Myth America

LiveScience has an interesting feature up this week: the best-known science myths. Some choice excerpts:

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.

Humans use only 10 percent of their brains
This media darling has been around for at least a century. Fortunately, it's just not true. MRI imaging clearly demonstrates—with fancy colors no less—that humans put most of their cerebral cortex to good use, even while dozing

Water drains backwards in the Southern Hemisphere due to the Earth's rotation
Not only is the Earth's rotation too weak to affect the direction of water flowing in a drain, tests you can easily perform in a few washrooms will show that water whirlpools both ways depending on the sink's structure, not the hemisphere.

A penny dropped from the top of a tall building could kill a pedestrian
A penny isn't the most aerodynamic of weapons. A combination of its shape and wind friction means that, tossed even from the 1,250-foot Empire State Building, it would travel fast enough merely to sting an unlucky pedestrian.

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.