Top secret is awesome but not sciency. DS and I highly recommend the brainwaves - we jumped right to the older ones but they also make younger ones depending on content level. If he likes magic school bus they have science kits which spin off the books. If be wants to do things with question and answer - brainpop jr - was worth the fee cause you can get full content for up to 3rd grade. Also AMNH.org - natural history museum website. Has a whole kid section. I have more but out will finish post later!