I need a good science experiment for kids?

This experiment got quite a few people in my old school quite exited about doing experiments, its also easy to set up and there's usually no mess (unless you smash the the boiling tube its in like my old teacher did) All you have to do is put the jelly baby in a potassium chlorate solution and heat it then drop the baby in and it screams while producing a bright light. http://en.wikipedia.org/wiki/Screaming_jelly_babies

Mentos and coke explosion! Make your own soda experiment Volcano eruption Homemade bread(explain how yeast works) Bottle rockets Egg drop-the kids make boxes that are "egg proof" by padding the interior any way they like. You put an egg in each box and drop it from a high point. See which egg(s) survived and explain why that design worked. Have them test the different taste pallets on the tongue and where they are located by tasting different kinds of food/putting them on different places on the tongue and taking data on where the specific pallets are.