Wondering what elementary school students are required to learn about your field? There are two good resources for this: the National Science Education Standards, and Benchmarks for Science Literacy.
I came upon this informative article (Tanner and Allen, 2002) in the journal Cell Biology Education that outlines the core concepts that students in various age ranges are expected to know in my field, cell biology.
Nice overview of how these concepts start simply and increase in complexity and nuance over the years.
If you would like help digging up the relevant standards for your field of science, give me a holler in the comments! I will post them on the blog.