My 6th-Grade son just explained to me why Superman is able to fly on earth, but not on Krypton.  Something about molecular density and gravity being less here than there . . . whatever!  That's it.  I'm removing him from his co-op Physics class. And I think he officially knows more than me.

(Last week we were making up some missed experiments here at home.  I was explaining the results all wrong . . . and he figured it out.  Duhhh!)