25 Popular Science Myths Debunked

A major goal of education is the debunking of miseducation. That means spotting and correcting the many myths emanating from the internet, folk wisdom, and word of mouth. We have all been taken in, at some point or another, by a modern myth. Fortunately, we're here to help you with a new series debunking many of these modern myths. This installment aims to clear up some commonly held misconceptions in the field of science. The truth, as they say, shall set you free.

Physics Myths

1. A penny dropped from the empire state building can kill a person on the sidewalk
This myth says that if you were to drop a penny from the top of the Empire State Building, it would accelerate to the point that it could kill a person on the sidewalk below. This is just bad physics. In reality, the penny will reach terminal velocity of about 30-100 miles per hour depending on the wind. It's still a jerk move to drop a penny from up there. It might hurt, but it wouldn't kill anyone. Either way, you would fare better to just keep the change.

2. There are only three states of matter: solid, liquid and gas
Don't forget plasma. That makes four states. Plasma isn't some gel or goo, it's more like superheated ions and electrons. It's sometimes called “ionized gas.” When cooled, it becomes gas, but then it takes on different properties, too. So it's not quite right to think of it as a kind of “gas.” Plasma is more like a flame. Lightning, fire, the sun, and the tail of comets are all plasmas. Most any element or chemical compound can become plasma if heated high enough, but since plasma is just ions and electrons, the molecules have broken down. Water, for example, can be reduced to plasma, but it's no longer H2O; it's not even hydrogen or oxygen. And You definitely wouldn't want to drink it.

3. Toilet flushes spin a different direction in the Southern Hemisphere
Both directions can be found in both hemispheres. There is some science behind this myth, but it doesn't really apply to toilet flushes. Typically, this myth calls upon the Coriolis Effect, where flow patterns are effected by the earth's rotation. That helps explains things like the Gulf Stream, or hurricanes, but toilet flushes and even tornados are too small to be influenced directly by the Coriolis Effect. Instead, the direction of spiral is a product of other features such as the design of the toilet, the plumbing, and water pressure.

4. Glass is a high viscosity liquid
Obviously glass isn't like water or even like molasses, but could it be characterized as having super high viscosity such that it is an ultra-slow flowing liquid? Well, no. This myth arises from the fact that window glass in older buildings is typically thicker at the base. Supposedly, the glass was evenly thick but gradually “sagged” over time, thickening the base. In reality, glass is categorized as a solid, but in "olden days" it was difficult to get a perfectly even pane of glass using old fashioned methods. When a craftsman made a reasonably flat piece of glass, he would then cut the glass to size, and if one side was thicker than the other, he'd put that side at the bottom for stability. Not everything sags with age.

5. Lightning never strikes the same place twice
This myth is not only wrong, it's dangerously wrong. Lightning often strikes the same place twice, at least within a close vicinity. If you find yourself standing around outdoors during a lightning storm, there is no outdoorsman or forecaster who'd recommend you go stand where lightning has already struck as if you are somehow protected at that spot. Instead, you need to find shelter, stay away from windows and avoid touching anything metal or electrical. And it's always a good idea to suspend your golf game or kite-flying till the storm passes.

6. Astrology
According to 60s soul-pop group The 5th Dimension, "This is the dawning of the age of Aquarius," or at least it was back in 1969. Apparently, the current pattern and position of stars many light years away from here is supposed to inform us about the geo-political outlook of human civilization. Astrology is also supposed to tell us things regarding our birthdays. Each of us was born in certain months corresponding to our own zodiac sign: Aquarius, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagitarius, Capricorn, and Pisces. (The Chinese Zodiac offers 12 different avatars). And somehow each of these signs, describing a pattern of stars in the sky currently or at the time of our birth, is also supposed to tell us about ourselves, our fortune, and our fate. How so? Well, that's the problem. Modern science took a different turn when it came to studying stars. Astronomy got picked for the team, and Astrology was left standing in the cold, estranged from science. Modern science distinguished theories by their predictive power, testability, and essentially, the "scientific method." While astronomy made the cut, astrology did not. Its theories are too esoteric, supernatural, vague, unfalsifiable, or generally unreliable. However, even though astrology hasn't passed muster as real science, it survives today largely in the form of amusing horoscopes and dodgy singles-bars (Hey babe, what's your sign?).

