This fun and interactive rocket science game came to me from one of the kind people reviewing my book before it gets released. This is very cool and fun!
http://exploration.grc.nasa.gov/education/rocket/BottleRocket/sim.htm
There are a few versions, built for different ages. I’ll be eager to get some reactions from anyone who tries them. If you have questions about them you can ask and I’ll do my best to answer.
NASA water rocket simulator screenshot