My child has program online that they can use at home. It's called iStation and while it was meant to teach reading, it has this free science add-on that my daughter loves. The program includes games, readings, mini-lectures and quizzes. She's gone through it all, really loves it, and I'd like to get her a subscription to something similar for Christmas.

I'm not looking for something (like real experiments) that I'd have to oversee. I'm looking for something she can play with by herself.

My child is in K. The program is for grade 3--but suggestions don't have to be above grade level. I think anything meant for K-4 would be fine for her. She can read, so reading is not an issue, but this program will highlight words and read them to you, which I like because it does ensure she is reading correctly. But it doesn't have to have that. At the end of the day what I'm looking for is engaging material that will let her continue to explore on her own.

Any suggestions?