Here is an excellent site to teach your elementary aged kids about electricity. It clearly explains all those scary things like volts, amps, watts and where it all came from. It's divided into sections where you can learn such things as the history of electricity, what it is, how it works, how we use it and what happens to us when the power goes off. There are several simple experiments and I would suggest making the electromagnet or the charger since you don't need a multitester to see if it works. If you're feeling really ambitious, there's even a section on circuits where you can learn how to build your own. It's a fun experience and all you need is a lightbulb to see if they actually work.

There are a number of biographies about people who worked with electricity, such as Andre Ampere, Thomas Edison and Allesandro Volta. There's even a quiz (with answers) to see if you have learned the lessons.