Re: Why do tall things fall harder?

What excellent perception!  Lynn is absolutely right: the higher the object
(in this case the ruler) is when you drop it, the faster it will be going
when it hits the "seesaw" and the more 'kick' it will impart.  All objects
fall with the same acceleration in your local gravity field.  (Just why
this is so turns out to be a very deep and interesting question.)  As long
as the dropped object is much more massive than the cork or the seesaw,
the height reached by the cork should only depend on the height from which
the ruler is dropped.  And if you substitute a book, say, for the ruler,
and drop it from the same height (measured from the middle of the object),
then the cork should reach the same height.  Of course, there are a few
details I am ignoring here (the effect of the small masses of the cork
and the seesaw, friction, rotation of the objects, air resistance, etc),
but I would expect these all to be pretty small in your case.  Lynn sounds
like she has the makings of a fine scientist!