Facts you learned in school that are no longer true

Though Pluto had been recognized as the ninth and smallest planet in our solar system for decades, its status was downgraded to a dwarf planet in 2006. The discovery of other Kuiper Belt Objects that are roughly the same size as Pluto led to its change in status.

Oral hygiene and dentistry weren't exactly stellar in the 18th century, so it makes sense that George Washington and many of his contemporaries had false teeth. However, the first president’s teeth weren’t actually made of wood, as many students learn, but of lead, human teeth, cow teeth, and ivory.  

The idea of van Gogh slicing off his ear fits well with the idea of the tortured artist, but unfortunately, this fact isn’t true. In 2009, two German historians released a book that claims that van Gogh actually lost the ear in a sword fight with artist Paul Gauguin.

Christopher Columbus may have a holiday named after him, but he didn’t actually discover America. Though the explorer did land on several islands in what is now the Bahamas, he never actually set foot on the North American continent. Bad news: He most likely didn’t sail here in the Niña, Pinta  and Santa Maria either.

Sir Isaac Newton still can be credited with discovering gravity, but he didn't get his bright idea after being smacked in the head by a falling apple. His brain wave actually occurred after watching an apple fall from a tree.

The German-born physicist was certainly eccentric, but that didn’t make him a bad student. Though teachers might like to tell students that Einstein wasn’t always good at math to encourage them, he was actually always successful in school.

Almost every detail that students are taught about the origin of Thanksgiving is false. No turkey or pumpkin pie was served, the Pilgrims didn’t invite the Native Americans to their table, and they didn’t celebrate Thanksgiving on the fourth Thursday in November.

Satellites orbiting Earth can see the Great Wall of China, but that’s not the only man-made structure that’s visible. If the weather conditions are right, astronauts in the International Space Station can see the pyramids, large bridges, and other large cities.

The cartoon depiction of the raindrop looks a lot like a tear, but scientists say this isn’t accurate. Most falling raindrops actually look flat—more like hamburger buns—according to the United States Geological Survey.

Despite what your English teacher may have said, you can actually start a sentence with a conjunction. Grammar purists won't be happy about it, but who cares?

Possibly confused by the fact that some of your veins appear blue, many schoolchildren believe that blood only turns red when it’s exposed to oxygen. However, this just isn’t true.

Odds are, some resourceful parent or teacher decided to make up this untruth to stop kids from swallowing gum. Though chewing gum isn’t as easily digested as other foods, it won’t remain in your body for any length of time.

July 4, 1776 was the day the 12 colonies signed the Declaration of Independence. In reality, America didn’t become truly free until after the country won the Revolutionary War.

Two substances are actually harder than diamond: wurtzite boron nitride and lonsdaleite. However, since both are unstable in nature and extremely rare, you’re very unlikely to encounter either.

Biology classes typically include a lesson on the classification of life. Many children learned that there are five classifications—animals, plants, bacteria, fungi, and protists—but scientists now believe that there are as many as eight.

There is a nugget of truth to this idea: About 90 percent of brain cells are white matter and are never used for thinking. However, all parts of the human brain are in use at all times—just not specifically for thought.

These reptiles do frequently change colors, but they don’t use these special abilities to camouflage themselves. Instead, chameleons use different colors to communicate with each other and control their body temperature.  

Teachers thought they were absolutely correct when they taught students that Earth was the only planet to contain water. However, recent NASA findings reveal that liquid water also flows on Mars.

No one is claiming that goldfish are particularly bright, but they at least deserve a little bit more credit than most people give them. Studies have shown that goldfish appear to remember what happens around them for as long as 12 days.

Saying that the United States is a democracy might be oversimplifying our government. In fact, the founders established the country as a republic that combined elements of monarchy, aristocracy, and democracy.

During the mass hysteria about witchcraft culminating in the Salem Witch Trials, witches were sentenced to death. However, they weren’t actually burned—instead, most were hanged.

An article written in the 1970s speculated that the Salem Witch Trials were actually triggered by ergot poisoning. Ergot—a fungus that can grow on rye in wet conditions—very possibly made its way into early settlers’ bread, but its hallucinogenic properties were likely not strong enough to cause such mass hysteria.

Despite the popular image of Pilgrims wearing all black and white with a wide-brimmed hat and buckled shoes, this stereotype isn’t true. Black and white outfits were typically reserved for Sundays and special occasions, while men and women wore all kinds of colors during the week.

Children who grew up between the 1970s and 90s likely remember the food pyramid, a visual aid that taught students to eat mostly carbs, then vegetables and fruit, then meat and dairy products. Since then, the United States Department of Agriculture has totally overhauled its nutrition program to promote a more balanced diet of whole grains, fruit, vegetables, and protein.

Many pimply teenagers probably remember a health teacher instructing them to lay off the chocolate to clear up their skin. While there is some evidence that sugar can exacerbate acne, most doctors agree that chocolate itself can’t cause breakouts.

Here’s another common lesson that teachers likely used to make their lives easier: You can safely eat anything that drops on the floor as long as it didn’t rest there for longer than five seconds. In reality, however, it only takes a fraction of a second for bacteria to contaminate a piece of food.

Though parents still probably don’t like the idea of their kids drinking coffee at a young age, they’ll have to find another rationale to stop them. There is no evidence that caffeine can have significant impacts on physical growth.

In 1974, Dr. William Cook wrote a letter to the American Academy of Pediatrics detailing his belief that sugar causes hyperactivity in children. The idea took off from there, though studies have failed to find any link between the two.

Dogs do see colors differently than humans, but they’re not actually colorblind. In fact, canines can see blues and greens, and have better vision in low light than humans.

Teachers often used this fun fact to teach physics principles like velocity. However, the math just doesn’t add up: At most, a penny falling from the top of the Empire State Building would hurt you quite a bit.