Earth Primer is an app that teaches earth science through game-like simulations. It's an interactive textbook that permits you to raise up volcanoes, shift techtonic plates, and sculpt sand with wind. None of the info will be new to anyone with a high school education, but it does a nice job illustrating concepts with short simulations, and it's fun to play with. [This is not an advertisement.]
I've only just started goofing around with the app, but I'm hoping it will build in complexity and become more like a sandbox in which I can try building some landscapes. I'm in the early stages of worldbuilding for a planned book (the stage comprised mostly of daydreams) in which the geological environment plays a meaningful role in the action. I'd like my world to be at least plausibly authentic.
Regardless, I'd like to hand Earth Primer over to some kids and see what they make of it.