Aside from being a rather catchy song by the Doobie Brothers, what a fool believes could make for a really long list. We’ll try to keep it brief here. But I have to say that after reading the long-winded explanation of April Fools on Wikipedia, I can’t help but wonder if maybe the entry itself is a prank. Anyway, here are some scientific facts that a fool commonly believes:

A penny dropped from a very high building can kill a pedestrian below.
Not true. It might smart a bit though.

Friction with air heats objects as they enter the atmosphere.
Not true. It’s compression of the air in front of the object that causes all the heat.

There is no gravity in space.
Not true. Objects in “space” are simply in “free fall”.

If you kill a brain cell it is never replaced.
Not true. A long-lived myth debunked around 1998 by actual research.

There is a dark side of the moon.
Not true. We just never see one side. It receives sunlight regularly.