Let’s face it, nobody’s perfect. Once in a while everyone gets something wrong that they previously felt so confident was right. But don’t sweat it, it happens all the time in the sciences. In fact, challenging our preconceived notions is often times the only way we can further our knowledge of the things in nature that we don’t quite yet have a complete understanding of. So before go thinking you’ve got it all figured out, you should probably familiarize yourself with these 15 common misconceptions that people everywhere are still trying to pass off as factual information.

15. Cracking Your Joints Will Lead to Arthritis

Cracking knuckles and joints are still a relatively mysterious phenomenon. Though there are numerous theories as to why joints crack or pop, the exact cause is still unknown. Nevertheless, the general consensus among the professionals seems to be that cracking your joints isn’t harmful and it won’t lead to arthritis. However, if the cracking is accompanied by pain, there could be underlying problems with the structures of the joint, such as injured ligaments or loose cartilage.

14. Reading in Dim Light Will Ruin Your Eyes

Just like eating carrots won’t improve your vision, reading in dim light won’t ruin it. In fact, the only harm reading in a dimly lit environment might cause is a little extra eyestrain, which should go away in a few moments if you simply rest your eyes. Of course, this misconception should have been corrected long ago given the fact that prior to the 1900s people had been reading by dim candlelight for centuries without there being reports of a rapidly deteriorating eyesight epidemic.

13. People With Tourette Syndrome Are Always Shouting Profanity

Despite the common misconception that Tourette syndrome is characterized by sudden uncontrollable bursts of profanity, only 10 percent of Tourette patients actually exhibit that symptom. The vast majority have much milder expressions such as tics, shoulder-shrugging, rapid blinking and compulsive throat-clearing.

There is, however, a very small faction of Tourette patients who have a condition known as Coprolalia. This is an extreme example of a vocal tic marked by the involuntary utterance of obscenities, profanities and derogatory remarks.

12. Eating Carrots Will Improve Your Eyesight

If you were a picky eater as a child you can probably remember your parents telling you that you’ll need to wear glasses if you don’t eat all of your carrots. While it’s true that carrots are a good source of vitamin A, which promotes healthy skin and eyes, eating them won’t give you sharper vision. In truth, the supposed link between carrots and better vision stems more from manufactured propaganda than any actual science. During World War II, Britain’s air ministry put the word out that a vegetable-rich diet helped pilots to better see Nazi bombers in the sky at night. That was a lie fabricated to prevent the Nazi’s from discovering the existence of Interception Radar, which alerted allies of incoming bombers before and was the real reason for the Royal Air Force’s successful defense.

So even though eating carrots won’t give you more acute vision, believing they did might have helped us win World War II.

11. The Color Red Gets Bulls Overexcited

As early as the 1700s Spanish matadors began using a small red cape, or muleta, in bullfighting. Ever since then, the myth has been perpetuated that the color red drives bulls mad.

MythBusters actually tested this idea by placing makeshift matadors in an arena. Each of the dummies were holding a different colored flag and the aim was to see if one particular color seemed draw the bull’s attention more than the others. The test showed that red, blue and white flags got equal, half-hearted attacks when they were motionless. An aggressive charge response from the bull could only be evoked by flags that were being waved.

As it turns out, the color red doesn’t seem to make bulls charge or get fired up in the slightest. In fact, bulls don’t seem to have any sort of color preference at all. They’ll just go for whatever object happens to be moving the most.

10. Chameleons Change Colors to Blend in With Their Surroundings

Chameleons are famously known for being able to change color. They achieve this feat by way of specialized cells called chromatophores that are able to change their hue.

Most people think that chameleons change color in response to their environment to better enable them to blend in with their surroundings and hide from predators; however, this actually isn’t the case. The real reason why chameleons change color is for communication. Depending on their color, they can signal aggression, receptiveness, mating behavior, and a host of other moods. So a perfectly calm chameleon might have a pale green appearance, while a chameleon that’s looking to mate will take on a bright yellow color.

9. The Right Half of Your Brain Controls Creativity While the Left Half Controls Logic

It has been a long-standing belief that people are either right-brained or left-brained and their nature, in turn, is either based on creativity or logic. But the idea that our brain has a dominant side responsible for governing our character—the things we’re interested in and the ways we conduct ourselves—is complete nonsense according to scientific research.

Using brain imaging techniques, neuroscientists have show that while the brain does use different sides to carry out certain functions, there is no one side that’s shown to be dominant over the other when it comes to determining our personality. Really, the biggest difference between the two sides is that the brain’s right hemisphere controls the muscles on the left side of the body, while the left hemisphere controls the muscles on the right side of the body.

