accurate. Bats are not blind. They are fascinating creatures. Some bats have eyes as large as their brains. The Mexican free-tailed bat uses echolocation but also has good vision. The common vampire bat sees well in low light. Bats are important pollinators and pest controllers. They are not blind. Next time you hear "blind as a bat," you can correct the speaker!

The Great Wall is not visible from space! The myth originated in the 1930s and was repeated by Richard Halliburton. Astronauts have confirmed they cannot see the Wall. The Wall is only about 30 feet (9 meters) wide – far too narrow to resolve from orbit. The human eye can resolve objects about 0.1 mile (0.16 km) across from low Earth orbit. The Wall's materials (stone and earth) blend with the natural landscape. The myth is a classic example of a popular historical falsehood. The Great Wall is 13,000 miles (21,000 km) long, but its thin profile makes it invisible from space. Some astronauts have reported seeing the lights of cities or large rivers, but not the Wall. The first Chinese astronaut, Yang Liwei (2003), confirmed that the Wall is not visible. The myth is often repeated because it sounds impressive. However, cities and highways can be seen at night (lights). The Wall is not illuminated. The Great Wall is still an incredible engineering achievement, but it is not visible from space. This myth has been debunked by many astronauts. Now you know the truth!

The tongue map is a myth! The classic "taste map" (sweet at the tip, sour on the sides, salty at the front sides, bitter at the back) was a misunderstanding of a 1901 study by German scientist David Hänig. He found that different areas had slightly different thresholds for detection, but the differences were small. Modern science has shown that taste receptors for all five tastes are found throughout the tongue. The myth persists because it is taught in many textbooks and classrooms. However, scientists have known for decades that it is false. Taste buds contain receptor cells for multiple tastes. The myth is a classic example of how science can be misrepresented. The five basic tastes are sweet, sour, salty, bitter, and umami (savory). Umami was discovered by a Japanese scientist (Kikunae Ikeda) in 1908. The tongue map is a myth. Now you know the truth! The sense of taste is complex and involves smell (olfaction) as well. Next time someone shows you a tongue map, you can correct them.

The spider-swallowing myth is false! There is no scientific evidence that anyone swallows spiders while sleeping. Spiders are afraid of humans. They avoid open spaces and vibrations (like breathing and heartbeat). A sleeping person is a dangerous environment (rolling over, breathing). Spiders would not voluntarily crawl into a mouth. The myth was intentionally created as a hoax to demonstrate how false information spreads. It has been debunked by many experts. The idea is ridiculous if you think about it: why would a spider crawl into a warm, moist, moving, breathing cave? They wouldn't. The myth persists because it is shocking and people love to share it. But it is false. Now you can debunk this myth! Spiders are beneficial (they eat insects) and are not out to crawl into your mouth. You can sleep soundly knowing that no spiders are being swallowed. The myth is a classic example of an urban legend. Always check your sources. The internet is full of false information. This myth has been widely debunked by Snopes, the BBC, and many scientists. So next time you hear someone say "Did you know you swallow eight spiders a year?" you can say "That's a myth!"