These are 2 clips from a Jr. High science assemblies of 400 students each.
http://www.youtube.com/user/SBelliveau?feature=mhee#p/u/7/fBgH22LDBQo
http://www.youtube.com/user/SBelliveau?feature=mhee#p/u/6/miiJXKEfSAs
Students of all ages love the hovercraft and the rocket car.