8. Daddy Longlegs Are the Most Venomous Spiders in the World but Their Mouths Are Too Small to Bite Humans

A widespread myth claims that daddy longlegs are the world’s most venomous spiders and that the only reason we humans are safe from them is because their fangs are too small and weak to break through our skin. But it turns out that assumption is incorrect on both accounts. Daddy longlegs typically live in dark, moist places and feed mainly on rotting vegetable and animal matter. They don’t have fangs or venom glands, therefore they could never poison something as large as a person. However, it is worth mentioning that some daddy longlegs can produce defensive secretions that could be poisonous to very small animals if ingested.

7. You Can Catch a Cold From Cold Weather

Why is winter known as the cold season? It’s a common observation that when the weather gets cold outside, people tend to get sick more. But this doesn’t really have anything to do with the actual temperature outside, rather, it’s related to the way we behave when the temperature drops. According to Dr. Sorana Segal-Maurer of the Division of Infectious Disease at New York Hospital Queens, when the weather turns cold we all run indoors where we remain in close quarters and breathe recycled air that likely has a higher concentration of viruses than it would in the summer months. The dry, cold conditions also make it easier for viruses to spread from person to person.

6. Rabbits Love Carrots

Like humans, rabbits like to eat a wide variety of foods, but for some strange reason there are a lot of people who think they’d be perfectly happy living off nothing but carrots. The reality is rabbits don’t eat root vegetables of any kind in the wild, meaning carrots were never actually a part of their natural diet.

In 2012, the RSPCA even found that feeding your pet bunny carrots can have a negative effect on their health because it can lead to tooth decay and digestive problems.

So if rabbits don’t really eat carrots, where the heck did that notion come from in the first place? As it would happen, all evidence points towards Bugs Bunny.

5. Different Parts of Your Tongue Sense Different Tastes

In school many of us were taught that our tongues have different areas that contain specific taste receptors that are sensitive to sweet, sour, salty or bitter foods. Now scientists say that lesson was all a lie. They’ve discovered that each of the several thousand sensors on our tongue can recognize any of those tastes and it’s really the way our brain interprets the information that determines how things taste rather than what part of our tongue the food touches.

4. Eating a Lot of Sugar Will Give You an Energy Rush

Lots of parents will swear that a single piece of birthday cake will transform their child from an obedient little angel into a wild frosting-faced animal that bounces around the room and screams at the top of their lungs. But according to a double-blind research study conducted in 1994, eating a lot of sugar doesn’t affect kids’ behavior or cognitive skills. There is something that does change when children are seen gobbling up a lot of sugar though, their parents’ expectations.

In a separate study it was found that any parent who thought their kid had just had a sugar fix was more likely to report the child as being hyperactive, even if the supposed sugar fix was just a placebo.

Of course, this doesn’t mean you should just give your kids all the sugar they want now, there are still plenty of good reasons to moderate sugary treats—fear of turning them into crazy little sugar monsters just isn’t one of them.

3. Undercover Police Officers Have to Identify Themselves if You Ask Them

This is actually a big misconception. Any law requiring and undercover police officer to identify themselves would put them in danger. An undercover cop is only required to identify themselves if they are taking some sort of legal action against you. Otherwise, officers are permitted to lie when interrogating someone as long as the deception doesn’t force an innocent person to confess to crimes they didn’t commit. For this reason, many jurisdictions require interrogations to be recorded.

An example of a legal lie would be if an officer told a suspect that he has a video tape of the crime in question being committed. Since an innocent person would have nothing to fear given this knowledge, it’s of no concern to them. However, a guilty suspect would probably be worried if the police had him on tape committing the crime, so it could solicit a confession.

2. You Only Use 10 Percent of Your Brain

This is one of the most annoying misconceptions that always seems to pop up in Hollywood science fiction films, where some normal person takes a wonder drug or undergoes a procedure that allows them to use a larger percentage of their brain—instantly gifting them with superhuman abilities. This perpetuated notion that large parts of the brain remain unused, and could subsequently be “activated,” is wholly the domain of urban legend. Though there are still enough mysteries concerning the brain that haven’t yet been solved, the physiology of brain mapping indicates that all areas of the brain have a function, they’re just not all operational at the same time. And if they were, you’d probably be experiencing a nasty seizure.

1. You Were The Fastest Sperm

In the case of sperm, it’s been a long-held belief that the fastest swimmers have the best chances of fertilizing the egg. However, recent research has now proved that idea to be nothing more than a myth.

Using fruit flies, a team of researchers at Syracuse University was able to monitor sperm in real time as it made its way through the female reproductive tract. They noticed that sperm from each mating period would swim through the female bursa into the storage area and remain there until the eggs were released. It is in the storage area where the sperm fight it out to see who gets to fertilize the egg. After each mating period, new sperm will try to get rid of the sperm from previous mating sessions. The female will then eject the displaced sperm, eliminating them from the mating game. Interestingly, it was also noted that the longer slow-moving sperm were better at replacing their rivals, which had the effect of making them less likely to be ejected from the storage area when compared to their faster moving counterparts.

According to the scientist, the discovery that slower moving sperm possess this sort of advantage seems very counterintuitive.