The myth: Food that you drop on the floor is OK to eat if you pick it up within five seconds (a.k.a. the "Five Second Rule"). The reality: Germs are on the floor, and if food lands on the germs, they will stick to the food immediately. This is especially true in the kitchen, where bacteria such as salmonella thrive. Seen here is a salmonella culture, so ask yourself: Do you want to eat that?
Image Credit: AP Photo/Elaine Thompson
The myth: Acids will burn your skin, and even disfigure you. The reality: Hundreds of different acids exist, and most of them aren't strong enough to damage your skin. Vinegar and citric acid are two weak acids that we consume frequently. However, some acids are corrosive. Hydrochloric, nitric and sulfuric acids can damage skin -- like that of the woman in this picture, who was burned by sulfuric acid from batteries -- but not all acids will do so.
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The myth: Brain cells don't regenerate. The reality: The reason people believe this myth is that scientists thought for a long time that complex brains would be disrupted by new cell growth. In 1998, however, scientists in Sweden and at the Salk Institute in La Jolla, Calif., discovered that brain cells can regenerate. The learning and memory center of the brain can create new cells. Even better news is that Steve Stice, a University of Georgia stem cell researcher, discovered a process to create replicas of human embryonic stem cells that can morph into brain cells. Shown above are stem cells from a tank in his lab in Athens, Ga., Tuesday, March 13, 2007.
Image Credit: AP Photo/John Bazemore
The myth: A penny dropped from a tall building can kill someone on the ground. The reality: While people may think a penny dropped from the Empire State Building would pick up enough speed to kill a person on the ground, this just isn't true. The non-aerodynamic nature of a penny, as well as its relatively small mass, keeps this from happening. A person on the ground would most certainly feel a sting from the impact, but the penny wouldn't kill.
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The myth: Lightning doesn't strike the same place twice. The reality: Lightning can absolutely strike the same place twice. In fact, it's actually quite common -- the Empire State Building is struck by lightning about 25 times per year, for example. Lightning favors tall buildings and trees, but in a large field, lightning is likely to strike the tallest object several times before it moves sufficiently far away to find another tall target. Above, multiple bolts of lightning strike the ground in the desert north of Scottsdale, Ariz., during a late evening storm.
Image Credit: AP Photo/Scott Troyanos
The myth: There's no gravity in space. The reality: Yes, there is a lot of gravity in space. So much, in fact, that gravity is what causes stars to orbit the center of a galaxy, Earth to orbit the sun and a satellite to orbit the Earth. The reason that astronauts seem to be weightless in space is that they are orbiting Earth; they're falling towards it, but moving sufficiently sideways to miss it. In short, they're falling but never landing. At orbit height, about 250 miles (402 kilometers) above Earth, gravity is only reduced by 10 percent.
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The myth: There is a dark side of the moon. The reality: The dark side of the moon only exists as a Pink Floyd album. The sun illuminates every part of the moon at some point. There is, however, a side of the moon that is never visible from Earth. This is caused by tidal locking, which causes the moon to take just as long to rotate around its own axis as it does to revolve around Earth. We always see the same side of the moon, but the other side isn't always dark -- when we have a crescent moon, sunlight mostly illuminates the side we don't see.
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The myth: Evolution means getting better, or going from "lower" to "higher." The reality: Though natural selection weeds out less advantageous genes from the gene pool, imperfect organisms often survive. Mosses, fungi, sharks and crayfish, among others, have remained basically unchanged over long periods of time. Other species have changed a lot, and not always in ways that seem like obvious improvements. Evolving to be more "fit" doesn't necessarily mean a species makes "progress" -- it just means it is more likely to survive and reproduce in its environment.
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The myth: Humans explode in the vacuum of space. The reality: This comes from science fiction movies, not real life. Humans can survive brief encounters with empty space as long as they fully exhale beforehand. This keeps the lungs from bursting, which would send air into the bloodstream. Without oxygen, however, the person will pass into unconsciousness and die from asphyxiation. This is one reason why space suits are so important: They let us breathe in the vacuum of space.
