Why do two superballs made of the same material that are different
sizes and weights bounce at different heights?

I am assuming that the two balls are dropped from the same height.

One obvious answer is that the shape / size of one superball might
make it more efficient than another.

However, there's another possibility, and it depends on what you mean
by 'height'.  You need to clarify your question: what are the relative
heights of the two balls when they are dropped?  To be exact, when the
two balls are released, are they released so that their bases are at
the same height, their centres are at the same height, or their tops
are at the same height?

I dropped two superballs from the exact same height, 40 inches, one
being double the size and weight of the other, made out of the exact
same material.The larger ball bounced up to 21' where the smaller ball
bounced back up to 24'. Could you just explain to me in simplest form
why that is,
 for my results of my science project.

Hello, I'm not sure if this project is over my head, I'm in the 5th
grade and when I asked a professor at a university to help me it
seemed a little too much for me to comprehend, also he said he didn't
have the time to go into detail. I'm not allowed to change my
hypothesis that I thought up so if you can help me with a formulas of
some kind that would be great, I don't know what I'm up against here,
I would definetly like to show my class how figure it out.Hope this
helps, thanks josh

Hi josh112,

The following web page describes the same situation as yours, but
comes to the opposite conclusion and suggests that the larger ball
should bounce higher.

Balls: Does Size Count?
http://van.hep.uiuc.edu/van/qa/section/Making_Stuff_Move/Friction/20020525041759.htm

The idea is that if you double the size of a ball, the area facing the
air is multiplied by 4, and the weight is multiplied by 8 (according
to standard formulae for cross-sectional area and volume of a sphere).

So, the reasoning is that the ratio of surface area to weight is
smaller for the larger ball, so it should be slowed less by friction
with the air as it falls and rebounds.

If you got the opposite result, I imagine it must have something to do
with the mechanics of the bounce itself, and I'm afraid I can't help
you there.

Maybe I'll try two differnent balls of the same material, thank-you
this was fun anyways josh