Really, the only thing you need to teach before Computer Science, is reading writing calculating, some maths, some physics, and that's about it.

Maybe not even. Alan Kay & co, with Scratch, used to teach physics and Science (with a big S) with the aid of programming. One of my favourite example was the teaching of Galilean physics by filming the fall of a rock. The reported result was that without the computer, almost no child could understand how it worked. With the computer, almost all children were able to derive a model by themselves —I suppose with some guidance.