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The myth: Synthetic chemicals are dangerous. The reality: Many chemicals made in laboratories and factories are exactly the same as those found in nature, and very few synthetic products are as toxic as natural substances. Some natural chemicals are fatal. Cyanide is a natural substance, and it's fatal at a dose of 10,000 mcg. Botulism is natural, but a thimbleful could kill half the people in a city. Even common plants like poison oak and poison ivy are dangerous. On the other hand, the majority of prescription drugs are synthetic, and they've helped dramatically increase life expectancy.
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The myth: We only use 10 percent of our brains. The reality: If this is true, why is it that damaging almost any part of the brain inhibits some vital cognitive or regulatory function? Variations of this myth state that each of us only uses 10 or 20 percent of our dearest organ, but in fact, imaging technologies like fMRI reveal that we use most or all of our brains in one way or another. What is certainly true is that we all fall short of our maximum intellectual potential in the way we live our lives -- which is probably the metaphorical origin of this pseudo-factoid.
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The myth: Going out in chilly weather causes you to catch cold. The reality: A cold is caused by a viral infection of the respiratory system. Viruses don't magically appear in your body because you went out to get the mail without your scarf and mittens. Most of the time, we contract viruses when we come into close contact with other people who are already infected, which means you're putting yourself at greater risk for disease by staying inside by the fire with your friends and family than you would if you wandered off into the icy woods all alone.
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The myth: Studies show vaccines cause autism. The reality: There is no salient evidence linking childhood vaccines to autism spectrum disorders (ASD). This myth has a clearer origin than most: A 1998 paper in the respected medical journal The Lancet seemed to indicate that the common MMR vaccine could lead to the development of ASD. Not only was this study later retracted and denounced by the journal, but many characterized it as a work of outright scientific fraud, in which researchers had tampered with the data to fit the desired conclusions. Despite this retraction, many parents have remained wary of vaccines. While there's no conclusive proof that vaccines do not cause ASD, no significant research stands to show that it does.
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The myth: Rubber tires protect a car from lightning. The reality: The tires have nothing to do with it. If you're unlucky enough to be caught out in a thunderstorm, it is certainly safer to be inside a car than outside. Cars provide fairly strong fortification against lightning strikes, but not for the reason you'd think. When lightning strikes an automobile, it's actually the car's metal exterior frame that protects the passengers, acting as a conductor and passing the electrical current right along to the ground. This is the reason that a convertible, no matter how rubber its tires are, can't protect you like a hardtop vehicle.
Image Credit: AP Photo/Marcio Jose Sanchez
The myth: Sugar makes children hyperactive. The reality: Let them eat cake! Researchers have found no substantial link between the consumption of sugar and hyperactivity. A meta-analysis published by the Journal of the American Medical Association found that over 16 qualified studies, researchers could identify no significant correlation between sugar intake and cognitive performance or behavior. Of course, there are plenty of well-established links between sugar intake and obesity (as well as other problems), so parents should still know when to take away the cotton candy.
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The myth: The Big Bang theory explains how the universe was created or began to exist. The reality: The Big Bang theory extrapolates from our observations about the present universe that the early universe underwent a massive, rapid expansion that has continued to this day. Some people have interpreted the data to postulate that time, space, matter and energy had a beginning in the finite past, but the central value of the Big Bang theory is the explanation of the early expansion of the universe -- not how the universe came into being.
Image Credit: Courtesy NASA
The myth: The Earth is closer to the sun in summer. The reality: It's just not. In fact, the exact opposite is true for people who live above the equator: The Earth is closest to the sun in January, which is a winter month in the Northern Hemisphere. Of course, for people in the Southern Hemisphere, January's the best time to hit the beach and enjoy a cool glass of lemonade in the afternoon. So what causes the seasons if not distance to the sun? It's the tilt of the Earth's axis. The Earth wobbles as it rotates. Thus, your summer months are the time when your part of the globe receives the most direct sunlight, and winter months are the time when the sun's rays reach you at an oblique angle.
Image Credit: NASA
The myth: Albert Einstein flunked his math classes in school. The reality: Einstein, by all accounts, was always good at math. Other versions of this myth allege that Einstein was an all-around poor student. There's no evidence for this; in fact, remaining records indicate that the young Albert did very well in his classes and received high marks. It's a wonderful excuse for underachieving kids to feed their parents: "Even Einstein got D's!" Unfortunately, you can take no refuge in the idea of a slacker Einstein -- so study up.
