I've been using the Hoffmann electrolysis device in class to splitting water molecules into H an O gases. I mix them and BANG!!!. Or I keep them separate and show the burning properties of both. This is a great demo for our chapter on Chemical Reactions and the PBS episode of Secrets of the Dead: What happened to the Hindenburg. I highly recommend this video. Great chemistry and history and kids say " that's were the "Oh the humanity" quote comes from".
Sci fair next week. My students that have chose to do this for their project have not all been spending the time checking in with the other coach. This is my poor managerial skills. Next year I need to make sure ALL my kids are meeting with me each week. I focused only on the sci oly kids. Hey live and learn. Improve 10% per year.
I hope this helps,
Love to Teach, and Teach with Passion!
It's not Magic, It's Science!