An apple a day keeps the doctor away, coffee stunts your growth, and eating carrots will give you enhanced vision at night, right? Wrong. Many perfectly-educated people are led astray by various advertising campaigns, well-written articles on the internet, or even an annoying friend who seems to think they know every interesting fact on the planet. However, many of these “facts” have little to no scientific evidence to back them up or in some cases have significant evidence against them.

MYTH: Popping or cracking knuckles causes arthritis.

The sound popping or cracking knuckles makes does not come from the rubbing together of bones or cartilage but rather from air bubbles trapped in between the knuckles of fingers and toes alike. When someone pops or cracks their knuckles, they are simply releasing that air which makes a sort of popping noise.

MYTH: An hour of exercise a day is good enough.

The United States is the eighteenth most obese country in the world. As a result,  advertising campaigns aiming to combat this problem have sprung up around the nation, many of them specifically focusing on children. NFL Play 60 is a major campaign, encouraging students to get up and get active for sixty minutes a day; however, exercise alone is not always enough. According to USC Professor of Medicine and Engineering David Agus, sitting for five or more hours in a day, on a health basis, is the equivalent of smoking a pack of cigarettes every day.

MYTH: It takes seven years for gum to dissolve in your stomach if swallowed.

Chewing gum has surely become a staple in every adolescent’s diet just as spreading this myth has become a habit of every parent, teacher, and babysitter. But scientists have time and time again proven that gum passes through the digestive tract just like any other substance your body does not need or cannot digest. Only in rare cases does it ever cause more than just a small stomach ache.

MYTH: The tryptophan in turkey causes sleepiness.

It has been a few months now since that big Thanksgiving Day feast when everyone gathers around the dining room table to chow down on their favorite foods, including that tryptophan-filled turkey. After dinner, everyone huddles around the TV to watch the annual football game only to pass out somewhere around the start of the second quarter. It has to be all that turkey, right? After all, it does have sleep-inducing tryptophan in it. But, while scientists say tryptophan can chemically help a person relax, there is simply not enough of it in turkey for it to affect a human being’s consciousness. Instead, the likely culprit is the amount one eats, not what they eat.