Science demo help..?

Question

which of these demos should i do? please get in before Friday. Thanks!

first three: dancing raisins, blow up balloon with lemon, and balloon blown up inside bottle. These three are found at http://www.elmhurst.edu/~chm/demos/

and the last one: http://scifun.chem.wisc.edu/HOMEEXPTS/rubberband.html

this is for 8th grade. and it has to relate to life science some way.. and demonstrate a scientific principle.

Answer 1

I like the blow up ballon with lemon. My second choice would be the dancing raisins. :)