What science experiments can i do with groups of about 10 little children?

The kid s are from 5-11, and they need to be suitable for these ages, and they need to be easy to do.
Answer
The baking soda and vinegar experiment is the best, but the tasting experiment is also fun. pair up the kids, one is blind folded and try and map out the tongue for sweet, sour, bitter etc areas. used to love that at school!