Whats an experiment i can conduct to show the surface area to volume ratio affects the rate of diffusion?

It is for a biology practicle test i have to complete at school, so it has to be relatively easy to conduct. It also has to be easy to draw conclusions form, as I have to write a report about it. I however can't do the agar jelly experiment because the entire cl has already conducted it. An example my teacher used was apple pieces cut into halfs and quarters ( though i'm not allowed to use that one either). Any other ideas. I have 'yahooed it, but to no prevail. Please if anyone have conducted a similar experiment please help me! I would really appreciate any help.