Was watching QI today and Stephen Fry (the host) said something along these lines. 'This is one of those things I find hard to believe but that I know is true. If you hold a bullet in one hand and a gun in the other at the same height, and fire the gun and drop the bullet at the same time which lands on the ground first?' And all the contestants said the bullet from your hand. Of course.
Except the answer is that they hit the ground at the same time. They all struggled to believe this and appealed to scientists in the crowd to back Stephen Fry up.
Earlier in the show, they mentioned the fact that heavy things hit the ground at the same time as light things when dropped, and my mum found this very hard to believe. I thought everyone knew this, because it's been drummed into me for at least two and a half years now. Fun.
Hooray for Physics and the counter intuitive things it comes up with.