We’re taught loads of scientific facts formally or informally from an early age. And they’re all said to be true and reinforced by our common sharing of them. As time progresses, scientists use new methods to find some of those facts (or, in some cases, rumors that are so pervasive they enter the common psyche as perceived true facts) wrong. In this list, we break down some so-called “facts” we believed to be true and show what the science really says.
Heavy drinking kills brain cells
Over drinking is not the only way alcohol kills brain cells. It can also kill them from a deficiency of thiamine for those getting most of their calories from alcohol and, for very heavy drinkers, from excitotoxicity (nerve cells being killed from overabundant neurotransmitter presence) when dropping alcohol “cold turkey”. It’s true that everything is best in moderation, even when it comes to detox.
Lightning doesn't strike the same place twice
Lightning can and does strike the same place twice. Since lightning’s aim is to find the fastest path to the ground, tall buildings, trees, and such are at the greatest risk because the higher the object, the more likely it is to be struck.
The tongue has specific taste zones
The tongue doesn’t actually have specific receptor areas for bitter, sour, salty, and sweet flavors. In fact, there is a fifth taste (umami, for savory/meaty flavors) and all zones of the tongue can sense all flavors.
A penny dropped from the Empire State Building can kill you
A penny dropped from the Empire State Building’s height won’t kill you on street level. Terminal velocity (the maximum speed an object can reach in free fall) for a penny is, at its fastest, 50 mph (80 kmh) – not enough to give you more than a bump for a bit.
Being in a vacuum causes our eyes to pop out
A human body or any organism won’t comically explode if put into a vacuum. Rather, the lack of oxygen would cause you to lose consciousness and die after just a few minutes.
Blood in your veins is blue
The de-oxygenated blood returning to the heart through the veins is not truly blue. (It’s actually a darker red.) School diagrams show veins in blue for clarity, but the blue color for veins actually comes from light hitting our skin and scattering into the wavelength on the color spectrum we notice as blue.
Your fingers swell up from water
The swelling of your fingers at the pool or after long showers isn’t from absorbing water, rather it’s from your body narrowing blood vessels by contracting their muscle walls, causing them to look wrinkled. It’s believed this may have given our ancestors better grip in wet areas, though it’s been shown we can’t handle things any better with wrinkled digits.
Sunflowers follow the sun across the sky
Sunflowers don’t follow the sun across the sky but point East all day. Before the famous flower heads appear, though, the baby buds follow the sun to set the soon-to-be flowers in the right direction. Plants can be smart too.
Gum takes 7 years to digest
Maybe you remember hearing on The Magic School Bus that gum takes 7 years to digest. Not so. Gum, being indigestible as insoluble fiber, passes through your digestive system at the same rate as whatever else you ate that day.
Goldie the fish has a memory of 5 seconds
Your home goldfish has a better memory than you think. A goldfish’s memory doesn’t last just a few seconds; rather, it’s upward of a few months.
Bats can't see
Bats aren’t blind. Most smaller bat species do primarily use echolocation (sound waves) to find their way around, but all bats have working eyes. Larger bats even rely on their night vision as opposed to echolocation.
Bulls are driven mad by red
Bulls don’t charge a matador’s cape because it’s red; they see red as another shade of gray. The matador’s taunting and flag waving is what causes bulls to charge.
The asteroid impact killed off all the dinosaurs
Not all dinosaurs died during the asteroid impact marking the end of the Cretaceous period. Modern-day birds trace their ancestry to smaller theropod dinosaurs that survived the impact (though how, is still a mystery).
Drinking alcohol warms you up
In a sad blow to everyone who lives in the far north, booze won’t really make you feel warmer. (Now, tingly? That’s another story.) Drinking alcohol dilates (expands) blood vessels, bringing a higher quantity of warm blood to near-surface skin. Your body temperature actually lowers due to heat transfer between shallow vessels and the cold air.
Seasons are due to how close we are to the sun
Earth’s seasons aren’t due to our proximity to the sun. It’s due to Earth’s 23.4 degree tilt.
Drink 8 glasses of water a day
The 8 glasses a day is an overly generalized rule, much like the 2,000-calorie diet. How much water you need depends on the temperature of your environment, your activity level, your size, and other variables.
Water flows the opposite way in the different hemispheres
Water doesn’t flow down the toilet in different directions in the Northern and Southern Hemispheres. The Coriolis effect (the curvature of winds, currents, and other bits moving across Earth’s surface due to the rotation on its axis) is most often cited for the supposed reversed flow, but systems have to be massive for the Earth’s rotation to have any effect. The best example is a hurricane or typhoon.
Middle Ages life expectancy was 30 years old
Though life expectancy was much lower in the Middle Ages, it was nowhere near as low as 30. Life expectancy is more of an average so the high rate of infant mortality at the time pulled the rate way down. Some modern methods don’t factor a person into the average until they’ve reached aged 12.
Overloading on Vitamin C keeps you from getting sick
Drinking orange juice (or downing a bunch of Vitamin C) doesn’t keep you from getting a cold, but it can shorten the duration once you have one.
Don't go swimming for 30 minutes after eating
No more waiting to take a dip after eating. Though swimming at high intensity (think Michael Phelps) may lead to cramps, for those of us not training on an Olympic-level, the old tale of increased blood flow to the stomach for digestion doesn’t cause us to cramp up in the pool. Drinking alcohol and swimming? That’s a different story.
Humans only use 10% of our brains
People only use 10% of their brains right? Wrong! Though only a small amount of neurons are firing at any one moment, the rest are still playing a role somewhere.
An earthworm cut in half will grow into two worms
Earthworms don’t grow into two worms when cut in half. Only the front part (with the mouth) will continue feeding and live on.
We have five senses
Not to say we’re all instant superheroes, but scientists today have determined that we have up to 20 senses, including thermoception (temperature) and equilibrioception (balance).
Metal in the microwave will burn the circuits
Putting metal in a microwave won’t fry its electronics. It’s still dangerous, as metal objects can become hot enough to cause damage to your skin or the microwave, but it won’t send it to the graveyard.
You can see the Great Wall of China from the moon
The Great Wall of China can’t be seen from the moon. Even from a low Earth orbit like where the International Space Station lies it’s barely visible and even then you would need phenomenal eyesight and perfectly clear weather conditions.