Kevin, Check with the school that you are presenting at, many of the schools are current with modern technology.  For example, at my school, you can do a power point presentation to the whole cafeteria/gym/library/etc. where everyone can see due to the system we have, smart boards, etc.  Mutimodality is the best way to go.  Key thing I say that is important when working with any children is to remember they can tell if you are afraid and they will 'feed' on it.  Most the kids this time of year are ready for summer break, with that in mind: keep it light, keep it fun,  make it relevant to them.