Sorry if this has been brought up before...

I decided to do some afterschooling for my underchallenged DS6 (2nd grade). Looks like we're going with once/week physics. My idea behind this is to give him some math challenge as it comes up in physics - rather than more drill-type math.

Anyone have recommendations for an organized approach to teaching physics to a young kid? Some online (esp. free grin) resources would be much appreciated.

Thanks!