Here is a link to Live Science and their list of the most popular myths in science. And for your reading pleasure I present a few of these myths.
It takes seven years to digest gum
While it may prove a bit more difficult to break down than organic foodstuffs, chewing gum gets no special treatment from the digestive system. Doctors figure this old wives’ tale was invented to prevent kids from swallowing the rubbery substance.
The five second rule
Having an arbitrary rule justifying the consumption of food dropped on the floor within a certain time frame is convenient, especially when said food is a brownie. Unfortunately, tests (and logic) confirm that germs will stick to most foods right on contact.
The Great Wall of China is the only manmade structure visible from space
There are several variations on this folkloric statement, and they’re all quantifiably false. Astronauts can spot the Great Wall from low-Earth orbit, along with plenty of other things like the Giza pyramids and even airport runways. But they can’t see the Wall from the Moon.