A1) BrainPOP has a wide selection of short videos. It requires a subscription, but some are available for free. Here’s one they have for circuits (via YouTube: https://www.youtube.com/watch?v=Ww6xYGu3O10)

A2) The best way to explain anything is hands on. The Exploratorium has some great activities based on circuit blocks http://bit.ly/circuit-boards that are suitable for this age group.

A3) Here’s a fun game http://pbskids.org/designsquad/games/fidgit_factory/ and PBS LearningMedia has a few http://witf.pbslearningmedia.org/resource/phy03.sci.phys.mfe.lp_electric/electric-circuits/