Here is an example I found describing the 4 science "requirements" for K in Common Core.
I believe Common Core (so far?) just has standards for Math and ELA.
http://www.corestandards.org/read-the-standards/I suppose each state has science standards, and I came across this effort for uniform standards. (I know nothing about it. I just saw it now.)
http://www.nextgenscience.org/Personally I wouldn't bother with "what you need to know in grade X". And I wouldn't get a grade X science "curriculum".
We're looking for a combination of books, videos, activities (e.g. science museum visits), to let the kids learn. With the right resources I think curious children will learn what they need in science. (But as a parent I will nevertheless watch the standards just to check that in the long run we have it covered.)
