I shared a few Google Apps with the kids in 3PA today, and they asked that I pass them on.
The free BioDigital Human App gives a 3D view of different systems in the human body and has loads of information about different medical conditions.
Readability is an app that will remove all ads, videos, and links on any website the kids want to read information on, like Ancient Egypt. I use this at school all the time. It will appear as a red chair on your Google Chrome browser, just click on "read now" to filter out all the extra stuff.
Epic, is, well epic!!! It's an online library with thousands of books. It's free for educators, but for at home use there is a fee. It's pretty amazing.