My 6 year old continues to amaze me with new science experiments she develops on her own. Just the other weekend morning she comes into bed with my wife and I, shows us a big smile and says "I have two science experiments to do!" Naturally we ask what they are and this is what she has to say.
1. Mix orange juice and water and see what happens.
2. Mix orange juice and chocolate milk and see what happens.
Granted, these aren't the most interesting science experiments in the world, but they are ones she developed herself. We didn't do the science experiments on that day due to other things we had going on, but they are on the list. Even though it seems silly, she wants to discover what happens, and letting her do that is extremely important in the development of a young scientist. At one time or another we were all scientists. There's no need for me to squash the science excitement she has just because I think the experiment is silly. Sometimes the silliest experiments turn out very cool. Case in point, here's the link to the snow/milk experiment my daughter developed. It seemed silly at first, but the results were very cool!