Magic school bus also has science kits. DS started with them at 4, he adored the books and loved doing the kits. They are nice jumping off points for deeper discussions too. Just read though for the "let sit for 3 days and observe" until I figured out that you had to do the instant gratification experiments alongside the over days experiments (mold) DS got a little grumpy! Just meant we were doing things out of order.

DeHe