Definitely have them work with actual circuits, it reinforces concepts and sometimes appears on the actual event at tournaments. What are snap circuits, are they those the ones that have "circuit boards" and you can "snap" the various pieces on? I think trying to work with making circuits with alligator clip wires. Its odd in a way and hard to wrap your head around it because the circuits don't appear square as the diagrams are
, but I have seen at a tournament tho. I think you can easily form circuits with those, maybe try using light bulbs instead of resisters, although I'm not entirely sure we're you'd be able to buy them.
Another tool you should have at hand is a multimeter, it can check if the batteries dead or not, the current and resistance running through the circuit and basically offers more hands on activity. (Also in case any event asks for knowledge asks for that
) For websites I think the Wiki, The Physics Classroom, and the Hyper physics are all good places to start.
Anyone else want to add anything?