Plant and Tree Myths

7. Bananas grow on Trees
Bananas grow on something the size of trees, but the Banana "tree" is not actually a tree. The banana plant, which can grow up to 25 feet, is actually the world's largest perennial herb. When you carefully inspect a banana plant, you'll notice that it doesn't have woody fibers. It has strong stalks and leaves, yet it lacks the trunk and branches that would qualify it as a tree. Another related fact is that bananas are berries, since they don't produce mature seeds. So does that mean a banana split is a “herb berry” Sundae?

8. The largest living organism is the blue whale/the redwood forest/Titanosaur/etc.
The Blue whale might be the largest ocean creature. The Redwood Forest may include the tallest trees. The Titanosaur may have been the largest dinosaur in its day. And a collection of aspen trees found in Utah called Pando might be the oldest in the world. But the largest living organism on planet earth is the humongous honey fungus in the Oregon Blue Mountains. This single organism has thousands of mushroom fruiting bodies roughly 2.4 miles across. The bad news is that it's spreading. But, on the bright side, its mushrooms are edible. Bon appetit!

9. The mustard seed is the smallest seed
Many seeds are smaller than the mustard seed including duckweed, watermeal, and poppy seeds. The smallest seed on record is the orchid seed. But even though the mustard seed isn't the smallest, it's still pretty small, especially when compared to other seeds sown by ancient and modern gardeners. This myth has biblical origins. In the biblical account, Jesus is reported as saying that faith is like the mustard seed, which is "the smallest seed on earth" yet it grows to be the largest garden plant giving shelter to birds of the air (Mark 4:30-32). The error may be in the mind of the reader, interpreting literally what was a generalization or hyperbole (exaggerated phrasing common in informal language). Moreover, the mustard seed was quite possibly the smallest seed that that audience would have known, and it could have produced the largest garden plant they would have had in their gardens in ancient Israel.

Human Myths

10. We have five senses
Besides the five empirical senses (sight/visual, sound/auditory, touch/tactile, taste/gustatory, and smell/olfactory), there are at least four other senses that are rarely cited: proprioception—sensing one's orientation in space; thermoception—sense of temperature; equilibrioception—sense of balance; and interoception—sense of one's physiological condition. The next time someone talks about their "5 senses," you can say that you have "9 senses" and then sit back and let them think you have superpowers.

11. Piltdown Man

This one is not so much a myth as an outright hoax. In 1912, at Piltdown Village in Sussex England, Dr. Charles Dawson came across an astonishing fossil, a skull and jaw bone with mixed human-ape features. This discovery came to be known as “Piltdown man” and was widely touted as the best specimen of the “missing link” between man and ape. The problem? Carbon dating methods later revealed it was no older than 50,000 years, disqualifying it from “missing link” status. Moreover, the skull and jaw had marks of artificial staining and a workman's file. Apparently, Dawson, his students, or his colleagues had combined fragments of jaw and skull from two different species, human and ape, artificially stained the pieces to give the appearance of age, and filed down the teeth and jaw to make them fit with the skull fragments. While this myth is now a well-known hoax, it was touted as a legitimate discovery until the 1950's—40 years later! School children were taught the hoax was fact until their text books were updated. Piltdown was a letdown and one of history's worst science debacles.

12. Human beings evolved from apes
Even the most rabid critics and most rabid supporters of evolution can agree on this point. The standard evolutionary account is that human beings and the higher apes (gorillas, bonobos, orangutans, etc.) evolved from a common ancestor often referred to as the “missing link.” Humans did evolve from an ancestor that was far more ape-like than humans. But this is far from saying that humans evolved from apes. Humans did not evolve from chimps, rather they shared a common ancestor.