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The myth: Humans evolved from chimpanzees. The reality: You are not looking at your distant grandfather -- you're looking at your distant cousin. Humans and chimpanzees evolved from the same common ancestor. Human beings share at least 95 percent of their DNA with chimpanzees, and studies of comparative anatomy and comparative genetics can show us really how much our bodies have in common with those of our hairy relatives. The reason for the similarity is that we have a common ancestor; the reason for the difference is that our genetic paths diverged at some point in the past, and we evolved different characteristics in the intervening years.
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The myth: Antibiotics kill viruses. The reality: Antibiotics are wonderful little targeted poisons that help your body kill bacteria -- that's bacteria, not viruses. Furthermore, you can't exactly "kill" a virus at all, since a virus is not really alive to begin with. When a disgusting flu or cold sets in, we all wish we could take a pill to chase it away. Unfortunately, you can't battle the germs that cause cold and flu this way, and in many cases, taking antibiotics for a viral infection could make the problem worse. Stick to your doctor's advice and only take antibiotics when he or she specifically prescribes them.
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The myth: A full moon makes people go nuts. The reality: You're only especially liable to commit murders on a full moon if you're a werewolf. For centuries, nearly all cultures have ascribed mystical powers and otherworldly influence to the bright, round face of a full moon. In fact, the English words "lunacy" and "lunatic" come from the word "lunar" -- having to do with the moon. But despite the general consent of human mythology, this notion is not borne out by science, and multiple investigations have found no substantial link between the phases of the moon and murder, aggression, insanity, vandalism of national monuments, prank phone calls, or human sacrifice rituals.
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The myth: After you die, your fingernails continue to grow. The reality: Not a bit! Think about it -- how would this even be possible? Body tissues need to burn energy taken in as food in order to grow. People don't keep eating or processing nutrition after they die. Also: At death, the heart stops pumping blood. So how would the fingers receive the oxygen needed to keep the tissues alive and produce new keratin? A similar myth also claims that human hair continues to grow after a person departs this mortal coil. It's understandable that one might assume this if one takes the Cryptkeeper as an anatomically correct illustration of a human corpse, but the jury is in on this one: Hair and fingernails stop growing when you die.
Image Credit: © iStockphoto.com/Loretta Hostettler
The myth: A penny placed on a railroad track can derail a train. The reality: Get real. Freight trains weigh many thousands of tons. This would be kind of like saying you could capsize a barge with a firecracker. The U.S. Federal Railroad Administration has no record of a coin wrecking a train, though larger obstructions like cars and rocks have caused deadly derailments, so locomotives are by no means invincible. And for that matter, neither are you -- while pennies don't derail trains, plenty of people have themselves been hit by trains or otherwise killed while trying to flatten pennies on railroad tracks. If you really want to smash a penny flat, take it to one of those machines in the gift shop.
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The myth: Bats are blind. The reality: Bats see just fine, thank you very much. Bats like Chiroderma villosum (shown above) have eyes, and their eyes work. It's as simple as that. So what's the origin of this myth? Like dogs, bats rely heavily on other senses like hearing and smell. In fact, using a hyper-advanced sound-based system called echolocation, bats are able to maintain their bearings while flying at night and to hunt nearly invisible prey in the dark. It may be the fact that these creatures are unfazed by darkness that has led people to assume their eyes are vestigial.
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The myth: The Coriolis effect is what determines the clockwise or counterclockwise rotation of water in a flushed toilet. The reality: Sadly, this is one of the rare instances in which Lisa Simpson gets the science wrong. In the sixth-season Simpsons
episode "Bart vs. Australia," Lisa educates her brother on the Coriolis effect, which she claims causes water to drain counterclockwise in the Northern Hemisphere and clockwise in the Southern. This is not really true. The Coriolis effect is the name for an inertial force that determines the trajectory of objects moving within a rotating frame of reference. For example, it helps us understand how the rotation of the Earth affects the movement of weather patterns. The amount of water in your toilet is too small to be affected by Coriolis.
Now that you've seen our Big Myths of Everyday Science Pictures, check out our 10 Science Principles You See in Action Every Day