30 Things Most People Still Believe That Science Has Long Debunked
Over time, many widely accepted beliefs have been passed down through generations. These beliefs, often rooted in tradition, anecdote, or outdated science, have shaped our understanding of the world. However, as scientific knowledge advances, some of these long-held ideas are being proven incorrect. In this article, we explore 30 popular beliefs that have been dispelled by scientific evidence. It's time to rethink what we thought we knew!
1. The Five-Second Rule
The popular belief that food dropped on the floor is safe to eat if picked up within five seconds has been debunked. Research shows that bacteria can contaminate food instantly, regardless of how long it stays on the ground. The type of surface and food plays a bigger role in contamination than the time factor.
2. Humans Have Five Senses
We’ve all been taught that humans have five senses: sight, hearing, touch, taste, and smell. However, science shows that humans have many more senses, including balance (vestibular sense), temperature (thermoception), and even proprioception (sense of body position).
3. Goldfish Have a Three-Second Memory
The belief that goldfish have a memory span of only three seconds is a myth. Studies have shown that goldfish have a memory that lasts weeks, if not months. They can be trained to perform tasks, recognize shapes, and even differentiate between different types of music.
4. Cracking Knuckles Causes Arthritis
For years, people believed that cracking your knuckles could lead to arthritis. Scientific studies, however, have found no evidence to support this claim. The sound of cracking is caused by gas bubbles bursting in the synovial fluid, not by damage to the joints.
5. Humans Only Use 10% of Their Brains
The idea that we only use 10% of our brains is a myth perpetuated by popular culture. Modern neuroscience has shown that virtually every part of the brain has a known function, and we use all of our brain's capacity, though not all at once.
6. Sugar Makes Kids Hyperactive
The belief that sugar causes hyperactivity in children is widespread, but scientific studies have found no direct link. The perceived hyperactivity is more likely due to the excitement of events like parties where sugary foods are often consumed.
7. You Lose Most Body Heat Through Your Head
It was long believed that up to 80% of body heat is lost through the head, but science has proven this incorrect. Heat is lost from any exposed part of the body, and the head is no different from other parts when uncovered.
8. Vitamins from Supplements Are Better Than from Food
Many people believe that taking vitamins in supplement form is better or more effective than getting them from food. However, studies have shown that vitamins from natural food sources are more readily absorbed and utilized by the body than synthetic supplements.
9. Cholesterol-Rich Foods Cause Heart Disease
The belief that all cholesterol is bad and leads to heart disease has been challenged by newer research. It’s now understood that not all cholesterol is harmful; in fact, the body needs “good” HDL cholesterol. The emphasis is now on understanding the role of LDL cholesterol, diet, and lifestyle in heart health.
10. Lightning Never Strikes the Same Place Twice
Contrary to this popular myth, lightning can strike the same place more than once, especially in areas that are tall, pointy, and isolated, like skyscrapers or tall trees. Some locations, like the Empire State Building, are struck by lightning multiple times each year.
11. The Great Wall of China is Visible from Space
The belief that the Great Wall of China is the only man-made object visible from space is false. Astronauts have reported that it is very difficult to see the wall without aid, and many other man-made structures are more visible, like roads and cities.
12. The Tongue Has Different Taste Zones
The idea that different parts of the tongue are responsible for tasting sweet, salty, sour, and bitter flavors has been debunked. All taste buds can detect all flavors, though some areas are more sensitive to certain tastes than others.
13. You Should Drink 8 Glasses of Water a Day
The “8×8 rule” (eight 8-ounce glasses of water a day) has been widely accepted but lacks scientific backing. The amount of water a person needs depends on various factors like age, activity level, and environment. Much of our hydration also comes from food and other beverages.
14. Shaving Makes Hair Grow Back Thicker
Shaving hair does not make it grow back thicker or darker. The blunt tip of the shaved hair may make it appear thicker as it grows, but the texture, color, and growth rate of the hair remain unchanged.
15. Bulls Hate the Color Red
The belief that bulls are enraged by the color red is not accurate. Bulls are actually color-blind to red. They react to the movement of the matador's cape, not the color itself.
16. You Can Catch a Cold from Being Cold
While the name “cold” suggests a link to low temperatures, the common cold is caused by viruses, not by being cold or wet. Cold weather may contribute to catching a cold indirectly by encouraging indoor gatherings where viruses spread more easily.
17. Carrots Improve Night Vision
While carrots are rich in Vitamin A, which is important for eye health, eating them doesn't give you superhuman night vision. This myth originated from wartime propaganda to explain British pilots' improved night-time accuracy without revealing their use of radar technology.
18. Gum Takes Seven Years to Digest
It’s a common myth that swallowed gum stays in your stomach for seven years. In reality, gum passes through your digestive system relatively intact and is excreted like any other indigestible substance within a few days.
19. Hair and Fingernails Continue to Grow After Death
Contrary to popular belief, hair and fingernails do not continue to grow after death. What actually happens is that the skin dehydrates and retracts, making it appear as though nails and hair are longer.
20. A Penny Dropped from a Skyscraper Can Kill Someone
The myth that a penny dropped from a tall building could kill someone is false. Physics shows that due to its shape and terminal velocity, a penny would not have enough mass or speed to cause fatal damage.
21. You Can See the Great Wall of China from Space
A popular misconception is that the Great Wall of China is the only man-made structure visible from space. In reality, it's almost impossible to see with the naked eye, while other structures like highways and airports are more visible.
22. Humans and Dinosaurs Coexisted
Despite some cultural representations, humans and dinosaurs did not live at the same time. Dinosaurs went extinct about 65 million years ago, whereas humans evolved around 200,000 years ago.
23. Eating Turkey Makes You Sleepy
Many believe that eating turkey makes you sleepy because it contains tryptophan. However, the amount of tryptophan in turkey is not enough to cause drowsiness. The sleepiness after a big meal is due to the overall heavy intake of calories and carbohydrates.
24. Bats Are Blind
The saying “blind as a bat” is misleading. While bats do use echolocation to navigate in the dark, most bats have perfectly good eyesight and can see quite well.
25. You Can Get Warts from Frogs or Toads
Warts are caused by the human papillomavirus (HPV), not frogs or toads. The myth likely originated from the appearance of warts on amphibian skin, which is unrelated to human warts.
26. Antibiotics Kill Viruses
Antibiotics are only effective against bacterial infections, not viruses. Taking antibiotics for viral infections like the flu or cold is not only ineffective but can also contribute to antibiotic resistance.
27. Birds Will Abandon Their Young If You Touch Them
Many people believe that if a human touches a baby bird, its mother will abandon it. This is false; most birds have a poor sense of smell and will not abandon their chicks due to human contact.
28. Eating Spicy Foods Can Cause Stomach Ulcers
It was long thought that spicy foods could cause stomach ulcers, but we now know that most ulcers are caused by a bacterial infection (H. pylori) or the overuse of certain medications, like NSAIDs.
29. Chameleons Change Color to Blend In with Their Surroundings
Chameleons change color primarily for communication, temperature regulation, and mood, not just to blend into their surroundings. Their color changes are more about signaling than camouflage.
30. The Color of Blood Is Blue Inside the Body
Despite what some diagrams show, human blood is never blue. Blood is always red; it is bright red when oxygenated and dark red when it is deoxygenated.
