"This universal iOS app comes from the "Gee, I wish I had this when I was a kid" category. Monster Physics teaches science, but in a fun way. You create your avatar then assemble a contraption from pieces available in the app. Wheels, cannons and all sorts of parts. You can weld things together and make moving joints. There are 68 items that can be used to make your gadget.
Then your creation gets rendered, and the true laws of physics will apply. Will the object roll smoothly, fly like an airplane or make a space flight? Several of my designs failed, and that is where the learning takes place. After awhile I was literally flying high."
Via John Pearce