17 Science “Facts” That Are Actually Not True (2023)

RD.COM Knowledge Facts

How many do you still believe?

1/18

shop_py/Shutterstock

Fact or fiction?

Science is hard enough to understand, especially when there are so many “facts” floating around that aren’t actually true. You’ve probably heard more than half of the facts below. Here’s the real science behind them. To help your brain grow even more, here are some weird facts that most people don’t know.

2/18

Nataliya Sdobnikova/Shutterstock

Myth: Water conducts electricity

While this is a science myth, it doesn’t mean you should bring your toaster in the bath with you. The reason you shouldn’t swim in a lightning storm doesn’t have to do with the water itself. Pure water is actually an insulator, which means it doesn’t conduct electricity. The danger comes from the minerals and chemicals in it, which are made up of electrically-charged ions. While pure water is theoretically safe around electricity, it’s nearly impossible to find in the real world because even distilled water has ions. Check out these other 51 “fun facts” that are total lies.

3/18

Bart Sadowski/Shutterstock

Myth: Blood is blue in your body

A widely shared myth is that blood is blue until it is exposed to air or replenishes its oxygen. Because veins are a greenish-blue, that theory sounds reasonable enough. But the fact is, human blood looks the same in your body as outside: red. That hue is brighter when it’s oxygen-rich, and darker when it needs that oxygen replenished, but it’s red all the same. The tissue covering your veins affects how the light is absorbed and scattered, which is why the blood circulating your body looks blue. Here are some other crazy things you never knew about your body.

4/18

Baishev/Shutterstock

Myth: Dinosaurs were scaly beasts

The giant, scaly lizards you see in Jurassic Park probably don’t look that close to what actual dinosaurs looked like. While scientists are still debating what the oldest and biggest species were covered with, one thing is for sure: At least some had feathers. Velociraptor arm fossils have bumps that look just like the ones keeping modern birds’ wings in place, and the bones of a Siberian species discovered in 2014 were surrounded by imprints of feathers. While some scientists argue larger species like the Tyrannosaurus rex didn’t need big feathers, others theorize that they had at least some form of light feathering, like how elephants are mammals but don’t have thick fur. You’ll think that these 75 mind-blowing facts are made up (but they aren’t).

5/18

Luisma Tapia/Shutterstock

Myth: Humans only use 10 percent of their brains

The idea of unlocking hidden brain power might make a compelling storyline for a movie, but it simply doesn’t work that way in real life. One fact playing into the myth is that 90 percent of brain cells are “white matter” that help neurons survive, and only ten percent is the “grey matter” of neurons in charge of thinking. But that white matter could never be used for brain power, so claiming 90% of our brain is wasted is like saying you waste peanuts when you throw out the shells. Any fMRI scan will show you that even saying a few words lights up way more than ten percent of your brain. Scientists haven’t uncovered any area of the brain (much less 90% of it!) that doesn’t affect thought, movement, or emotion in some capacity.

6/18

Wuttichok Panichiwarapun/Shutterstock

Myth: The Great Wall of China is the only man-made structure you can see from the moon

Interestingly, this myth has been around at least since 1932, when a Ripley’s Believe it or Not! cartoon deemed the Great Wall of China to be “the mightiest work of man—the only one that would be visible to the human eye from the moon.” Of course, that was almost 30 years before a machine would touch down on the moon, so the claim was entirely unfounded. Astronauts have now confirmed that even the Great Wall actually can’t be seen from space, except at low altitudes. Even at those (relatively) low heights, it’s actually easier to see roads and plane runways, whose colors don’t blend into the ground like the Great Wall’s do. Not that the landmark isn’t impressive—find out what it’s really like to repair the Great Wall of China.

7/18

Anna Om/Shutterstock

Myth: Chameleons change color to match their surroundings

Yes, chameleons can change color by stretching and relaxing cells that contain crystals, which affects how the light is reflected. They can’t change to any color to match their surroundings, though, and their color changes don’t have much to do with camouflage. Instead, chameleons use the crystals mainly for communication (dark colors signal aggression, like when a female doesn’t want to mate), but also temperature control (lighter colors reflect the heat). The dull brown and green “resting colors” of chameleons blend in with their surroundings until they switch it up, so they’re actually more camouflaged before they change color. Other animals are masters at hiding, too—can you spot the animals camouflaged in these photos?

8/18

Procy/Shutterstock

Myth: Neanderthals were a less evolved human ancestor

First of all, let’s get one thing straight: Neanderthals aren’t ancestors to modern humans. The two species lived at the same time, mostly in different areas of the globe. When the species did cross paths, there’s even evidence that they interbred. But evidence doesn’t suggest they were cognitively inferior to humans. Fossils show Neanderthals made tools, used fire, cleaned their teeth, ate medicinal plants, buried their dead, and maybe even cared for their sick and wounded. Scientists no longer think Homo sapiens wiped out their Neanderthal cousins. Neanderthals likely were already dying out as the climate changed, while modern humans’ trade networks, diverse diets, and innovative tools helped them survive. You probably never learned these science facts in school.

9/18

trialhuni/Shutterstock

Myth: Earth is the only planet with water

Of course, we have yet to find any intelligent life living off interstellar water, but H2O isn’t unique to Earth. Dark streaks that change on Mars suggest there isn’t just ice on the Red Planet—liquid saltwater likely flows on it. What’s more, NASA discovered that beneath a layer of ice on Jupiter’s moon Europa, there’s an ocean containing twice as much water as we have on Earth. Could faraway planets with water sustain intelligent life? Only time will tell. Here are some more crazy facts about the earth you never learned in school.

