As my young son was getting older, he became interested in dinosaurs (as nearly every young child does at one point or another). I relied on what I learned to teach him. I found resources. I took him to museums. I did what I was supposed to do and what every other parent did. I realized there were so many topics, central and foundational topics, that should be discussed at the same time!
If you talk about dinosaurs, you should also talk about how dinosaurs became dinosaurs. In order to do that, you need to talk about the origins of life, and so on. The next thing I know, I'm imagining a comprehensive prehuman science course--this course.