13. Humans use only 10% of their brains
The human brain is quite busy all day and night using about 20% of the body's resources and never really “turning off” until death. Meanwhile, most every part of the brain is busy doing all sorts of things even when you aren't paying attention. In fact, various parts of your brain are active all the time, far more than the mythical 10%. Depending on how you use your brain, and how you care for it, there's always the possibility of tapping into unrealized potential but it's not because your gray matter was sitting idle before. Learning a new skill, gaining a new memory, or thinking about a person's face can all stimulate your brain in different ways but they aren't activating an unused part. Instead, they are utilizing an active part for a new purpose.

Animal Myths

14. Bats are blind
Bats see in black and white. And at night they see better than we do. They lack color receptors; but in low light, we can't see colors either. Try it some time. On a dark night or in a pitch black room, turn on a flashlight and point it at something colorful; then slowly cover the light till that color fades into shades of black and white. Perhaps this myth about blind bats arose from the fact that bats don't see as well as we can in daylight, or because they have sonar and can navigate without sight. They see just fine for their environment. We could say that bats see better than most referees, but that's not saying much.

15. Sharks don't get cancer

Sharks do get cancer, but not very often. Sharks have a compound called an “angiogenin inhibitor” that reduces a tumor's ability to form blood vessels for processing waste products. As a result, tumors die by effectively drowning in their own waste. Because of this compound, shark cartilage holds some promise for cancer research. But so far sharks haven't been able to cure cancer for themselves or anyone else. No human use for this compound has yet been developed. So don't pull out your wallet the next time a “Shark oil” salesman comes through town promising a cure for cancer.

16. A severed earthworm will regenerate into two earthworms
This myth is close, but not quite right. Planarian flatworms, when severed, can regenerate into two or more new worms, but earthworms cannot. Earthworms have a distinct head and tail, and while the head portion can regenerate a new tail, the tail cannot regenerate a new head. Earthworms still have a remarkable ability to regenerate most of their body if injured. But planarian flatworms can regenerate a whole body from a severed part as small as 1/300th of the original worm. That's like growing a new “you” from just your pinky toe!

17. Elephants are afraid of mice
This myth seems to have originated from children's stories. It would look funny for such a big creature to be scared of such a little one. Regardless, elephants have no particular fear of mice. They do however have poor vision and are fairly slow moving. That means elephants might be big and strong, and even brave, but they can still be startled when a small animal, like a mouse or bird, darts past and surprises the lumbering pachyderm.

18. Bulls become angry at the color red
Bulls and other cattle are partially color-blind and cannot see the color red. They are, however, testy and defensive creatures that will charge when threatened, frightened, angry or just annoyed. Their fight or flight instinct is simply biased toward "fight." In bull fights, the matador may wield a red cape (the muleta), but it is the matador's taunting, threats, and overall behavior that make the bull charge. Bulls don't mind the sight of red, but they do however get angry at the sight of jerks. But who can blame them for that?

19. Goldfish have a 3-7 second memory
Of all the sea creatures, the octopus is probably the smartest, blue whales are the biggest, and goldfish are neither. But to be fair to the poor little guy, he's pretty adorable for his size, and he's not as dumb and forgetful as you might have heard. Goldfish can learn basic survival skills and remember them for up to three months. They can even tell time. In lab tests they could be conditioned to push a lever for food at roughly the same time each day. That 3-month memory is much longer than 7 seconds. They need a reasonably long-term memory in order to find and recall food sources and avoid the hideouts of their predators. While goldfish might remember past seven seconds, their attention span still grades pretty low, right around the level of teenagers.

20. Duck quacks don't echo
Duck quacks, honks, yelps and squeaks do echo. Perhaps this myth arose from the landscape of duck ponds. When a duck quacks from a low-lying duck pond, in a flat landscape, there's nothing for the sound waves to echo against. And even if there were some hills and mountains nearby, the quacks could be too faint to produce an audible echo. That's a matter of volume that applies to any sound. Duck quacks have no special sonic quality to prevent echoing. You can test this yourself. Grab a duck and take it inside a gym. As it squirms and spews a litany of squeaky profanities, you'll hear the gym filled with reverberant quacking.