10/18

Iurii Stepanov/Shutterstock

Myth: It takes seven years to digest chewing gum

Don’t freak out if you can’t find a trashcan and need to swallow your gum. The truth is that your body can’t digest gum, not even in seven years. That doesn’t mean it sticks inside your system, though. It will pass through your digestive system without being broken down, then come out in the bathroom like anything else. If kids swallow too much, the gum could block their intestines, but that’s extremely rare. If you’ve already spit your gum out, here’s how to get it off your carpet.

11/18

Lamyai/Shutterstock

Myth: Goldfish have three-second memories

Fish are smarter than you think. One study found the freshwater fish African Cichlid could remember the feeding zone of an aquarium after moving to a different tank for 12 days. Lest you think goldfish are any different, another study looked specifically at goldfish and whether they could tell the difference between two different classical songs. They weren’t quick learners, but after more than 100 sessions, the fish would bite a bead associated with the correct song 75% of the time. If their memories were really three seconds, that kind of training wouldn’t be possible. Here are some more science trivia questions most people get wrong.

12/18

Nixx-Photography/Shutterstock

Myth: A penny dropped from the Empire State building could kill

The story goes that even an innocent penny dropped from the 1,250-foot-tall Empire State Building would build up enough speed on the way down to kill a bystander below. In reality, though, it wouldn’t do much damage—if any. First of all, air resistance called “drag force” would mean the penny would stop accelerating at some point, and reach its max speed about 50 feetfrom its drop point, according to Scientific American. By the time it reached the ground, it would be moving just 25 miles per hour. That might sting, but it wouldn’t be enough force to break your skull. The TV show MythBusters took the theory to an extreme and shot a penny at 3,000 feet per second, but even that wasn’t strong enough to break bones. While you’ve got that penny in hand, here aresome brilliant uses for it.

13/18

Aleksandra Duda/Shutterstock

Myth: Ostriches bury their heads in the sand

The birds would die of suffocation if they actually stuck their heads underground when scared. Instead, they actually lie with their head and neck flat against the ground if a predator is approaching. Their light-colored head and neck blend in with the ground, which could explain why people assumed their heads were underground from faraway, according to the San Diego Zoo. For more animal facts, check out the 12 of the smartest species on the planet.

14/18

rthoma/Shutterstock

Myth: Opossums sleep hanging by their tails

You’ve probably seen cartoons—maybe even photos—of opossums lounging upside-down from their tails. While opossum tails are strong enough to grasp branches and even hold the animals’ weight for a short period, adults are too heavy for their tails to support them for long, so they can’t stay like that while sleeping. These favorite facts that you’ve always believed are also actually false.

15/18

Max Lashcheuski/Shutterstock

Myth: Sugar makes kids hyper

Don’t blame the cake if your kid is acting out at a party. The “sugar high” theory started in 1978, when one study found that kids with hyperkinesis, a hyperactivity disorder, had low blood sugar, which, weirdly enough, can be a sign of eating too much sugar. That study was later discredited when researchers realized that the “abnormally low” blood sugar was actually considered normal. Since then, double-blind studies (the scientific gold standard) have shown that sugar doesn’t make kids any more hyper than a placebo. If anything, it’s probably your own expectations. One 1994 study found that after five- to seven-year-old boys took a placebo, the moms who were told their sons had eaten a large dose of sugar were more likely to say their kid was acting hyper. Your kid might also just be excited to let loose with their friends at a party. Here are some other reasons your kid might act out when you’re around.

16/18

Visual Generation/Shutterstock

Myth: Lightning never strikes the same place twice

Anyone familiar with lightning rods could probably already tell you there’s nothing stopping lightning from hitting the same spot twice. The Empire State Building, for example, once endured eight strikes in 24 minutes during a storm. Even without a lightning rod, there’s nothing keeping lightning away from the spot that just got hit. In fact, the features that made the spot likely to get hit once—height, presence of standing water, or terrain shape, for example—would be just as attractive to a second bolt, according to the National Severe Storms Laboratory. Check out the science mysteries no one has figured out.

17/18

solarseven/Shutterstock

Myth: Common belief in the Middle Ages was the Earth was flat, but it’s really a perfect sphere

Surprise! Both parts of this myth are false. Scholars have known the Earth is round for thousands of years. The Greek philosopher Pythagoras first suggested the idea around 500 B.C., though his thought process had to do with the fact that he thought spheres were the most perfect shape. Still, Aristotle actually found physical evidence backing up his predecessor’s theory. By the time the first century A.D. rolled around, any educated Greek or Roman believed in a round planet. When Christopher Columbus took on his voyage, the fear was that the oceans would be too big, not that he’d fall off the face of the Earth. In perhaps the biggest twist, though, Earth isn’t a perfect sphere; the North and South Poles are flattened slightly. Don’t miss these other 18 lessons your history teacher lied about.

18/18

Rost9/Shutterstock

Myth: Genes determine race

You might think people who look superficially different would have big differences in their genes, but that’s not the case. According to the National Human Genome Research Institute, humans share 99.9 percent of their genes with each other. Even that 0.1 percent doesn’t have any racial markers. In fact, a groundbreaking 2002 study revealed there is more genetic diversity between people of African descent than between Africans and Eurasians. You can use your genes to trace your ancestors’ geography, but that doesn’t directly tie in to race. Case in point: Sickle cell anemia isn’t a general “African” disease, as it’s normally described; it’s more common in West Africans, but it’s also widespread among Mediterranean, Arabian, and Indian populations. Now, read on for 100 interesting facts about practically everything.

Marissa Laliberte-Simonian is a London-based associate editor with the global promotions team at WebMD’s Medscape.com and was previously a staff writer for Reader's Digest. Her work has also appeared in Business Insider, Parents magazine, CreakyJoints, and the Baltimore Sun. You can find her on Instagram @marissasimonian.