It is awesome that your son has an interest in this stuff! What in particular fascinates him? I have always found it is easiest to have kids learn when it not j

It is awesome that your son has an interest in this stuff! What in particular fascinates him? I have always found it is easiest to have kids learn when it not just something they are theoretically interested in, but also has a practical application. Does he find flashlights cool? If so, build your own. Find a way to apply what he is learning and see if he can use it to solve a "problem" around the house (is a door open that shouldn't be, or make a signal his chore is complete or needs to be done).