Falling.

I occasionally (all the time) tease my students that I will throw them off the roof of the school, or throw things at them from the roof of the school (always to prove a physics point, I swear!).

On their most recent quiz, their answer to a question involving being dropped off the roof of the school needed to involve a  diagram. 

Apparently my students have mixed feelings about this. 

Some think it sounds fun.... 

and 

Some react with abject terror...

or