21. A mother bird will reject its baby if it's been touched by a human
Most birds have a poor sense of smell and wouldn't know the difference. So they the mother bird wouldn't know if their baby was handled by a human anyway. If you find a baby bird on the ground, it is probably learning to fly and shouldn't be touched anyway. Perhaps this myth about baby birds arose when well-meaning kids tried to help fallen baby birds back into their nests, or tried to pet baby birds that aren't yet strong enough to handle their clumsy touch. It's also not wise to touch baby birds because an angry mama bird might fly in your face or peck at your head and call you nasty names in bird language. Overall, mother birds are much more loyal to their babies than this myth suggests.

22. Houseflies have a lifespan of 24 hours
Lifespans in the animal kingdom, even within a species, can vary widely. Our average lifespan currently ranges from about 49 years in Swaziland to about 82 years in Japan. The world average, in 2010 was 67.2 years (for details see the CIA World-Factbook). House pets usually have a shorter life span. The oldest dogs cracked 29 years, and the oldest cat broke 38 years. While our unwanted buzzing guests, the common houseflies, don't average nearly as long a lifespan as our's, they can live up to a month. This myth probably mistakes the housefly for the mayfly, which, depending on the species, may have a lifespan between 5 minutes and 24 hours. Time really does fly for mayflies!

23. Ostriches stick their heads in the ground when scared
Ostriches aren't terribly smart birds, but this kind of behavior is beneath even them. Being large birds with small heads, it may look like they are hiding their heads whenever they bend down for food or nose through a small hollow for roots and seeds. So what do ostriches do when scared? They can run pretty fast, up to 31 mph. For comparison, the top speed clocked for any human is 28 mph. So ostriches are fast enough to escape a lot of predators. But if that doesn't work, ostriches have been known to respond like opossums by flopping to the ground and playing dead. It's not the most exciting defense mechanism, but apparently it works.

24. Birds die from eating wedding rice
The theory is that when a wedded couple walks the gauntlet of tossed rice, the ground is left covered in dry rice. Birds come by and eat the rice, then later drink water. The rice expands in the bird's stomachs. Kaboom! The birds explode, or just rupture internally. This theory doesn't work. The temperature inside the bird never gets hot enough to cook and swell the rice. If you've ever cooked rice, you may remember how the rice just sits at the bottom of the water pot until you raise the temperature enough to start cooking the rice. In short, the rice would need to be cooking to expand, and that would give the bird something much more important to worry about.

25. Dog mouths are cleaner than our mouths
Dog mouths are no cleaner, and are in fact, much dirtier than human mouths. Dogs are known to transmit rabies, tetanus, pasteurela and most any other contagious disease. Dog mouths are teeming with bacteria because they eat and lick all sorts of gross things like garbage, carcasses, and of course, poop. Since dogs don't have hands with opposable thumbs and they walk on all fours, they use their face and mouth to do a lot of things we would use our hands to do. A dog's mouth functions as its hands, its washcloth, its toilet paper and so on. Next time you want to let your dog lick your face, remember where that mouth has been. Dog mouths are very dirty.

Okay, I know we said "25 Science Myths" but here's one more. . .

26. Opossums sleep while hanging by their tails
This one is almost true, but their musculo-skeletal system doesn't allow it. Opossums (Didelphimorphia), not to be confused with Australian possums (Phalangeridae), are the most common marsupials in the Western Hemisphere and in North America. These curious little marsupials have some pretty incredible abilities, but sleeping upside down while hanging from their tails isn't one of them. They have almost total immunity to snake venom and rabies. They are also prolific omnivores capable of eating most anything that's not poisonous. They are excellent at controlling garden pests. They have a range of defense mechanisms beyond the most famous tactic of playing dead. They are great climbers, too, because of the opposable thumbs on their hindlimbs and their strong tails. Baby opossums are able to hang for a moment by their tails but only for a moment. Adult opossums are much too heavy to do this. And neither babies nor adult are known to sleep in that position. I'm sure they'd get a massive headache if they tried.

There you have it, 26 Science Myths Debunked. We welcome your comments below. If you are wondering about any other science claims that seem kind of fishy, ask us or check out the claim online. If these myths have made you wonder more about the world around you, the animal kingdom, or the physical laws behind it all, then maybe you should look into a science degree or even a degree in investigative journalism.