For Christmas, Cooper got a Snap Circuits Jr. kit, which is providing a lot of cause and effect fun. In fact, I’m not sure who is enjoying building the circuits more, Cooper or me. So far, we’ve built a light switch, a fan, a sound-activated speaker (it’s just like The Clapper!) and a station for testing the conductivity of various materials. With the latter we discovered that metal rings, pennies, paperclips and aluminum foil all conduct electricity, while drinking straws, plastic spatulas, cloth and paper don’t. They’re insulators.
Circuits are an area where I am definitely out of my element. A little Web research turned up a fantastic, visual explanation from San Jose’s Tech Museum…..here. Here’s what I learned: electricity is essentially moving electrons. Remember the atomic particles that orbit an atom’s nucleus like tiny moons circle a planet? That’s an electron. Good conductors have free electrons. When you apply energy, using a battery, for example, these negatively charged electrons move from positive nucleus to positive nucleus. Thus the electricity flows along the wires and into the lightbulb, where it turns the lightbulb on. The Tech Museum site also includes instructions for building your own series and parallel circuits at home without a Snap Circuits Jr. kit, though I think Snap Circuits Jr. is a safer way to play with electrical concepts.
While the circuits kit is labeled ages 8 and up, I a 5-year-old could easily play with this toy with some assistance. It’s very sturdy and will definitely stand up to some boy handling.
Kirsten W. Larson 
I keep eyeing these sets, I think my husband would LOVE it (and the boys too!). It seems like a really good way to get Dad involved. Glad to see a good review!
The circuit sets are great! My five-year-old keeps pulling the box out and building his own. When you are playing with electricity, kits are definitely safely then building your own, though it can be done.